Incidence of spontaneous abortion in clomiphene pregnancies.
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 < 0.01). Preclinical abortions were increased by clomiphene for all ages (5.8 versus 3.9%, P < 0.01) and for age > or = 30 years (8.0 versus 4.9%, P < 0.001), but not for age < 30 years (3.7 versus 3.0%). Clinical abortions were increased by clomiphene for age < 30 years (15.9 versus 11.2%) (P < 0.01), but not for age > 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 < 0.05). We conclude that the increase in abortion due to clomiphene is small and may be related to different causes for women aged < 30 and > or = 30 years, and also that clomiphene may decrease clinical abortions in patients with luteal insufficiency.
Dickey
R P
RP
Fertility Institute of New Orleans, Louisiana 70128, USA.
Taylor
S N
SN
Curole
D N
DN
Rye
P H
PH
Pyrzak
R
R
D000022:Abortion, Spontaneous / Q000209:etiology*; D000328:Adult; D002996:Clomiphene / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D005307:Fertilization in Vitro; D005640:Follicle Stimulating Hormone / Q000627:therapeutic use; D015181:Gamete Intrafallopian Transfer; D005865:Gestational Age; D006801:Humans; D008596:Menotropins / Q000627:therapeutic use; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies
D002996:Clomiphene; D008596:Menotropins; D005640:Follicle Stimulating Hormone