Impact of three-dimensionally measured endometrial volume on the pregnancy rate after intrauterine insemination.

Abstract

The success of artificial reproductive techniques not only depends on the quality of oocytes and spermatozoa but also on the receptivity of the endometrium. The aim of this study was to assess the role of endometrial volume measurement by three-dimensional ultrasound in predicting the pregnancy rate (PR) in women receiving controlled ovarian hyperstimulation followed by intrauterine insemination. 104 patients having intrauterine insemination (IUI) were included in this prospective trial. Ovarian hyperstimulation was performed with gonadotropins in 73 % of patients and with clomiphene citrate (CC) in 27 % of patients. Endometrial thickness, pattern and three-dimensional volume were measured immediately before insemination. In 104 IUI cycles a total of 14 clinical pregnancies were recorded (PR=13.5 %). The endometrial volume was 3.5 ml and was not significantly different in pregnant (4.0 +/- 1.5 ml) from non-pregnant women (3.4 +/- 1.9 ml). In the subgroup of women with an endometrial volume > or = 2 ml and trilaminar endometrium the pregnancy rate was 22 %, significantly higher than that in women without these two criteria (PR 6 %, p < 0.05). The negative predictive value of an endometrial volume < 2 ml for a clinical pregnancy after IUI was 96 %. Endometrial volume and thickness were significantly higher after ovarian hyperstimulation with gonadotropins (3.7 ml and 11.0 mm) than with CC (2.8 ml and 9.5 mm; p < 0.05). An endometrial volume < 2 ml at the day of insemination is associated with a poor likelihood of pregnancy. Endometrial volume measured by 3D ultrasound is a new objective parameter to predict endometrial receptivity.