Pregnant women who suffer from asthmatic symptoms, carrying a girl foetus are more likely to go through severe asthma symptoms than those carrying a male foetus, according to a recent study. Michael B. Bracken and other researchers at Yale School of Medicine studied 702 pregnant women throughout southern New England who were trained to assess their lung function for 10-day intervals at selected points in pregnancy.
Lung function and a number of other factors that might influence severity of the mother's asthma were recorded automatically. Asthma worsened in mothers with either male or female foetuses until about 30 weeks gestation, after which there was an improvement in the lung function. However, throughout pregnancy, mothers with a male foetus had a 10% better lung function. The American Journal of Epidemiology has published the research findings, which is the first and largest among studies to investigate the effect of foetal sex on the severity of the mother's asthma, and one of the largest to investigate the effect of foetal sex on any disease of the mother.
Asthma is one of the most common diseases associated with pregnancy. An upcoming study by the authors to be published this spring shows that eight to nine percent of pregnant women have a history of asthma.