{"id":531851,"date":"2026-05-29T12:47:19","date_gmt":"2026-05-29T12:47:19","guid":{"rendered":"https:\/\/veteo.eu\/?page_id=531851"},"modified":"2026-06-23T07:07:24","modified_gmt":"2026-06-23T07:07:24","slug":"equine-reproductive-endocrinology","status":"publish","type":"page","link":"https:\/\/veteo.eu\/en\/equine-reproductive-endocrinology\/","title":{"rendered":"Equine reproductive endocrinology"},"content":{"rendered":"<div class=\"wpb-content-wrapper\"><p>[vc_row bg_type=&#8221;bg_color&#8221; bg_override=&#8221;full&#8221; el_class=&#8221;en-st-pt en-st-pb&#8221; bg_color_value=&#8221;#F3F3F3&#8243;][vc_column width=&#8221;1\/2&#8243; css=&#8221;.vc_custom_1781257993450{padding-top: 0px !important;}&#8221; offset=&#8221;vc_col-lg-7&#8243;][vc_column_text css=&#8221;.vc_custom_1781257961589{margin-bottom: 20px !important;}&#8221;]<\/p>\n<h2 class=\"en-h2-red\"><strong>Endocrine diagnostics of reproductive disorders in horses<\/strong><\/h2>\n<p>[\/vc_column_text][vc_column_text css=&#8221;.vc_custom_1781611466658{margin-bottom: 35px !important;padding-right: 50px !important;}&#8221;]<\/p>\n<h3>An interactive endocrinology guide.<\/h3>\n<p><span style=\"color: #595959;\">Author: Agata Zagrajczuk, DVM, PhD<\/span>[\/vc_column_text][\/vc_column][vc_column width=&#8221;1\/2&#8243; offset=&#8221;vc_col-md-5&#8243; css=&#8221;.vc_custom_1781611442636{padding-top: 0px !important;}&#8221;][vc_column_text css=&#8221;.vc_custom_1781258554288{margin-bottom: 25px !important;padding-right: 50px !important;}&#8221;]<\/p>\n<h3 style=\"color: #000;\">Designed to help answer the following questions:<\/h3>\n<p>[\/vc_column_text][vc_row_inner][vc_column_inner el_class=&#8221;standard-arrow custom-red-arrow&#8221;]<div class=\"standard-arrow bullet-top\"><ul>\n<li style=\"color: #000 !important; font-size: 18px;\">What should be tested?<\/li>\n<li style=\"color: #000 !important; font-size: 18px;\">When should samples be collected?<\/li>\n<li style=\"color: #000 !important; font-size: 18px;\">How should test results be interpreted?<\/li>\n<\/ul>\n<\/div>[\/vc_column_inner][\/vc_row_inner][\/vc_column][\/vc_row][vc_row gap=&#8221;25&#8243; content_placement=&#8221;middle&#8221; el_class=&#8221;en-st-pt en-st-pb&#8221;][vc_column css=&#8221;.vc_custom_1781255986713{padding-top: 0px !important;}&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h2 class=\"en-h2-black\"><span class=\"TextRun SCXW75095428 BCX0\" lang=\"PL-PL\" xml:lang=\"PL-PL\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW75095428 BCX0\">Quick guide for test selection<\/span><\/span><\/h2>\n<p>[\/vc_column_text][vc_column_text css=&#8221;.vc_custom_1781265297166{margin-bottom: 0px !important;}&#8221; el_class=&#8221;diag-end-horses-wrapper&#8221;]<\/p>\n<table class=\"diag-end-horses\">\n<thead>\n<tr>\n<th width=\"300\"><span class=\"TextRun SCXW146415659 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW146415659 BCX0\">Clinical Problem<\/span><\/span><\/th>\n<th width=\"300\">Hormones<\/th>\n<th colspan=\"2\" width=\"180\">Sample<\/th>\n<th width=\"200\">When to Collect Samples<\/th>\n<th width=\"300\">Usefulness<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td rowspan=\"2\" width=\"300\">Granuloma Cell Tumour Diagnostics<\/td>\n<td width=\"300\"><a class=\"h-link\" href=\"#amh\">Anti-M\u00fcllerian Hormone (AMH)<\/a><\/td>\n<td colspan=\"2\" width=\"180\">Serum 0,5 mL<\/td>\n<td width=\"200\">At any stage of the oestrous cycle or pregnancy<\/td>\n<td width=\"300\">optimal<br \/>\n(determination recommended)<\/td>\n<\/tr>\n<tr>\n<td width=\"300\"><a class=\"h-link\" href=\"#testosterone\">Testosterone (T)<\/a><\/td>\n<td colspan=\"2\" width=\"180\">Serum 1 mL<\/td>\n<td width=\"200\">The stage of the reproductive cycle\/pregnancy and seasonal factors may affect the concentration (see the test information section for details)<\/td>\n<td width=\"300\">limited \u2013 the method is reliable only in certain cases*<\/td>\n<\/tr>\n<tr>\n<td rowspan=\"2\" width=\"300\">Other ovarian dysfunction disorders (anovulatory cycles, ovarian inactivity, absence of oestrous behaviour)<\/td>\n<td width=\"300\"><a class=\"h-link\" href=\"#estradiol-e2\">Estradiol (E2)<\/a><\/td>\n<td colspan=\"2\">Serum 1 mL<\/td>\n<td width=\"200\">Depending on the stage of the reproductive cycle or the dysfunction, an increase or decrease in the concentration may be expected.<\/td>\n<td width=\"300\">assessment of oestrous cycle stage and ovarian activity<\/td>\n<\/tr>\n<tr>\n<td width=\"300\"><a class=\"h-link\" href=\"#progesterone\">Progesterone<\/a><\/td>\n<td colspan=\"2\" width=\"180\">Serum 0,5 mL<\/td>\n<td width=\"300\">Depending on the stage of the reproductive cycle or the dysfunction, an increase or decrease in the concentration may be expected.<\/td>\n<td width=\"300\">assessment of oestrous cycle stage and ovarian activity<\/td>\n<\/tr>\n<tr>\n<td rowspan=\"6\" width=\"300\">Pregnancy confirmation<br \/>\nDifficulty maintaining pregnancy<\/td>\n<td width=\"300\"><a class=\"h-link\" href=\"#progesterone\">Progesterone<\/a><\/td>\n<td colspan=\"2\">Serum 1 mL<\/td>\n<td width=\"200\">Depending on the cycle phase or dysfunction a decrease or increase is expected more than 15 days after ovulation<\/td>\n<td width=\"300\">early pregnancy diagnosis and evaluation of corpus luteum function<\/td>\n<\/tr>\n<tr>\n<td rowspan=\"2\" width=\"300\"><a class=\"h-link\" href=\"#pmsg\">Pregnant Mare Serum Gonadotropin (PMSG\/eCG)<\/a><\/td>\n<\/tr>\n<tr>\n<td colspan=\"2\" width=\"107\">\n<div class=\"chilled-serum\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/veteo.eu\/wp-content\/uploads\/2026\/06\/chilled-serum.png\" alt=\"Surowica sch\u0142odzona\" width=\"23\" height=\"20\" \/>Chilled Serum 1 mL<\/div>\n<\/td>\n<td rowspan=\"2\" width=\"200\">Between 40 and 120 days of pregnancy<\/td>\n<td rowspan=\"2\" width=\"300\">pregnancy confirmation<\/td>\n<\/tr>\n<tr>\n<td rowspan=\"2\" width=\"300\"><a class=\"h-link\" href=\"#e1s\">Estrone Sulfate (E1S)<\/a><\/td>\n<\/tr>\n<tr>\n<td colspan=\"2\" width=\"107\">Serum 1 mL<\/td>\n<td width=\"200\">From day 80 of pregnancy to approximately one week before parturition<\/td>\n<td width=\"300\">pregnancy confirmation and placental function assessment*<\/td>\n<\/tr>\n<tr>\n<td width=\"300\"><a class=\"h-link\" href=\"#dhp-progesterone-ratio\">DHP\/Progesterone Ratio<\/a><br \/>\n(Luteo-Placental Shift)<\/td>\n<td colspan=\"2\" width=\"107\">Serum 1 mL<\/td>\n<td width=\"200\">Approx. 