Maternal anemia during pregnancy and slightly higher risk of asthma in male offspring.

AIM: We aimed to determine whether maternal hemoglobin levels or anemia during pregnancy are associated with the development of asthma among offspring.

METHODS

Data were retrieved from the birth register database of Kuopio University Hospital between 1989 and 2007 (n = 38 381). Hemoglobin levels were measured during three trimesters of pregnancy and anemia was defined according to the World Health Organization criteria. The prevalence of asthma was determined from the register of reimbursement for medication for asthma at the Finnish Social Security Institution. Cox proportional hazard regression analysis was performed to evaluate the possible associations between prenatal factors and development of asthma ever.

RESULTS

A total of 8198 (21.4%) women had anemia at some stage of pregnancy. Mild maternal anemia during the first trimester was associated with an increased risk of asthma among male offspring (adjusted hazard ratio, 1.46; 95% confidence interval, 1.11-1.94) compared with those with normal maternal hemoglobin levels. This finding remained significant also after applying the Bonferroni correction.

CONCLUSION

Male offspring with maternal anemia during the first trimester of pregnancy had significantly more asthma ever than the offspring of women with normal hemoglobin levels during pregnancy. These findings were not strong but suggest possible sex-specific effects of maternal health on prenatal programming and future risk of asthma.