Children born extremely premature to women who are overweight or obese before the pregnancy are at an increased risk for low scores on tests of intelligence and cognitive processes that influence self-regulation and control, according to researchers at Wake Forest Baptist Medical Centre.
“Roughly one-third of women entering pregnancy are either overweight or obese in this country, and that is a cause for concern,” said the study’s lead author Dr Elizabeth T Jensen, assistant professor of epidemiology in the division of public health sciences at Wake Forest Baptist Medical Centre. “There is accumulating medical evidence that there is a relationship between maternal obesity and neurocognitive function in children, and our study adds to this evidence.”
Jensen and her colleagues conducted the study to assess the association between maternal pre-pregnancy body mass index (BMI) and weight gain during pregnancy and children’s later cognitive abilities.
The study included 535 children previously enrolled in the NIH-funded, multi-centre Extremely Low Gestational Age Newborns study. The research team evaluated the relationship of both pre-pregnancy BMI and pregnancy weight gain to cognitive and academic outcomes in the children at age 10. In their analysis of the data the investigators found that mothers’ pre-pregnancy obesity increased the risk of their children scoring lower on verbal intelligence, spelling and cognitive control.
“Our study highlights that some of the adverse risk for infants born preterm lies within pre-pregnancy obesity, as opposed to excessive pregnancy weight gain,” Jensen said.
“Although the findings do not establish causality, they do suggest that behavioural interventions to reduce pre-pregnancy weight among women might mitigate some of these impairments in their children born preterm.”
Objective: To assess the association between maternal prepregnancy body mass index and adequacy of pregnancy weight gain in relation to neurocognitive function in school-aged children born extremely preterm.
Study design: Study participants were 535 ten-year-old children enrolled previously in the prospective multicenter Extremely Low Gestational Age Newborns cohort study who were products of singleton pregnancies. Soon after delivery, mothers provided information about prepregnancy weight. Prepregnancy body mass index and adequacy of weight gain were characterized based on this information. Children underwent a neurocognitive evaluation at 10 years of age.
Results: Maternal prepregnancy obesity was associated with increased odds of a lower score for Differential Ability Scales-II Verbal IQ, for Developmental Neuropsychological Assessment-II measures of processing speed and visual fine motor control, and for Wechsler Individual Achievement Test-III Spelling. Children born to mothers who gained an excessive amount of weight were at increased odds of a low score on the Oral and Written Language Scales Oral Expression assessment. Conversely, children whose mother did not gain an adequate amount of weight were at increased odds of a lower score on the Oral and Written Language Scales Oral Expression and Wechsler Individual Achievement Test-III Word Reading assessments.
Conclusion: In this cohort of infants born extremely preterm, maternal obesity was associated with poorer performance on some assessments of neurocognitive function. Our findings are consistent with the observational and experimental literature and suggest that opportunities may exist to mitigate risk through education and behavioral intervention before pregnancy.
Elizabeth T Jensen, Jelske W van der Burg, Thomas M O’Shea, Robert M Joseph, Elizabeth N Allred, Tim Heeren, Alan Leviton, Karl CK Kuban, Bhavesh Shah, Rachana Singh, Anne Smith, Deborah Klein, Susan McQuiston, Julie Rollins, Laurie Douglass, Janice Ware, Taryn Coster, Brandi Henson, Rachel Wilson, Kirsten McGhee, Patricia Lee, Aimee Asgarian, Anjali Sadhwani, Ellen Perrin, Emily Neger, Kathryn Mattern, Jenifer Walkowiak, Susan Barron, Jean Frazier, Lauren Venuti, Beth Powers, Ann Foley, Brian Dessureau, Molly Wood, Jill Damon-Minow, Richard Ehrenkranz, Jennifer Benjamin, Elaine Romano, Kathy Tsatsanis, Katarzyna Chawarska, Sophy Kim, Susan Dieterich, Karen Bearrs, T Michael O’Shea, Nancy Peters, Patricia Brown, Emily Ansusinha, Ellen Waldrep, Jackie Friedman, Gail Hounshell, Debbie Allred, Stephen C Engelke, Nancy Darden-Saad, Gary Stainback, Diane Warner, Janice Wereszczak, Janice Bernhardt, Joni McKeeman, Echo Meyer, Steve Pastyrnak, Wendy Burdo-Hartman, Julie Rathbun, Sarah Nota, Teri Crumb, Madeleine Lenski, Deborah Weiland, Megan Lloyd, Scott Hunter, Michael Msall, Rugile Ramoskaite, Suzanne Wiggins, Krissy Washington, Ryan Martin, Barbara Prendergast, Megan Scott, Judith Klarr, Beth Kring, Jennifer DeRidder, Kelly Vogt