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Progesterone Therapy for Some High Risk Pregnant Women Could Prevent Thousands of Premature Births

WHITE PLAINS, N.Y., JAN. 31, 2005 - Nearly 10,000 preterm births could have been prevented in 2002 if all pregnant women at high risk for a premature baby and eligible for weekly injections of a derivative of the hormone progesterone had received them, according to a new study published in the February issue of Obstetrics & Gynecology.

The result would have been a reduction in the overall rate of preterm birth (before 37 completed weeks gestation) in the United States of about 2 percent -- from the 2002 rate of 12.1 percent to 11.8 percent -- say Joann R. Petrini, Ph.D., M.P.H., and colleagues from the March of Dimes, the Centers for Disease Control and Prevention, the National Institute of Child Health and Human Development (NICHD), Albert Einstein College of Medicine, Maimonides Medical Center in New York, and the New Jersey and Missouri State Departments of Health who participated in the analyses.

The hormone derivative is known as 17P, short for 17 alpha-hydroxyprogesterone caproate.

"Two percent would be a modest reduction in the preterm birth rate, but preventing 10,000 premature births would be very significant," said Dr. Petrini. "Prematurity is a serious problem that affects 1 in 8 babies in the U.S., and 17P offers promise in an area where there have been few successes. In addition, we need more research into the underlying causes of prematurity to help women with other risk factors."

Assumptions used to estimate the impact of 17P on recurrent preterm birth were based on criteria from the promising findings of the clinical trial reported by Paul J. Meis, M.D., et al. for the NICHD Maternal-Fetal Medicine Units (MFMU) Network in The New England Journal of Medicine on June 12, 2003. These study results led to the 2003 Committee Opinion issued by the American College of Obstetrician's and Gynecologists, published in the October 2003 issue of Obstetrics & Gynecology,.

In the NICHD MFMU study, the use of 17P was restricted to women with singleton pregnancies and a documented history of a previous spontaneous preterm birth, who initiated prenatal care between 16 and 20 weeks gestation. When this protocol was followed, the risk of preterm birth to these eligible women was reduced by about one-third.

The authors of today's paper estimated that in 2002, about 30,000 recurrent preterm births occurred to women who were eligible for 17P, based on a spontaneous preterm birth recurrence rate of about 22 percent.

The ACOG Committee Opinion urges more research on the role of preventing preterm birth and reminds physicians that, until new results are available, to restrict the use of 17P to pregnant women with a history of spontaneous preterm birth, singleton gestation, who start prenatal care between 16-20 weeks of pregnancy.

Premature birth is a common, serious, and growing problem in the United States, the March of Dimes says. The rate of premature birth in the United States has risen 29 percent since 1981, with more than 470,000 babies born prematurely each year.

"Estimated Effect of 17 Alpha-Hydroxyprogesterone Caproate on Preterm Birth in the United States," by Joann R. Petrini, William M. Callaghan, Mark Klebanoff, Nancy S. Green, Eve M. Lackritz, Jennifer L. Howse, Richard H. Schwarz, and Karla Damus appeared in the February issue of Obstetrics & Gynecology, volume 105, number 2.

For free access to national, state, county and city-level maternal and infant health data, visit PeriStats, the source for perinatal statistics, at marchofdimes.com/PeriStats.

The March of Dimes is a national voluntary health agency whose mission is to improve the health of babies by preventing birth defects and infant mortality. Founded in 1938, the March of Dimes funds programs of research, community services, education, and advocacy to save babies and in 2003 launched a five-year campaign to address the increasing rate of premature birth. For more information, visit the March of Dimes Spanish Web site at www.nacersano.org or its English website at www.marchofdimes.com.