CDC scientists are collaborating with many partners, including state health departments, university researchers, and other health care professionals to understand why preterm births occur and what can be done to help prevent them. CDC’s Division of Reproductive Health is engaged in the following activities:
Science to Practice: 17-alpha hydroxyprogesterone caproate
In 2003, the NIH Maternal Fetal Medicine Network published results of a clinical trial that found pregnant women with a history of prior preterm birth who received weekly injections of 17-alpha hydroxyprogesterone caproate (17P) had significant reductions in preterm birth. To identify ways to translate these findings into clinical practice and public health programs, CDC is participating in collaborative research with the University of Cincinnati to evaluate factors associated with acceptance, use, and adherence to 17P in the context of routine prenatal care.
Vitamin D Studies
Vitamin D deficiency is estimated to affect 38% of U.S. reproductive-aged women and 28% of U.S. pregnant women. Among pregnant women, vitamin D deficiency varies significantly by racial and ethnic groups, ranging from 13% of non-Hispanic white women to 80% of non-Hispanic black women. Women who have low levels of vitamin D may be at higher risk for problems during pregnancy, including preterm birth. Because this is a new idea, research is needed to clarify this association. CDC is conducting a study in Michigan, North Carolina, and Washington State to examine vitamin D levels in stored blood samples of women who had a preterm birth. CDC is also funding researchers at the University of Pittsburgh to conduct a study examining whether vitamin D deficiency and variations in vitamin D receptor genes are associated with risk of preterm birth in pregnant women.
Research suggests there may be genetic factors causing preterm births, even when other known risks are taken into account. CDC is partnering with Michigan State University, Kansas University Medical Center, University of Tennessee in Memphis, California Department of Health Services, California Birth Defects Monitoring Program, and the March of Dimes Foundation on the following studies to answer this question:
- Immune System Gene Polymorphisms and Preterm Delivery: a study to evaluate the socioeconomic, clinical, biologic, and genetic factors associated with preterm birth.
- Functional Genomics and Proteomic Markers of Preterm Delivery: an investigation of oxygen independent and oxygen dependent defense mechanisms of the lower and upper genital tract and genes associated with regulating immune response to infection.
- California Very Preterm Birth Study: an evaluation of the social and biomedical factors and gene-environment interactions associated with very preterm birth (less than 34 weeks gestation) among black, Hispanic, and white infants.
Smoking in Pregnancy
Despite decreases in smoking prevalence over recent years, almost 25% of women of reproductive age are smokers, and 1 of 10 women report smoking at some point during pregnancy. In addition to a variety of negative pregnancy outcomes, tobacco use during pregnancy is associated with 10% of the cases of preterm birth. CDC is actively working to improve reproductive health outcomes through the reduction of smoking among women before, during, and after pregnancy in the United States and globally. Learn more about CDC’s work on tobacco use in pregnancy.
Surveillance, Data Quality, and Data Linkages
Much of CDC’s maternal and infant health surveillance, data quality improvement, and data linkage efforts revolve around birth certificates, the primary resource for learning about preterm birth rates in the United States. CDC partners with the National Center for Health Statistics (NCHS) and the National Association for Public Health Statistics and Information Systems (NAPHSIS) to promote the accurate recording of gestational age on birth certificates, that is critical to calculate the rate of preterm birth, better understand the impact of preterm birth, follow trends, and make recommendations about preventing preterm birth. CDC is also involved in data linkage projects for the jurisdictions of NYC and Kansas that link together birth certificate data with other administrative or survey data, including fetal death certificates, hospital discharge records, and PRAMS survey data. Linked data files allow researchers to study the factors that influence disability, disease, and death.
CDC staff work with the innovative text4baby program, the nation’s first free mobile health service, which has been implemented through an unprecedented public-private partnership. Text4baby was developed by the National Healthy Mothers, Healthy Babies Coalition, Voxiva, CTIA—The Wireless Foundation, the U.S. Department of Health and Human Services (HHS), and Johnson & Johnson, the founding sponsor. Since the national launch in February 2010, text4baby has reached more than 500,000 people with critical health and safety tips about pregnancy and a baby’s first year of life. The program aims are to reduce women’s barriers to accessing information and resources, increase their knowledge of key health topics, and increase their positive health behaviors. Women can sign up by texting BABY or BEBE (for Spanish) to 511411 to receive approximately 3 free text messages per week timed to their due date or their baby’s birth date.
Additional Sources of CDC Preterm Birth Data
The CDC National ART Surveillance System (NASS) is a nationwide system for monitoring ART use and outcomes. Analysis of NASS data has supported the evidence suggesting a higher risk for certain adverse outcomes, including preterm birth, among women who use ART.
The Pregnancy Risk Assessment Monitoring System (PRAMS) is a surveillance project of the CDC and state health departments. PRAMS collects state-specific, population-based data on maternal attitudes and experiences before, during, and shortly after pregnancy. PRAMS data have been used to analyze the characteristics of women who experienced preterm delivery.
CDC’s NCHS is the nation's principal health statistics agency. Through its relationship with vital registration systems throughout the country, NCHS collects, analyzes, and publishes data on a wide range of health indicators, including preterm birth. For more information, visit the NCHS birth data page.
Perinatal Quality Collaboratives
In 2011, CDC launched a new multiyear initiative to support the advancement of state-based Perinatal Quality Collaboratives (PQCs). The funded PQCs include the California Perinatal Quality Care Collaborative and California Maternal Quality Care Collaborative, the New York State Obstetrical and Neonatal Quality Collaborative, and the Ohio Perinatal Collaboration to Improve Birth Data and Prematurity Outcomes. The funded PQCs will focus on—
- Reducing elective inductions and cesarean sections without medical indication prior to 39 weeks gestation.
- Using steroids for pregnant women between 24 weeks and 34 weeks of gestation who are at risk of preterm delivery within 7 days.
- Reducing blood stream infections among infants with central lines in the neonatal intensive care units.
PQCs will also expand existing networks, document methods and barriers, and develop methods that can be used to expand capacity to other states and regions.
MCH Epidemiology Assignees
The Maternal and Child Health Epidemiology Program (MCHEP) assigns senior CDC epidemiologists and graduate-level fellows to state health departments and other public health agencies and organizations, where they focus on MCH epidemiology capacity building and applied research. The MCHEP has assigned more than 35 senior CDC epidemiologists focused on MCH epidemiology capacity building and applied research to 20 states since 1987. Assignees provide direct assistance to public health agencies on a variety of topics, including preterm birth.
Strong Start Initiative
The Department of Health and Human Services launched the Strong Start Initiative to increase healthy deliveries and reduce preterm births. To tackle this problem, the Center for Medicare and Medicaid Innovation has awarded grants to health care providers and community organizations to improve prenatal care to women covered by Medicaid or Children’s Health Insurance Program (CHIP). CDC is one of the federal agencies that helped identify Strong Start’s goals and focus and continues to provide initiative support.