Key takeaways:
- Nonmedically indicated formula supplementation occurred in more than one-quarter of term infants during postpartum hospitalization.
- Rates of in-hospital formula supplementation increased steadily over the 6-year study period.
- Infants born to mothers living in more socioeconomically marginalized neighborhoods had a greater risk of nonmedically indicated supplementation.
- Significant racial disparities were observed, with greater adjusted risks among Asian and Black mothers compared with White mothers.
- Findings highlight the need for targeted research and interventions to address inequities in early infant feeding practices.
There is a significant prevalence of nonmedically indicated formula supplementation which has been linked to socioeconomic marginalization and maternal racialization, according to a recent study published in JAMA Pediatrics.1
Despite recommendations to exclusively breastfeed infants for the first 6 months of life, discontinuation in the early postpartum period has been reported in 40% of mothers, with persistent sociodemographic disparities observed.2 Supplementation disparities have also been observed in Canada, such as increased rates among mothers with reduced socioeconomic status.1
“This warrants examination on a population level with a specific focus on nonmedically indicated supplementation,” wrote investigators.
Sociodemographic assessments
The population-based study was conducted to evaluate the link between maternal socioeconomic status, race, and nonmedically indicated supplementation of term-born infants. Data was obtained from the Better Outcomes Registry & Network, which manages information about all births in Ontario, Canada.
Singleton live births from April 1, 2015, to March 31, 2021, with available prenatal screening data were included in the analysis. Additional eligibility criteria included term births above the low birth weight cutoff and initiating breastfeeding.
Births outside of a hospital, missing hospital feeding data, surrogate birth, infant adoption, infant discharge to social services, or postpartum transfer to another hospital were excluded. Nonmedically indicated supplementation was reported during the postpartum hospital stay as the primary outcome.
Extracting race and socioeconomic data
Trained personnel extracted feeding data from medical records. Maternal socioeconomic status and race were reported as exposures, with the former reported on a neighborhood level by linking maternal postal codes to the 2021 Ontario Marginalization Index quintiles.
Antenatal health care professionals completed a prenatal screening form to provide maternal race data. Categories of maternal race and ethnicity included Asian, Black, White, and other. Maternal age at birth, birth hospital region, rural residence, prepregnancy body mass index, mental health concerns, and preexisting health conditions were reported as covariates.
There were 422,048 mother-infant dyads included in the final analysis. Increased odds of being a younger age, Asian or Black, giving birth at hospitals in metropolitan Toronto, smoking during pregnancy, and receiving in-hospital postpartum breastfeeding support were reported in patients living in more marginalized neighborhoods vs less marginalized.
Rates and trends in formula supplementation
Quintile 1 was considered the least marginalized. In comparison to this group, quintile 5 was more likely to live in socioeconomically marginalized neighborhoods and to give birth in metropolitan Toronto. Increased odds of multiparity were reported in Black and other racial groups.
Asian and Black groups less often presented with preexisting physical or mental health concerns. Nonmedically indicated hospital formula supplementation was reported in 27.3% of infants overall, with the following yearly rates:
- 23.4% in year 1
- 25.7% in year 2
- 27.4% in year 3
- 28% in year 4
- 27% in year 5
- 31.8% in year 6
Supplementation for medical reasons was reported in an additional 3.9% of infants. Quintiles 2 through 5 presented with a gradient of increased risk for non-medically indicated formula supplementation vs quintile 1. In model 2, this indicated an adjusted relative risk (aRR) of 1.68 among quintile 5 participants.
Associations with maternal race
There was also a significant correlation between maternal race and nonmedically indicated formula supplementation. An aRR of 2.69 was reported among Asian patients vs White patients, while Black patients had an aRR of 2.07 in comparison.
Finally, the aRR among the other racial group was 1.43. Overall, the results indicated high rates of formula supplementation, increasing over time and with disparities based on race and socioeconomic marginalization.
“Further research examining disparities in other… practices and associations with later breastfeeding outcomes among the diverse Canadian population is needed,” wrote investigators.
References
- Mildon A, Alton GD, Baxter JB, Underhill B, Sellen DW, O’Connor DL. Hospital formula supplementation postbreastfeeding initiation, neighborhood economy, and race. JAMA Pediatr. 2025. doi:10.1001/jamapediatrics.2025.5379
- Chan K, Labonté JM, Francis J, Zora H, Sawchuk S, Whitfield KC.Breastfeeding in Canada: predictors of initiation, exclusivity, and continuation from the 2017-2018 Canadian Community Health Survey.Appl Physiol Nutr Metab. 2023;48(3):256-269. doi:10.1139/apnm-2022-0333
