Problem Statement*
Jennifer Howse, Ph.D.
Not long ago, discourse on preterm birth was nearly always centered on the role of the mother. Increasingly, however, environmental hazards are being recognized as contributors to the devastating and costly problem of preterm birth. One purpose of this conference is to help establish a framework that will allow us to broaden our perspective and link our knowledge about environmental hazards to their potential effects on preterm birth. The work of the Honorable Paul Rogers, chair of the Roundtable on Environmental Health Sciences, Research, and Medicine, has been a major catalyst for this wider perspective.
The Institute of Medicine (IOM) is another positive force that is helping to redefine our thinking about preterm birth and its causes, and we are honored that the IOM has chosen to lend its weight to the examination of this issue. Several other important organizations are also represented at this workshop, including the National Institute of Environmental Health Sciences, the Environmental Protection Agency, and the Centers for Disease Control and Prevention, all critical partners in research efforts to identify potential environmental and social contributors to preterm birth.
The interest of the March of Dimes in preterm birth is long-standing. Our efforts began in the early 1960s after the battle against polio had largely been won. Prevention of birth defects and infant mortality became the clinical components of our mission at that time, and we are proud to have been leaders in creating a blueprint for the establishment of neonatal intensive care units in the
early 1970s. We also made contributions in research, particularly in respiratory therapy, which have helped extend the survival of infants in neonatal intensive care.
We can all take great pride and consolation in the sound record that we have achieved in this country since the early 1960s, and even earlier, in reducing infant mortality. Infant mortality rates have declined substantially since that time, although they have leveled off somewhat in recent years and 2010 targets are not yet in sight. However, juxtaposed against the declining infant mortality rate is the ever-increasing rate of preterm births, which rose from under 9 percent in 1980 to 11.6 percent in 2000, and which is considerably higher in the United States than in other industrialized countries. This increase is driven by a complex of factors that we are struggling to understand.
A possible approach to lowering preterm birth rates is to examine how they relate to race and ethnicity. An African-American baby’s risk for being born prematurely is nearly double that for a Caucasian baby. The risk is also higher for babies born to Native American and Hispanic women. For some time, the IOM has been at the forefront of noting such disparities and has been exploring possible links between preterm birth and environmental hazards.
The IOM’s 1999 report Toward Environmental Justice: Research, Education, and Health Policy Needs concluded that certain communities do tend to have higher levels of exposure to environmental toxicants. It also concluded that such exposure is compounded by various socioeconomic factors that often make these communities less able to deal with the problem, such as lower levels of education, higher levels of stress, and inadequate access to health care.
At the March of Dimes, we have believed for some time that progress toward understanding the biological and social aspects of labor and delivery needs to be accelerated. We have also noted that an epidemiological approach to understanding preterm labor has not yet received sufficient attention. During the past 10 years, the March of Dimes has invested resources in these issues. The investment was modest at first, but recently we have devoted many millions of research dollars to studying preterm birth.
In 1998, we initiated a focused perinatal epidemiological research portfolio called the Perinatal Epidemiological Research Initiative (PERI), an ongoing portfolio funded at just under $4 million. Through this portfolio, we seek to examine how the influence of external factors can be understood in terms of their biological plausibility. We did not expect the overwhelming response that we received from our request for proposals. More than 100 scientists from all over the world responded. We asked applicants to explain how they would conduct further exploration into the medical, psychological, and social factors that may combine with maternal and fetal biochemistry to lead to preterm birth. At the end of the review process, a panel of experts selected six promising epidemiological research projects for funding, including projects that focused on how elements such as infections, genetic predispositions, low socioeconomic status, stress, and
other factors can initiate pathways to preterm delivery. We have been very pleased with the PERI studies so far.
Preterm birth is a complicated public health problem for which answers will not be found in any one place. We have not yet definitively shown clear cause-and-effect relationships between environmental factors and preterm birth, and we do not yet fully understand what constitutes the fetal environment. Nevertheless, we are encouraged by the large amount of promising research currently under way, some of which is funded by agencies and organizations represented at this workshop. Indeed, many in attendance are instrumental to the progress being made in understanding preterm birth. For example, several studies have been undertaken to investigate the link between air pollution and preterm birth, to determine if serum levels of the pesticide 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT) and its metabolite 1,1-dichloro-2, 2-bis(chlorophenyl) ethylene (DDE), correlate with preterm births, and to examine drinking water quality for clues as to how chemicals such as polychlorinated biphenyls (PCBs) might influence birth outcomes. All of this work is crucial, although the many promising studies that are providing clues to the environmental aspects of preterm birth will require additional, confirmatory studies.
Our challenge, today and in the foreseeable future, is to remain open to the full range of possibilities for studying preterm birth, to learn from one another, and to share the conviction that eventually we can understand the triggers of this condition. Through this process and the appropriate targeting of resources, we can move forward and take the next step, which will be to fashion public health strategies and clinical interventions that will more fully protect the health of our newborns.