Ultrasound study of the endometrium during in vitro fertilization cycles.

Ultrasonography is a noninvasive technique for studying the characteristics of the endometrium. This method was used in our in vitro fertilization and embryo transfer program during the periovulatory period for determination of whether there exists a moment at which the uterine mucosa is most favorable for implantation of the ovum. The endometrial thickness was noted in the course of the periovulatory phase. No correlation was found between the ultrasound image and hormonal assays. The endometrial thickness was significantly greater (P less than 0.01) when the in vitro fertilization attempt resulted in a pregnancy, even when considering the number of embryos transferred. However, it was not possible to predict the probability of pregnancy with the use of endometrial thickness.