WIC 141
Low Birth Weight

Low birth weight and very low birth weight are defined as follows:

*Metric weight converted to pound and ounces for WIC clinic use.

See Clarification section for information on plotting growth measurements for preterm infants Risk 142 Preterm or Early Term Delivery.

Low birth weight (LBW) has been defined by the World Health Organization (WHO) as weight at birth of less than 2500 grams (5 pounds 8 ounces) regardless of gestational age (1, 2, 3, 4). This is based on epidemiological observations that infants weighing less than 2500 grams are at higher risk of neonatal mortality when compared with heavier infants (5, 6). LBW is further categorized into very low birth weight (VLBW, <1500 gm or 3.3 pounds) and extremely low birth weight (ELBW, <1000 gm or 2.2 pounds) (1). LBW is considered the single most important predictor of infant mortality, especially within the first months of life (6). Neonates with LBW have a 20 times greater risk of dying compared to infants of normal birth weight (3, 5). LBW contributes to a range of poor health outcomes including fetal and neonatal mortality and morbidity, and inhibited growth (1, 3, 4).

LBW is usually caused by intrauterine growth restriction (IUGR), preterm birth (PTB) or both (3, 4, 6). Preterm birth (an infant born at fewer than 37 weeks’ gestational age) is the most common cause of LBW (1). In the U.S., the rates of preterm births have increased from 10% to 12.5% in the past 25 years likely as a result of higher survival rates due to advances in perinatal medical care (4). LBW is more common in developing than developed countries. However, data on LBW in developing countries is often limited because a significant portion of births occur in homes or small health facilities, where cases of infants with LBW often go unreported leading to an underestimation of the prevalence of LBW (2). It is estimated that 20% of all births worldwide are LBW, representing more than 20 million births a year (7). In the U.S., approximately 1 in 12 infants (8%) is born with LBW (8, 9). The percentage of LBW infants has increased 4% among all racial groups from 2016-2021 in the U.S. (8). Since 2016, LBW rates increased a total of 1% for non-Hispanic White women, 7% for non-Hispanic Black women and 7.3% for Hispanic women (8). The rates of LBW among different racial and ethnic groups in the U.S. are (9):

• 1 in 7 Black infants (14%)
• 1 in 12 Asian infants (8%)
• 1 in 13 Native American or Alaska Native infants (8%)
• 1 in 14 Latinx infants (7%)
• 1 in 14 White infants (7%)

Black infants are more than twice as likely to be born with a LBW or to die in their first year of life as White infants (9). Rates of very low birthweight (VLBW) infants comprise only 1.0% of live births in the U.S. but Black mothers are 2.6 times more likely to have a VLBW infant than White mothers (10, 11). The increased likelihood of LBW in Black infants has been associated with mothers who are unmarried, unemployed, lower income, younger, and receive federal government assistance to pay for rent (10, 12, 13, 14, 15, 16). Yet even with the presence of traditional protective factors such as marriage, education, and being non-smokers, Black women still experience LBW at higher rates than Whites (12, 14, 15, 16). Institutional racism (differences in access to resources by race as well as differences in policies, laws and practices that reinforce racial inequity) may explain racial disparities in LBW between Black and White women (12, 14, 15, 16). Black women are at a higher risk of chronic stress due to adverse social determinants including low socioeconomic status, housing insecurity, and experience racism as a stressor and weathering (discrimination that worsens with age) (12, 14, 15, 16). Black mothers, when compared to other racial or ethnic groups, have the highest rate of LBW babies despite whether they were born in the U.S. or in another country (12, 17, 18). However, multiple studies have shown Black infants born to mothers who are immigrants experience LBW at rates similar to infants born to White mothers, suggesting the presence of other factors affecting birth weight for non-immigrant Black mothers (12, 17, 18). U.S. born Black women have more exposure to racism as a major stressor that negatively impacts maternal health while foreign born Black women do not report perceiving racism in the same way (12, 17). In addition, foreign-born Black women may have more positive social determinants such as higher levels of education and income, and access to better health care (12, 17, 18). This issue is very complex and continued research is needed focusing on the factors contributing to the inequitable racial gap in LBW.

