Higher maternal prenatal weight may adversely influence offspring cognition and behaviour

1. In this cohort study, higher maternal prenatal body mass index was associated with worse neurocognitive development in offspring.

2. Children born to women with higher maternal weight status should be followed closely for neurodevelopmental and behavioral concerns and referred appropriately for early intervention and support.

Evidence Rating Level: 2 (Good)

Study Rundown: There are a host of early childhood exposures associated with fetal brain development as well as childhood cognition and behavior, including environmental insults/toxicants, psychosocial stress, and infant nutrition. Due to the recent rise in the global prevalence of obesity, including in women of child-bearing age, the long-term effects of maternal prenatal weight status on offspring cognition and behavior have become an area of particular interest. This cohort study, using data from a breastfeeding intervention trial in Belarus, sought to evaluate associations between maternal prenatal body mass index (BMI) and cognition and behavior of offspring born full-term in a setting where the overall prevalence of maternal and child obesity was low. The main endpoints of the analysis were 1) offspring cognition assessed by pediatricians using the Wechsler Abbreviated Scales of Intelligence (WASI) at 6.5 years and the computerized self-administered NeuroTrax battery at 16 years (both with an approximate mean [SD] of 100 [15]), and 2) child behavior rated by parents and teachers using the Strengths and Difficulties Questionnaire (SDQ, range 0-40) at 6.5 years. Among 11,276 children included in the study, higher maternal BMI after 35 weeks’ gestation was associated with a slightly lower offspring intelligence quotient at 6.5 years and lower cognitive scores in multiple domains at 16 years. Associations adjusted for baseline sociodemographic characteristics as well as pregnancy complications and paternal weight and were not mediated by child weight. These findings suggested that children born to women with higher maternal BMI should be followed closely for neurodevelopmental and behavioral concerns and referred appropriately for early intervention and support. Additional longitudinal research looking into the mechanisms and negative synergistic effects by which environmental exposures, such as maternal prenatal weight and nutritional status can affect fetal brain development, is needed. A limitation of this study was that all participants were Belarusian, where the overall rates of obesity were low in the region and thus, diminishing the generalizability of the study’s findings.

Click to read the study in JAMA

Relevant Reading: PROBIT Study Group (Promotion of Breastfeeding Intervention Trial). Promotion of Breastfeeding Intervention Trial (PROBIT): a randomized trial in the Republic of Belarus

In-Depth [retrospective cohort]: This cohort study, PROBIT, included 11,276 patients (9,355 [83%] women aged 20 to 34 years, 10,128 (89.8%) married, 11,050 (98.0%) non-smokers during pregnancy) from a breastfeeding promotion intervention at 31 centers in Belarus. Offspring cognition and behavior were longitudinally assessed from birth (1996-1997) to adolescence (2017-2019) and compared with maternal BMI data from prenatal medical records. Primary exposure included maternal BMI, calculated as weight in kilograms divided by height in meters squared after 35 weeks’ gestation. Overall, each 5-unit increase in maternal BMI during pregnancy (mean [SD], 27.2 [3.8]) was associated with lower childhood WASI performance (-0.52 points; 95%CI, -0.87 to -0.17 points) at 6.5 years and lower scores on 5 of 7 NeuroTrax subscales and the global cognitive score at 16 years (-0.67 points; 95%CI, -1.06 to -0.29 points), with similar results after adjusting for sociodemographic characteristics. Furthermore, higher maternal BMI during pregnancy was associated with more teacher-reported behavioral problems via SDQ but not parent-reported behavioral problems (externalizing behaviors: 0.13 points; 95%CI, 0.02 to 0.24 points; total difficulties: 0.14 points, 95%CI, -0.02 to 0.30 points), with similar results for maternal BMI measured in the first trimester or postpartum. Conversely, higher 6.5-year paternal BMI was associated with improved child cognition (WASI verbal IQ: 0.42 points; 95%CI, 0.02 to 0.82 points; NeuroTrax executive function score: 0.68 points; 95%CI, 0.24 to 1.12 points) and fewer teacher-reported behavioral problems (total difficulties: -0.29 points; 95%CI, -0.46 to -0.11 points).

Image: PD

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