Kidsdata.org offers the percent and number of infants born at low birthweight, by age and race/ethnicity of mother. Low birthweight is defined as babies who are born at less than 2,500 grams (or about 5 lbs, 5 oz). Also available is the percent and number of infants born at very low birthweight, which is less than 1,500 grams (about 3 lbs, 3 oz). The percent and number of infants born preterm is available, as well. Preterm births refer to babies born before 37 completed weeks of pregnancy. More than two-thirds of low birthweight babies are born preterm (1).

1. March of Dimes. (2008). Low birthweight. Retrieved from: http://www.marchofdimes.com/professionals/medicalresources_lowbirthweight.html

In addition to being at higher risk of death during the first year of life, low birthweight babies are at increased risk of long-term disabilities, including developmental delays and learning disabilities, chronic respiratory problems, cerebral palsy, hearing and vision impairments, and autism (1, 2). Women who are more likely to give birth to low birthweight babies include those with low incomes, inadequate prenatal care, smoking habits, and those under age 16 or over age 45 (1).

Babies born prematurely also are at increased risk for similar adverse outcomes as low birthweight infants (3). Preterm birth is one of the leading causes of infant death in the U.S. (4). Most preterm babies require specialized care in a newborn intensive care unit (3). Women who are most likely to give birth preterm include those who have had a previous premature birth, those pregnant with twins, triplets, or more, and those with certain uterine abnormalities. In addition, demographic and behavioral factors can increase the risk of delivering preterm, including low socioeconomic status, being under age 17 or over age 35, inadequate prenatal care, and smoking during pregnancy (3). About 12% of all pregnancies in the U.S. result in preterm birth (4).

Sources for this narrative:

1. March of Dimes. (2008). Low birthweight. Retrieved from: http://www.marchofdimes.com/professionals/medicalresources_lowbirthweight.html
2. Pinto-Martin, J. A., et al. (2011). Prevalence of Autism Spectrum Disorder in adolescents born weighing <2000 grams. Pediatrics, 2010-2846. Retrieved from: http://pediatrics.aappublications.org/content/early/2011/10/14/peds.2010-2846.abstract
3. March of Dimes. (2009-2010). Premature birth. Retrieved from: http://www.marchofdimes.com/baby/premature_indepth.html
4. Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health. (2010). Preterm labor and birth. Retrieved from: http://www.nichd.nih.gov/health/topics/Preterm_Labor_and_Birth.cfm

Some of the risk factors for low birthweight and preterm birth can be influenced by public and institutional policy focused on education, prevention, and treatment. These factors include smoking, drinking alcohol, or using illicit substances during pregnancy; being a teenage mother, and being overweight or underweight. Preterm births also can be medically induced or occur through elective cesarean sections, and they are more likely to occur when a mother gives birth to more than one baby at a time.

According to research and subject experts, policy options that could influence low birthweight and preterm births include:

• Providing access to early and regular high-quality prenatal care (1)
• Ensuring that health care systems train clinicians on identifying smokers among pregnant women, and that evidence-based tobacco cessation services are available to pregnant women and reimbursed by insurance (2, 3)
• Sustaining adequate funding for universal screening for substance use among pregnant women, and for treatment services specifically designed for pregnant women who use alcohol or illicit drugs (4, 5)
• Supporting public education and systems change to reduce the number of non-medically indicated induced preterm deliveries and cesareans (6, 7)
• Promoting expanded research, education and demonstration projects aimed at reducing the rates of preterm labor and delivery (8)
• Supporting a comprehensive approach to women’s health, including integration of reproductive planning into women’s routine health care, as good health before conception can improve pregnancy outcomes; included in this approach should be a focus on increasing interpregnancy intervals (at least 12 months), recognizing that short intervals are associated with increased risk for preterm birth (9, 10)

For more policy ideas and research on this topic, see kidsdata.org’s Research & Links section, or visit the March of Dimes. Also see Policy Implications on kidsdata.org under the Prenatal Care, Infant Mortality, Teen Births and Teen Sexual Health topics.

Sources for this narrative:

