Maternal Lifestyle Changes Between Pregnancies Can Reduce Child Obesity

Credit: Adobe Stock/JenkoAtaman

Results of a study exploring how changes in a mother's weight and smoking habits between pregnancies affect the likelihood of their second child being overweight or obese by age four or five revealed that if mothers maintained a healthy weight and quit smoking before their second pregnancy, the chances of the second child being overweight or obese could significantly decrease.

As of 2020, 39 million kids under five years old had overweight or obesity worldwide, with a 9.2% prevalence of obesity in children age five to six and 22.7% in those age 10 to 11 in the United Kingdom. In the most deprived areas, the prevalence of obesity increased to 30.2%. These children are more likely to suffer from a variety of psychological and physical comorbidities, including behavioral and emotional disorders.

“Since overweight and obesity are difficult to reverse once established, the tracking of childhood adiposity into adulthood is of particular concern and once established, overweight and obesity are difficult to reverse,” wrote a team of investigators led by Elizabeth J. Taylor, PhD, associated with National Institute for Health and Care Research (NIHR) Southampton Biomedical Research Centre and the University of Southampton. “The role of prevention is therefore key and this research considers this further in the context of modifiable exposures after the birth of the first child and before the conception of the second.”

The study assessed the impact changes in maternal weight and smoking status between pregnancies on childhood overweight/obesity and obesity among second-born children. To do so, investigators extrapolated the healthcare records for 5,612 women from the SLOPE (Studying Lifecourse Obesity PrEdictors) study. They created hypothetical scenarios based on weight changes and smoking status both individually and in combination.

Most (60.7%) women began their first pregnancy with a normal body mass index (BMI; 18.5 and 24.9 kg/m2), while 26.1% (n = 1466) had a BMI between 25 and 29.9 kg/m2 and 13.1% (n = 737) had a BMI ≥ 30kg/m2.

Children with obesity or overweight/obesity were more likely to have mothers who started either their first or second pregnancies with overweight/obesity or obesity, had high weight gain between pregnancies and were smokers at the beginning of their first or second pregnancy.

At age four to five, 22.2% of second-born children had overweight/obesity and 8.5% had obesity. Investigators theorized that if all mothers began their second pregnancy with a BMI between 18.5 – 24.9 kg/m2 and all smokers quit smoking, these rates could be reduced to 18.6% and 6.2%, respectively.

Among mothers who started their first pregnancy within a healthy BMI range, and if current smokers stopped smoking, the natural course estimates for overweight/obesity and obesity could be reduced from 17.3% and 5.9% to 16.0% and 4.9%, respectively, for the second child. Among mothers who began their first pregnancy with a BMI of ≥30 kg/m2, if their BMI was in normal range before pregnancy number two, the natural course estimates of 38.6% and 17.7%, respectively, could be reduced to 31.3% and 12.5% for the second child. If women had a BMI between 25.0 – 29.9 kg/m2 before the second pregnancy, these estimates would be 34.5% and 14.6%, respectively.

“Interventions after the birth of the first child and before the conception of the second child could reduce the prevalence of overweight/obesity and obesity in second and subsequent children,” investigators wrote. “Support to encourage mothers who had healthy weight at the start of their first pregnancy to quit smoking and maintain their weight and support mothers who had obesity at the start of their first pregnancy to lose weight between pregnancies could have the greatest impact the health of mothers and their children.”