Does Prematurity Moderate the Association Between Breastfeeding Firstborn and Second-Born Children?

Preterm infants frequently face challenges in breastfeeding, leading to lower initiation rates and shorter durations compared to full-term infants. It is unclear how prematurity shapes breastfeeding behavior with subsequent births.

This study aims to determine how preterm birth of firstborn or second-born children moderated the association between first-birth breastfeeding experience and breastfeeding outcomes after a second birth.

This retrospective cohort study used 2011-2019 National Survey of Family Growth data and included individuals (N = 6,031) ages 18-49 with at least two singleton live births. Study outcomes were assessed for second-born children and included breastfeeding initiation and duration. The primary exposure was breastfeeding experience with the firstborn child, defined as the firstborn child receiving human milk for at least 1 week. Multivariable logistic regression was used to evaluate the interaction between the prematurity of the first or second child and the breastfeeding experience.

Breastfeeding experience with the first child increased the odds of breastfeeding initiation for the second child (OR = 16.98; 95% CI [13.53, 21.30]). The association was smaller if the first child was born preterm (OR = 12.09; 95% CI [7.15, 20.45]) or if the second child was born preterm (OR = 10.72; 95% CI [6.09, 18.87]). However, neither interaction term was statistically significant for preterm birth of first or second child. Additionally, prematurity did not moderate the association of breastfeeding experience with the breastfeeding duration of second children.

Helping primiparous individuals overcome barriers to breastfeeding increases the odds of breastfeeding in first- and second-born children, irrespective of prematurity.