Polycystic ovary syndrome (PCOS) is a notoriously heterogeneous, common reproductive disorder associated with many coexisting conditions, including hyperandrogenemia, obesity, insulin resistance and other signs of metabolic dysfunction. PCOS is often diagnosed in the context of anovulatory infertility. However, more recent research disclosed an association of PCOS with increased chances for pregnancy complications, adverse perinatal outcomes and suboptimal long-term health of children born to women with PCOS. This chapter provides an overview of current literature concerning obstetrical complications in women with PCOS, especially increased risk for gestational diabetes (OR 2.7–2.9), hypertensive disorders of pregnancy (including preeclampsia, OR 1.9–4.2) and preterm birth (OR 1.5–2.2). In addition, information regarding children’s outcomes is provided, including birth weight, cardiovascular health and neurodevelopmental health. Finally, pathological pathways including biomarker data in pregnancy and placenta morphology are discussed.

The lack of ovulatory cycles may be considered as a major problem for women seeking pregnancy. This is reflected by the fact that about 20 percent of couples visiting a fertility clinic with an unfulfilled wish to conceive present with anovulation [1]. Clinical manifestation of anovulation is oligomenorrhea (intermenstrual period > 35 days) or amenorrhea (intermenstrual period > 6 months). Although ovulation may occur in oligomenorrhea, the longer the time period between menstruations the smaller the chance of that cycle being ovulatory. Classification of anovulatory patients may be performed using the criteria of the World Health Organization (WHO) as determined by Rowe et al.