1. March of Dimes. (2008). Low birthweight. Retrieved from: http://www.marchofdimes.com/professionals/medicalresources_lowbirthweight.html
2. Centers for Disease Control and Prevention. (2011). Tobacco use and pregnancy. Retrieved from: http://www.cdc.gov/reproductivehealth/TobaccoUsePregnancy/
3. U.S. Department of Health and Human Services. (2008). Systems change: Treating tobacco use and dependence, based on the Public Health Service (PHS) clinical practice guideline—2008 update. Retrieved from: http://www.ahrq.gov/clinic/tobacco/systems.htm
4. Chasnoff, I. J., McGourty, R. F., Wells, A. M., & McCurties, S. (2008). Perinatal substance use screening in California. NTI Upstream. Retrieved from: http://www.adp.cahwnet.gov/Alcohol/pdf/PerinatalSubstanceUseSR.pdf
5. Brady, T. M., & Ashley, O. S. (2005). Women in substance abuse treatment: Results from the Alcohol and Drug Services Study (ADSS). US Department of Health and Human Services. Retrieved from: http://oas.samhsa.gov/WomenTX/WomenTX.htm#2.4
6. March of Dimes. (2010). Elimination of non-medically indicated (elective) deliveries before 39 weeks gestational age. California Maternal Quality Care Collaborative, California Department of Public Health. Retrieved from:  http://www.cdph.ca.gov/programs/mcah/Documents/MCAH-EliminationOfNon-MedicallyIndicatedDeliveries.pdf
7. Fleischman, A. R. (2010). What happens when babies are born too early? March of Dimes Foundation, Testimony before the US House of Representatives: Prematurity and Infant Mortality. Retrieved from: http://www.modimes.org/advocacy/prevention_indepth.html
8. U.S. Department of Health and Human Services, Office of Adolescent Health. (2010). Programs for replication. Retrieved from: http://www.hhs.gov/ash/oah/oah-initiatives/tpp/programs.html
9. DeFranco et al. (2007). A short interprenancy interval is a risk factor for preterm birth and its recurrence. American Journal of Obstetrics and Gynecology, 197(3), 264.e1-264.e6. Retrieved from: http://www.ajog.org/article/S0002-9378%2807%2900818-6/abstract
10. Wise, P. (2008). Transforming preconceptional, prenatal, and interconceptional care into a comprehensive commitment to women's health. Women’s Health Issues, 18(6), Supplement, S13-S18. Retrieved from: http://www.whijournal.com/article/S1049-3867(08)00109-6/fulltext

The percentage of California babies born at low birthweight increased from 6.1% in '99 to 6.9% in '05, and has remained fairly steady since then. County-level figures vary widely, from 4.9% to 7.8% in '10. That year, the state and all counties with available data met the national Healthy People 2020 objective of no more than 7.8% of infants with low birthweight. In '10, as in recent years, African American/Black mothers in California had a higher percentage of infants at low birthweight than mothers from other racial/ethnic groups. Differences by age of mother also are apparent; mothers age 45 and older, compared to younger mothers, had the highest percentage of low birthweight babies in California in '10, as in previous years.

California babies born at a very low birthweight has remained steady since '95, hovering between 1.1% and 1.2%. The state and all but two counties with available data in '10 met the Healthy People 2020 objective of no more than 1.4% of infants with very low birthweight.

In 2010, 10.0% of infants were born preterm, which represents a decline from the high of 11.2% in '05. As with low birthweight rates, county-level figures vary widely, from 6.4% to 13.3% of infants born preterm in '10. Among counties with available data, all but six met the Healthy People 2020 objective of no more than 11.4% of infants born prematurely.

• Association of Maternal and Child Health Programs
• ChildStats.gov, Federal Interagency Forum on Child and Family Statistics
• CityMatch
• Maternal and Infant Health Research, Centers for Disease Control and Prevention
• Pediatrics Journal
• RAND: Promising Practices Network
• The Maternal & Child Health Library at Georgetown University
• U.S. Maternal and Child Health Bureau

• 2011 Premature Birth Report Cards, The March of Dimes
• Closing the Black-White Gap in Birth Outcomes: A Life-Course Approach, 2010, Ethnicity and Disease, Lu et al.
• Differing Birth Weight among Infants of U.S.-Born Blacks, African-Born Blacks, and U.S.-Born Whites, 1997, New England Journal of Medicine, David & Collins
• Healthy Start National Evaluation 2006: Evidence of Trends, Risk Factors, and Intervention Strategies, U.S. Department of Health and Human Services, Health Resources and Services Administration, Maternal and Child Health Bureau
• Outcomes in Young Adulthood for Very-Low-Birth-Weight Infants, 2002, The New England Journal of Medicine, Hack et al.
• Preterm Birth: Causes, Consequences, and Prevention, 2006, Institute of Medicine
• Recommendations to Improve Preconception Health and Health Care --- United States, 04/21/2006, Centers for Disease Control and Prevention, Morbidity and Mortality Weekly Report, Johnson et al.
• Who Are America’s Poor Children? Examining Health Disparities by Race and Ethnicity, 07/2011, National Center for Children in Poverty

• San Diego County Report Card on Children & Families, 2011, The Children's Initiative and Johnson Group Consulting, Inc.
• Santa Barbara County Children's Scorecard, 2010, Santa Barbara County KIDS Network
• Tulare County Children’s Report Card 2010, 2011, Children's Services Network

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