The Surprising Way Asthma Affects Your Fertility

A new study links asthma, the chronic lung condition, with trouble getting pregnant. Here's what to do if you're asthmatic and trying to conceive.

The Surprising Way Asthma Affects Your Fertility wavebreakmedia/Shutterstock

If you are one of the eight percent of American women with asthma and are trying to conceive, you might already have a plan in place for how to control it when you become pregnant. But, a recent study published in the European Respiratory Journal showed that women with the disease may actually have a harder time just getting pregnant than women without it.

Effect on the body

Researchers monitored 245 women between the ages of 23 and 45 who were going through treatment for unexplained infertility in order to get pregnant. Ninety-six of the women were diagnosed with asthma either before or during their treatment. The average time it took the non-asthmatic women to get pregnant was 32.2 months, but it took the women with asthma 55.6 months. In addition, the women with asthma were less likely to get pregnant: 39.6 percent compared with 60.4 percent of the women without it—and the success rate got worse as the women got older. "We showed that asthma has a negative influence on fertility as it increases the time to pregnancy and possibly reduces birth rate, with an increasing tendency with age especially above 35 years old," the study's lead author Elisabeth Juul Gade, M.D., of the Respiratory Research Unit at Bispebjerg Hospital in Copenhagen, Denmark, tells Fit Pregnancy.

But the reasons for the link aren't totally clear. "Asthma is closely related to female reproductive life in several aspects, however, a causal relationship between asthma and subfertility [being less fertile] has never been established, despite subfertility often being seen clinically in asthmatic women," Dr. Gade says. Asthma causes chronic inflammation in the respiratory system—but that inflammation could also be more widespread throughout the body, making an unfriendly uterine environment, as Dr. Gade said in a previous study. And the hormone estrogen could make the inflammation from the disease worse.

So why would the effects of asthma be greater with age? Although the study didn't find conclusive evidence for the reason behind it, Dr. Gade and her colleagues think that the years exposed to low-grade inflammation in the body can take their toll. It's also possible that the condition can progress over time. "I think that the increased tendency with age possibly is connected to a longer duration of the asthmatic disease," Dr. Gade says. "The type and severity of asthma can change with age."

Should you take asthma meds?

The study also considered whether medications to treat asthma could be linked to infertility, and not the condition itself. But, the researchers didn't find any difference in pregnancy rates no matter what type of medication the women were on. Dr. Gade says her previous study backs that up. "From our former study in 2013 it seems as if it is the severity of asthma and not the medication that affects fertility," she says.

Although the subjects of this study were fertility patients, Dr. Gade believes that the findings would apply to the general population as well. So if you think you might have asthma or have been already diagnosed, she advises not to wait to try to conceive, given that the association with infertility increases with age. "Women with asthma should be informed of their increased risk of reduced fertility, especially above the age of 35 years, and therefore encouraged to start their reproductive life at an earlier age," she says. "I think the most important point is awareness of this issue among asthmatic women and clinicians."

And if you're actively trying to conceive, it's best to get your asthma under control with medication now. The risks of untreated asthma in pregnancy include preeclampsia, premature birth, poor growth and low birthweight—all due to the difficulty of getting oxygen to the growing baby. You should also avoid asthmatic triggers, including allergens like dust and pollen, irritants like cigarette smoke, and infections (so make sure to get your flu shot). "[If I were] an asthmatic women thinking of becoming pregnant, I would request to have my asthma treatment optimized pre-conception, as it is well known that being well treated for your asthma is important for the outcome of your pregnancy," Dr. Gade says.