100 to 120 days of pregnancy<\/td>\n<td width=\"300\">decision on discontinuation of gestagen supplementation<\/td>\n<\/tr>\n<tr>\n<td rowspan=\"3\" width=\"300\">Cryptorchidism \/ Testicular function disorders<\/td>\n<td width=\"300\"><a class=\"h-link\" href=\"#amh\">Anti-M\u00fcllerian Hormone (AMH)<\/a><\/td>\n<td colspan=\"2\" width=\"142\">Serum 0,5 mL<\/td>\n<td width=\"200\">Regardless of time of day \/ season<\/td>\n<td width=\"300\">optimal<br \/>\n(determination recommended)<\/td>\n<\/tr>\n<tr>\n<td width=\"300\"><a class=\"h-link\" href=\"#testosterone\">Testosterone (T)<\/a><\/td>\n<td colspan=\"2\" width=\"142\">Serum 1 mL<\/td>\n<td width=\"200\">Lowest values in the morning and during the non-breeding season; highest values in the afternoon and during the breeding season<\/td>\n<td width=\"300\">limited<\/td>\n<\/tr>\n<tr>\n<td width=\"300\"><a class=\"h-link\" href=\"#hcg\">hCG Stimulation Test in Stallions<\/a><br \/>\n(2x Testosterone Measurements)<\/td>\n<td colspan=\"2\" width=\"142\">Serum (2x 1 mL)<\/td>\n<td width=\"200\">Two blood samples collected 1\u20132 hours apart<\/td>\n<td width=\"300\">optimal<br \/>\n(recommended in case of equivocal AMH results)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span data-teams=\"true\">* See test descriptions for details<\/span>[\/vc_column_text][\/vc_column][\/vc_row][vc_row gap=&#8221;20&#8243; equal_height=&#8221;yes&#8221; content_placement=&#8221;top&#8221; bg_type=&#8221;bg_color&#8221; bg_override=&#8221;full&#8221; css=&#8221;.vc_custom_1781257363617{padding-top: 60px !important;padding-bottom: 25px !important;}&#8221; bg_color_value=&#8221;#F3F3F3&#8243; el_class=&#8221;endo-summary-desktop&#8221;][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781254770347{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3>Suspicion of granulosa cell tumour<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li>Anti-M\u00fcllerian Hormone (AMH)<\/li>\n<li>Testosterone (T)<\/li>\n<\/ul>\n<\/div>[\/vc_column][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781254773938{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3 style=\"line-height: 1.2;\">Other ovarian dysfunctions<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li>Estradiol (E2)<\/li>\n<li>Progesterone<\/li>\n<\/ul>\n<\/div>[\/vc_column][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781254778599{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3 style=\"line-height: 1.2;\">Pregnancy assessment<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li>Progesterone<\/li>\n<li><span class=\"TextRun SCXW146603835 BCX0\" lang=\"DE-DE\" xml:lang=\"DE-DE\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW146603835 BCX0\">Pregnant<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">\u00a0Mare Serum Gonadotropin<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">\u00a0(<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">PMSG\/<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">eCG<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">)<\/span><\/span><\/li>\n<li><span class=\"TextRun SCXW9565354 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW9565354 BCX0\">Estrone\u00a0<\/span><span class=\"NormalTextRun SCXW9565354 BCX0\">Sulfate<\/span><span class=\"NormalTextRun SCXW9565354 BCX0\"> (E1S)<\/span><\/span><\/li>\n<li><span class=\"TextRun SCXW6535694 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW6535694 BCX0\">DHP\/<\/span><span class=\"NormalTextRun SCXW6535694 BCX0\">P<\/span><span class=\"NormalTextRun SCXW6535694 BCX0\">rogesteron<\/span><span class=\"NormalTextRun SCXW6535694 BCX0\">e Ratio<\/span><\/span><br \/>\n(Luteo-Placental\u00a0Shift)<\/li>\n<\/ul>\n<\/div>[\/vc_column][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781254782916{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3 style=\"line-height: 1.2;\">Testicular dysfunction \/ cryptorchidism<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li><span class=\"TextRun SCXW56819748 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW56819748 BCX0\">Anti-M\u00fcllerian Hormone (AMH<\/span><\/span>)<\/li>\n<li>Testosterone (T)<\/li>\n<li><span class=\"NormalTextRun SCXW99887653 BCX0\">hCG<\/span><span class=\"NormalTextRun SCXW99887653 BCX0\">\u00a0Stimulation Test in Stallions<\/span><br \/>\n(2x Testosterone Measurements)<\/li>\n<\/ul>\n<\/div>[\/vc_column][\/vc_row][vc_row gap=&#8221;25&#8243; equal_height=&#8221;yes&#8221; content_placement=&#8221;bottom&#8221; bg_type=&#8221;bg_color&#8221; bg_override=&#8221;full&#8221; css=&#8221;.vc_custom_1781256055910{padding-bottom: 10px !important;}&#8221; bg_color_value=&#8221;#00000000&#8243; el_class=&#8221;a-us-why-us en-st-pt&#8221;][vc_column css=&#8221;.vc_custom_1781256062120{padding-top: 0px !important;}&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h2 class=\"en-h2-black\"><span class=\"TextRun SCXW75095428 BCX0\" lang=\"PL-PL\" xml:lang=\"PL-PL\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW75095428 BCX0\">Characteristics of measured hormones<\/span><\/span><\/h2>\n<p>[\/vc_column_text][vc_tta_accordion style=&#8221;flat&#8221; color=&#8221;juicy-pink&#8221; spacing=&#8221;10&#8243; c_icon=&#8221;chevron&#8221; c_position=&#8221;right&#8221; active_section=&#8221;1994488dgd&#8221; no_fill=&#8221;true&#8221; collapsible_all=&#8221;true&#8221; el_class=&#8221;endo-horse-accordion&#8221;][vc_tta_section title=&#8221;Anti-M\u00fcllerian Hormone (AMH)&#8221; tab_id=&#8221;amh&#8221;][vc_column_text css=&#8221;&#8221;]<strong>Purpose:<\/strong> Diagnosis of granulosa cell tumour (GCT) in mares and cryptorchidism\/testicular tissue remnants in males; post-castration evaluation (<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> )<\/p>\n<p><strong>Production site \/ physiological role:<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> granulosa cells of ovarian follicles (small follicles; decreased production of AMH in large preovulatory follicles)<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> Sertoli cells of the seminiferous tubules in the testes<\/p>\n<p><strong>Time for testing:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"NormalTextRun SCXW106617009 BCX0\">absence of\u00a0<\/span><span class=\"NormalTextRun SCXW106617009 BCX0\">estrus<\/span><span class=\"NormalTextRun SCXW106617009 BCX0\">\u00a0or irregular cycles<\/span> <strong>(regnancy and normal cyclic activity do not exclude GCT)<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> behavioural changes ranging from nymphomania to stallion-like behaviour, but often no visible changes<br \/>\n<strong><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> typically one markedly enlarged ovary<\/strong>, the second ovary inactive (note that tumours may be bilateral)<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"TextRun SCXW59220852 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW59220852 BCX0\">higher probability in mares over 10 years of age, although it may occur at any age<\/span><\/span><span class=\"TextRun SCXW84368773 BCX0\" lang=\"PL-PL\" xml:lang=\"PL-PL\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW84368773 