Predictors of Breastfeeding Duration in the New Hampshire Birth Cohort Study

Abstract

Introduction: Breastfeeding has significant health benefits for infants and birthing persons, including reduced risk of chronic disease. The American Academy of Pediatrics recommends exclusively breastfeeding infants for 6 months and recently extended its recommendation for continuing to breastfeed with supplementation of solid foods from one to two years. Studies consistently identify lower breastfeeding rates among US infants, with regional and demographic variability. We examined breastfeeding in birthing person-infant pairs among healthy, term pregnancies enrolled in the New Hampshire Birth Cohort Study between 2010 and 2017 (n = 1176).

Methods: Birthing persons 18-45 years old were enrolled during prenatal care visits at ~ 24-28 weeks gestation and have been followed since enrollment. Breastfeeding status was obtained from postpartum questionnaires. Birthing person and infant health and sociodemographic information was abstracted from medical records and prenatal and postpartum questionnaires. We evaluated the effects of birthing person age, education, relationship status, pre-pregnancy body mass index, gestational weight gain (GWG), smoking and parity, and infant sex, ponderal index, gestational age and delivery mode on breastfeeding initiation and duration using modified Poisson and multivariable linear regression.

Results: Among healthy, term pregnancies, 96% of infants were breastfed at least once. Only 29% and 28% were exclusively breastfed at 6-months or received any breastmilk at 12-months, respectively. Higher birthing person age, education, and parity, being married, excessive GWG, and older gestational age at delivery were associated with better breastfeeding outcomes. Smoking, obesity, and cesarean delivery were negatively associated with breastfeeding outcomes.

Conclusions: Given the public health importance of breastfeeding for infants and birthing persons, interventions are needed to support birthing persons to extend their breastfeeding duration.

Keywords: Breastfeeding duration; Breastfeeding initiation; New Hampshire Birth Cohort Study (NHBCS); Predictors.

Figure 1.

Adjusted multivariable linear regression estimates (beta ± 95% CI) of predictors of exclusive breastfeeding duration. Betas (•) and 95% confidence intervals for birthing person and infant characteristics. The vertical line represents the null and points located on this line denote the reference level for categorical variables (e.g., never smoker vs. current smoker). Predictors with betas located to the left of the null are negatively associated with exclusive breastfeeding duration, whereas predictors with betas located to the right of the null are positively associated. Green asterisks (*) and bold, italicized betas and 95% CIs reflect those predictors which are significantly associated with exclusive breastfeeding duration among birthing persons in our study. BMI – pre-pregnancy body mass index; GWG – gestational weight gain.

Figure 2.

Adjusted multivariable linear regression estimates (beta ± 95% CI) of predictors of any breastfeeding duration. Betas (•) and 95% confidence intervals for birthing person and infant characteristics. The vertical line represents the null and points located on this line denote the reference level for categorical variables (e.g., never smoker vs. current smoker). Predictors with betas located to the left of the null are negatively associated with any breastfeeding duration, whereas predictors with betas located to the right of the null are positively associated. Green asterisks (*) and bold, italicized betas and 95% CIs reflect those predictors which are significantly associated with any breastfeeding duration among birthing persons in our study. BMI – pre-pregnancy body mass index; GWG – gestational weight gain.