No respiratory risk to children from mother's prepregnancy use of combo OCs

A large study has found no increased risk for respiratory problems such as infections, wheezing, and asthma in the children of women who used combination estrogen-progestin oral contraceptives before becoming pregnant.

Using the Norwegian Mother and Child Cohort database of 100,000 pregnancies with follow-up information on children up to age 7 or 8 years, researchers examined associations between the type of oral contraceptive (combination or progestin-only) used by mothers before pregnancy and 3 types of respiratory outcomes: lower respiratory tract infections in 60,225 children followed to 6 months of age; lower respiratory tract infections and wheezing in 42,520 children followed to 18 months of age; and development of asthma in 24,472 children followed to 36 months of age.

The use of combination oral contraceptives before pregnancy wasn’t associated with lower respiratory infections, wheezing, or asthma. Progestin-only contraceptive use in the year before pregnancy showed a slight positive association with wheezing (adjusted odds ratio, 1.19; 95% Confidence Interval, 1.05-1.34) in children 6 to 8 months of age.

“Overall, birth control pills don’t appear to increase risk for respiratory tract infections or symptoms of asthma,” says lead author Dana Hancock, PhD. “This research should provide reassurance to mothers that their prior use of oral contraceptives won’t have an impact on respiratory symptoms in their children.”

Hancock speculates that the slightly increased risk for wheezing in children of women who used progestin-only contraception may be the result of residual confounding because women in the Norwegian cohort used progestin-only pills much less often than combination pills. She notes that, although the association between wheezing and progestin-only pills was small, future studies of respiratory and other childhood outcomes may need to examine the 2 types of oral contraceptives separately.

The study was published online February 7 in Pediatric Allergy and Immunology.