BackgroundAsthma is the most common potentially serious medical complication in pregnancy. The purpose of this study was to determine the association between maternal asthma and a spectrum of adverse neonatal and maternal outcomes.MethodsEvents during pregnancy and birth outcome were evaluated in 34 asthmatic as well as 1569 non-asthmatic pregnant women who were enrolled in a prospective cohort study undertaken at the antenatal clinics of Mobini Hospital in Iran. The women were interviewed and classified according to clinical severity and asthma control as per GINA guidelines. Information on asthma symptoms was collected by a questionnaire as well as by spirometry and physical examination. All subjects were followed until delivery, and postpartum charts were reviewed to assess neonatal and maternal outcomes. Eosinophil cells counts were obtained and total IgE was measured by ELISA. Results were assessed by multivariate logistic regression adjusting for maternal age and parity, and for birth outcomes, for gestational diabetes, and hypertension/pre-eclampsia.ResultsThe well-known relationship between family history of asthma and asthma in pregnancy was again supported (p < 0.001). Women with asthma had more bleeding events 3 weeks or more before delivery (OR 3.30, 95% CI 1.41–7.26), more often placenta problems (OR 6.86, 95% CI 1.42–33.02), and gestational diabetes mellitus (OR 3.82, 95% CI 1.06–13.75). No significant differences between asthmatic and non-asthmatic mothers regarding duration of gestation, birthweight, low Apgar scores, or neonatal respiratory difficulties were found. Total IgE antibody levels and eosinophil counts did not differ by asthma control and severity.ConclusionsAsthma in pregnancy poses some risk for pregnancy complications and adverse perinatal outcomes. Managing asthma effectively throughout pregnancy could benefit women and their babies and help to reduce the health burden associated with asthma during pregnancy.