Low Birthweight

Low birthweight (LBW), defined as birth weights below 5 pounds, 8 ounces (<2,500 grams), is a leading cause of infant mortality in the United States,[1] and is inequitably distributed across race/ethnicity groups.[2] Nationally, Black, American Indian/Alaska Native, and Native Hawaiian or Other Pacific Islander women had disproportionately high shares of low birthweight births compared to White women. The national Healthy People 2030 objectives, set by the U.S. Department of Health and Human Services, includes objectives for improving the health and safety of infants, including reduction of infant deaths. Reducing infants born with low birthweight, preterm births, and sudden infant death syndrome can contribute to reductions in infant deaths.[3]
To measure the prevalence of low birthweight, the County of San Diego Health and Human Services' Maternal, Child, and Family Health Services Branch analyzes birth data from the California Department of Public Health's Center for Health Statistics and Informatics.[4] The data are by region of the birthing parent’s residence, their race and ethnicity, nativity, age, educational attainment, and other characteristics.
Because these data show wide gaps between racial groups and it is expected that County action can mitigate this inequity, the prevalence of low birthweight is shown by race. National estimates also find that Black women are twice as likely as White women to have babies with low birthweight when controlling for poverty.[5] As indicated in the California Dignity in Pregnancy and Childbirth Act, “there is a growing body of evidence that Black women are often treated unfairly and unequally in the health care system.”[6]
In 2021 in the United States, 8.5% of all infants were born with low birthweight;[7] the U.S. performs poorly on this metric compared to other developed countries.[8] In California in 2021, the percentage of babies born with low birthweight was 7.3%.[9] In 2021 in San Diego County, 6.9% of infants were born with low birthweight. Infants born to African American/Black or Asian mothers were more likely to have low birthweight compared to infants born to mothers in the county overall (Figure 1). South, Central, North Central, and East HHSA Service Regions had higher percentages of births with low birthweight compared to the county overall, although the difference was small (6.9% overall vs. 7.0-7.5% for those areas) (Figure 4).
Families in poverty are disproportionately impacted by infant mortality,[10] perhaps because of limited healthcare access, a poorly integrated healthcare system, nutrition deficits, and poorer environmental conditions in low-income neighborhoods.[11],[12],[13],[14],[15] Public health interventions, including improving healthcare access,[16] reducing particle air pollution,[17] and nutrition interventions[18] can dramatically reduce low birthweight.
The County of San Diego runs several programs that may help address low birthweight, including some targeted for populations who are particularly at risk. These include the Black Infant Health Program[19], the Perinatal Equity Initiative[20], First 5 First Steps[21], the Nurse Family Partnership Program, and the Maternal Child Health Program.[22] Although County policy and programs may not be able to solve all problems that lead to low birthweight, they can be leveraged to improve environmental conditions, nutrition, access to healthcare and community resources, and medical treatment for at-risk pregnant people. 

Data Information
Data Source: State of California, Department of Public Health, Center for Health Statistics and Informatics, California Comprehensive Birth Files. Prepared by the County of San Diego, Health and Human Services Agency, Public Health Services, Maternal, Child and Family Health Services (www.sdmcfhs.org), 11/18/2022.
  • Persons of Hispanic or Latino ethnicity may belong to any race group. All categories except Hispanic or Latino include persons for whom race is known but ethnicity is non-Hispanic or unknown.
  • Percentages for the categories of Native American/Alaskan, Pacific Islander, and Unknown Nativity are based on a very small number of births and should be interpreted with caution. A percentage was not calculated and shown for the categories of Other Race and Undetermined/Unknown Gender of Infant because the reported numbers were too low.
