Eligible women will be identified in the late first or early second trimesters. Once recruited, women will be randomly assigned to either 81 mg or 162 mg per day dosing schedules. The randomization scheme will vary based on the body mass index (BMI) with separate schemes for women \<=30 kg/m2 versus \>30 kg/m2. Ultrasonographic assessment of biophysical biomarkers will be obtained at 11-16 weeks, 18-22 weeks, and 28-32 weeks gestation. Biologic samples of serum and urine will be obtained at the 11-16 week and 28-32 week visit. Upon delivery, cord blood and a placental specimen will also be obtained. Medication treatment will continue until 36 weeks gestation. Pregnancy and neonatal outcome data will be recorded.
