Sex Differences in Maternal Restrictive Feeding Practices in the Intervention Nurses Start Infants Growing on Healthy Trajectories Study

Background: Intervention Nurses Start Infants Growing on Healthy Trajectories tested an early life responsive parenting (RP) intervention designed for obesity prevention. Body mass index z-score at age 3 years was lower for the RP group versus controls with a larger effect for girls than boys. We sought to determine if child sex was associated with differing maternal feeding practices and whether sex moderated intervention effects on feeding. Design/Methods: Mothers (N = 279) completed the Infant Feeding Styles Questionnaire (IFSQ) at 28 weeks, the Structure and Control in Parent Feeding (SCPF) at 1, 2, and 3 years, and the Child Feeding Questionnaire (CFQ) at 3 years. Study aims were tested using 2-way analysis of variance and repeated measures. Results: Mothers reported greater restriction (limiting food quantity) for boys at 28 weeks (IFSQ: 3.0 ± 1.1 vs 2.8 ± 1.0, P = .07) and across annual measurements from age 1 to 3 years (SCPF: P = .04). At age 3, the intervention group effect on restriction differed by sex (CFQ: P = .047) such that higher restriction was reported by RP group mothers of boys versus girls (3.4 ± 0.7 vs 3.0 ± 0.9, P = .002) with no control group sex difference (3.4 ± 0.8 vs 3.3 ± 0.9, P = .79). There were no sex differences or sex by intervention group interactions in other reported feeding practices at any assessment (ie, structure-based feeding, pressure). Conclusions: Mothers of boys used more restrictive feeding through age 3. These findings may be partially explained by previously reported better self-soothing and self-regulation abilities of participating girls.