Objectives To investigate obstetric outcomes in Danish women with different phenotypes of polycystic ovary syndrome (PCOS) and isolated hyperandrogenism (HA) and describe the risk of adverse obstetric outcomes in women with PCOS and HA compared to controls. Design Cohort study. Setting Odense University Hospital, Denmark. Population Women with PCOS were identified prospectively starting in 1997. Singleton pregnancies in women with PCOS and HA during 2003-2011 were included (n = 199). A control group was matched to the patient cohort according to date of childbirth (n = 995). Methods Data on clinical characteristics and obstetric outcomes were collected in patients with PCOS and HA and controls. In PCOS and HA, total and free testosterone, sex hormone binding globulin, and hemoglobin A1c were measured outside pregnancy. During pregnancy, oral glucose tolerance tests were performed in 39 patients and 123 controls according to Danish national guidelines. PCOS phenotypes were based on the Rotterdam criteria. Main outcome measures Gestational diabetes mellitus, pregnancy-induced hypertension, preeclampsia, delivery by emergency cesarean section, preterm delivery and anthropometric measures in the newborn. Results The incidence of adverse obstetric outcomes and anthropometric measures among the newborns were comparable between different phenotypes of PCOS and patients with HA. In the oral glucose tolerance test, patients had a higher risk of gestational diabetes mellitus compared with controls; the odds ratio (95% confidence interval) was 3.3 (1.5-6.9) after adjustment for age, parity, and body mass index (p = 0.002). The incidence of other adverse obstetric outcomes was similar in patients and controls. Conclusions Obstetric outcomes were comparable in women with different PCOS phenotypes.