LBW infants are more likely than infants whose weight is normal to have medical problems that may include (1, 3, 4, 9):

• Respiratory: Respiratory Distress Syndrome (RDS). Infants with RDS do not have a protein called surfactant that keeps small air sacs in an infant’s lungs from collapsing. Treatment with surfactant helps these infants breathe more easily. Infants who have RDS also may need oxygen and other medical support to help their lungs work.
• Neurological: Intraventricular Hemorrhage (IVH). Bleeding in the brain.
• Cardiovascular: Patent ductus arteriosus. Patent ductus arteriosus is when an opening between 2 major blood vessels leading from the heart does not close properly. This can cause extra blood to flow to the lungs. In many infants who have patent ductus arteriosus, the opening closes on its own within a few days after birth. Some infants need medicine or surgery to close the opening.
• Gastrointestinal: Necrotizing enterocolitis (NEC) is a gastrointestinal disease that involves infection and inflammation that causes damage and the death of cells in some or all the intestines.
• Jaundice: An excess of bilirubin due to the infant’s liver not adequately removing it from the bloodstream.
• Retinopathy of prematurity: When an infant’s retinas do not fully develop in the weeks after birth.
• Immunological: Sepsis, pneumonia, or meningitis. In an infant who is born prematurely, the immune system may not be fully developed and may not be able to fight off infection.

When LBW infants become children, they tend to have lower neurodevelopmental scores in the areas of language, cognition, and motor skills compared to term normal birth weight infants (19). There is also evidence that LBW infants have a higher risk of developing chronic health conditions later in life including (4, 9):

• Diabetes
• Heart disease
• High blood pressure
• Metabolic syndrome
• Obesity
• Stroke

Nutrition for Infants with LBW and VLBW

The LBW or VLBW infant may begin life with a compromised nutritional status and require a form of nutrition support (human milk fortifier, special infant formula, tube feeding) (1). Some of these infants, especially ones with VLBW, will need supplemental feedings because they have limited nutrient reserves at birth and are subject to physiological and metabolic stresses that increase their nutrient needs (1, 20). Providing breast milk to these infants in the first month of life has been linked to improved growth and development (1). While infant formula can be used to offer higher amounts of macronutrients than breast milk, it can be harder to digest for LBW and VLBW infants (21). Breast milk contains beneficial biological components, including immunoglobulins, cytokines, growth factors, hormones, antimicrobial agents, immune cells, stem cells, prebiotic oligosaccharides, and probiotic bacteria (1). Mother’s own milk has been associated with multiple health benefits for LBW and VLBW infants, including lower incidences of necrotizing enterocolitis (NEC), late-onset sepsis, chronic lung disease, retinopathy of prematurity, and neurodevelopmental impairment (20, 21, 22, 23). Pasteurized donor breast milk is recommended when mother’s own milk is not available or sufficient (23). LBW infants that are supplemented with fortified pasteurized donor milk have a greater risk of growth failure than those fed mother’s own milk (23).

For VLBW infants, breast milk often requires fortification with human milk fortifiers in order to meet their nutritional needs (23). Assistance in early milk expression should be available to mothers within 6 to 8 hours of birth of any VLBW infant because of the need for early and frequent milk expression to maintain milk supply (23). The use of breast milk is lower among VLBW infants with non-Hispanic Black mothers, compared with those with non-Hispanic White mothers. Approaches that have been shown to reduce Black and White disparities in breastfeeding in the NICU setting, include peer counselor programs and support groups, assistance with breast pump acquisition, and transportation for mothers to visit the hospital (23).

