Risk of multiple gestation after ovulation induction in polycystic ovary syndrome

OBJECTIVE: To compare the incidence of multiple gestation following treatment with clomiphene citrate (CC), metformin (MET) or gonadotropins in polycystic ovary syndrome (PCOS) patients undergoing ovulation induction. STUDY DESIGN: This was a retrospective, cohort study performed in an academic reproductive endocrine practice. PCOS patients presenting for first-trimester ultrasound were identified and assigned to 1 of 3 groups: CC-resistant patients who conceived after use of metformin +/- CC (group A), CC-resistant patients who conceived after gonadotropins (group B) and PCOS patients who conceived with CC only (group C). Multiple pregnancy outcome data were collected by chart review and patient interview. RESULTS: One hundred one pregnancies were identified in PCOS patients who had conceived after ovulation induction (OI). The rate of multiple gestation was higher in group B (36%) than in A (0%) or C (11%). CONCLUSION: The rate of multiple births was significantly lower with MET use during OI. Because multiple gestation is associated with higher complication rates and medical costs, our data offer an additional reason for use of MET for OI in PCOS patients who fail CC.