Increased risk of preterm delivery and pre-eclampsia in women with polycystic ovary syndrome and hyperandrogenaemia

ObjectiveTo study the risk of adverse pregnancy outcomes in women with polycystic ovary syndrome (PCOS), and to examine the role of hyperandrogenaemia. DesignCohort study. SettingSingleton pregnancies in women with PCOS identified at a private fertility clinic during 1997-2010 and a background population including all singleton deliveries at Hvidovre Hospital, Denmark, in 2005. PopulationA cohort of 459 women with PCOS and a background population of 5409 women. MethodsObstetric outcomes were extracted from national Danish registries and odds ratios (ORs) were calculated by multiple logistic regression analysis, adjusting for age, parity, and body mass index. Main outcome measuresRisk of pre-eclampsia, preterm delivery, and small for gestational age offspring in the entire PCOS population and in a subsample with hyperandrogenaemia. ResultsWomen with PCOS had an increased risk of preterm delivery <37weeks of gestation (OR 2.28; 95% confidence interval, 95% CI, 1.51-3.45; P<0.0001). The elevated risk was confined to hyperandrogenic women with PCOS: preterm delivery before 37weeks of gestation (OR 2.78; 95% CI 1.62-4.77; P<0.0001), and was not seen in normoandrogenic women with PCOS (OR 1.35; 95% CI 0.54-3.39; P=0.52). The overall risk of pre-eclampsia was not elevated (OR 1.69; 95% CI 0.99-2.88; P=0.05) compared with the background population, but was significantly increased in the hyperandrogenic subsample (OR 2.41; 95% CI 1.26-4.58; P<0.001). The risk of small for gestational age offspring was similar in all groups. ConclusionWomen with PCOS had an increased risk of preterm delivery compared with the background population. The increased risk was confined to hyperandrogenic women with PCOS who had a two-fold increased risk of preterm delivery and pre-eclampsia.