WIC Nutrition Services for Infants with LBW and VLBW

WIC services can directly support LBW and VLBW infants and their caregivers, as they may have unique feeding difficulties. LBW and VLBW infants may be born preterm so their delivery is often unexpected, and a mother may not have made decisions about how to feed her infant yet. These infants may require additional calories, extra breastfeeding support, and/or the use of a human milk fortifier or special infant formula. WIC can support LBW and VLBW infants and their caregivers through:

• Providing breastfeeding education to mothers. This has been shown to increase breastfeeding intent and decrease maternal anxiety. Education may include information on the health benefits of mother’s own milk, the need for early and frequent milk expression, the role of skin-to-skin contact, nonnutritive suckling, direct breastfeeding when physiologically appropriate, and technical information on proper milk handling, storage, and transport (23).
• Referring to a WIC breastfeeding peer counseling program, if available.
• Promoting and supporting breastfeeding as the normative standard for infant nutrition and providing early and frequent breastfeeding support.
• Recommending the use of a hospital grade electric breast pump for expressing milk if the infant is in the NICU or the infant is unable to breastfeed directly from the breast.
• Providing anticipatory guidance about potential feeding challenges.
• Monitoring the child’s growth to ensure healthy weight gain.
• Providing nutrition education for mothers/caregivers and appropriate referrals as necessary for growth, feeding, health, and/or infant developmental issues.
• Discouraging families from direct milk sharing and the purchase of breast milk from Internet-based sources as both practices are associated with risks of bacterial or viral contamination of non-pasteurized milk and the possibility of exposure to medications, other substances, and unsafe handling practices (23).

1. Cutland CL, Lackritz EM, Mallett-Moore T, Bardají A, Chandrasekaran R, Lahariya C, Nisar MI, Tapia MD, Pathirana J, Kochhar S, Muñoz FM; Brighton Collaboration Low Birth Weight Working Group. Low birth weight: Case definition & guidelines for data collection, analysis, and presentation of maternal immunization safety data. Vaccine. 2017 Dec 4;35(48 Pt A):6492-6500. https://doi.org/10.1016/j.vaccine.2017.01.049

2. World Health Organization. [Internet]. Nutrition Landscape Information System. Low Birth Weight. Available at: https://www.who.int/data/nutrition/nlis/info/low-birth-weight. Accessed October 2022.

3. Raymond, J. and Morrow, K. Krause and Mahan’s Food & the Nutrition Care Process, 15th edition: 2021 pages 912-914.

4. Nakano Y. Adult-Onset Diseases in Low-Birth-Weight Infants: Association with Adipose Tissue Maldevelopment. J Atheroscler Thromb. 2020 May 1;27(5):397-405. https://doi.org/10.5551/jat.rv17039.

5. Hughes MM, Black RE, Katz J. 2500-g Low Birth Weight Cutoff: History and Implications for Future Research and Policy. Matern Child Health J. 2017 Feb;21(2):283-289. https://doi.org/10.1007/s10995-016-2131-9.

6. Hailu LD, Kebede DL. Determinants of Low Birth Weight among Deliveries at a Referral Hospital in Northern Ethiopia. Biomed Res Int. 2018 Apr 23;2018:8169615. https://doi.org/10.1155/2018/8169615.

7. World Health Organization. [Internet]. Publications. Global Nutrition Targets 2025: low birth weight policy brief. Available at: https://www.who.int/publications/i/item/WHO-NMH-NHD-14.5. Accessed October 2022

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8. Centers for Disease Control and Prevention. [Internet]. National Center for Health Statistics. Birthweight and Gestation. Available at: https://www.cdc.gov/nchs/fastats/birthweight.htm. Accessed April 2023.

9. March of Dimes. [Internet]. Complications. Low Birthweight. Available at: https://www.marchofdimes.org/complications/low-birthweight.aspx. Accessed October 2022.

10. Cho J, Chien LC, Holditch-Davis D. Sociodemographic and Biological Factors of Health Disparities of Mothers and Their Very Low Birth-Weight Infants. Adv Neonatal Care. 2022 Oct 1;22(5):E169-E181. https://doi.org/10.1097/anc.0000000000000997.

11. Dzau, V. J., M. McClellan, J. M. McGinnis, and E. M. Finkelman, editors. 2017. Vital directions for health & health care: An initiative of the National Academy of Medicine. Washington, DC: National Academy of Medicine. Available at: https://nam.edu/wp-content/uploads/2018/02/Vital-Directions-for-Health-and-Health-Care-Final-Publication-022718.pdf.

12. Clay SL, Ibe-Lamberts K, Kelly KD, Nii-Aponsah H, Woodson MJ, Tines F, Mehdi SA. US-Born Black Women and Black Immigrant Women: an Exploration of Disparities in Health Care and Sociodemographic Factors Related to Low Birth Weight. J Racial Ethn Health Disparities. 2022 Nov 30. https://doi.org/10.1007/s40615-022-01477-2.

13. National Academies of Sciences, Engineering, and Medicine. 2020. Birth Settings in America: Improving Outcomes, Quality, Access, and Choice. Washington, DC: National Academies Press. https://doi.org/10.17226/25636.

14. Clay S, Griffin M, Averhart W. Black/White disparities in pregnant women in the United States: An examination of risk factors associated with Black/White racial identity. Health Soc Care Community. 2018 Feb 28. https://doi.org/10.1111/hsc.12565.

15. Clay SL. Black/White disparities in low-birth-weight pregnancy outcomes: an exploration of differences in health factors within a vulnerable population. International Journal of Health Promotion and Education. 2021. https://doi.org/10.1080/14635240.2021.1931934.

16. Clay SL, Woodson MJ, Kersh R. An Exploration of Socio-demographic, Economic, and Environmental Factors in Black/White Disparities in Low Birth Weight Outcomes: A Cross-Sectional Study. J Res Health Sci. 2021 May 12;21(2):e00511. https://pmc.ncbi.nlm.nih.gov/articles/PMC8957679/.

17. Andrasfay T, Goldman N. Intergenerational Change in Birthweight: Effects of Foreign-born Status and Race/Ethnicity. Epidemiology. 2020 Sep;31(5):649-658. https://doi.org/10.1097%2FEDE.0000000000001217.

18. Wartko PD, Wong EY, Enquobahrie DA. Maternal Birthplace is Associated with Low Birth Weight Within Racial/Ethnic Groups. Matern Child Health J. 2017 Jun;21(6):1358-1366. https://doi.org/10.1007%2Fs10995-016-2241-4.

19. Upadhyay RP, Taneja S, Ranjitkar S, Mazumder S, Bhandari N, Dua T, Shrestha L, Strand TA. Factors determining cognitive, motor and language scores in low birth weight infants from North India. PLoS One. 2021 May 12;16(5):e0251387. https://doi.org/10.1371/journal.pone.0251387.

20. Brown JVE, Walsh V, McGuire W. Formula versus maternal breast milk for feeding preterm or low birth weight infants. Cochrane Database Syst Rev. 2019 Aug 12;8(8):CD002972. https://doi.org/10.1002/14651858.cd002972.pub3.

21. Miller J, Tonkin E, Damarell RA, McPhee AJ, Suganuma M, Suganuma H, Middleton PF, Makrides M, Collins CT. A Systematic Review and Meta-Analysis of Human Milk Feeding and Morbidity in Very Low Birth Weight Infants. Nutrients. 2018 May 31;10(6):707. https://doi.org/10.3390/nu10060707.

22. Quigley M, Embleton ND, McGuire W. Formula versus donor breast milk for feeding preterm or low birth weight infants. Cochrane Database Syst Rev. 2018 Jun 20;6(6):CD002971. https://doi.org/10.1002/14651858.cd002971.pub4.

23. Parker MG, Stellwagen LM, Noble L, Kim JH, Poindexter BB, Puopolo KM; SECTION ON BREASTFEEDING, COMMITTEE ON NUTRITION, COMMITTEE ON FETUS AND NEWBORN. Promoting Human Milk and Breastfeeding for the Very Low Birth Weight Infant. Pediatrics. 2021 Nov;148(5):e2021054272. https://doi.org/10.1542/peds.2021-054272.