Study links maternal obesity during pregnancy to behavioral problems in boys

Researchers highlight the need for women to enter pregnancy at a healthy weight to promote healthy behavioral and emotional development in their children, particularly boys, in a new study published in the American Journal of Preventive Medicine

Ann Arbor, MI, July 13, 2017

Maternal obesity and child neurodevelopmental problems have both increased in the U.S. and scientists have suggested a possible link. A new study has found that the heavier mothers were when they entered pregnancy, the higher the risk of behavior problems for their sons. However, it did not show the same effects in girls. The results are reported in the American Journal of Preventive Medicine.

“The study results suggest that early intervention with women to attain healthy weights before they become pregnant is critical to their health and the health of their future children,” commented senior investigator Barbara Abrams, DrPH, of the Division of Epidemiology, School of Public Health, University of California, Berkeley.

The Centers for Disease Control and Prevention estimates that 15 out of every 100 women of childbearing age are severely obese. Recent studies have linked high maternal weight, before and during pregnancy, to child behavior and particularly to problems such as attention deficit hyperactivity disorder. Some evidence also points to a possible link with internalizing problems, such as depression. These problems can have negative effects on school performance and relationships with others.

Researchers used the U.S. National Longitudinal Survey of Youth 1979 (NLSY79) to investigate whether maternal pre-pregnancy body-mass index (BMI) is associated with behavioral problems among school-age children. They assessed whether the effect is modified by race or gender, as well as by race and gender simultaneously. This analysis included nearly 5,000 female NLSY79 study participants and their biological children, who were studied between 1986 and 2012 as part of the NLSY Children and Young Adults (NLSYCYA) cohort. Behavioral problems were assessed every two years for children aged 4–14 years using maternal report of the Behavior Problems Index (BPI), a widely used 28–item questionnaire, to determine whether they exhibited specific behaviors in the past three months. Because early puberty is a time when behavioral problems tend to emerge, this study focused on children aged 9–11 years.

Approximately 65% percent of the mothers were normal weight, 8% underweight, and 10% obese, of whom 3.5% were BMI 35 or higher. Underweight women were younger, less likely to be married, and had the lowest education, income, and Armed Forces Qualifying Test scores.

The study showed that boys whose mothers entered pregnancy obese were at higher risk for behavior problems at ages 9-11 years. Data indicated that the heavier mothers were when they entered pregnancy, the higher the risk for behavioral problems to develop in their sons. Boys whose mothers were underweight pre-pregnancy also showed higher risk for behavior problems. The study did not show the same effects in girls, and there were no differences for race.

“Past research looking at a variety of exposures during pregnancy (ranging from stress to chemicals) has shown that boys tend to be more vulnerable to these exposures in utero than girls,” explained investigator Juliana Deardorff, PhD, of the Community Health Sciences Division, School of Public Health, University of California, Berkeley. “Our study extends this work to maternal obesity.”

“It is the first study to document gender differences, and one of a handful of studies to show that pre-pregnancy underweight, in addition to obesity, may be problematic,” she continued. “Future research should examine whether the gender differences reported here for ages 9–11 years persist into adolescence or shift as children get older.”


Notes for editors
The article is “Maternal Prepregnancy Weight and Children’s Behavioral and Emotional Outcomes,” by Julianna Deardorff, PhD, Louisa H. Smith, MS, Lucia Petito, MA, Hyunju Kim, MPH, and Barbara F. Abrams, DrPH ( It will appear in the American Journal of Preventive Medicine, volume 53, issue 4 (October 2017) published by Elsevier.

Full text of this article is available to credentialed journalists upon request; contact Julie Fielding at +1 734-615-6041 or Journalists wishing to interview the authors should contact Julianna Deardorff at +1 510-642-7334 or

This research was supported by Award Number R01MD006104 from the National Center on Minority Health and Health Disparities. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center on Minority Health and Health Disparities or the National Institutes of Health. The NIH had no role in study design; collection, analysis, and interpretation of data; writing the report; and the decision to submit the report for publication. This research was conducted with restricted access to Bureau of Labor Statistics (BLS) data. The views expressed here do not reflect the views of the BLS.

About the American Journal of Preventive Medicine
The American Journal of Preventive Medicine is the official journal of the American College of Preventive Medicine and the Association for Prevention Teaching and Research. It publishes articles in the areas of prevention research, teaching, practice and policy. Original research is published on interventions aimed at the prevention of chronic and acute disease and the promotion of individual and community health. The journal features papers that address the primary and secondary prevention of important clinical, behavioral and public health issues such as injury and violence, infectious disease, women's health, smoking, sedentary behaviors and physical activity, nutrition, diabetes, obesity, and alcohol and drug abuse. Papers also address educational initiatives aimed at improving the ability of health professionals to provide effective clinical prevention and public health services. The journal also publishes official policy statements from the two co-sponsoring organizations, health services research pertinent to prevention and public health, review articles, media reviews, and editorials.

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