Ultrasonic evaluation of endometrial growth in women with normal cycles during spontaneous and stimulated cycles.

Ultrasound scanning of the endometrium was performed through the menstrual cycle in normal, ovulating women in 20 unstimulated cycles (A), 13 clomiphene citrate (CC)/human menopausal gonadotrophin (HMG)/human chorionic gonadotrophin (HCG)-stimulated cycles (B) and 20 CC/HMG/HCG-stimulated cycles with oocyte collection (C). A total of 294 endometrial scans were performed and the texture and thickness of the endometrium registered. All data were related to the day of the luteinizing hormone (LH) peak or to HCG administration (day 0). There was no difference between groups in the image of the endometrium, which consisted of thin echogenic lines from day -10 until day 0 (99%). Three thin echogenic lines were seen in the pre-ovulatory endometrium in all cycles. During the luteal phase, confluent, thick echogenic lines were observed in all but two cycles, where the pre-ovulatory pattern persisted. The endometrium reached a mean thickness at days -1 to +1 of 6.4 mm in group A and 6.1 mm in groups B and C together. The endometrium was thinner at days -7 to -5 and -4 to -2 in groups B and C together (2.7 mm and 4.2 mm) compared with group A (4.6 mm and 5.8 mm) despite increased serum levels of oestradiol. At days +2 to +4, the endometrium was thicker in groups B and C together (7.2 mm) compared with group A (5.3 mm).