Long-Acting β₂-Agonists and Risk of Hypertensive Disorders of Pregnancy: A Cohort Study

Maternal asthma has been found to be associated with an increased risk of hypertensive disorders of pregnancy (HDP), that is, gestational hypertension, preeclampsia, and eclampsia. There is limited data, however, regarding the relationship between the use of long-acting beta-agonists (LABAs) during pregnancy and these outcomes.

To investigate whether exposure to a LABA in addition to an inhaled corticosteroid increases the risk of HDP or preeclampsia/eclampsia, as compared with nonexposure to LABAs, in pregnant women with asthma.

A cohort of 8,936 pregnancies in women with asthma who delivered between 1998 and 2010 was reconstructed using Quebec (Canada) health administrative databases. Cox proportional hazard regression models, adjusted for potential confounders, were used for statistical analyses. The primary exposure was LABA use (yes/no) measured on the first day of the 20th week of pregnancy. HDP were identified on the basis of recorded diagnoses and on prescriptions of antihypertensive drugs filled on or after the first day of week 20 of gestation.

There were 567 (6.3%) cases of HDP and 256 (2.9%) cases of preeclampsia/eclampsia in the cohort, and the rates of both disorders were similar in women exposed or not exposed to LABAs. LABA use was not associated with increased risks of HDP (adjusted hazard ratio, 0.96; 95% CI, 0.69-1.33) or preeclampsia/eclampsia (adjusted hazard ratio, 0.89; 95% CI, 0.53-1.50).

The results of this study provide evidence suggesting the safety of LABAs for the treatment of asthma in pregnancy, in terms of the risks of HDP and preeclampsia/eclampsia.