Recent research based on clinical observations linked asthma in women with prolonged efforts to become pregnant and a decreased birth rate. Published in the European Respiratory Journal and titled “Fertility outcomes in asthma: a clinical study of 245 women with unexplained infertility,” the study adds to previous research identifying a correlation between asthma and fertility.
Asthma currently affects between 5 percent and 10 percent of the world’s population, or nearly 23.4 million people. Despite being more frequent among young boys, if the disease develops after puberty, women are equally affected.
Evidence concerning a link between asthma and fertility has been controversial, especially given that many of the previous studies relied on questionnaire data or samples of a small size. In this study, researchers analyzed 245 women with undetermined fertility problems, ages 23 to 45, undergoing fertility treatments. The women were tested for asthma and allergies and administered questionnaires. The team monitored participants during their treatments for at least 12 months, until they either had a successful pregnancy, stopped treatment, or the observations concluded.
From the cohort analyzed, 96 women had a previous asthma diagnosis or were diagnosed after entering the study. The results showed that the median total time to pregnancy was 32.2 months in non-asthmatic women and 55.6 months in women with the condition. Successful conceptions were also less frequent for asthmatic women, with only 39.6 percent becoming pregnant compared to 60.4 percent of non-asthmatic women. The trend intensified with advancing age.
“This finding in a clinical trial setting adds new weight to the epidemiological evidence suggesting a link between asthma and fertility. We have seen here that asthma seems to have a negative influence on fertility as it increases time to pregnancy and even more so with age,” Dr. Elisabeth Juul Gade, the study’s lead author, said in a press release. “We do not yet know the causal relationship; it may be complex with different types of asthma, psychological well-being, asthma medication and hormones all play a role. Given this new evidence, we believe that clinicians should encourage women with asthma to become pregnant at an earlier age and optimise their treatment for asthma pre-conception. Patient education is also of paramount importance as adherence to treatment may be enhanced if patients are informed of this link.”