Extreme weight gain during pregnancy may contribute to risk factors for early childhood asthma, say researchers from University of South Carolina. They found obesity nearly doubled a woman’s chances of having a child who developed asthma by age 4. Extreme-low weight gain (<5 kg) and extreme-high weight gain (≥25 kg) were both associated with increased risk of asthma.
At 9 months, 2 years, and 4 years, 5%, 8%, and 12% of children, respectively, were diagnosed with asthma. Overall, 15% of children were diagnosed with asthma by age 4. Every 1.0 unit increase in maternal body mass index was associated with increased odds of asthma in children.
Childhood asthma already is believed to have inutero origins, the researchers say. They cite a study that found 40% of children with a diagnosis of asthma by age 7 had reduced airflow and bronchial responsiveness as neonates. Research suggests that maternal weight and gestational weight gain may change the intrauterine environment and affect the development of asthma.
The researchers say, to their knowledge, no studies have examined the association between gestational weight gain and asthma in offspring in a nationally representative sample of children in the U.S. Moreover, previous studies did not account for gestational age, which can affect the amount of weight gained.
Although the researchers note that no single risk factor can entirely account for childhood asthma, maternal obesity is one that is modifiable.