Delivery patterns and reproductive efficiency among groups of differing socioeconomic status and ethnic origins.
D000022:Abortion, Spontaneous / Q000453:epidemiology*; D005007:Ethnology; D005260:Female; D005313:Fetal Death / Q000453:epidemiology*; D006801:Humans; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D011271:Pregnancy, Ectopic / Q000453:epidemiology*; D012098:Reproduction; D012924:Social Conditions