SAN FRANCISCO (AP) _ Obstetricians say they may have discovered a powerful new solution to the dramatic rise in premature births in the last two decades.
A North Carolina doctor was scheduled to present results Thursday of a groundbreaking study that showed the hormone progesterone prevented premature births in a surprisingly high number of high-risk pregnancies.
``The evidence of this treatment's effectiveness was so dramatic, the research was stopped early,'' said the study's lead researcher, Dr. Paul Meis of Wake Forest University Baptist Medical Center.
Progesterone is naturally produced by the ovaries. It softens the uterus lining into a spongy bed that holds a fertilized egg.
Weekly injections of the hormone reduced the chance of premature births by 34 percent in the 306 high-risk women who received the therapy, the study reported. Another 153 women were injected with a placebo. All the women had previously given birth prematurely, the single biggest indication of risk.
The study was carried out at the 19 centers that comprise the Maternal Fetal Medicine Units Network under the National Institutes of Health. Meis was to unveil the results in San Francisco at the annual meeting of the Society for Maternal-Fetal Medicine.
``The results are so good that it's surprising,'' said Dr. Fredric Frigoletto, chief of obstetrics at Massachusetts General Hospital in Boston. ``No intervention that we have ever applied has had any measurable effect. This is very good news.''
Doctors have prescribed progesterone for years to help infertile and menopausal women.
Meis said progesterone had been previously toyed with as a preventive treatment for premature births in the 1960s and 1970s, but no one has completed a serious study on the subject.
``I think it's going to awaken people to an old idea that kind of slipped away,'' said Dr. Alan DeCherney, chair of the Obstetrics and Gynecology department at the University of California, Los Angeles.
About 476,000 babies were born too soon last year _ a 27 percent increase since 1981, according to the March of Dimes.
Last year, one in eight babies was born before the 37th week of pregnancy, which is considered full term.
``The problem is huge,'' said Dr. Nancy S. Green, a New York City pediatrician and medical director of the March of Dimes. Last week she announced the organization's $75 million, five-year program to reduce premature births.
Babies born prematurely are at increased risk for neurological, hearing and behavioral problems. The average hospital charge in 2000 for a premature baby was $58,000, compared to $4,300 for a typical newborn, according to the March of Dimes.
Some of the increase in premature births can be attributed to more older women giving birth and the explosion of obesity in the country, Green said. But fully half of premature births have no known cause, Green said.
The March of Dimes said black women give birth prematurely at disproportionately high rates: 17.5 percent of all births to black women last year were premature, compared to the national average of 11.9 percent.
Frigoletto said that high rate has been studied extensively _ but no definitive, scientific conclusions have been drawn.
In Meis' study, 59 percent of the women were black. The researchers concluded that race didn't influence the hormone's effectiveness.
``I think it really will attract a lot of interest,'' Meis said of the study. ``This is the first fairly effective treatment for pre-term births.''