BCX0\" data-ccp-parastyle=\"Normal (Web)\">\u00a0<\/span><\/span><span class=\"EOP SCXW84368773 BCX0\" data-ccp-props=\"{&quot;134233117&quot;:true,&quot;134233118&quot;:true,&quot;201341983&quot;:0,&quot;335559685&quot;:280,&quot;335559740&quot;:240,&quot;335559991&quot;:14}\">\u00a0<\/span><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> <span class=\"NormalTextRun SCXW59220852 BCX0\">absence of one or both testes in the scrotum with concurrent stallion-like\u00a0<\/span><span class=\"NormalTextRun SCXW59220852 BCX0\">behaviour<\/span><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> <span class=\"TextRun SCXW33450566 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW33450566 BCX0\">breed predisposition to cryptorchidism especially in American Quarter Horse and Percheron<\/span><\/span><\/p>\n<p><span class=\"NormalTextRun SCXW187398269 BCX0\">Aggressive\u00a0<\/span><span class=\"NormalTextRun SCXW187398269 BCX0\">behaviour<\/span><span class=\"NormalTextRun SCXW187398269 BCX0\">\u00a0is often interpreted as a sign of a granulosa cell\u00a0<\/span><span class=\"NormalTextRun SCXW187398269 BCX0\">tumour<\/span><span class=\"NormalTextRun SCXW187398269 BCX0\">\u00a0or active testicular tissue; however, studies indicate that this correlation is weak. In such cases, laboratory-based diagnostics provide an objective tool, particularly useful when imaging or palpation findings are inconclusive<\/span><span class=\"NormalTextRun SCXW187398269 BCX0\">.<\/span><\/p>\n<p><strong>Sample:<\/strong> serum 0,5 mL<\/p>\n<p><strong>Method:<\/strong> ELISA<\/p>\n<p><strong>Sample collection:<\/strong> <span class=\"TextRun SCXW128793308 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW128793308 BCX0\">independent of oestrous cycle stage<\/span><\/span>[\/vc_column_text][vc_column_text css=&#8221;&#8221; el_class=&#8221;table-interpretation-wrapper&#8221;]<\/p>\n<table class=\"table-interpretation\">\n<thead>\n<tr>\n<th style=\"text-align: center;\" colspan=\"2\"><strong>Interpretation<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td width=\"50%\"><strong>Healthy mares<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&lt; 4 ng\/mL<br \/>\n&lt; 28,6 pmol\/L<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Mares with\u202fGCT<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&gt; 4 ng\/mL<br \/>\n&gt; 28,6 pmol\/L<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Stallions \u2013 active testicular tissue<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&gt; 0,27 ng\/mL<br \/>\n&gt; 1,9 pmol\/L<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Cryptorchidism\/males with testicular dysfunction<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&lt; 0,27 ng\/mL<br \/>\n&lt; 1,9 pmol\/L<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>[\/vc_column_text][vc_column_text css=&#8221;&#8221;]<strong>Advantages:<\/strong> rapid, routine test<\/p>\n<p><strong>Limitations:<\/strong> severe haemolysis \u2013 the test will be cancelled, mild haemolysis may cause result distortion<\/p>\n<p class=\"note\"><em><span style=\"font-family: 'Arial',sans-serif; color: #555555;\"><u>Note: if results are inconsistent with clinical findings, re-testing or confirmation with a different method is recommended.<\/u><\/span><\/em><\/p>\n<p>[\/vc_column_text][vc_row_inner][vc_column_inner width=&#8221;1\/2&#8243;][vc_single_image image=&#8221;532145&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781079995247{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;.vc_custom_1781079720714{margin-bottom: 35px !important;}&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Histological image of a healthy mare\u2019s ovary.<\/strong> Photo by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][vc_column_inner width=&#8221;1\/2&#8243;][vc_single_image image=&#8221;532149&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781080005550{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;.vc_custom_1781079780993{margin-bottom: 35px !important;}&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Histopathological image of a granulosa cell tumour in a mare.<\/strong> Photo by S. Brunk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner width=&#8221;1\/2&#8243; offset=&#8221;vc_col-sm-offset-3&#8243;][vc_single_image image=&#8221;532153&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781080015673{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;.vc_custom_1781079785157{margin-bottom: 22px !important;}&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Histopathological image of a granulosa cell tumour in a mare.<\/strong> Photo by S. Brunk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][\/vc_tta_section][vc_tta_section title=&#8221;Testosterone (T)&#8221; tab_id=&#8221;testosterone&#8221;][vc_column_text css=&#8221;.vc_custom_1781870633406{margin-bottom: 22px !important;}&#8221;]<strong><span class=\"TextRun SCXW205937895 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW205937895 BCX0\">Purpose<\/span><\/span>:<\/strong> <span class=\"TextRun SCXW205937895 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW205937895 BCX0\">Diagnosis of cryptorchidism \/ testicular tissue remnants and assessment of testicular function in males; post-castration evaluation<\/span><\/span> (<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/>), <span class=\"NormalTextRun SCXW113223387 BCX0\">diagnosis of granulosa cell\u00a0<\/span><span class=\"NormalTextRun SCXW113223387 BCX0\">tumor<\/span><span class=\"NormalTextRun SCXW113223387 BCX0\">\u00a0(GCT) in mares<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW170949691 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW170949691 BCX0\">Production site<\/span><\/span>:<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"NormalTextRun SCXW170949691 BCX0\">ovarian hilus cells<\/span><span class=\"NormalTextRun SCXW170949691 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW170949691 BCX0\">and t<\/span><span class=\"NormalTextRun SCXW170949691 BCX0\">heca<\/span><span class=\"NormalTextRun SCXW170949691 BCX0\">\u00a0cells<\/span><span class=\"NormalTextRun SCXW170949691 BCX0\">\u00a0of follicle<\/span><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> <span class=\"TextRun SCXW170949691 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW170949691 BCX0\">Leydig (interstitial) cells in the testes<\/span><\/span><\/p>\n<p><strong><span class=\"TextRun SCXW78151467 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW78151467 BCX0\">Time for testing<\/span><\/span>:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> absence of one or both testes in the scrotum with concurrent stallion-like behavior<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> breed