Effects of clomiphene citrate on the endometrial thickness and echogenic pattern of the endometrium

Fertil Steril. 1997 Feb;67(2):256-60. doi: 10.1016/S0015-0282(97)81907-3.


Objective: To study the effects of clomiphene citrate (CC) on the endometrium by ultrasound and to reveal the echogenic difference between the control cycle and the CC cycle.

Design: Retrospective study of patients before and during a CC treatment.

Setting: Department of Obstetrics and Gynecology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.

Patient(s): Seventy-nine infertile women who had a spontaneous ovulation and a normal luteal function.

Intervention(s): Patients received 50 mg/d CC between days 5 and 9 of the menstrual cycle.

Main outcome measure(s): Endometrial thickness, echogenic pattern of the endometrium, serum E2 content, and E2 and P receptor contents in the endometrium.

Result(s): Endometrial thickness was significantly thinner during the CC cycle (7.6 +/- 1.4 mm, mean +/- SD, n = 79) than during the control cycle (8.5 +/- 1.7 mm, n = 79) on late proliferative days, but there was no significant difference on midsecretory days (10.8 +/- 2.2 mm during the CC cycle, n = 79; 11.2 +/- 2.2 mm during the control cycle, n = 79). The echogenic patterns, however, were different between the two cycles on midsecretory days. Moreover, the incidence in which patients showed a grade 3 endometrium on midsecretory days was significantly higher during the conceived CC cycle compared with the not-conceived CC cycle. Serum E2 levels were significantly higher, but E2 receptor contents in the endometrium were significantly lower during the CC cycle (67 +/- 46 fmol/mg, n = 13) compared with the control cycle (123 +/- 89 fmol/mg, n = 15) on late proliferative days.

Conclusion(s): Clomiphene citrate affected the echogenic pattern of the endometrium, and most of the endometrium showed a grade 3 pattern on midsecretory days during the conceived CC cycle. Under the CC treatment, the comfortable endometrium for embryos might be different from the control cycle.

MeSH terms

  • Adult
  • Clomiphene / pharmacology*
  • Endometrium / diagnostic imaging
  • Endometrium / drug effects*
  • Endometrium / metabolism
  • Female
  • Humans
  • Receptors, Estradiol / metabolism
  • Receptors, Progesterone / metabolism
  • Reference Values
  • Ultrasonography


  • Receptors, Estradiol
  • Receptors, Progesterone
  • Clomiphene