Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. There is an increasing body of evidence indicating that PCOS may have significant implications for pregnancy outcomes and long-term health of a woman and her offspring. Whether or not PCOS itself or the symptoms that coincide with PCOS, like obesity and fertility treatment, are responsible for these increased risks is a continuing matter of debate. Miscarriage rates among women with PCOS are believed to be increased compared with normal fertile women, although supporting evidence is limited. Pregnant women with PCOS experience a higher incidence of perinatal morbidity from gestational diabetes, pregnancy-induced hypertension, and preeclampsia. Their babies are at an increased risk of neonatal complications, such as preterm birth and admission at a neonatal intensive care unit. Pre-pregnancy, antenatal, and intrapartum care should be aimed at reducing these risks. The use of insulin sensitizing drugs to decrease hyperinsulinemic insulin resistance has been proposed during pregnancy to reduce the risk of developing preeclampsia or gestational diabetes. Although metformin appears to be safe, there are too few data from prospective, randomized controlled trials to support treatment during pregnancy.