Identifying the optimal gestational weight gain for infant health

The days of “eating for 2” and seeing pregnancy as a time to not worry about calorie consumption has changed as more knowledge about the impact of weight gain on the mother has become available. The potential link between gestational weight gain and infant morbidity and mortality remains unclear. A recent report sought to identify optimal gestational weight gain ranges that are linked with a reduced risk of infant morbidity and mortality.¹

The report’s investigators linked birth and infant death data between 2011 and 2015 to look for association of gestational weight gain with infant morbidity and mortality. Their 2 main outcomes were significant morbidity, which was defined as seizures, antibiotic therapy, surfactant therapy, admission to the neonatal intensive care unit, and any assisted ventilation; as well as infant mortality at younger than 1 year of age, which was split into (<1 hour, 1-23 hours, 1-6 days, 7-27 days, or 28-365 days after birth

There were 15,759,945 mother/child pairs included in the study. Mothers had an average age of 28.1 years and gained 14.1 kg during pregnancy. The average gestational weight gain decreased with body mass index category: underweight, 15.7 [6.4] kg; normal weight, 15.4 [6.2] kg; overweight, 14.2 [7.4] kg; obesity class 1, 12.2 [8.0] kg; obesity class 2, 10.3 [8.4] kg; obesity class 3, 8.2 [9.2] kg; P < .001. In this cohort, 8.8% of the newborns had significant morbidity, with the lowest prevalence occurring in infant born to women in the normal weight body mass index class and the highest in infant born to women with class 3 obesity. Additionally, 0.34% of infants died within a year of birth, with the highest rate occurring in infants with mothers who had class 3 obesity and the lowest found in infants born to mothers with a normal weight body mass index class. Investigators determined that optimal gestational weight gain ranges were 12.0 to less than 24.0 kg for underweight and normal weight women, 10.0 to less than 20.0 kg for overweight women, 8.0 to less than 16.0 kg for women with class 1 obesity, 6.0 to less than 16.0 kg for class 2 obesity, and 6.0 to less than 10.0 kg for class 3 obesity. They noted that the lower bounds of the ranges were higher than existing recommendations for overweight women and those with class 1-3 obesity.

They concluded that extremes of gestational weight gain were tied to an increased risk of negative outcomes for the infant, which held across all body mass index categories. They believe that this indicated that weight maintenance and loss should not be used for routine guidelines.

Reference

1. Wang L, Zhang X, Chen T, et al. Association of gestational weight gain with infant morbidity and mortality in the United States. JAMA Netw Open. 2021;4(12):e2141498. doi:10.1001/jamanetworkopen.2021.41498