 2. Women who present with viable pregnancy between 28 and 37 weeks gestation, and having a threatened preterm labor which is defined as 2 uterine contractions at 28-37 weeks gestation, The onset of labor may be determined by documented uterine contractions at least one every 10 minutes and ruptured fetal membranes or documented cervical change with an estimated length of less than 1cm or cervical dilation of more than 2 cm. Threatened preterm labor may be diagnosed when there are documented uterine contractions but no evidence of cervical change. 