predisposition to cryptorchidism, especially in American Quarter Horse and Percheron<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> absence of estrus or irregular cycles (pregnancy and normal cyclic activity do not exclude GCT)<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> behavioural changes \u2013 especially stallion-like behaviour (e.g. mounting other mares), nymphomania, suggesting the presence of a theca cell component in GCT responsible for increased testosterone concentrations<br \/>\n<strong><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"TextRun SCXW78151467 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW78151467 BCX0\">typically one markedly enlarged ovary<\/span><\/span><\/strong>, <span class=\"TextRun SCXW78151467 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW78151467 BCX0\">the second ovary inactive (note that tumours may be bilateral)<\/span><\/span><span class=\"LineBreakBlob BlobObject DragDrop SCXW78151467 BCX0\"><span class=\"SCXW78151467 BCX0\">\u00a0<\/span><\/span><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> usually in mares over 10 years of age, although it may occur at any age<\/p>\n<p><strong>Note<\/strong> \u2013 <span class=\"TextRun SCXW103453782 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW103453782 BCX0\">Testosterone measurement is only meaningful in cases where a theca cell component is present, associated with increased concentrations of this hormone. Its presence may be suspected in cases of<\/span><\/span> <strong>somatic masculinisation (i.e. increased muscle mass, clitoral hypertrophy, \u201ccresty neck\u201d)<\/strong> <span class=\"NormalTextRun SCXW103453782 BCX0\">and\/or stallion-like behaviour, i.e. mounting other mares and flehmen response in the presence of mares<\/span><span class=\"NormalTextRun SCXW103453782 BCX0\">\u00a0during\u00a0<\/span><span class=\"NormalTextRun SCXW103453782 BCX0\">oestrous.<\/span><\/p>\n<p><span class=\"TextRun SCXW222030958 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW222030958 BCX0\">Aggressive behaviour is often interpreted as a sign of a granulosa cell tumour or active testicular tissue; however, studies indicate that this correlation is weak. In such cases, laboratory-based diagnostics provide an objective tool, particularly useful when imaging or palpation findings are inconclusive<\/span><span class=\"NormalTextRun SCXW222030958 BCX0\">.<\/span><\/span><span class=\"EOP SCXW222030958 BCX0\" data-ccp-props=\"{}\">\u00a0<\/span><\/p>\n<p><strong>Sample:<\/strong> serum 1 mL<\/p>\n<p><strong>Method:<\/strong> RIA<\/p>\n<p><strong>Material collection:<\/strong><br \/>\nin<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"TextRun SCXW154050793 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW154050793 BCX0\">there are diurnal and seasonal variations in<\/span><span class=\"NormalTextRun SCXW154050793 BCX0\">\u00a0the<\/span><span class=\"NormalTextRun SCXW154050793 BCX0\">\u00a0concentration<\/span><\/span><span class=\"LineBreakBlob BlobObject DragDrop SCXW154050793 BCX0\"><span class=\"SCXW154050793 BCX0\">\u00a0<\/span><\/span><br \/>\nin<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"NormalTextRun SCXW154050793 BCX0\">the concentration\u00a0<\/span><span class=\"NormalTextRun SCXW154050793 BCX0\">physiologically increases during oestrus<\/span>[\/vc_column_text][vc_column_text css=&#8221;&#8221; el_class=&#8221;table-interpretation-wrapper&#8221;]<\/p>\n<table class=\"table-interpretation\">\n<thead>\n<tr>\n<th style=\"text-align: center;\" colspan=\"2\"><strong>Interpretation<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td width=\"50%\"><strong>Stallions\/cryptorchidism \u2013 active testicular tissue<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&gt; 0,13 ng\/mL<br \/>\n&gt; 130 pg\/mL<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Cryptorchidism\/males with testicular dysfunction<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&lt; 0,13 ng\/mL<br \/>\n&lt; 130 pg\/mL<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Geldings<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&lt; 0,06 ng\/mL<br \/>\n&lt; 60 pg\/mL<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Healthy mares<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&lt; 0,06 ng\/mL<br \/>\n&lt; 60 pg\/mL<\/td>\n<\/tr>\n<tr>\n<td width=\"50%\"><strong>Mares with\u202fGCT<\/strong><\/td>\n<td style=\"text-align: center;\" width=\"50%\">&gt; 0,06 ng\/mL<br \/>\n&gt; 60 pg\/mL<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>[\/vc_column_text][vc_column_text css=&#8221;.vc_custom_1781082240873{margin-bottom: 22px !important;}&#8221;]<strong><span class=\"TextRun SCXW230293270 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230293270 BCX0\">Advantages<\/span><\/span>:<\/strong> <span class=\"NormalTextRun SCXW230293270 BCX0\">relatively low cost of\u00a0<\/span><span class=\"NormalTextRun SCXW230293270 BCX0\">determination<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW6804624 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW6804624 BCX0\">Limitations<\/span><\/span>:<\/strong> <span class=\"NormalTextRun SCXW227198933 BCX0\">interpretation difficulties \u2013 testosterone results in stallions may occasionally show falsely low values, due both to diurnal fluctuations of the hormone and\u00a0<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">sample collection<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">during the<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">non-<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">breeding season (e.g. in winter).<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">It should also be noted that sexual maturity (around 2 years of age) does not equate to full\u00a0<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">sexual<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">\u00a0maturity<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">\u00a0for breeding<\/span><span class=\"NormalTextRun SCXW227198933 BCX0\">\u00a0\u2014 stallions reach maximal hormonal testicular function only at 4\u20135 years of age, although this timing is individually variable Therefore, if hormonal results do not correspond with clinical findings, it is advisable to repeat the test or use an\u00a0<\/span><a class=\"h-link\" href=\"#hcg\">hCG stimulation test<\/a>, which allows precise assessment of testicular testosterone-producing capacity<span class=\"NormalTextRun SCXW227198933 BCX0\">.<\/span><\/p>\n<p class=\"note\"><em><span style=\"font-family: 'Arial',sans-serif; color: #555555;\"><u>Note: if results are inconsistent with clinical findings, re-testing or confirmation with a different method is recommended.