Excessive Gestational Weight Gain, Independent of Body Mass Index, Is Associated With Child Fat Mass Index at Age 2 Years in the Growing life, Optimizing Wellness Study.

Background: Excessive gestational weight gain (eGWG) increases risk for pregnancy complications and future obesity for pregnant persons and children. Yet, it is unclear whether eGWG leads to higher child adiposity at 2 years, independent of the pregnant person's body mass index (BMI) while considering important covariates. Moreover, understanding the characteristics of pregnant persons experiencing eGWG will help design future targeted interventions.

Objective: The objectives of the analyses were to assess the association between eGWG and childhood adiposity at age 2 years, while controlling for pregnant persons' BMI and other important covariates and to describe the characteristics of pregnant persons who experience eGWG during their second pregnancy.

Design: This is a secondary analysis of 221 pregnant persons and their children aged 2 years who were enrolled in the Growing Life, Optimizing Wellness longitudinal observational study.

Participants/setting: Participants were recruited between 2011 and 2014 in central Arkansas. Participants were secundigravida persons with BMI 18.5 to 35, older than age 20 years, and who conceived without assistance.

Main Outcome Measures: The main outcome measure was fat mass index of children aged 2 years measured by quantitative nuclear magnetic resonance imaging. Secondary outcomes included first pregnancy GWG, dietary and physical activity characteristics between pregnancies, second pregnancy nausea levels, and motivation level to adhere to the GWG guidelines.

Statistical Analysis Performed: Multivariable regression analyses were used to examine the associations between GWG and childhood fat mass index at age 2 years. Pearson correlations and Wilcoxon rank sum tests were used to identify the characteristics of pregnant persons who experienced eGWG.

Results: Pregnant persons' eGWG (β = .503; P = .03) was positively associated with child adiposity at age 2 years independent of maternal BMI (P = 0.3). Pregnant persons who experienced eGWG during their second pregnancy had greater odds of eGWG during first pregnancies (odds ratio 7.5; P < .001), dieting behavior (odds ratio 14.3; P = .02), and low motivation to adhere to the GWG guidelines (odds ratio 11.2; P = .009). Fewer participants had eGWG during their second pregnancy (52.5%) compared with their first pregnancy (66.8%), which was different by BMI groups (BMI 18.5 to 24.9: 23.6% decrease in participants who gained eGWG, BMI 25 to 29.9: 20.0% decrease, and BMI ≥ 30: 37.9% decrease).

Conclusions: eGWG among pregnant persons is associated with child adiposity at age 2 years. Pregnant persons who experienced eGWG during their second pregnancy reported low motivation to gain weight within guidelines, eGWG in first pregnancy, and reported prior dieting behavior. Future research focusing on patients with these characteristics may increase success of interventions designed to limit eGWG.