Many Women Drop Asthma Medication During Pregnancy

The results of a study analyzing patterns of asthma medication prescription from 1994 to 2009 suggest that awareness of the importance of controlling asthma during pregnancy needs to be improved.

Many women stop taking medication to control their asthma early in pregnancy despite potential health risks, according to the results of a study published online on October 15, 2012, in the Journal of Allergy and Clinical Immunology. Among the dangers of poor asthma control during pregnancy are preeclampsia, preterm delivery, and low birth weight.

The researchers drew on the InterAction Database, which includes data on prescriptions filled at 55 pharmacies in the northern Netherlands covering a population of approximately 500,000 patients from 1994 through 2009. The study cohort included prescription data on 25,709 pregnancies. Of these, 2072 pregnancies in 1695 women had at least 1 prescription for asthma medication or oral corticosteroids during the period spanning from 1 year before pregnancy to 6 months after birth.

The researchers found different patterns of asthma medication prescription among women who became pregnant between 1994 and 2003 and those who became pregnant between 2004 and 2009. There were more prescriptions for asthma medication between 2004 and 2009 than between 1994 and 2003. There was no significant change in prescription of asthma medication during pregnancy between 1994 and 2003. However, between 2004 and 2009, there was a significant decrease in prescriptions for asthma medication during the first trimester of pregnancy compared with the 3 months before pregnancy, with a particularly pronounced drop in prescriptions for long-acting bronchodilators.

From 2004 through 2009, of 647 pregnancies with at least 3 prescriptions for asthma drugs during the year before pregnancy, 247 (38.2%) had no prescriptions for any asthma medication during the first trimester. The same was true for 105 (29.2%) of 359 pregnancies with at least 3 prescriptions for asthma controller medications in the year before pregnancy. The decrease in prescriptions for long-acting bronchodilators in the first trimester of pregnancy occurred in women of all ages, although among women older than 31 years the decrease was compensated for by increased prescription of short-acting bronchodilators and inhaled corticosteroids.

The researchers note that long-acting bronchodilators tend to be prescribed when a moderate dose of inhaled corticosteroids fails to achieve adequate control, meaning that they tend to be given to patients with more severe asthma in whom discontinuation can lead to severe symptoms of respiratory distress. Among women included in the study who stopped using long-acting bronchodilators early in pregnancy, more than 10% who had not had a prescription for a short-acting bronchodilator before pregnancy had one during pregnancy, suggesting that they experienced a worsening of symptoms and reduced asthma control. Women who stopped controller therapy during pregnancy also appeared to be more prone to exacerbations.

The researchers conclude that many women stop or reduce their use of asthma medications during pregnancy and that strategies to safely control asthma during pregnancy are needed.