<\/u><\/span><\/em><\/p>\n<p>[\/vc_column_text][\/vc_tta_section][vc_tta_section title=&#8221;hCG Stimulation Test in Stallions&#8221; tab_id=&#8221;hcg&#8221;][vc_column_text css=&#8221;.vc_custom_1781870649222{margin-bottom: 22px !important;}&#8221;]<strong>Purpose:<\/strong> Assessment of testicular function and differentiation between cryptorchidism and geldings<\/p>\n<p><strong>Time for testing:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> <strong>gold standard<\/strong> in cases of inconclusive basal testosterone results. The stimulation test has higher sensitivity.<\/p>\n<p><span class=\"NormalTextRun SCXW79493289 BCX0\">Indications are the same as for testosterone measurement, but the test is more accurate than basal testosterone (T) determination, as it provides an assessment of the increase in T following LH stimulation (<\/span><span class=\"NormalTextRun SCXW79493289 BCX0\">hCG<\/span><span class=\"NormalTextRun SCXW79493289 BCX0\">\u00a0acts similarly to LH and FSH, with predominantly LH-like activity). Consequently, it significantly (although not completely) reduces uncertainty related to physiological fluctuations in testosterone concentrations.<\/span><\/p>\n<p><strong>Sample:<\/strong> serum (2x 1 mL)<\/p>\n<p><strong>Method:<\/strong> RIA<\/p>\n<p><strong>Sample collection:<\/strong><br \/>\n<span class=\"TextRun SCXW92456480 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW92456480 BCX0\">Two blood samples are collection in <\/span><\/span><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/male-pointer.png\" width=\"15\" height=\"15\" \/> . <span class=\"TextRun SCXW57249596 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW57249596 BCX0\">The first<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a0(ba<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">sal)<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">sample is taken prior to\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">hCG<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a0administration<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">,\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">then IV administration of<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a05000 \u2013 10000 IU\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">hCG<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\/<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">horse and<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">t<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">he second blood sample is collected 1\u20132 hours after<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">hCG<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">\u00a0administration<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">.\u00a0<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">Higher testosterone concentrations may be observed during the breeding season<\/span><span class=\"NormalTextRun SCXW57249596 BCX0\">.<\/span><\/span><span class=\"EOP SCXW57249596 BCX0\" data-ccp-props=\"{}\">\u00a0<\/span><\/p>\n<p><strong>Interpretation:<\/strong><br \/>\nA \u22652-fold increase compared to basal testosterone indicates the presence of functional testicular tissue (stallion or cryptorchidism)<br \/>\nNo significant increase indicates a gelding<\/p>\n<p><strong>Advantages:<\/strong> higher diagnostic accuracy than a single (basal) testosterone measurement<\/p>\n<p><strong>Limitations:<\/strong> possible delayed response to hCG (after 120 minutes or later). Some studies suggest reduced responsiveness to hCG in stallions below 18 months and when tested during winter.[\/vc_column_text][\/vc_tta_section][vc_tta_section title=&#8221;Progesterone&#8221; tab_id=&#8221;progesterone&#8221;][vc_column_text css=&#8221;&#8221;]<strong><span class=\"TextRun SCXW117895858 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW117895858 BCX0\">Purpose<\/span><\/span>:<\/strong> <span class=\"TextRun SCXW40358971 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW40358971 BCX0\">assessment of corpus luteum function, confirmation of ovulation, evaluation of oestrous cycle stage (oestrus vs. dioestrus), early pregnancy diagnosis<\/span><\/span><span class=\"EOP SCXW40358971 BCX0\" data-ccp-props=\"{}\">\u00a0<\/span><\/p>\n<p><strong>Production site \/ physiological role: <\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"TextRun SCXW109235822 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW109235822 BCX0\">corpus luteum (CL) of the ovary<\/span><\/span><\/p>\n<p><strong>Time for testing:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> absence of oestrus or irregular cycles<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> up to approx. 45\u201360 days of pregnancy when assessing CL function or making decisions regarding altrenogest supplementation<\/p>\n<p>Progesterone measurement is not recommended in mid and late pregnancy.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> after 100\u2013120 days of pregnancy in mares, pregnancy maintenance is supported by placental progestogens <b>other than progesterone<\/b><\/p>\n<p><strong>Sample:<\/strong> serum 0,5 mL<\/p>\n<p><strong>Method:<\/strong> CLIA<\/p>\n<p><strong>Sample collection: <\/strong>ependent on the purpose of testing; cycle or pregnancy stage must be taken into account<\/p>\n<p><strong>Interpretation:<\/strong><br \/>\n3.2 nmol\/L (1,00 ng\/mL) endocrinologically active CL (dioestrus\/pregnancy\/persistent CL)<br \/>\n\u2265 12.8 nmol\/L (4,00 ng\/mL) progesterone concentration considered safe in early pregnancy<\/p>\n<p><strong>Advantages:<\/strong> rapid, routine test<\/p>\n<p><strong>Limitations:<\/strong> <span class=\"NormalTextRun SCXW173348818 BCX0\">interpretation difficulties \u2013 in early pregnancy, marked fluctuations in progesterone concentration may occur\u00a0<\/span><span class=\"NormalTextRun SCXW173348818 BCX0\">and<\/span><span class=\"NormalTextRun SCXW173348818 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW173348818 BCX0\">have no<\/span><span class=\"NormalTextRun SCXW173348818 BCX0\">\u00a0diagnostic significance. <\/span><\/p>\n<p><span class=\"NormalTextRun SCXW173348818 BCX0\">In cases of early embryonic death with persistent CL, progesterone concentrations may still\u00a0<\/span><span class=\"NormalTextRun SCXW173348818 BCX0\">indicate pregnancy. Results should always be interpreted in conjunction with ultrasonographic findings<\/span><span class=\"NormalTextRun SCXW173348818 BCX0\">.<\/span>[\/vc_column_text][vc_row_inner][vc_column_inner width=&#8221;1\/2&#8243;][vc_single_image image=&#8221;532160&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781083727062{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;.vc_custom_1781083502784{margin-bottom: 22px !important;}&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Pregnancy in a mare (23rd day after ovulation).