Women with asthma are more likely to undergo fertility treatment than those without the disease, suggests new research.
Some 12 percent of pregnant women had received fertility treatment compared with only 7 percent in the control group, found the study at Hvidovre Hospital in Denmark. The findings add to increasing evidence of a relationship between asthma and fertility.
'There is a wealth of existing research linking asthma and hormones and this study adds to our knowledge on the subject,' said Dr Samantha Walker, director of research and policy at Asthma UK, who was not involved in the study.
The 744 pregnant women with asthma who gave birth at the hospital between 2007 and 2013 were each matched to three women without asthma in a control group of 2136. The results of the comparison took into account other factors that could have affected outcomes including age, body mass index, a history of smoking, previous children, and single or same sex partnership. However, the study was not able to take income, lifestyle or socioeconomic factors into account. The results were presented at the European Respiratory Society International Congress in Milan, Italy.
However, the study does not prove that asthma itself reduced fertility. Instead, the researchers suggest their findings show that improving asthma control in women may improve their chances of getting pregnant.
'We don't have the hard-core evidence, but based on what we know, it seems very likely that good asthma control will improve fertility in women with asthma by reducing the time it takes to become pregnant and, therefore, the need for fertility treatment,' said Professor Charlotte Suppli Ulrik who supervised the study at the hospital.
She added: 'However, when it comes to fertility for women, age is a crucial factor - so the message, particularly for women with asthma, is don't wait too long, as it might reduce your chances of having children.'
Professor Suppli Ulrik's team is setting up follow-up studies to further investigate a relationship between asthma and fertility including the effects of good asthma control.
Asthma remains one of the most common chronic conditions for women during their reproductive years. The causes of asthma are not completely understood and both genetic and environmental factors affect its development. In the UK alone, it is estimated that 5.4 million people are currently receiving treatment for asthma.