Walking on thin endometrium.

PURPOSE OF REVIEW: Endometrial thickness has been regarded a predictor of success in assisted reproductive technology cycles and it seems a common practice to cancel embryo transfer when it is below a cut-off. However, various cut-offs have been proposed without a causal relationship between endometrial thickness and embryo implantation being established, casting doubt on the current dogma.

RECENT FINDINGS: Methodological limitations of the available studies on endometrial thickness are increasingly recognized and better designed studies do not demonstrate a cut-off value which requires cancelling an embryo transfer.

SUMMARY: Endometrium is important for implantation and a healthy pregnancy; however, ultrasound measured thickness does not seem to be a good marker of endometrial function.