IVF Associated With Increased Risk for Childhood Asthma

Lara C. Pullen, PhD

December 06, 2012

Children who were born after a prolonged time to conception are more likely to be diagnosed with asthma, experience wheezing in the last year, and be prescribed anti-asthmatic medication. This association is particularly true for children born after assisted reproduction technologies (ART). Investigators cannot explain the mechanism behind this association.

Claire Carson, PhD, from the University of Oxford in the United Kingdom, and colleagues present the results of the Millennium Cohort Study in an article published online December 5 in Human Reproduction. The UK-wide prospective study included 18,818 children who were recruited at 9 months of age. The authors analyzed data from follow-up surveys at 5 and 7 years (n = 13,041 and n = 11,585, respectively).

The authors compared the children of subfertile couples with the children of parents who conceived within 12 months of planning their conception. They also compared the different groups of subfertile parents (ie, ovulation induction and ART).

The researchers adjusted for social circumstances as well as contributors to the "hygiene hypotheses" such as firstborn status, presence of siblings, and childcare type. The results revealed a well-recognized socioeconomic gradient in childhood asthma.

At 5 years of age, children from subfertile parents were significantly more likely to experience asthma (adjusted odds ratio, 1.39; 95% confidence interval, 1.07 - 1.80). Unadjusted results suggest that unplanned and mistimed children are at greater risk for asthma and wheezing, but these results disappear when the data are adjusted for social circumstances.

The authors suggest that the increased asthma rates in this patient population may be a result of ART patients being overly protective. They also note that women with asthma are more likely to report prolonged childlessness, although this does not seem to affect the ultimate number of live births.

These results contradict the results from a previously published Swedish study indicating that infertility treatment had little effect on asthma patterns as measured by prescribed asthma medications.

This project was funded by a grant from the Medical Research Council. The authors have disclosed no relevant financial relationships.

Hum Reprod. Published online December 5, 2012. Full text