Factors Associated with First Formula Introduction in Infants of Mothers Who Intended to Exclusively Breastfeed

Background: Breastfeeding is a significant predictor of infant and maternal health outcomes. In-hospital formula use both decreases breastfeeding exclusivity after hospital discharge and increases early breastfeeding cessation among mothers with intention to exclusively breastfeed. The exclusive breastfeeding rate at Stony Brook University Hospital (SBUH) is approximately 30%.

Primary objective: Identify the most commonly documented reasons for first formula introduction in our Newborn Nursery in infants of mothers who intended to breastfeed.

Secondary objective: Identify any demographic or hospital care factors associated with formula introduction in infants of mothers who intended to breastfeed.

Methods: We did a retrospective chart review of 99 mother-infant dyads in 2019 in which the mother intended to exclusively breastfeed. Within this cohort we compared a variety of perinatal factors in infants who exclusively breastfed to those who received formula during hospital stay. The infants who received formula (n = 46) comprised only those who received three formula feeds or less to minimize a possible confounding factor of ambivalent maternal intentions to breastfeed. We also looked at the documented reasons for first formula introduction in these infants.

Results: The most common reason documented for first formula introduction was maternal request (54%), followed by weight loss (17%) and hypoglycemia (8.6%). First formula introduction was 2.8 times more likely to occur during the night shift compared to the day shift. The odds ratio for exclusive breastfeeding was 0.32 (95% CI 0.11-0.94) in infants with hypoglycemia risk factors. The adjusted odds ratio for exclusive breastfeeding was 0.28 (95% CI 0.08-0.98) for infants delivered by a staff obstetrician (OB) compared to the midwives or a private OB.

Conclusion: Our results inform targets for improved breastfeeding support at SBUH. Increasing breastfeeding support staff at night may reduce the rate of formula introduction during those hours when mothers are fatigued and fewer staff is available. Our data also suggest that hypoglycemia risk factors rather than hypoglycemia itself is a risk factor for formula introduction, suggesting a possible role for provider or maternal anxiety related to the potential for a hypoglycemic episode. Quality improvement initiatives looking to standardize breastfeeding education and support during prenatal care, as well as in the hospital, may also help to improve rates of exclusive breastfeeding.