Return to Preterm Birth

CDC is participating in cooperative research with investigators at Michigan State University that builds on an NIH-funded, multi-ethnic community-based study of women from 62 clinics in 5 Michigan communities. The work of the CDC cooperative agreement expanded the Pregnancy Outcomes & Community Health (POUCH) study to evaluate of genomics and preterm birth among maternal-infant dyads. The study is focusing on immune system-related polymorphisms. The two main aims of this research are:

• to identify immune system-related gene polymorphisms and evaluate their associations with pregnancy outcome in a case-cohort design of mothers and offspring
• to develop prediction models for preterm delivery categorized by gestational week at delivery, clinical circumstances, placental pathology, and other predictors

In 2005, the NIH Maternal Fetal Medicine Network published results of a clinical trial that found that weekly injections of 17-alpha hydroxyprogesterone caproate (17P) was associated with a significant reduction of preterm birth among women with a history of prior preterm birth. To identify ways to translate these findings into clinical practice and public health programs CDC is participating in cooperative research with the University of Cincinnati to evaluate factors associated with acceptance of, use of, and adherence to 17P in the context of routine obstetrical care. The study will also investigate progesterone receptor genes of mothers and infants to explore possible mechanisms of action of 17P. Enrollment in this observational study is ongoing. The aims of this research are:

• to gain a better understanding of the clinical use of 17-P by identifying those who may be eligible for its administration for the prevention of preterm birth and evaluate the barriers to patient acceptance and adherence to 17-P use including socio-cultural and racial differences
• to determine if there are differences in the human progesterone receptor gene that explain responders and non-responders of 17-P treatment.

A collaborative project with University of Kansas, University of Tennessee at Memphis, and CDC is investigating oxygen independent and oxygen dependent defense mechanisms of the lower and upper genital tract and genes associated with regulating the inflammatory cascade. The study of genomics and proteomics will explore if cervico-vaginal biomarkers associated with altered innate immunity can be used to identify women at risk weeks or months before onset of preterm delivery. The specific aims of this project are:

• to determine the natural history of proteins involved in the defense mechanisms of the lower and upper genital tract in preventing ascending infection leading to PTB.
• to determine if local and systemic markers of the maternal/fetal inflammatory response are different for women who have received 17-alpha hydroxyprogesterone caproate (17P) in the context of their routine prenatal care versus women who did not receive 17P.

The vast majority of severe infant morbidity and mortality associated with preterm birth is due to very preterm birth (less than 32 weeks gestation). Information from large, population-based cohorts is needed to evaluate genetic, clinical, and social factors associated with very preterm birth and racial disparities in maternal and infant health. In collaboration with the California Department of Health Services and California Birth Defects and Monitoring Program, CDC is investigating the risk for very preterm birth using an existing large biobank of blood specimens from routine testing of pregnant women and infant blood spots from newborn screening. The biobank is linked to clinical information from medical record review, birth certificate data, prenatal screening data, newborn screening data and geocoded data on neighborhood stressors. Genomic investigations will focus on endocrine and inflammatory pathway genes. In this way, social and biomedical factors and gene-environment interactions associated with very preterm birth can be evaluated among black, Hispanic, and white infants. Because of the large size of the biobank utilized for this study (specimens from approximately 600,000 births), this is a unique opportunity to examine the risk factors for very preterm birth, the contribution of both maternal and infant genetic factors, and factors in multiple racial/ethnic groups.

CDC researchers are collaborating with the American College of Obstetricians and Gynecologists to conduct a survey among obstetricians regarding their knowledge, beliefs, and practices regarding the use of 17-hydroxyprogesterone caproate (17P) for the prevention of preterm birth. The survey will focus on provider use, drug availability, and patient acceptance and adherence.

Although births less than 32 weeks gestation are at highest risk for infant morbidity and mortality, infants born at 34–36 weeks gestation account for most preterm births; this group, referred to as “late preterm birth” is increasing at a greater rate than all other preterm births. The consequences of late preterm birth have not been adequately defined. CDC researchers are working with existing national databases to try and understand the consequences of late preterm birth for the infant as well as the reasons for the increasing rate of late preterm birth. In addition, CDC has funded surveillance in the State of Massachusetts that links birth records, maternal, infant, and child hospitalization records, and other clinical and public health databases. Investigators have used this database (Pregnancy to early Life Longitudinally Linked [PELL]) to begin exploring the phenomenon of late preterm birth.
 

Page last reviewed: 9/19/07
Page last modified: 9/19/07
Content source: Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion