Receipt of Breast Milk by Gestational Age — United States, 2017

Katelyn V. Chiang, MPH; Andrea J. Sharma, PhD; Jennifer M. Nelson, MD; Christine K. Olson, MD; Cria G. Perrine, PhD


Morbidity and Mortality Weekly Report. 2019;68(22):489-493. 

In This Article

Abstract and Introduction


Breast milk is the optimal source of infant nutrition. For the nearly one in 10 infants born prematurely in the United States annually,[1] breast milk is especially beneficial, helping prevent sepsis and necrotizing enterocolitis and promoting neurologic development.[2] National estimates of newborn feeding practices by gestational age have not been available previously. CDC analyzed 2017 birth certificate data from 48 states and the District of Columbia (3,194,873; 82.7% of all births) to describe receipt of breast milk among extremely preterm (20–27 weeks), early preterm (28–33 weeks), late preterm (34–36 weeks), and term (≥37 weeks) infants with further stratification by maternal and infant characteristics. The prevalence of infants receiving any breast milk was 83.9% overall and varied by gestational age, with 71.3% of extremely preterm infants, 76.0% of early preterm infants, 77.3% of late preterm infants, and 84.6% of term infants receiving any breast milk. Disparities in receipt of breast milk by several sociodemographic factors, including maternal race/ethnicity, were noted across gestational age groups. These estimates suggest that many infants, particularly infants at high risk for medical complications, might not be receiving breast milk. Efforts are needed to increase the implementation of existing evidence-based policies and practices that support breast milk feeding, particularly for medically fragile infants.[2,3]

The National Vital Statistics System birth data are a census of all live births in the United States. Federal guidance includes procedures for collecting uniform birth data using the U.S. Standard Certificate of Live Birth.[4]* Data collected include nutrition information determined from medical record indication of receipt of any breast milk or colostrum during the period between delivery and hospital discharge, including both mother's own and donor breast milk.[4] Preterm infants often have extended hospital stays;[5] however, state statutes require completion and filing of birth certificates soon after delivery, usually within 5–10 days of birth. Therefore, among preterm infants, this item likely captures receipt of breast milk only between delivery and completion of the birth certificate. Gestational age was ascertained from the birth certificate's obstetric estimate of completed weeks of gestation and categorized as extremely preterm (20–27 weeks), early preterm (28–33 weeks), late preterm (34–36 weeks), and term (≥37 weeks).[4] On birth certificates, maternal sociodemographic data are typically collected through maternal self-report and neonatal intensive care unit (NICU) admission is collected from the medical record.[4]

Analysis was restricted to infants with gestational ages ≥20 weeks who were not transferred to another facility within 24 hours of delivery and who were living at the time of birth certificate completion. Only births delivered to residents of 48 states and the District of Columbia in 2017 were included; births delivered to residents of California and Michigan were not available for analysis (15.1% of U.S. resident births). The percentage of infants who received breast milk was calculated overall and by gestational age using SAS (version 9.4; SAS Institute). Receipt of breast milk was further stratified by maternal characteristics and infant NICU admission.

Overall, 83.9% of infants received breast milk during the first few days of life (Table). Term infants were more likely to have received breast milk than were preterm infants, with percentages increasing with gestational age: 71.3% of extremely preterm infants, 76.0% of early preterm infants, 77.3% of late preterm infants, and 84.6% of term infants.

Among extremely preterm infants, 67.1% of those delivered to black mothers and 60.7% of those delivered to American Indian/Alaska Native mothers received breast milk, compared with approximately 75% of extremely preterm infants delivered to mothers of other racial/ethnic groups. This racial/ethnic disparity was observed across gestational age groups. In general, across gestational age groups, infants of mothers who were younger, less educated, unmarried, and participating in Medicaid or the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) were less likely to receive breast milk than were infants of older, more educated, and married mothers, those with private insurance, other coverage, or who were self-pay, and those not participating in WIC. In addition, receipt of breast milk by NICU admission differed by gestational age, with higher prevalences of receipt of breast milk among late preterm and term infants who were not admitted to a NICU.

Gestational age terms are those commonly used by various medical, research, and public health organizations. However, because there is a lack of consensus regarding the age ranges for each category, categories were defined in this report using completed weeks' gestation as the following: extremely preterm (20–27 weeks), early preterm (28–33 weeks), late preterm (34–36 weeks), and term (≥37 weeks). The lower limit of 20 completed weeks' gestation was used to exclude births where resuscitation was unlikely.