The endometrium: is thickness all that counts?

The commonly used 7 mm threshold for endometrial thickness in assisted reproductive technology lacks strong evidence and stems from outdated data. Recent studies show that live birth outcomes are comparable even with linings of less than 7 mm, particularly when using euploid embryos. Measurement variability, confounding factors and differing clinical practices limit the reliability of endometrial thickness as a standalone predictor. While extremely thin linings may warrant further evaluation, rigid cut-off values are unjustified. Endometrial thickness should be integrated into a broader, individualized assessment rather than drive clinical decisions in isolation.