Decline in perinatal mortality.
D001724:Birth Weight; D002140:California; D002585:Cesarean Section / Q000706:statistics & numerical data; D005260:Female; D005313:Fetal Death / Q000453:epidemiology*; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D009519:New York City; D011247:Pregnancy; D014187:Transportation of Patients