If it’s a girl, pregnancy may worsen asthma

Doctors have long known that asthma symptoms can worsen during pregnancy. But now researchers have found that women expecting girls may suffer more symptoms than those expecting boys.

“Asthma can become unstable and unpredictable during pregnancy,” said Peter G. Gibson, a professor at Hunter Medical Research Institute in Newcastle, Australia. “We are trying to understand why this happens.”

Gibson studied 151 pregnant women: 80 asthmatics who daily inhaled steroid sprays (generally considered safer for the unborn child than oral steroids), 38 asthmatics who used no steroids and 33 nonasthmatic women.

He found that 60% of asthmatic women carrying boys were symptom-free during their pregnancies and had no nighttime breathing problems from their 18th to their 30th weeks. By contrast, 61% of asthmatic women carrying girls were symptom-free at 18 weeks but by 30 weeks, 72% of them had symptoms and used more medication. Nighttime breathing problems among women carrying girls rose significantly from week 18 to week 30.

Gibson suggested that inflammation of a pregnant woman’s airways may cause a female fetus to produce some kind of hormone that worsens maternal asthma. However, it’s also possible that higher levels of male sex hormones associated with male fetuses somehow protect the mother’s airways.

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Jane E. Allen