However, in 2003, two encouraging studies found that treatment with the hormone progesterone reduced the incidence of premature birth in women who had already had a preterm birth. This group is at especially high risk of another early delivery. According to the American College of Obstetricians and Gynecologists (ACOG), progesterone treatment (sometimes called 17p) should be used only for women who meet all these criteria:

• Had a previous preterm delivery of a single baby (not twins, triplets or more)
• Began labor on their own (labor was not induced)
• Are pregnant again with just one baby

Researchers continue to study whether other high-risk women, including those pregnant with twins or more, also may benefit from treatment with 17P.

A number of studies have looked at the effectiveness of antibiotic treatment in reducing the risk of preterm delivery. Antibiotic treatment appears to help prolong pregnancy in women with premature rupture of the members (the bag of waters breaks before 37 weeks). This condition (also called PROM) often results in preterm delivery. 

Antibiotics have also been given to women with vaginal infections, such as bacterial vaginosis (BV) and trichomoniasis. These woman may have an increased risk of premature delivery. But most studies have failed to show that antibiotics reduce the risk of early birth in most women with these genital infections.

Some studies suggest that a procedure called cerclage (the doctor puts a stitch in the cervix to help keep it closed) may help reduce the risk of preterm delivery in some women who have had a previous preterm delivery and who also have certain cervical abnormalities. The doctor removes the stitch at around 37 weeks of pregnancy.

Today women who develop preterm labor before about 34 weeks of pregnancy are often treated with one of several drugs (called tocolytics). These drugs often delay delivery for about 48 hours—buying some extra time to treat the pregnant woman with corticosteroid drugs. Corticosteroids speed maturation of fetal lungs and other organs, reducing the risk of infant deaths and serious complications of prematurity, including respiratory distress syndrome (breathing problems) and bleeding in the brain. Doctors recommend corticosteroids if a woman is likely to deliver before 34 weeks. 

For more information, go to Treating Preterm Labor. If you have had a premature baby before, go to Preventing Premature Birth.

May 2007