Have you had a premature baby before? If you have and are pregnant again or want to become pregnant, a new type of treatment may help prevent another preterm birth.

Women who have given birth to a premature baby are at increased risk of having another early birth. In 2003, two research studies found that a form of the hormone progesterone (17P) reduced the rate of premature birth for some of the women in this group. 

The studies reported no serious side effects for either the mother or the baby. None of the babies born after their mothers received 17P had birth defects. Long-term follow-up of the study participants has not been done.

17P should be used only for pregnant women who meet these three criteria:

• They have already been pregnant at least once with a single baby (not twins or more).
• With that baby, they began labor on their own before 37 completed weeks of pregnancy. Medical professionals did not use drugs or other methods to start labor.
• They are currently pregnant again with a single baby.

There are no studies showing that 17P prevents premature birth in other women. For instance, it has not been tested for women who are pregnant with twins or who have a short cervix. Researchers are continuing to study 17P and premature birth.

17P Treatment 
Women being treated with 17P receive weekly shots. Preferably, the woman starts receiving shots between 16 and 20 weeks of pregnancy. 17P is not available at drug stores. Health care providers must order it through special pharmacies.

If you have already had a premature baby, ask your health care provider whether 17P might be a good choice for you.

Will Insurance Pay for Treatment?
Not all private insurance companies or state Medicaid programs pay for 17P. Check with your insurer before starting treatment. Your doctor may also be able to provide information.