Asthma linked to increase in fertility treatment

Women with asthma are more likely to have fertility treatment before giving birth than non-asthmatic women, according to new research presented today (Tuesday) at the European Respiratory Society International Congress.

Among 744 pregnant asthmatic women enrolled in the Management of Asthma During Pregnancy programme at the Hvidovre Hospital, Hvidovre, Denmark, and who gave birth between 2007 and 2013, 12% had received fertility treatment compared to 7% of the 2,136 non-asthmatic women in the control group.

Although the study does not prove that asthma played a role in reducing fertility in some women, the researchers say it suggests that improving women's asthma control might help them to become pregnant more easily.

Professor Charlotte Suppli Ulrik, from the Department of Respiratory Medicine at Hvidovre Hospital, who supervised the study, said: "We don't have the hard-core evidence, but based on what we know, it seems very likely that good asthma control will improve fertility in women with asthma by reducing the time it takes to become pregnant and, therefore, the need for fertility treatment.

"However, when it comes to fertility for women, age is a crucial factor - so the message, particularly for women with asthma, is don't wait too long, as it might reduce your chances of having children."

Prof Suppli Ulrik and colleagues are setting up studies to investigate further the association between asthma and fertility, including a study addressing the impact of good asthma control on fertility. "Further studies are needed to confirm our findings," she said.

Pregnant women were eligible for the study if they had a diagnosis of asthma and had their first visit to the respiratory clinic within the first 18 weeks of pregnancy. Each asthmatic woman was matched with three consecutive non-asthmatic women who gave birth at the hospital; these women made up the control group. The researchers looked at whether the births in both groups were due to spontaneous conception, or whether the women had had assisted reproductive technology (e.g. in vitro fertilisation - IVF) or intrauterine insemination, regardless of the cause of the infertility.

Women in the asthmatic group and the control group were similar with regard to age, with an average age of 31.3 years in the asthmatic group (ranging from 17 to 44 years old) and 30.9 years in the control group (ranging from 17 to 45 years old). The researchers adjusted their results to take account of factors that could affect the results such as age, body mass index, whether or not the women smoked, had had previous children, were single or in a same-sex partnership. However, Prof Suppli Ulrik said they could not rule out that the two groups might differ with regard to income, life style and socio-economic factors.