Download & Other Tools
- Definition: Percentage of infants born prior to 37 weeks of gestation.Number of infants born prior to 37 weeks of gestation.
- Data Source: California Dept. of Public Health, Center for Health Statistics, Birth Statistical Master Files; Centers for Disease Control & Prevention, Natality data on CDC WONDER; Martin, et al. (2013), Births: Final Data for 2012. National Vital Statistics Reports, 62(9) (Mar. 2014).
- Footnote: Calculated from date of last reported mensus. The county-level data reflect the mother's county of residence, not the county in which the birth occurred. LNE (Low Number Event) refers to data that have been suppressed because there were fewer than 20 preterm births. Data exclude infants for whom preterm birth information is missing. N/A means that data are not available.
- Measures of Low Birthweight and Preterm Births on Kidsdata.org
For this topic, kidsdata.org offers the following measures:
- 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, 8 oz).
- Percent and number of infants born at very low birthweight, which is less than 1,500 grams (about 3 lbs, 5 oz).
- Percent and number of infants born preterm, which refers to births before 37 completed weeks of pregnancy. More than two-thirds of low birthweight babies are born preterm (1).
1. March of Dimes. (2012). Low birthweight. Retrieved from: http://www.marchofdimes.com/baby/low-birthweight.aspx
- Low Birthweight and Preterm Births
- Infant Mortality
- Prenatal Care
- Teen Births
- Why This Topic Is Important
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 1 in 8 of all pregnancies in the U.S. result in preterm birth (1).
Sources for this narrative:
1. March of Dimes. (2008). Low birthweight. Retrieved from: http://www.marchofdimes.com/baby/low-birthweight.aspx
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 babies. 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. (2013). Preterm labor and birth: Overview. Retrieved from: http://www.nichd.nih.gov/health/topics/preterm/Pages/default.aspx
- How Children Are Faring
The percentage of California babies born at low birthweight increased from 6.1% in 1999 to 6.9% in 2005, and has remained fairly steady since then. At the local level, percentages range from 4.9% to 7.7% in 2012 among counties with available data. The state and all counties with data in 2012 met the national Healthy People 2020 objective of no more than 7.8% of infants with low birthweight. However, figures vary by demographic group. For example, California mothers age 45 and older consistently have the highest percentages of low birthweight babies (21.4% in 2012), compared to younger mothers. Among California's racial/ethnic groups with available data, African American/Black mothers consistently have the highest percentages of infants at low birthweight (12.0% in 2012).
California babies born at a very low birthweight has remained steady since 1995, hovering between 1.1% and 1.2%. The state and all but two counties with available data in 2012 met the Healthy People 2020 objective of no more than 1.4% of infants with very low birthweight.
In 2012, 9.6% of infants were born preterm, which represents a decline from the high of 11.2% in 2005. At the county-level, figures range from 6.8% to 12.1% of infants born preterm in 2012. Among counties with available data, all but three met the Healthy People 2020 objective of no more than 11.4% of infants born prematurely.
- Policy Implications
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 (1).
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, including ensuring that pregnant women get adequate and appropriate nutrition (1), and avoiding increased risks of delivering early due to overweight and obesity (2)
- 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 (1)
- 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 (3)
- Addressing depression and depressive symptoms in pregnant women as depression has been found to have an impact on the incidence of preterm labor and low birthweight (4)
- Supporting a comprehensive approach to women’s health (1), including integration of reproductive planning into women’s routine health care by ensuring access to medical and dental services; 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 (5)
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. Annie E. Casey Foundation. (2009). Preventing low birthweight. Kids count indicator brief. Retrieved from: http://www.aecf.org/KnowledgeCenter/Publications.aspx?pubguid=%7B950E85EE-C2B4-466E-AA20-AE2010384A17%7D
2. McDonald, S. D., et al. (2010). Overweight and obesity in mothers and risk of preterm birth and low birth weight infants: Systematic review and meta-analyses. British Medical Journal. 341(3248). Retrieved from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2907482/
3. Chasnoff, I. J., et al. (2008). Perinatal substance use screening in California. NTI Upstream. Retrieved from: http://www.cdph.ca.gov/HealthInfo/healthyliving/childfamily/Documents/MO-ChasnoffPerinatalSubstanceUseScreeningReport-10-24-08.pdf
4. Grote, N., et al. A meta-analysis of depression during pregnancy and the risk of preterm, low birthweight, and intrauterine growth restriction. JAMA Psychiatry, 67(10), 1012-1024. Retrieved from: http://archpsyc.jamanetwork.com/article.aspx?articleid=210887
5. 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
- Websites with Related Information
- Association of Maternal and Child Health Programs
- California Maternal Quality Care Collaborative
- California Perinatal Quality Care Collaborative
- ChildStats.gov, Forum on Child and Family Statistics
- CityMatch, National Organization of Urban Maternal Child Health Leaders
- Maternal and Infant Health Research, Centers for Disease Control and Prevention
- RAND: Promising Practices Network
- The Maternal & Child Health Library at Georgetown University
- U.S. Department of Health and Human Services: Health Resources and Services Administration, Maternal and Child Health
- Key Reports
- Cardiovascular Risk Factors in Adolescents Born Preterm, 9/1/2014, Pediatrics, Sipola-Leppänen, M., et al.
- Elimination of Non-Medically Indicated (Elective) Deliveries Before 39 Weeks Gestational Age, 8/31/2011
- 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
- Kids Count Indicator Brief: Preventing Low Birthweight, 7/2009, The Annie E. Casey Foundation
- Meta-Analysis of Neurobehavioral Outcomes in Very Preterm and/or Very Low Weight Children, 7/2009, Pediatrics, Aarnoudse-Moens, et al.
- Premature Birth Report Cards, The March of Dimes
- Preterm Birth: Causes, Consequences, and Prevention, 2006, Institute of Medicine
- Term Pregnancy: A Period of Heterogeneous Risk for Infant Mortality, 6/2011, Reddy, U. M., et al.
- Trends in Birth Weight and Gestational Length Among Singleton Term Births in the United States 1990-2005, 2/2010, American Journal of Obstetrics and Gynecology, Donahue, et al.
- Understanding Racial and Ethnic Disparities in U.S. Infant Mortality Rates, 9/2011, Centers for Disease Control and Prevention, MacDorman, M. F., & Mathews, M. S.
- Who Are America’s Poor Children? Examining Health Disparities by Race and Ethnicity, 7/2011, National Center for Children in Poverty, Seith, D., & Kalof, C.
- County/Regional Reports
- 2014 Youth Wellbeing Report Card: Santa Monica, California, 2014, Cradle to Career Working Group
- Fresno Community Scorecard, Fresno Business Council and ValleyPBS
- San Diego County Report Card on Children & Families, 2013, The Children's Initiative and Johnson Group Consulting, Inc.
- Santa Barbara County Children's Scorecard, 2011, Santa Barbara County KIDS Network
- Tulare County Children’s Report Card 2010, 2011, Children's Services Network
- Tuolumne County Profile 2012
- More Data Sources For Low Birthweight and Preterm Births
- Robert Wood Johnson County Health Rankings & Roadmaps
- The Youngest Americans: A Statistical Portrait of Infants and Toddlers in the United States, 2013, Child Trends, Murphey, D., Cooper, M., & Forry, N.