Mother's Own Milk Provision During the First 12 Weeks of Life by Gestational Age.

Importance: Although mother's own milk (MOM) is associated with reduced risk of neonatal complications of prematurity and improved neurodevelopmental outcomes, to our knowledge, there have been no large US studies reporting rates of MOM feeding initiation and sustained MOM feedings by gestational age (GA).

Objective: To compare rates of MOM feeding initiation and continuation at 12 weeks for infants by GA.

Design, Setting, And Participants: This retrospective cross-sectional study used state-level surveillance data for maternal characteristics and behaviors before and after pregnancy. Participants were women who gave birth from January 1 through December 31, 2021, in 36 US jurisdictions (33 states, the District of Columbia, New York City, and Puerto Rico) and completed the Pregnancy Risk Assessment Monitoring System (PRAMS) questionnaire. Data were analyzed from July 2023 to April 2024.

Exposure: Infant GA, including early preterm (EPT; ≤27 weeks' gestation), moderately preterm (MPT; 28-33 weeks' gestation), late preterm (LPT; 34-36 weeks' gestation), and early term to postterm (≥37 weeks' gestation).

Main Outcomes And Measures: MOM feeding initiation and continuation at 12 weeks after delivery. Weighted multivariable binary logistic regression models were used to test the association between MOM feeding initiation and continued provision at 12 weeks after delivery by infant GA.

Results: Among 29 098 births, there were 0.4% EPT, 1.8% MPT, 6.7% LPT, and 91.1% early-term to postterm infants. Unadjusted MOM feeding initiation was highest for EPT infants (89.7% [95% CI, 85.0%-94.7%]) and lowest for LPT infants (81.8% [95% CI, 79.5%-84.1%]). For infants that initially received MOM, 71.6% (95% CI, 70.7%-72.6%) of early-term to postterm infants still received MOM at 12 weeks followed by 63.1% (95% CI, 52.9%-73.2%) of EPT infants, 61.2% (95% CI, 58.0%-64.3%) of LPT infants, and 58.6% (95% CI, 53.4%-63.8%) of MPT infants. After adjusting for maternal characteristics, LPT infants were 4.4 (95% CI, -6.7 to -2.1) percentage points less likely to initiate MOM feedings and those who received any MOM were 6.7 (95% CI, -9.9 to -3.5) percentage points less likely to receive MOM at 12 weeks compared with early-term to postterm infants. There were no differences in adjusted initiation or continuation rates among EPT (3.1 [95% CI, -1.4 to 7.5] percentage points for initiation and -0.0 [95% CI, -8.6 to 8.6] percentage points for continuation) or MPT (2.4 [95% CI, -0.5 to 5.3] percentage points for initiation and -3.3 [95% CI, -8.0 to 1.5] percentage points for continuation) infants compared with early-term to postterm infants.

Conclusions And Relevance: This cross-sectional study found that MOM feeding initiation and continuation rates at 12 weeks after birth for LPT infants were substantially lower than rates for infants with other GAs. Research is needed to pinpoint barriers to MOM feeding initiation and continuation in this vulnerable population of infants.