WASHINGTON, DC—Although a recent CDC report shows that there has been a small decline in the preterm birth rate in the US, levels of preterm births remain higher than at any point in the 1980s and 1990s, government officials told a House subcommittee. “Preterm birth is an important risk for infant mortality. More than one-third of infant deaths can be directly attributed to preterm birth,” said William Callaghan, MD, acting chief for the Maternal and Infant Health Branch in CDC’s Division of Reproductive Health.

Preterm birth is defined as being born at least three weeks before the predicted due date. In May, CDC released a report showing that the preterm birth rate declined nationally from 12.8% to 12.3% of live births from 2006 to 2008. Despite this decrease, more than half a million infants are born too soon, putting them at risk for a number of health problems, including infant mortality.

At a hearing held in May by the House Energy and Commerce Subcommittee on Health, subcommittee members wanted to know what should be done to reduce the rate of preterm births. “Despite the recent decrease, preterm birth remains a pressing health issue which deserves ample attention,” said subcommittee Chairman Rep Frank Pallone, D-NJ.

Addressing Preterm Births

Preterm birth is the second leading cause of all infant mortality. In general, about 50% of preterm births occur spontaneously following premature labor. According to NIH, possible causes for spontaneous preterm birth include intrauterine infection or inflammation, uterine bleeding, excessive uterine stretch, maternal psychosocial stress, and fetal physiological stress.

Preterm birth is the leading cause of neurological disability, such as cerebral palsy and intellectual disabilities in children. It is also costly to the healthcare system, according to Callaghan. “In 2005, it was estimated that the costs associated with preterm birth were $26.2 billion dollars.”

Callaghan told the subcommittee that the problem of preterm births and infant mortality is an especially critical issue in the African-American community, where African-American women are one and half times more likely to deliver a preterm infant compared to white women. The infant mortality rate for black infants is more than twice that of white infants.

Subcommittee members wanted to know why the rate of preterm births is higher among African-American women than white women. “Understanding that is one of the holy grails in all of perinatal health and perinatal medicine,” Callaghan responded. “These are disparities that we have seen over and over again.”

Callaghan said that even when they adjust for socioeconomic factors and education levels, the gap in the preterm infant rate between African-American women and white women does not disappear. “In fact, the gaps are even greater when we look at the difference between the most-well-off African-American women and the most well-off white women.”

Researchers are trying to identify factors to explain the disparities by examining genetics, socio-economic status, stress, and maternal education, among other factors. NIH will hold a scientific workshop in August of 2010 focused on disparities in infant mortality, still birth, and preterm birth with the goal of identifying factors associated with the disparities and to design a plan to advance research on the topic.

Research and Data Collection

Both CDC and NIH are involved with preterm birth research. Catherine Spong, MD, chief of the Pregnancy and Perinatology Branch at NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), said that NICHD funds four research networks around the country that focus on aspects of preterm births and infant mortality.

Spong said that NICHD recently funded the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be. The study will examine the mechanisms and predicators of adverse pregnancy outcomes in nulliparous women in a multicenter cohort study. Women for whom the current pregnancy will lead to their first delivery comprise about 40% of the US births each year. Adverse pregnancy outcomes are unpredictable in these women because there is no information from previous pregnancy outcomes. “The aim of this large, multicenter cohort study is to identify markers early in pregnancy that will identify women at the highest risk for preterm birth, preeclampsia, fetal growth restriction, and stillbirth.”

One study that CDC is involved in is a study to better understand why late preterm births, which are births occurring between 34 and 36 weeks gestation, have increased and driven the overall preterm birth rate up during the last several decades. In a small CDC study in metropolitan Atlanta researchers will identify late preterm births and review the medical records of these women and infants. Researchers would like to determine whether it is feasible to expect that answers can be found in these medical records to explain why and how the preterm birth occurred.

Callaghan said that CDC also conducts surveillance of preterm births by collecting birth and death certificates. CDC is able to use birth certificate information to evaluate factors such as tobacco use, race, mother’s education, and the infant’s birth weight, allowing the agency to identify variations in rates of preterm births at the state and county levels. When birth certificate information is linked to information on death certificates, CDC is also able to look at causes of death for babies who died during the first year of their life.

Organizations

Representatives from organizations testified about public health interventions that could be instituted to reduce preterm births.

Both the American Congress of Obstetricians and Gynecologists (ACOG) and the March of Dimes urged Congress to support the reauthorization of the PREEMIE Act, a law that authorizes funding to expand research, surveillance, and projects to investigate and prevent the causes of preterm birth. The act expires at the end of FY 2011. “We hope that one of the outcomes of this hearing is that you will agree to work with us to draft and obtain swift enactment of legislation authorizing and expanding upon the progress made as a result of the 2006 PREEMIE Act,” said Alan Fleischman, MD, March of Dimes senior vice president and medical director.

Charles Mahan, MD, dean and professor emeritus at the University of South Florida College of Public Health and the Lawton and Rhea Chiles Center for Healthy Mothers and Healthy Babies, testified that an immediate step that Congress could take to reduce the number of preterm births is to not permit Medicaid to pay for elective inductions and elective cesareans at any stage of pregnancy.

ACOG recommends that cesarean delivery on maternal request in the absence of a medical reason should not be performed before gestational age of 39 weeks has been determined, unless lung maturity in the baby has been documented. ACOG does not recommend cesarean delivery on maternal request for women desiring several children, given the health risks associated with it.

Mahan stated, however, that he did not agree with elective inductions and cesareans at any state of pregnancy. Elective C-sections are hazardous to the health of the mother and the baby and are not “equivalent to having a vaginal birth,” Mahan stated. “You could pick up the phone, call CMS, and tell Medicaid to stop paying for elective inductions and cesareans at any stage of pregnancy,” he told subcommittee members.

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