Complications of pregnancy in obese women with asthma may have more to do with obesity than with asthma, researchers report in the medical journal Obstetrics and Gynecology.

Lead investigator Dr. Israel Hendler told Reuters Health that his team hypothesized that “since obesity and asthma go together, the adverse outcomes shown in asthmatic women during pregnancy are due to the obese state and not to the asthma status.”

Asthmatic women, he continued, “have more cesarean deliveries and more preeclampsia, because they are more obese and not because of their asthma status. We also showed that obese women have more asthma exacerbations during pregnancy.”

Hendler of Hutzel Hospital-Wayne State University, Detroit, and a multicenter team studied data on about 1,700 asthmatic women and more than 800 pregnant women without asthma, the “control” group.

Some 30.7 percent of the asthmatic women were obese, compared with 25.5 percent of controls. Obese women, regardless of asthma status were 60 percent more likely to undergo cesarean delivery. These women were also 70 percent more likely to develop preeclampsia or high blood pressure and more than four times more likely to develop pregnancy-related diabetes.

There were no significant differences in rates of asthma improvement between obese and non-obese women (20.6 percent versus 23.6 percent). There were also no significant differences in rates of asthma deterioration (33.3 percent versus 28.8 percent). However, obese women were 30 percent more likely to have asthma exacerbations.

Given these findings, the researchers conclude that further study is needed on “the effects of excess weight gain and weight reduction on the course of asthma during pregnancy.”

SOURCE: Obstetrics and Gynecology, July 2006.