Objective: To study the risk of adverse pregnancy outcomes in women with polycystic ovary syndrome Design: Population based cohort study. Participants: patient attending OPD in ChalmedaAnand Rao institute of medical sciences 100 births among women with a diagnosis of polycystic ovary syndrome and 100 births among women without such a diagnosis. Main outcome measures: Risk of adverse pregnancy outcomes (gestational diabetes, pre-eclampsia, preterm birth, stillbirth, neonatal death, low Apgar score (<7 at five minutes), meconium aspiration, large for gestational age, macrosomia, small for gestational age), adjusted for maternal characteristics (body mass index, age), socioeconomic factors Results: Women with polycystic ovary syndrome were more often obese. Polycystic ovary syndrome was strongly associated with pre-eclampsia and very preterm birth and the risk of gestational diabetes was more than doubled . Infants born to mothers with polycystic ovary syndrome were more prone to be large for gestational age and were at increased risk of meconium aspiration and having a low Apgar score (<7) at five minutes Conclusions: Women with polycystic ovary syndrome are at increased risk of adverse pregnancy and birth outcomes These women may need increased surveillance during pregnancy and parturition.