Background: Prepregnancy overweight/obesity (OW/OB) is a strong risk factor for child obesity. Few studies have identified modifiable factors that mitigate this risk. Objective: The objective of this study was to determine if prenatal social support buffers the effect of prepregnancy OW/OB on child birth weight z-score (BWz) and weight-for-age z-score (WFAz) trajectory. Methods: We performed a longitudinal secondary analysis of 524 mother-infant pairs enrolled in a randomized controlled trial of the Starting Early Program, a child obesity prevention program for Hispanic families with low income. Social support was assessed in the third trimester of pregnancy; maternal prepregnancy OW/OB and child WFAz from birth to age 3 years were obtained from medical records. Linear regression and multilevel modeling tested the effects of maternal prepregnancy OW/OB on child weight outcomes, and whether prenatal social support moderated these effects. Results: Prepregnancy OW/OB was associated with significantly higher child BWz (B = 0.23, p = 0.01) and WFAz trajectories (B = 0.19, 0.01). The interaction between social support and prepregnancy OW/OB was negatively related to child BWz (B = -0.26, p = 0.02) and WFAz trajectory (B = -0.40, p = 0.047). Conclusions: Prenatal social support may be protective against the intergenerational transmission of obesity risk. Interventions for the prevention of child obesity should consider incorporating social support into their design. Clinical Trial Registration Number: NCT01541761.
Keywords: Hispanic; childhood obesity; infancy; obesity prevention; pregnancy; social support.