Updated by the Progyny Editorial Team \u2014 September 2025.<\/p>\n\n\n\n
Endometrial receptivity testing, often called an endometrial receptivity assay (ERA), is a diagnostic biopsy of the uterus. The goal is to identify the window of progesterone exposure that is most favorable for an embryo to implant.<\/p>\n\n\n\n
This test is not recommended for everyone.<\/strong> That\u2019s because research has not shown consistent improvements in live birth rates compared with standard embryo transfer timing. Professional organizations caution that the evidence is limited, so many reproductive endocrinologists (REIs), or fertility specialists, reserve it for select situations.<\/p>\n\n\n\n Understanding why timing matters can help explain the test\u2019s purpose. In a natural menstrual cycle, after ovulation, your body produces the hormone progesterone. Progesterone prepares the uterus for implantation and supports early pregnancy, but the exact timing of this process can vary slightly from person to person.<\/p>\n\n\n\n Your doctor may suggest this test if:<\/p>\n\n\n\n Talk with your doctor to see if this test is right for you.<\/p>\n\n\n\n If your doctor suggests an ERA biopsy, here\u2019s what typically happens:<\/p>\n\n\n\n At the lab, specialists analyze genes from the tissue sample to assess whether your uterine lining is receptive to an embryo.<\/p>\n\n\n\n They usually fall into one of three categories:<\/p>\n\n\n\n Receptive<\/strong><\/p>\n\n\n\n Your lining was within the window of implantation, meaning progesterone exposure was timed correctly. Your doctor may recommend using the same protocol for the actual transfer.<\/p>\n\n\n\n Pre-receptive<\/strong><\/p>\n\n\n\n Your lining was not ready yet due to insufficient progesterone exposure. Your future transfer cycle may include additional time on progesterone \u2014 often 12 to 24 hours more than the standard six days.<\/p>\n\n\n\n Post-receptive<\/strong><\/p>\n\n\n\n Your lining had already passed the ideal window. This suggests progesterone started too early. A repeat biopsy may be needed to confirm timing, and your transfer protocol may shorten progesterone exposure by 12 to 24 hours.<\/p>\n\n\n\n Occasionally, results are inconclusive. In that case, a repeat mock cycle and biopsy may be required.<\/p>\n\n\n\n Hormones are generally consistent from month to month, but certain factors can influence your implantation window. This test may help fine-tune the timing of embryo transfer, but it\u2019s not recommended for everyone. Talk with your doctor to learn more.<\/p>\n\n\n\n Progyny is here for you, too. Please contact your Progyny Care Advocate for support.<\/p>\n\n\n\n Disclaimer<\/strong>: The information provided by Progyny is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider for medical guidance.<\/p>\n","protected":false},"excerpt":{"rendered":" Updated by the Progyny Editorial Team \u2014 September 2025. Endometrial receptivity testing, often called an endometrial receptivity assay (ERA), is […]<\/p>\n","protected":false},"author":45,"featured_media":24016,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[230,241,229],"tags":[],"class_list":["post-24014","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-education","category-fertility-testing","category-ivf-facts"],"yoast_head":"\nWhy your REI may suggest this test<\/h2>\n\n\n\n
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How the test works<\/h2>\n\n\n\n
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Understanding the results<\/h2>\n\n\n\n
Key takeaway<\/h2>\n\n\n\n