<\/strong> Photo by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][vc_column_inner width=&#8221;1\/2&#8243;][vc_single_image image=&#8221;532164&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781083736566{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Post-mortem image of a mare\u2019s ovary after ovulation.<\/strong> Photo by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][vc_column_inner width=&#8221;1\/2&#8243; offset=&#8221;vc_col-sm-offset-3&#8243;][vc_single_image image=&#8221;532168&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781083747520{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Post-mortem image of a mare\u2019s ovary with an active, mature corpus luteum<\/strong><br \/>\nPhoto by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][\/vc_tta_section][vc_tta_section title=&#8221;Estradiol (E2)&#8221; tab_id=&#8221;estradiol-e2&#8243;][vc_column_text css=&#8221;&#8221;]<strong><span class=\"TextRun SCXW138151475 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW138151475 BCX0\">Purpose<\/span><\/span>:<\/strong> <span class=\"NormalTextRun SCXW80172234 BCX0\">Assessment of the stage of the\u00a0<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">estrous<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">\u00a0cycle and ovarian activity. Elevated levels are observed in pregnant mares after day 60 of gestation. A marked increase in concentration may also indicate the presence of a persistent anovulatory ovarian follicle. During a silent heat (silent\u00a0<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">oestrus<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">),\u00a0<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">estradiol<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">\u00a0concentrations may be lower than those observed during a normal\u00a0<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">oestrus<\/span><span class=\"NormalTextRun SCXW80172234 BCX0\">\u00a0cycle.<\/span><\/p>\n<p><strong>Production site \/ physiological role: <\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> ovary \u2013 preovulatory follicle<\/p>\n<p><strong>Time for testing\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> absence of oestrus or irregular oestrous cycles<\/p>\n<p><strong>Sample:<\/strong> serum 1 mL<\/p>\n<p><strong>Method:<\/strong> RIA<\/p>\n<p><strong>Sample collection: <\/strong>it depends on the purpose of the test \u2013 the stage of the oestrous cycle or pregnancy should be taken into account.<\/p>\n<p><strong>Interpretation:<\/strong><br \/>\n<span class=\"NormalTextRun SCXW200744118 BCX0\">&lt; 10\u00a0<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">pg<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\/m<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">L<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\u00a0\u2013 small follicles, corresponding to the dioestrus phase \/ early follicular phase \/ seasonal anoestrus<\/span><br \/>\n<span class=\"TextRun SCXW200744118 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW200744118 BCX0\">11\u201315\u00a0<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">pg<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\/m<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">L<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\u00a0\u2013 medium follicles (diameter\u00a0<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">approx.<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\u00a020\u201330 mm), corresponding to the follicular phase<\/span><\/span><span class=\"LineBreakBlob BlobObject DragDrop SCXW200744118 BCX0\"><span class=\"SCXW200744118 BCX0\">\u00a0<\/span><\/span><br \/>\n<span class=\"NormalTextRun SCXW200744118 BCX0\">&gt; 15\u00a0<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">pg<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\/m<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">L<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\u00a0\u2013 large follicle (diameter \u2265\u00a0<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">approx.<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\u00a030 mm; preovulatory follicle), corresponding to oestrus<\/span><br \/>\n<span class=\"NormalTextRun SCXW200744118 BCX0\">&gt; 30\u00a0<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">pg<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\/m<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">L<\/span><span class=\"NormalTextRun SCXW200744118 BCX0\">\u00a0\u2013 suspicion of granulosa cell tumour or persistent anovulatory follicle<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW72304516 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW72304516 BCX0\">Advantages<\/span><\/span>:<\/strong> <span class=\"TextRun SCXW211251091 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW211251091 BCX0\">routine examination for the detection of subclinical ovarian follicular activity<\/span><span class=\"NormalTextRun SCXW211251091 BCX0\">.<\/span><\/span><span class=\"EOP SCXW211251091 BCX0\" data-ccp-props=\"{}\">\u00a0<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW138188362 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW138188362 BCX0\">Limitations<\/span><\/span>:<\/strong> <span class=\"TextRun SCXW248310844 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW248310844 BCX0\">T<\/span><span class=\"NormalTextRun SCXW248310844 BCX0\">he test results should be interpreted in conjunction with ultrasonographic\u00a0<\/span><span class=\"NormalTextRun SCXW248310844 BCX0\">findings<\/span><span class=\"NormalTextRun SCXW248310844 BCX0\">.<\/span><\/span><span class=\"EOP SCXW248310844 BCX0\" data-ccp-props=\"{}\">\u00a0<\/span>[\/vc_column_text][vc_row_inner][vc_column_inner width=&#8221;1\/2&#8243;][vc_single_image image=&#8221;532175&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781085725096{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Ultrasonographic image of the mare\u2019s ovary showing small follicles.<\/strong> Photo by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][vc_column_inner width=&#8221;1\/2&#8243;][vc_single_image image=&#8221;532179&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781085739082{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Persistent Anovulatory Follicle (PAF) \u2013 early stage of luteinisation.