Women who are overweight when they become pregnant and women who gain excessive weight during pregnancy are more likely to develop complications that affect their health as well as that of their unborn child. Now, a large new study has found another negative impact of being an overweight mom: childhood asthma. The findings were published online on July 21 in the journal Pediatrics.
The authors note that environmental or lifestyle exposures of a developing infant may affect the development of childhood asthma. Therefore, they conducted a meta-analysis to determine whether maternal obesity in pregnancy or increased maternal gestational weight gain increased the risk of asthma in offspring. (A meta-analysis is a compilation of data from several studies to clarify a point.) The researchers reviewed all pertinent studies published until October 2013 in PubMed, Embase, CINAHL, Scopus, The Cochrane Database, and Ovid. They conducted a statistical analysis of the data to determine the overall risk of childhood asthma.
The researchers located 14 pertinent studies (108,321 mother–child pairs). Twelve of the studies reported maternal obesity, and five reported gestational weight gain. The ages of the children ranged from 14 months to 16 years. Maternal obesity in pregnancy was associated with higher odds of asthma or wheeze at any time (1.31-fold increased risk) or current (1.21-fold increased risk); each 1-kg/m2 (1 kg = 2.2 lbs) increase in maternal body mass index (BMI) was associated with a 2% to 3% increase in the risk of childhood asthma. High gestational weight gain was associated with higher odds of asthma or wheeze at any time (1.16-fold increased risk). In contrast, maternal underweight and low gestational weight gain were not associated with childhood asthma or wheeze. A statistical analysis of the data found a negative association of borderline significance for maternal asthma history. The researchers noted that significant heterogeneity was found among the studies, meaning that the studies were not similar. Therefore, they recommended that standardized approaches were needed for future studies on the topic.
The authors concluded that maternal obesity in pregnancy or high gestational weight gain during pregnancy are associated with an increased risk of childhood asthma. They noted that this finding may be particularly significant for mothers without a history of asthma. They recommended that future, well-structured studies were needed.
The authors are affiliated with Children’s Hospital of Pittsburgh (Pittsburgh, Pennsylvania), University of Pittsburgh Medical School (Pittsburgh, Pennsylvania), Magee-Womens Hospital (Pittsburgh, Pennsylvania), and Lurie Children’s Hospital (Chicago, Illinois).
Take home message:
The best course of action is to shed excess pounds before attempting a pregnancy and to avoid excess weight gain during pregnancy. Obstetricians stress weight control during pregnancy and they and/or their staff can provide guidance in this regard.