Treatment with a gel containing the hormone progesterone can cut the risk of premature births by more than 40 percent in women with short cervixes, according to an analysis released on Wednesday.
The so-called meta-analysis, which pooled published results of five large clinical trials, showed that treatment with a vaginal gel helped prevent pre-term births in 42 percent of women with a short cervix, a key risk factor.
The treatment also cut the rate of breathing problems and reduced the need for placing the baby on a ventilator, the team found. The analysis included data from five clinical trials involving 775 women and 927 babies.
Dr. Roberto Romero, chief of the perinatology research branch of the National Institutes of Health, said the analysis "provides compelling evidence" that vaginal progesterone prevents pre-term birth and reduces rates of death and hospitalization in babies whose mothers have a short cervix.
Romero and others estimate that routine ultrasound screening and progesterone treatment for women with a short cervix could prevent as many as 45,000 pre-term births in the United States, saving more than $500 million in health costs.
Progesterone is a natural hormone produced by the ovaries and the placenta, and it has been used for more than 15 years to help women carry babies to full term after in vitro fertilization.
Doctors suspect women with a short cervix, the part of the uterus that opens and shortens during labor, may not have enough of this hormone, and giving it during pregnancy in a gel form helps prolong their pregnancies.
The results of this analysis "have the potential to result in a sea change in obstetrical practice in the U.S. and Europe and eventually in the rest of the world," said Dr. Thomas Garite, editor-in-chief of the American Journal of Obstetrics and Gynecology, which published the study online.
"Prematurity is the leading cause of death and damage for newly born babies and despite enormous efforts, no impact has been made in the rate of pre-term birth, which is actually rising in recent years."
The analysis adds weight to prior studies suggesting that progesterone helps prevent prematurity.
In April, Romero published a study of the vaginal gel made by Columbia Laboratories Inc and Watson Pharmaceuticals Inc showing progesterone treatment cut premature births by 45 percent in women with a short cervix, raising hopes for a simple way to prevent premature birth in these women.
Based on the latest findings, the researchers say pregnant women should routinely get an ultrasound to detect a short cervix between 19 and 24 weeks of gestation. Women found to have a short cervix should be considered for progesterone therapy.
In the United States, 12.8 percent of babies were born prematurely in 2008, raising their risk of dying in their first year and having breathing difficulties, cerebral palsy, learning disabilities, blindness and deafness.
About 12.9 million births worldwide are pre-term, occurring before the 37th week of gestation, including 11 million in Africa and Asia, 900,000 in Latin America and the Caribbean, and 500,000 each in Europe and the United States.