The Influence of a Sister's Breastfeeding Experience on a Mother's Breastfeeding Behavior: Is There an...

Intergenerational transmission of breastfeeding attitudes and behaviors from mother to daughter are well known, but there is limited research on intragenerational transmission of breastfeeding attitudes or behaviors within families. This study aimed to understand how initiation and duration of breastfeeding are influenced by past breastfeeding experiences of sisters among women in a longitudinal population-based cohort. Data were obtained on women enrolled in the 1979 National Longitudinal Survey of Youth (NLSY) who had at least one child enrolled in a substudy of cohort members' children. For each mother in the study, we determined whether any of her sisters also enrolled in the main NLSY study had previously breastfed one of their children. Mothers whose sister(s) had prior breastfeeding experience were more likely to breastfeed their first-born child on unadjusted analysis (70% versus 45%, chi-square p < 0.001) and had a longer median of breastfeeding duration (median 14.5 versus 12 weeks, rank-sum p = 0.039). However, on a multivariable analysis accounting for potential confounding by maternal characteristics, infant characteristics, and differences among households, sisters' breastfeeding experience was no longer independently associated with the likelihood of breastfeeding initiation (odds ratio: 1.16; confidence interval [95% CI]: 0.73-1.85; p = 0.520) or the hazard of breastfeeding discontinuation (hazard ratio: 0.96; 95% CI: 0.82-1.12; p = 0.598). After adjusting for socioeconomic characteristics, intragenerational transmission of breastfeeding behavior was negligible among mothers raised in the same household. Other forms of intragenerational transmission (e.g., influence of extended family members) may be more salient influences on women's decision to breastfeed.