Clomiphene citrate and pregnancy outcome

Data from Australia and elsewhere have shown consistently that adverse perinatal outcomes such as preterm birth and perinatal mortality are more common in pregnancies resulting from assisted conception with IVF and GIFT than normally conceived pregnancies. Factors that may contribute to the excess of poor outcomes include maternal factors, the assisted conception procedures themselves and possibly the influence of drugs used to induce superovulation. This review examines the medical literature describing pregnancies following ovulation induction with one of the drugs used to induce superovulation, clomiphene citrate, and compares their outcomes with Australian IVF and GIFT pregnancy outcomes. The review shows that whilst some studies have suggested higher rates of ectopic pregnancy, spontaneous abortion and congenital malformations in clomiphene citrate induced pregnancies, the findings are inconsistent and the data are flawed. There are only very poor data available on the incidence of preterm birth. Multiple pregnancy is a well-recognized adverse outcome of clomiphene citrate induced pregnancies. Attempts to improve perinatal outcomes of pregnancies following assisted conception will be helped by a better understanding of the relative contributions of maternal and treatment factors and further studies of pregnancy outcome after ovulation induction are needed.