Healthy women who are pregnant with their first child will be included in the study. Information about their general health will be gathered. These women will be screened for pelvic disorders at the start and end of study. Three-dimensional ultrasound will be performed three times: 12-24 weeks, 34-39 weeks and 4-6 weeks after delivery. Fetal measurements will be included in the third trimester ultrasound for prediction of estimated birth weight. The relationship of the predicted fetal weight and the likelihood of having a successful vaginal delivery will be studied. Images will be analyzed for pelvic muscles function and injuries. Information regarding the length of labor, types of delivery and vaginal tears will be gathered. The information obtained will be analyzed to look for the strength of correlation of variables to the outcomes.