Trends in out-of-hospital births.
D036861:Delivery, Obstetric; D005260:Female; D006700:Home Childbirth; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D008880:Midwifery; D009309:National Center for Health Statistics, U.S.; D009721:Nurse Midwives; D014481:United States; D014492:United States Public Health Service