References
  1. KFF. (November 2022). Racial Disparities in Maternal and Infant Health: Current Status and Efforts to Address Them. Retrieved August 4, 2023. https://www.kff.org/racial-equity-and-health-policy/issue-brief/racial-disparities-in-maternal-and-infant-health-current-status-and-efforts-to-address-them/
  2. Healthy People 2030. (n.d.). Reduce the rate of infant deaths—Healthy People 2030. Retrieved September 30, 2022, from https://health.gov/healthypeople/objectives-and-data/browse-objectives/infants/reduce-rate-infant-deaths-mich-02
  3. Maternal, Child, and Family Health Services (MCFHS); Health & Human Services; County of San Diego. (2023). Statistics. Retrieved April 10, 2023, from https://www.sandiegocounty.gov/content/sdc/hhsa/programs/phs/maternal_child_family_health_services/MCFHSstatistics.html
  4. Innovative prenatal care initiative shows early signs of potential for improving birth outcomes. (n.d.). Urban Institute. Retrieved September 30, 2022, from https://www.urban.org/urban-wire/innovative-prenatal-care-initiative-shows-early-signs-potential-improving-birth-outcomes
  5. SB 464—California Senate. (n.d.). Retrieved September 1, 2022, from https://openstates.org/ca/bills/20192020/SB464/
  6. Rothwell, J. (2015). Starting behind: Low birth weight in the United States. Brookings. https://www.brookings.edu/blog/social-mobility-memos/2015/03/04/starting-behind-low-birth-weight-in-the-united-states/
  7. Stats of the States—Low Birthweight Births. (2022, February 25). https://www.cdc.gov/nchs/pressroom/sosmap/lbw_births/lbw.htm
  8. Chen, A., Oster, E., & Williams, H. (2014). Why is Infant Mortality Higher in the US than in Europe? (No. w20525; p. w20525). National Bureau of Economic Research. https://doi.org/10.3386/w20525
  9. Neggers, Y., & Crowe, K. (2013). Low birth weight outcomes: Why better in Cuba than Alabama? The Journal of the American Board of Family Medicine, 26(2), 187–195. https://doi.org/10.3122/jabfm.2013.02.120227
  10. Li, X., Huang, S., Jiao, A., Yang, X., Yun, J., Wang, Y., Xue, X., Chu, Y., Liu, F., Liu, Y., Ren, M., Chen, X., Li, N., Lu, Y., Mao, Z., Tian, L., & Xiang, H. (2017). Association between ambient fine particulate matter and preterm birth or term low birth weight: An updated systematic review and meta-analysis. Environmental Pollution, 227, 596–605. https://doi.org/10.1016/j.envpol.2017.03.055
  11. Lopes, K. da S., Ota, E., Shakya, P., Dagvadorj, A., Balogun, O. O., Peña-Rosas, J. P., De-Regil, L. M., & Mori, R. (2017). Effects of nutrition interventions during pregnancy on low birth weight: An overview of systematic reviews. BMJ Global Health, 2(3), e000389. https://doi.org/10.1136/bmjgh-2017-000389
  12. Sabo, S., Wightman, P., McCue, K., Butler, M., Pilling, V., Jimenez, D. J., Celaya, M., & Rumann, S. (2021). Addressing maternal and child health equity through a community health worker home visiting intervention to reduce low birth weight: Retrospective quasi-experimental study of the Arizona Health Start Programme. BMJ Open, 11(6), e045014. https://doi.org/10.1136/bmjopen-2020-045014
  13. Rothwell, J. (2015). Starting behind: Low birth weight in the United States. Brookings. Retrieved from https://www.brookings.edu/blog/social-mobility-memos/2015/03/04/starting-behind-low-birth-weight-in-the-united-states/
  14. Sabo, S., Wightman, P., McCue, K., Butler, M., Pilling, V., Jimenez, D. J., Celaya, M., & Rumann, S. (2021). Addressing maternal and child health equity through a community health worker home visiting intervention to reduce low birth weight: Retrospective quasi-experimental study of the Arizona Health Start Programme. BMJ Open, 11(6), e045014. https://doi.org/10.1136/bmjopen-2020-045014
  15. Li, X., Huang, S., Jiao, A., Yang, X., Yun, J., Wang, Y., Xue, X., Chu, Y., Liu, F., Liu, Y., Ren, M., Chen, X., Li, N., Lu, Y., Mao, Z., Tian, L., & Xiang, H. (2017). Association between ambient fine particulate matter and preterm birth or term low birth weight: An updated systematic review and meta-analysis. Environmental Pollution, 227, 596–605. https://doi.org/10.1016/j.envpol.2017.03.055
  16. Lopes, K. da S., Ota, E., Shakya, P., Dagvadorj, A., Balogun, O. O., Peña-Rosas, J. P., De-Regil, L. M., & Mori, R. (2017). Effects of nutrition interventions during pregnancy on low birth weight: An overview of systematic reviews. BMJ Global Health, 2(3), e000389. https://doi.org/10.1136/bmjgh-2017-000389
  17. Black Infant Health Program.(n.d.) Health and Human Services Agency San Diego County. Retrieved September 18, 2023, from https://www.sandiegocounty.gov/content/sdc/hhsa/programs/phs/black_infant_health_program.html
  18. The Perinatal Equity Initiative. (n.d) Black Legacy Now. Retrieved September 18, 2023, from https://www.blacklegacynowsd.com/?msclkid=bc9739eabd0411ec8c2a1f6b894251d0
  19. First 5 First Steps Home Visiting Program. (n.d.) First 5 San Diego. Retrieved September 18, 2023, from https://first5sandiego.org/programs/family/first-5-first-steps-home-visiting-program/
  20. Home Visiting Programs. (n.d.) Medical Care Services San Diego County. Retrieved September 18, 2023, from https://www.sandiegocounty.gov/content/sdc/hhsa/programs/mcsd/Office-of-Nursing-Excellence/Home-Visiting-Program.html
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Updated February 7, 2024