Randomization is a process similar to a lottery.
Neither the researchers nor the participant will be able to influence to which group they are assigned. Two out of three patients in the study will get the 17P, so the chances of getting the hormone are two times greater than getting the placebo. Participants will receive these injections until they have reached the 37th week of their pregnancy, or until they deliver, whichever comes first. They will return to the Magee-Womens Hospital Outpatient Clinic area or be seen in their doctor's office each week until the end of their pregnancy. A total of 500 patients will be included in this study from 13 participating institutions around the country.