A new study suggests that women with asthma could have more difficulty conceiving, resulting in prolonged time to pregnancy. Researchers say the study, published in the European Respiratory Journal, adds to previous research suggesting that asthma impacts fertility.
According to the Centers for Disease Control and Prevention (CDC), about
Women are more likely than men to have asthma, which makes this current study particularly important.
Although the coexistence of infertility and asthma has been previously observed, this recent study investigates the link between asthma and delayed pregnancy in a large-scale analysis of twins.
The researchers, from Bispebjerg University Hospital in Denmark, looked at data from a cohort study of over 15,000 twins who were aged 12-41 years, and who completed a questionnaire about asthma and fertility.
Twins were used for the study so that direct comparisons could be made between sisters. The researchers note this also allowed them to use a sample representative of the whole population, from all social groups, without needing to measure genetic and lifestyle data for each individual.
The women were then divided into asthma and non-asthma groups, and they were then further divided into sub-groups for those treated for asthma and those not treated.
Each woman was asked whether she had been trying to get pregnant for a year or more without success.
The researchers found that in the group with asthma, a “significantly higher proportion” of women (27%) experienced prolonged time to pregnancy, compared with the group of women who did not have asthma (21.6%).
In the group of women whose asthma was untreated, the risk of delayed conception increased by a significant amount, compared with women whose asthma had been treated, at 30.5% versus 23.8%.
Additionally, the researchers observed that as a general trend, women with asthma over the age of 30 had a longer waiting time to pregnancy, compared with women under the age of 30, at 32.2% versus 24.9%.
But the researchers do note that ultimately, women with asthma gave birth to the same number of children on average as the women without asthma, adding that women with asthma tended to have children at an earlier stage in their lives.
As the negative effect of asthma on fertility increases with age and grows with the intensity of the condition, the researchers say this indicates “that a systemic disease (asthma) characterized by systemic inflammation also can involve reproductive processes.”
Dr. Elisabeth Juul Gade, lead author of the study, says:
“Our results shed light on the complex interactions between fertility and asthma. Although we observed women with asthma experiencing longer waiting times to pregnancy, our findings suggest that if women take their medication and control their asthma, they can reduce this delay.”
“Despite the delay,” she adds, “our overall results suggest that women with asthma had the same number of children, which is due to the fact that they tend to conceive at an earlier age compared to those without, getting a head start on their reproductive life.”
Medical News Today recently reported on a study that suggested personality may affect fertility rates.