<\/strong> Photo by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][vc_row_inner][vc_column_inner width=&#8221;1\/2&#8243; offset=&#8221;vc_col-sm-offset-3&#8243;][vc_single_image image=&#8221;532183&#8243; img_size=&#8221;&#8221; alignment=&#8221;center&#8221; onclick=&#8221;link_image&#8221; css=&#8221;.vc_custom_1781085749316{margin-bottom: 15px !important;}&#8221; el_class=&#8221;endo-img-size&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<p style=\"text-align: center;\"><em><strong>Persistent Anovulatory Follicle (PAF) \u2013 advanced stage of luteinisation<\/strong> Photo by A. Zagrajczuk, DVM, PhD<\/em><\/p>\n<p>[\/vc_column_text][\/vc_column_inner][\/vc_row_inner][\/vc_tta_section][vc_tta_section title=&#8221;PMSG (eCG, equine chorionic gonadotropin; previously known as pregnant mare serum gonadotropin)&#8221; tab_id=&#8221;pmsg&#8221;][vc_column_text css=&#8221;&#8221;]<strong>Purpose:<\/strong> <span class=\"TextRun SCXW90834144 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW90834144 BCX0\">confirmation of pregnancy between 40 and 120 days of gestation.\u00a0<\/span><\/span><span class=\"TextRun SCXW90834144 BCX0\" lang=\"PL-PL\" xml:lang=\"PL-PL\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW90834144 BCX0\">Not\u00a0<\/span><span class=\"NormalTextRun SCXW90834144 BCX0\">applicable<\/span><span class=\"NormalTextRun SCXW90834144 BCX0\">\u00a0in\u00a0<\/span><span class=\"NormalTextRun SCXW90834144 BCX0\">donkeys<\/span><\/span><\/p>\n<p><strong>Production site \/ physiological role: <\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"NormalTextRun SCXW116169403 BCX0\">Produced in endometrial cups \u2013\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">foetal<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">-derived structures embedded in the uterine\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">mucosa<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0of the mare, formed\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">as a result of<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0trophoblast cell invasion (embryonic tissue) into the endometrium during early pregnancy. Equine chorionic gonadotropin (<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">eCG<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">) has both FSH (predominantly) and LH activity, leading to the formation of accessory corpora lutea in mares\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">approx.<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0between<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">day<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a040 and 45 of gestation. This mechanism ensures the maintenance of sufficiently high progesterone concentrations necessary to sustain pregnancy until it can be maintained by placental\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">progestogens<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">, i.e. around\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">day<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">100 to 120 of gestation. Occasionally, the action of\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">eCG<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0may also indirectly lead to the manifestation of oestrous behaviour in pregnant mares, as\u00a0<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">eCG<\/span><span class=\"NormalTextRun SCXW116169403 BCX0\">\u00a0stimulates follicular growth, resulting in increased oestradiol production responsible for oestrous signs.<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW23145315 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW23145315 BCX0\">Time for testing<\/span><\/span>:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"NormalTextRun SCXW62444413 BCX0\">s<\/span><span class=\"NormalTextRun SCXW62444413 BCX0\">uspicion\/confirmation of pregnancy between<\/span><span class=\"NormalTextRun SCXW62444413 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW62444413 BCX0\">days<\/span><span class=\"NormalTextRun SCXW62444413 BCX0\">\u00a040 and 120 of gestation<\/span><span class=\"NormalTextRun SCXW62444413 BCX0\">.\u00a0<\/span><span class=\"NormalTextRun SCXW62444413 BCX0\">Endometrial cups undergo regression at a later stage.<\/span><\/p>\n<p><strong>Sample:<\/strong> serum 1 mL (chilled)<\/p>\n<p><strong>Method:<\/strong> ELISA<\/p>\n<p><strong>Sample collection: <\/strong>etween days 40 and 120 after ovulation<\/p>\n<p><strong>Interpretation: <\/strong>descriptive<\/p>\n<p><strong>Advantages:<\/strong> routine test<\/p>\n<p><strong>Limitations:<\/strong> <span class=\"TextRun SCXW265435375 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW265435375 BCX0\">Possible false-positive results \u2013 in cases of\u00a0<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">foetal<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">\u00a0death, if endometrial cups fail to regress (persistent endometrial cups),\u00a0<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">eCG<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">\u00a0concentrations may remain at levels indicative of pregnancy. Cases of endometrial cup persistence beyond 140 days of gestation have also been reported; however, these are extremely rare (<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">approx.<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">\u00a0<\/span><\/span><span class=\"TextRun SCXW265435375 BCX0\" lang=\"PL-PL\" xml:lang=\"PL-PL\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW265435375 BCX0\">1\u20132% of\u00a0<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">mares<\/span><span class=\"NormalTextRun SCXW265435375 BCX0\">).<\/span><\/span><span class=\"EOP SCXW265435375 BCX0\" data-ccp-props=\"{}\">\u00a0<\/span>[\/vc_column_text][\/vc_tta_section][vc_tta_section title=&#8221;Estrone Sulfate (E1S)&#8221; tab_id=&#8221;e1s&#8221;][vc_column_text css=&#8221;&#8221;]<strong>Purpose:<\/strong> <span class=\"NormalTextRun SCXW96401961 BCX0\">Pregnancy diagnosis from day 80 in mares and day 120 in jennies. Results obtained after day 110 of gestation in mares are the most reliable and clinically useful. Additionally, they provide information on foetal viability and placental\u00a0<\/span><span class=\"NormalTextRun SCXW96401961 BCX0\">function.<\/span><\/p>\n<p><strong>Production site \/ physiological role: <\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> <span class=\"NormalTextRun SCXW212524749 BCX0\">Placenta \u2013 formed via synthesis from DHEA produced in the foetal gonads, with secretion markedly increasing between days 100 and 240 of gestation, after which it begins to decline. The placenta converts DHEA into \u201cpregnancy\u201d oestrogens, predominantly estrone\u00a0<\/span><span class=\"NormalTextRun SCXW212524749 BCX0\">sul<\/span><span class=\"NormalTextRun SCXW212524749 BCX0\">f<\/span><span class=\"NormalTextRun SCXW212524749 BCX0\">ate<\/span><span class=\"NormalTextRun SCXW212524749 BCX0\">.