Safety of Fluticasone Propionate Prescribed for Asthma During Pregnancy: A UK Population-Based Cohort Study.

BACKGROUND Asthma is commonly treated during pregnancy, yet data on the safety of asthma medicines used during pregnancy are sparse. OBJECTIVE The objective of this study was to evaluate the safety of the inhaled corticosteroid (ICS) fluticasone propionate (FP), alone and in fixed-dose combination with salmeterol (FSC) in terms of the risk of all major congenital malformations (MCMs), compared with all other non-FP ICS. METHODS Women with asthma who had a pregnancy between January 1, 2000, and December 31, 2010, were identified in the United Kingdom's Clinical Practice Research Datalink. Exposure to asthma medicines during the first trimester of pregnancy was based on issued prescriptions. The mothers' and infants' medical records were linked where possible, and pregnancy outcomes with an MCM diagnosed by age 1 year were identified based on medical codes in the mother's and infant's medical records, including those MCMs prenatally diagnosed that ended in an induced pregnancy termination. The absolute and relative risks of an MCM after different ICS exposures, stratified by the asthma treatment intensity level, were calculated. RESULTS A total of 14,654 mother-infant pairs were identified, of which 6,174 received an ICS prescription during the first trimester, in addition to 13 first trimester ICS exposed pregnancies that ended in an induced termination after a prenatal MCM diagnosis. In total, 5,362 pregnancies were eligible for the primary analysis at age 1 year. The absolute risk of an MCM after any first trimester FP exposure was 2.4% (CI95 0.8-4.1) and 2.7% (CI95 1.8-3.6) for the "moderate" and "considerable/severe" asthma treatment intensity levels, respectively. The adjusted odds ratios when compared with non-FP ICS were 1.1 (CI95 0.5-2.3) and 1.2 (CI95 0.7-2.0) for the "moderate" and "considerable/severe" intensity levels; risks for any FP and for FSC did not differ substantially. CONCLUSION No increase in the overall risk of MCMs was identified after first trimester FP exposure compared with non-FP ICS.