This is the final article of the three-part report of the National Birth Center Study. Eight percent of the mothers or infants had serious complications; 16% were transferred, 12% before and 4% after the deliveries. Fifteen percent of transfers were emergencies. Nulliparous women were much more likely than parous women to experience dystocia, be transferred, or have cesarean sections. Seventy-five percent of the nulliparous women gave birth in the centers, compared with 95% of the parous women. Eighty-four percent of the women had at least one postpartum home or office visit. There were 11,814 mothers, no maternal deaths, and 15 intrapartum/neonatal deaths (1.3/1,000 births, 0.7 excluding congenital [Text missing in PDF]omalies). Postterm deliveries with macrosomic infants, placental abruption, sustained fetal distress, and thick meconium were associated with high mortality. Mortality was very low for those not transferred and much lower for transfers during labor as compared with those after the delivery. Women with no medical/obstetric risk factors had the lowest rates of transfers and serious complications. Except for postterm pregnancies, the intrapartum/neonatal mortality rate for birth center clients was not higher than rates from studies of low-risk hospital births, and the cesarean section rate was lower. There is no evidence that hospitals are a safer place for low-risk births.