<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW46613828 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW46613828 BCX0\">Time for testing<\/span><\/span>:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> suspicion\/confirmation of late pregnancy (from day 80 after ovulation)<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> supportive in cases of: suspected impaired foetal viability or placental insufficiency<\/p>\n<p><strong>Sample:<\/strong> serum 1 mL<\/p>\n<p><strong>Method:<\/strong> RIA<\/p>\n<p><strong>Sample collection: <\/strong>from day 80 of gestation (after ovulation) to approx. one week prior to the expected term of foaling<\/p>\n<p><strong>Interpretation: <\/strong><br \/>\nBetween day 80 and 100 after fertilisation, values &gt; 10 ng\/mL indicate pregnancy.<br \/>\nAfter day 100 after fertilisation, values &gt; 100 ng\/mL indicate pregnancy.<br \/>\nIn the case of a negative result after day 80 of gestation, pregnancy is unlikely (test sensitivity 95\u201398%).<\/p>\n<p>Prior to making any important clinical decisions, a clinical examination is recommended.<\/p>\n<p><strong>Advantages:<\/strong> one of the few laboratory parameters useful in the assessment of foetal welfare and placental function<\/p>\n<p><strong>Limitations:<\/strong> relatively long turnaround time. In the assessment of placental function and foetal viability, a sudden, clearly diagnostic decrease in E1S concentration is detectable only approx. 2 days before foetal death\/abortion. [\/vc_column_text][\/vc_tta_section][vc_tta_section title=&#8221;DHP \/ progesterone ratio (luteo-placental shift)&#8221; tab_id=&#8221;dhp-progesterone-ratio&#8221;][vc_column_text css=&#8221;&#8221;]<strong>Purpose:<\/strong> <span class=\"NormalTextRun SCXW211420850 BCX0\">determination of the time point at which pregnancy maintenance is taken over by placental progest<\/span><span class=\"NormalTextRun SCXW211420850 BCX0\">o<\/span><span class=\"NormalTextRun SCXW211420850 BCX0\">gens (<\/span><span class=\"NormalTextRun SCXW211420850 BCX0\">luteo<\/span><span class=\"NormalTextRun SCXW211420850 BCX0\">-placental shift)<\/span><span class=\"NormalTextRun SCXW211420850 BCX0\">.<\/span><\/p>\n<p><strong><span class=\"TextRun SCXW175052525 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW175052525 BCX0\">Production site \/ physiological role<\/span><\/span>:<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> progesterone \u2013 produced by the corpus luteum (CL), responsible for maintenance of pregnancy until approx. day 100.<br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> DHP (5\u03b1-dihydroprogesterone) \u2013 the main progestogen produced by the placenta with high affinity for progesterone receptors and strong biological activity<\/p>\n<p><strong>Time for testing:\u00a0<\/strong><br \/>\n<img loading=\"lazy\" decoding=\"async\" src=\"\/wp-content\/uploads\/2026\/06\/female-pointer.png\" width=\"16\" height=\"16\" \/> To support the decision to discontinue altrenogest supplementation (between days 100 and 120 of gestation), without the risk of premature cessation of pharmacotherapy.<br \/>\nThe result precisely indicates placental maturation.<br \/>\nRepeated measurements of DHP in the same mare provide additional information on normal placental function in advanced pregnancy.<\/p>\n<p><strong>Sample:<\/strong> serum 1 mL<\/p>\n<p><strong>Metohod:<\/strong> LC\u2013MS (Liquid Chromatography \u2013 Mass Spectrometry)<\/p>\n<p><strong>Sample collection: <\/strong>between days 100 and 120 of gestation<\/p>\n<p><strong>Interpretation: <\/strong><br \/>\nIn non-pregnant mares or during early pregnancy, the 5\u03b1-DHP\/progesterone ratio is &lt;1. After the luteo-placental shift, around days 100\u2013120 of gestation, the 5\u03b1-DHP to progesterone ratio is &gt;1.<\/p>\n<p><strong>Advantages:<\/strong> highly accurate test.<\/p>\n<p><strong>Limitations:<\/strong> as a potential marker of placental inflammatory conditions, it should be reassessed through repeat measurements and interpreted alongside other parameters. [\/vc_column_text][\/vc_tta_section][\/vc_tta_accordion][\/vc_column][\/vc_row][vc_row gap=&#8221;20&#8243; equal_height=&#8221;yes&#8221; content_placement=&#8221;top&#8221; bg_type=&#8221;bg_color&#8221; bg_override=&#8221;full&#8221; css=&#8221;.vc_custom_1781257351922{padding-top: 60px !important;padding-bottom: 25px !important;}&#8221; bg_color_value=&#8221;#F3F3F3&#8243; el_class=&#8221;endo-summary-mobile&#8221;][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781255124787{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3 style=\"font-size: 16px; line-height: 1.2;\">Suspicion of granulosa cell tumour<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li>Anti-M\u00fcllerian Hormone (AMH)<\/li>\n<li>Testosterone (T)<\/li>\n<\/ul>\n<\/div>[\/vc_column][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781255127960{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3 style=\"font-size: 16px; line-height: 1.2;\">Other ovarian dysfunctions<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li>Estradiol (E2)<\/li>\n<li>Progesterone<\/li>\n<\/ul>\n<\/div>[\/vc_column][vc_column width=&#8221;1\/4&#8243; css=&#8221;.vc_custom_1781255138470{padding-top: 0px !important;}&#8221; el_class=&#8221;standard-arrow custom-red-arrow&#8221;][vc_column_text css=&#8221;&#8221;]<\/p>\n<h3 style=\"font-size: 16px; line-height: 1.2;\">Pregnancy assessment<\/h3>\n<p>[\/vc_column_text]<div class=\"standard-arrow list-divider bullet-top\"><ul>\n<li>Progesterone<\/li>\n<li><span class=\"TextRun SCXW146603835 BCX0\" lang=\"DE-DE\" xml:lang=\"DE-DE\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW146603835 BCX0\">Pregnant<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">\u00a0Mare Serum Gonadotropin<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">\u00a0(<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">PMSG\/<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">eCG<\/span><span class=\"NormalTextRun SCXW146603835 BCX0\">)<\/span><\/span><\/li>\n<li><span class=\"TextRun SCXW9565354 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW9565354 BCX0\">Estrone\u00a0<\/span><span class=\"NormalTextRun SCXW9565354 BCX0\">Sulfate<\/span><span class=\"NormalTextRun SCXW9565354 BCX0\"> (E1S)<\/span><\/span><\/li>\n<li><span class=\"TextRun SCXW6535694 BCX0\" lang=\"EN-GB\" xml:lang=\"EN-GB\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW6535694 BCX0\">DHP\/<\/span><span class=\"NormalTextRun SCXW6535694 BCX0\">P<\/span><span class=\"NormalTextRun SCXW6535694 BCX0\">rogesteron<\/span><span class=\"NormalTextRun SCXW6535694 BCX0\">e Ratio<\/span><\/span><br \/>\n(Luteo-Placental\u00a0Shift)<\/li>\n<\/ul>\n<\/div>[\/vc_column][vc_column width=&#8221;1\/4&#8243; 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