Population is mothers between the ages of 18 and 34 years of age with a single intrauterine pregnancy between 37 weeks and 41 weeks gestational age. (Both very young mothers and women 35 and older have increased risk of premature delivery.) The patients will have an admission diagnosis of either active labor or spontaneous rupture of membranes. Active labor is defined as uterine contractions resulting in changes either in the cervical dilatation, the effacement of the cervix and/or descent of the fetal head in the pelvis.