Endometrial thickness cannot predict ongoing pregnancy achievement in cycles stimulated with clomiphene citrate for intrauterine insemination.

To date, limited data exist concerning the relation between endometrial thickness on the day of human chorionic gonadotrohin (HCG) administration and ongoing pregnancy achievement in cycles stimulated with clomiphene citrate for intrauterine insemination (IUI). In a prospective study, 168 couples were stimulated with clomiphene citrate from day 3 to day 7 of the cycle and endometrial thickness was assessed by ultrasound three times on the day of ovulation triggering. Ovulation was induced with HCG as soon as >/=1 follicle of >/=17 mm was present at ultrasound independently of endometrial thickness. IUI was performed 36 h after HCG administration. The main outcome measure was ongoing pregnancy. No difference was observed in endometrial thickness between patients who did or did not achieve an ongoing pregnancy (7.6 +/- 0.3 versus 7.6 +/- 0.2 respectively; P = 0.7). No discriminative ability of endometrial thickness on the achievement of ongoing pregnancy could be shown by receiver operating characteristic (ROC) curve analysis (area under the ROC curve 0.51, 95% CI: 0.44-0.59). In conclusion, endometrial thickness cannot predict ongoing pregnancy achievement in IUI cycles stimulated with clomiphene citrate.