Perinatal complications associated with maternal asthma during pregnancy

Asthma is one of the most common medical illnesses occurring in pregnancy and its incidence amongst the obstetric population is increasing. Previous studies have suggested that asthma is not a benign illness in pregnancy, and can contribute towards increased rates of pregnancy complications.

We undertook a retrospective audit of 6458 deliveries during 2008 at The Royal Women's Hospital to determine the perinatal outcomes for women with a self-reported diagnosis of asthma.

We found that 501 (7.8%) deliveries were to women who identified themselves as asthmatics. Of these, 15.6% reported exacerbations of their asthma symptoms during pregnancy, with the remainder reporting improvement or stabilization. There was an increased rate of preterm birth (12.9%) in the asthmatic population, compared to the non-asthmatic population (OR = 1.48, CI [1.12-1.95], P = 0.005). Asthma remained significantly associated with an increased risk of preterm birth after adjusting for maternal smoking status using logistic regression analysis (Adjusted OR 1.41, CI [1.07-1.86], P = 0.01). Women were also at increased risk of developing pre-eclampsia (OR 1.71, CI [1.09-2.67], P = 0.02) but not fetal growth restriction. Women identifying themselves as asthmatics were also more likely to deliver by caesarean section (OR 1.32, CI [1.09-1.6], P = 0.003).

These findings suggest that maternal asthma may be associated with an increased risk of preterm birth, pre-eclampsia and caesarean delivery.