Incidence of spontaneous abortion in clomiphene pregnancies.
- PubMed: 9021363
The purpose of this study was to determine whether the use of clomiphene results in a higher incidence of spontaneous abortion than occurs naturally in subfertile patients. Reproductive outcomes of 1744 clomiphene pregnancies were compared to outcomes of 3245 spontaneous pregnancies in a prospective study. Abortion was classified as clinical if a sac was seen on ultrasound or if it occurred after 6 gestational weeks, and as preclinical if a quantitative human chorionic gonadotrophin (HCG) was > or = 25 mIU and no sac was seen or abortion occurred earlier. The overall incidence of abortion was higher for clomiphene pregnancies (23.7%), compared with spontaneous pregnancies (20.4%) (P or = 30 years (8.0 versus 4.9%, P or = 30 years (20.1 versus 22.3%) or all ages (18.0 versus 16.4%). Clinical abortions occurred 22% less often following clomiphene compared with spontaneous pregnancies for patients with luteal insufficiency (18.3 versus 23.6%, P or = 30 years, and also that clomiphene may decrease clinical abortions in patients with luteal insufficiency.