Both using and stopping asthma medicines in pregnancy linked with poor outcomes

Women who are prescribed asthma medicines, including those who discontinue their medicines during pregnancy, are more likely to give birth prematurely or have a child with a low birth weight, according to a study in PLoS One​[1]​.

Researchers linked pregnancy and breastfeeding data for 117,717 births in Wales between 2000 and 2010 with maternal prescription data.  

Pregnancies terminated for foetal anomalies; infants with congenital anomalies and those exposed to other substances associated with adverse perinatal outcomes were excluded. The congenital anomalies outcomes are reported elsewhere​[2]​. 

The researchers found that premature births of fewer than 32 weeks’ gestation were more likely in women prescribed asthma medicines and women who discontinued their asthma medicines, compared with women who did not take asthma medicines (adjusted odds ratio [aOR] 1.21, 95% confidence interval [CI] 0.96–1.53, and aOR 1.53, 95% CI 1.11–2.10, respectively).  

Low birth weight occurred more frequently for women prescribed asthma medicines (aOR 1.09, 95% CI 1.01–1.19). For women who discontinued asthma medicines, odds ratios were similar but interval estimates included no difference (aOR 1.10, 95% CI 0.98–1.25). Breastfeeding rates were also reduced. 

 “These findings identify unmet needs amongst women discontinuing prescriptions and militate against medication reduction in pregnancy,” the researchers said.  

“Reduced risks with [inhaled corticosteroids] suggest that increased monitoring, targeted support and active asthma management are needed before, during and after pregnancy,” they concluded.