The Intervention Nurses Start Infants Growing on Healthy Trajectories (INSIGHT) responsive parenting intervention for firstborns impacts feeding of secondborns

Background: The Intervention Nurses Start Infant Growing on Healthy Trajectories (INSIGHT) study's responsive parenting (RP) intervention, initiated in early infancy, prevented the use of nonresponsive, controlling feeding practices and promoted use of structure-based feeding among first-time parents compared with controls. Objectives: We sought to examine the spillover effect of the RP intervention on maternal feeding practices with their secondborn (SB) infants enrolled in an observational-only study, SIBSIGHT, and to test the moderating effect of spacing of births. Methods: SB infants of mothers participating in the INSIGHT study were enrolled into the observation-only ancillary study, SIBSIGHT. SBs were healthy singleton infants ≥36 weeks of gestation. Infant feeding practices (i.e., food to soothe, structure vs. control-based practices) were assessed using validated questionnaires: Babies Need Soothing Questionnaire, Infant Feeding Styles Questionnaire, and the Structure and Control in Parent Feeding Questionnaire. Results: SBs (n = 117 [RP: 57, control: 60]; 43% male) were delivered 2.5 ± 0.8 y after firstborns (FBs). At age 1 y, the Structure and Control in Parent Feeding Questionnaire revealed that the mothers in the RP group used more consistent feeding routines (4.19 [0.43] compared with 3.77 [0.62], P = 0.0006, Cohen's D: 0.69) compared with control group mothers. From the Infant Feeding Styles Questionnaire, RP group mothers also used less nonresponsive, controlling feeding practices such as pressuring their SB infant to finish (1.81 [0.52] compared with 2.24 [0.68], P = 0.001, Cohen's D: 0.68) compared with controls. In contrast to our hypotheses, no differences were detected in bottle-feeding practices such as putting to bed with a bottle/sippy cup or adding cereal to the bottle, despite observing study group differences in FBs. Spacing of births did not moderate intervention effects. Conclusions: RP guidance given to mothers of FBs may prevent the use of some nonresponsive, controlling feeding practices while establishing consistent feeding routines in subsequent siblings.