Progesterone Prevents Preterm Birth in Some Women
Effective in women with short cervix, ineffective in women pregnant with twins
WEDNESDAY, Aug. 1 (HealthDay News) -- Progesterone is effective in preventing premature birth in women with a short cervix but ineffective in preventing premature birth in women pregnant with twins, according to two studies in the Aug. 2 issue of the New England Journal of Medicine.
In the first study, Kypros H. Nicolaides, M.D., from King's College Hospital Medical School in London, and colleagues randomly assigned 413 pregnant women with a cervix less than 15 mm long to 200 mg vaginal progesterone per night or placebo from 24 weeks to 34 weeks of gestation. They found that progesterone treatment significantly reduced the risk of spontaneous delivery before 34 weeks gestation (relative risk 0.56) and tended to reduce the risk of neonatal morbidity (relative risk 0.59).
In the second study, Dwight J. Rouse, M.D., from the University of Alabama in Birmingham, and colleagues randomly assigned 665 women pregnant with twins to intramuscular injections with 17 alpha-hydroxyprogesterone caproate or placebo starting at 16 weeks to 20 weeks gestation to 35 weeks. They found that the risk of delivery or fetal death before 35 weeks and the risk of serious adverse neonatal events were similar in both groups (relative risk 1.1 for both).
"Even if progesterone therapy is effective for some women who are at risk of preterm labor, reliable evidence is needed about long-term effects on the children before it could be widely recommended," Jim G. Thornton, M.D., from the University of Nottingham in the United Kingdom wrote in an accompanying editorial.