In addition, this medication has been previously used in pregnant women without any evidence of significant harm to the mother or fetus. Women will be approached for enrollment in the study during their hospitalization for preterm labor. If they choose to enroll, they will have weekly MD visits at the obstetrical clinic, daily use of vaginal progesterone that will be self administered, and routine obstetric care at the time of recurrent labor and delivery. The daily progesterone is not a part of routine care for these patients. In addition, we will ask patients to fill out a written questionaire one week after starting the medication to describe any subjective symptoms that may be associated with this medication. Finally, we will assess the peripheral levels of progesterone with a blood draw prior to starting the mediation, one week after starting the medication, and at the time of recurrent pre-term labor or delivery. The first two of these blood draws will be in addition to the standard treatment. The final blood draw will involve collecting an extra sample at a time when the participant would normally have blood drawn as a part of routine care.