Antenatal care for the normal patient.

Screening protocols for low-risk obstetric patients are used to identify those at risk for adverse perinatal outcome. Gestational diabetes screening is best performed by administering 50 g of glucose in the nonfasting state, with plasma glucose values above 140 mg/dL at 1 hour considered abnormal. Assay of maternal serum alpha-fetoprotein is primarily used to identify pregnancies at risk for neural tube defects and other structural anomalies. However, an elevated value may also identify patients at increased risk for a number of abnormal pregnancy outcomes, even when the fetus is free from defects. Patients who have previously had a cesarean section are now strongly encouraged to undergo a trial of labor and to attempt a vaginal birth. Such a course is not without risk, and catastrophic complications can develop. Careful patient selection, appropriate counseling, and close management are necessary in this situation.