Reproductive healthLecture
Thin endometrium — should embryo transfer be cancelled?
Thin endometrium remains one of the most debated topics in reproductive medicine. Is it justified to cancel transfer at a thickness of <7 mm? Analysis of the evidence base — from classical work of the late 1980s to current multicentre cohorts (~30,000 cycles) — shows that with proper work-up (exclusion of intracavitary pathology and premature progesterone exposure), the live birth rate at thickness <7 mm remains in the 42–47% range.
Audio: MultiSubtitles: EN · UA · RU28 min
Baris Ata
Professor, MD, MSc
Dean of Koç University School of Medicine, and Professor and Head of its Department of Obstetrics and Gynecology. A reproductive endocrinology and infertility subspecialist focusing on female infertility, IVF and endometriosis. Holds leadership positions in international fertility societies and serves as an editor for international journals.
Istanbul, TürkiyeLinkedIn →
Few practices in reproductive medicine are as widely accepted yet as poorly evidenced as the cancellation of embryo transfer for thin endometrium. The lecture proposes a logical framework — four sequential questions — that must all be answered convincingly before cancellation can be justified. None of the four, on closer examination, holds up.
Question one: is the endometrium really «thin»?
There is no biological consensus on the threshold. The literature cutoffs span 6 to 14 mm, with the widely-quoted 7 mm threshold tracing back to a small cohort study from the late 1980s, when vaginal ultrasound was not yet standard and sample sizes were modest. Live births at thickness below 4 mm have been published. The threshold is convention, not biology.
