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

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. 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. 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). 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.