Food and non-food reinforcement among pregnant women

Excessive gestational weight gain (GWG) in pregnancy may be driven in part by greater motivation to eat, and studying the relative reinforcing value of food versus non-food commodities may provide insight into factors important for excessive GWG. This study was a cross-sectional examination of the relationship between women meeting the Institute of Medicine (IOM) guidelines for GWG and the relative reinforcing value of food vs. non-food commodities during pregnancy. Two-hundred and thirty-three pregnant women (1st trimester, n = 44; 2nd trimester, n = 105; 3rd trimester, n = 84), aged 18-40, were recruited via a crowdsourcing platform and completed an online survey. Relative food reinforcement (RRVfood), relative non-food activity reinforcement (RRVactive) and relative non-food cognitively enriching activity reinforcement (RRVcognitive) were measured by a questionnaire at the point of contact. Self-reports of gestational age and weight gain during pregnancy were collected. The relationship between food and non-food reinforcement was assessed based on IOM classifications for weight gain during pregnancy. After adjustment for women's education level and parity, higher RRVfood (p = 0.036) and lower RRVcognitive (p = 0.040) responses were associated with greater GWG. Food reinforcing ratio (FRR) analysis was then conducted to systematically examine the effect of non-food behaviors on GWG when food reinforcement was accounted for. Women who gained below the IOM weight gain guidelines had significantly higher FRRcognitive than those gaining above (p = 0.013), indicating cognitively enriching activities may better compete with food among pregnant women. Interventions that help to increase the reinforcing value of cognitively enriching activities may be a new avenue to regulate eating to minimize GWG.