Preterm birth is a delivery of a baby before 37 weeks of pregnancy. According to the March of Dimes, about 12 percent of babies in the U.S. are born prematurely. The majority of preterm births occur between 32 and 36 weeks gestation.

Babies who are born too soon face a number of medical problems. These babies are smaller and less developed than full-term babies. Preterm babies have underdeveloped lungs and may require a ventilator for breathing assistance. The infants have difficulty regulating body temperature, feeding and fighting infection. They are at higher risk for jaundice, anemia, respiratory distress, vision and hearing problems and brain damage. Very premature babies may spend weeks in the neonatal intensive care unit (NICU) getting the specialized care they need to survive.

Risk Factors for Preterm Birth

About three-quarters of preterm births occur spontaneously. Researchers have identified three groups of women who are at greatest risk of preterm labor and birth: women who are carrying more than one baby, women with a history of a prior preterm birth and women with certain cervical or uterine abnormalities.

Other risk factors associated with preterm birth are smoking, use of alcohol or illegal drugs, little or no prenatal care, domestic violence, high stress levels, low income and standing for long periods of time. Medical conditions in the mother (such as diabetes, high blood pressure, vaginal infections, obesity, clotting disorders and vaginal bleeding) also increase the risk of preterm birth.

Reducing the Risk of Preterm Birth

A few years, ago, researchers discovered they could reduce the risk of preterm labor and delivery in high-risk women by giving them hydroxyprogesterone (17P, or 17-alpha Hydroxyprogesterone Caproate). The drug is a derivative of the hormone, progesterone.

In an earlier study, doctors gave 17P to a group of women pregnant who had a history of preterm birth and were pregnant with a single fetus. Women who received the drug reduced their risk of preterm delivery by one-third, compared to women who received a placebo.

Now researchers want to find out if 17P can reduce the risk of preterm delivery in women pregnant with twins and triplets, who have a greater risk of preterm birth. The study is called STTARS: A Randomized Study of Seventeen Alpha-Hydroxyprogesterone Caproate in Twins and Triplets. It's going on at 14 sites across the country.

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