Sonographic evaluation of the endometrium in in vitro fertilization IVF cycles: A way to predict pregnancy?

The endometrial thickness and echogenic pattern were prospectively evaluated in 100 patients undergoing IVF-treatment. On the day before oocyte aspiration (day-1) the endometrium was significantly thicker in the group of patients achieving an ongoing pregnancy than in the group that failed to conceive. The minimal endometrial thickness on day-1 compatible with an ongoing pregnancy was 9 mm. Before oocyte aspiration two different endometrial patterns could be distinguished, a multilayered, 'triple line', hypoechogenic endometrium (A) and an isoechogenic pattern (B). Other studies have, in addition, described a hyperechogenic endometrium with a poor pregnancy rate but that pattern could in the present study only be demonstrated after follicle aspiration, 32 clinical pregnancies occurred. Among patients with endometrial pattern A, 36% conceived and among patients with pattern B 23% conceived which was not significantly different. It is concluded that the day before aspiration an endometrial thickness of at least 9 mm appears to be required for an ongoing pregnancy. In all cases a triple line (hypo-or isoechogenic) pattern was evident before aspiration.