Women who use only short-acting asthma medications take longer to become pregnant than non-asthmatic women or women taking long-acting medications, a new international research study suggests.
After looking at the data of more than 5,600 women in Australia, New Zealand, the U.K. and Ireland, researchers found evidence pointing to a problem with short-acting asthma relievers and fertility.
The study, conducted by University of Adelaide’s Robinson Research Institute researchers and led by Luke Grzeskowiak, PhD, is titled “Asthma treatment impacts time to pregnancy: evidence from the international SCOPE study.” It was published in the European Respiratory Journal.
According to the team, asthma is estimated to affect about 8 to 13 percent of pregnant women worldwide. While maternal asthma has been associated consistently with significant perinatal morbidities, its impact on fertility is not clear.
Given the limited and controversial evidence available, researchers wanted to determine the impact of asthma and asthma medication use on fertility and time to pregnancy.
“Five to ten percent of all women around the world have asthma and it is one of the most common chronic medical conditions in women of reproductive age. Several studies have identified a link between asthma and female infertility, but the impact of asthma treatments on fertility has been unclear,” Grzeskowiak said in a press release.
“Studying the effect of asthma treatments in women who are pregnant or trying to get pregnant is important as women often express concerns about exposing their unborn babies to potentially harmful effects of medications.” he said.
Using data from the international Screening for Pregnancy Endpoints (SCOPE) study, researchers looked at detailed records of more than 5,600 women in the early stages of their first pregnancy. About 10 percent of the women reportedly had asthma and, overall, they stated they took longer to get pregnant.
The team analyzed the women according to the type of asthma treatment they were using.
Researchers noticed that women using short-acting relievers (beta-agonists) took about 20 percent longer, on average, to conceive. These women also were 30 percent more likely to have taken more than a year to conceive. These differences were sustained even after taking into account other factors known to influence fertility, such as age and weight.
No difference in fertility was found between women using long-acting asthma treatments (like inhaled corticosteroids) and women without asthma.
“This study shows that women using short-acting asthma relievers take longer to get pregnant. On the other hand, continued use of long-acting asthma preventers to control asthma seems to protect fertility and reduce the time it takes women with asthma to become pregnant. This could lead to a reduction in the need for fertility treatments,” said Grzeskowiak.
“There is plenty of evidence that maternal asthma has a negative impact on the health of pregnant mothers and their babies, and so our general advice is that women should take steps to get their asthma under control before trying to conceive,” Grzeskowiak added.
It is not clear, however, how asthma or asthma treatments lead to fertility issues.
The researchers hypothesized that perhaps asthma causes inflammation in other parts of the body (not just in the lungs), including the uterus, or that it can affect the health of eggs in the ovaries.
“Inhaled corticosteroids suppress the immune system, whereas short-acting asthma treatments do not alter immune function. In women who are only using relievers it’s possible that, while their asthma symptoms may improve, inflammation may still be present in the lungs and other organs in the body,” Grzeskowiak said.
These results provide reassurance for asthmatic women using inhaled corticosteroids that they do not appear to reduce fertility, according to the researchers.
The team now plans to investigate whether improving asthma control also could improve fertility outcomes among asthmatic women who are undergoing fertility treatments.