Asthma impacts time to pregnancy

Asthmatic women may take longer to become pregnant, according to a new study published in The European Respiratory Journal.

Researchers from the Bispebjerg University Hospital in Denmark studied 15,250 Danish twins, aged 12 to 41 years, who had participated in a questionnaire study that included questions about asthma and fertility. The women were divided into asthmatic or non-asthmatic groups and the asthmatic group was further divided into treated and non-treated asthmatics. Multiple regression analysis was used to study the difference in time to pregnancy and pregnancy outcomes in asthmatic and non-asthmatic women.

The time to pregnancy for women with asthma was longer than in women without the condition, 27% vs. 21.6%, odds ratio (OR) = 1.31 (1.1 – 1.6), P = 0.009. The association remained significant even after age, age at menarche, body mass index, and socioeconomic status were taken into account (P = 0.05 OR 1.25 [1 – 1.6]). The effect of asthma on fertility was more pronounced in women older than age 30 (32.2% vs. 24.9%, P = 0.04, OR = 1.44 [1.1 – 1.9]).  

Women who did not treat their asthma had a significantly elevated risk of prolonged time to pregnancy, compared to healthy women (OR = 1.79 (1.22 – 2.66), P = 0.004). Treated asthma also was associated with delay in achieving pregnancy (OR = 1.40, p = 0.004), but less so than in women in the untreated arm.

The study authors concluded that asthma can cause a delay in becoming pregnant and that it can become more pronounced if the condition is not treated or if a woman is older than age 30. However, they found that asthmatic women tended to begin their families earlier than non-asthmatics, meaning that the average number of children was roughly equal.

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