Women with asthma are at increased risk for numerous complications of pregnancy, labor and delivery, suggests a new study of nearly 225,000 pregnant U.S. women. The findings are concerning, say the authors, because asthma is the most common chronic disease during pregnancy and its rates continue to rise. In the study, 7.6% of the women had asthma. These women experienced increased odds of preeclampsia (14%), preterm birth (17%), low birthweight (16%), placenta previa (30%), placental abruption (22%), bleeding (9%), pulmonary embolism (71%) and gestational diabetes (11%), even after adjusting for risk factors. They were also less likely to experience spontaneous labor and vaginal delivery. The study, published in the American Journal of Obstetrics & Gynecology, involved data collected from 12 centers in the U.S. between 2002 and 2008. More research is needed, conclude the authors, to identify factors that predict poor obstetric outcomes and to determine if targeted treatment can benefit vulnerable women. Read the abstract.