Pre-pregnancy contraceptive pill use not linked to asthma in children
MedWire News: The use of the combined estrogen-progestin oral contraceptive pill before pregnancy is not associated with an increased risk for lower respiratory tract infections or wheezing or asthma in children, study results show.
"This should provide reassurance to the vast majority of women using oral contraceptive pills during their childbearing years," said lead researcher Stephanie London, from the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, USA.
The findings, presented at the annual meeting of the American Academy of Allergy, Asthma and Immunology in San Francisco, California, USA, refute previous suggestions that the use of oral contraceptive pills before pregnancy could disrupt immunologic balance and influence fetal respiratory development.
London and team assessed the use of combined estrogen-progestin and progestin-only contraceptive pills in the year before pregnancy among 54,256 women who gave birth to 60,225 children between 1999 and 2007.
Of the children, 42,520 were followed up for lower respiratory tract infections and wheezing until the age of 18 months, and 24,472 were followed up for asthma until the age of 36 months.
After accounting for factors such as maternal history of asthma and atopy, maternal age, smoking, pre-pregnancy body mass index, breast feeding, and the child's gender and gestational age, the researchers found that children born to women who used the combined oral contraceptive pill (n=19,786; 33%) were no more likely to suffer lower respiratory tract infections than those born to women who did not, at an odds ratio (OR) of 1.03.
Children born to women who used the combined oral contraceptive pill were also no more likely to suffer from wheezing and asthma than other children, at adjusted ORs of 1.02 and 1.05, respectively.
However, the team found that children born to women who used the progestin-only contraceptive pill in the year before pregnancy (n=3286; 5.0%) had a slightly increased risk for wheezing at between the ages of 6 and 8 months, at an adjusted OR of 1.19.
But due to the relatively small number women used this type of oral contraceptive pill, the researchers suggest that this finding may be due to residual confounding.
London concluded: "Our findings suggest that maternal use of the much more commonly prescribed combined pill was not associated with respiratory outcomes (lower respiratory tract infections, wheezing, or asthma) in early childhood."
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By Mark Cowen