Greater gestational weight gain linked to higher BMI z score for girls, not boys
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Girls whose mothers had high gestational weight gain have a greater BMI z score than girls whose mothers had normal gestational weight gain, but a similar difference is not observed for boys, according to study data.
“Girls appear to be more vulnerable than boys to the adverse effects of high pregnancy weight gain,” Beth Widen, PhD, RD, assistant professor in the department of nutritional sciences at the University of Texas at Austin, told Healio. “We observed that girls exposed to high prenatal weight gain have more adverse growth and adiposity patterns from mid-childhood and into early adolescence, compared to girls exposed to other weight prenatal change patterns.”
Widen and colleagues analyzed data from the Columbia Center for Children’s Environmental Health Mothers and Newborns Study, a prospective birth cohort in which Dominican and African American expectant mothers were enrolled during their third trimester of pregnancy at New York-Presbyterian Hospital and Harlem Hospital Center. Women aged 18 to 35 years with no self-reported diabetes, hypertension, HIV, drug use or smoking during pregnancy were included. Demographics were collected during a third trimester interview. Prenatal medical history, including prenatal weight measurements and gestational age at delivery, was obtained through medical records. Up to seven child height and weight measurements were recorded at age 5, 7, 9 and 11 years as well as during as many as three other project visits. Researchers used a latent class model to jointly fit prenatal weight patterns with sex-specific child body composition trajectories for body fat percentage, weight circumference and BMI z score.
The findings were published in Obesity.
There were 337 mother-child pairings included in the study. Of the mothers, 54% had a normal-weight BMI before pregnancy, 23.1% had overweight and 22.8% had obesity.
Researchers classified mothers into four gestational weight-change trajectories:
- “rapid, slow, moderate,” with high weight gain in the first trimester that slowed during the second and third trimesters;
- “loss, moderate, rapid,” with weight loss in the first trimester followed by higher weight gain in the second and third trimesters;
- “slow, moderate, moderate,” with slow weight gain in the first trimester before increasing to more than 1 lb per week in the second and third trimesters; and
- “always slow,” in which weight gain was moderate throughout pregnancy.
Researchers identified four child body composition trajectories from the joint model stratified by sex. There were differences in the divergence of growth patterns between boys and girls. The biggest difference was observed in offspring of mothers with a “rapid, slow, moderate” gestational weight gain, in which girls had higher estimates for BMI z score, waist circumference and body fat percentage than girls from mothers of other gestational weight gain patterns. Boys with mothers in the “rapid, slow, moderate” gestational weight gain trajectory had the second highest estimated BMI z score after age 10 years compared with the other trajectories, but waist circumference was lower than the other three groups. Girls of mothers in the “loss, moderate, rapid” group had lower trajectories for BMI z score, waist circumference and body fat percentage than the other groups, whereas boys from mothers in the “loss, moderate, rapid” group had similar composition compared with the other gestational weight trajectories.
Boys from mothers in the “slow, moderate, moderate” trajectory had a higher BMI z score and body fat percentage in early adolescence than those from mothers in other trajectories. Boys with mothers in the “always slow” gestational weight change trajectory had a lower BMI z score and body fat percentage than other groups but had the highest estimated waist circumference in early adolescence.
“The sex specific associations were really surprising and highlight the need to examine for sex-specific effects in epidemiologic and clinical research rather than only controlling for sex as a covariate,” Widen said.
In addition, Widen said more research is needed to assess the roles of diet and physical activity during pregnancy and whether patterns are associated with prenatal weight change and offspring body composition.
For more information:
Beth Widen, PhD, RD, can be reached at elizabeth.widen@austin.utexas.edu.
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