Women with asthma may be more likely to experience miscarriage and require fertility treatment, though their overall chances of having a live birth remain unaffected, according to the results of a new study presented at the European Respiratory Society Congress in Vienna.

The data demonstrated that women with asthma had a higher rate of fetal loss compared to women without asthma (17.0% vs 15.7%) and were more likely to undergo fertility treatment (5.6% vs 5.0%). The live birth rates were equivalent between those with and without asthma, with 77% in both groups.

The research, led by Anne Vejen Hansen, MD, from the Department of Respiratory Medicine at Copenhagen University Hospital, included 769,880 women born between 1976 and 1999 and followed from 1994 to 2017. Women who regularly used anti-asthma medication were classified as having asthma. Asthma was identified by repeated redemption of anti-asthmatic medications, with severity classified according to the 2018 Global Initiative for Asthma (GINA) guidelines.

The adjusted hazard ratio (HR) for requiring fertility treatment in women with asthma was 1.12 (95% confidence interval [CI], 1.08-1.15). Women with more severe asthma, particularly those classified under GINA steps 4-5, exhibited the highest risk of fertility treatment (HR 1.62, 95% CI, 1.43-1.83). Women with three or more exacerbations also faced an elevated risk (HR 1.38, 95% CI, 1.19-1.60).

Asthma severity and frequent exacerbations are potentially linked to systemic inflammation affecting reproductive health. Future studies are planned to investigate the potential impact of male asthma on fertility.

"The fact that the more severe the asthma, the more the problems with fertility, suggests that uncontrolled asthma is the problem, and we should be helping women to get their asthma under control," said Lena Uller, PhD, Chair of the ERS Group on Airway Pharmacology and Treatment at Lund University.