Endometrial sonographic characters predicting pregnancy following recurrent clomiphene induction in unexplained infertility

Patients with unexplained infertility managed repeatedly with clomiphene citrate need parameters to predict pregnancy to save them further unsuccessful trials and shorten their treatment to pregnancy interval. Ovulation was induced in 226 unexplained infertility patients, who had three previous failed cycles, with 100 mg clomiphene citrate (CC) from days 3 to 7 of the cycle. Human chorionic gonadotrophin (HCG) injection (10,000 IU i.m.) was given and timed intercourse was recommended when a leading follicle reached >17 mm and serum oestradiol exceeded 200 pg/ml. A receiver operating characteristic (ROC) curve showed that endometrial thickness >11.60 mm was associated with the lowest, while values >5.50 mm were associated with the highest chance of pregnancy. An endometrial thickness of 7.05 mm showed the best sensitivity and specificity. Patients with endometrial thickness <7.05 mm (n = 98) had significantly more clinical pregnancies (28.6 versus 8.9%), fewer days until HCG injection, thicker endometrium, higher serum progesterone measured on days 20–22 and more triple layer endometria than patients with endometrial thickness ≥7.05 mm (n = 56). It is concluded that endometrial thickness range of 5.50–8.25 mm and triple layer endometrium are highly predictive for pregnancy in patients with unexplained infertility induced with CC after repeated failures. Endometrial thickness of 11.60 mm was associated with a low chance of pregnancy.