NEW ORLEANS — Women who put on more than the recommended weight during pregnancy increase the chances that their offspring will be overweight before they reach their 10th birthday, according to findings from a retrospective cohort study of 7,674 women.
The findings from this study, which is the largest to date on the subject, have important implications for counseling pregnant women, Brian Wrotniak, Ph.D., said at the annual meeting of NAASO, the Obesity Society.
Mothers-to-be who gained more than the weight recommended by the Institute of Medicine had a 44% greater likelihood of having offspring who were overweight at 7 years of age than did women who did not exceed the weight-gain recommendations during their pregnancy.
Study investigators reviewed data from the Collaborative Perinatal Project, a multicenter, multiethnic study that was initiated in 1959 to investigate risk factors for cerebral palsy in children, said Dr. Wrotniak of Children's Hospital of Philadelphia.
The association between excess weight gain during pregnancy and an overweight child by age 7 years was even stronger for women who were underweight at the time they became pregnant, he said.
The link between the mother's weight gain during pregnancy and her child's excess weight in later years remained significant after adjustment for the gender of the child, gestational age, infant birth weight, first-born status, mother's race, maternal age, maternal body mass index, smoking, and study site, the researchers reported.
“How much weight to gain depends on the mother's prepregnancy BMI. For women of normal weight, the recommendations for weight gain during [a singleton] pregnancy are 12.5–18 kg, but for women who are overweight, 7–11.5 kg is the recommended range,” Dr. Wrotniak said.
The Collaborative Perinatal Project data were collected in the 1960s. At that time, 11% of the cohort exceeded pregnancy weight-gain recommendations. Today, almost half—46% of expectant mothers—are gaining more weight than they should during their pregnancies, Dr. Wrotniak said.
“From a public health standpoint, helping women to develop healthy eating and physical activity habits and to achieve a healthier weight before becoming pregnant, and to adhere to weight gain recommendations during pregnancy, may be an effective way to help prevent childhood obesity.
“With almost half of women exceeding the recommendations, such counseling could have a sizeable impact on future obesity in children,” the study authors concluded.