TABLE 1—
Definition of San Diego Birth Center Study Aggregate Variables
| Prior pregnancy risk/major medical risk factor |
| Chronic hypertension |
| Chronic renal disease |
| Diabetes mellitus |
| Heart disease, class II–IV |
| HIV antibody positive |
| Prior pregnancy complications except cesarean section delivery and prior vaginal birth after cesarean section |
| Major antepartum morbidity |
| Placenta previa |
| Placental abruption |
| Gestational diabetes |
| Pregnancy-induced hypertension, severe |
| Pregnancy-induced hypertension, with eclampsia |
| Pyelonephritis |
| Intrauterine fetal death |
| Rh sensitization |
| Other (per clinical review) |
| Major intrapartum morbidity |
| Cord prolapse |
| Placenta previa |
| Placental abruption |
| Pregnancy-induced hypertension, severe |
| Pregnancy-induced hypertension, with eclampsia |
| Heavy/thick meconium |
| Gestational age < 34 weeks at birth |
| Rupture of uterine scar |
| Hemorrhage ≥ 1000 cubic centimeters |
| Shoulder dystocia |
| Fourth-degree perineal laceration |
| Cervical laceration requiring repair |
| Sulcus laceration requiring repair |
| Intrauterine fetal death |
| Other (per clinical review) |
| Major maternal postpartum morbidity |
| Anesthesia complications |
| Disseminated intravascular coagulation |
| Pulmonary embolus |
| Hematoma |
| Pregnancy-induced hypertension, severe |
| Pregnancy-induced hypertension, with eclampsia |
| Maternal death |
| Other (per clinical review) |
| Major neonatal morbidity |
| Seizures |
| Asphyxia |
| Bacterial infection other than sepsis |
| Bronchopulmonary dysplasia |
| Cardiac failure |
| Hypovolemia, hypotension, shock |
| Intraventricular hemorrhage |
| Necrotizing enterocolitis |
| Persistent pulmonary hypertension |
| Pneumonia |
| Renal failure |
| Respiratory distress syndrome |
| Retinopathy of prematurity |
| Rh disease |
| Sepsis |
| Gestational age < 34 weeks at birth |
| Other (per clinical review), including palsy or fracture |