Differences in duration of pregnancy. Negro and white women of low socioeconomic class.
D000328:Adult; D001741:Black or African American; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011247:Pregnancy; D011295:Prenatal Care; D012924:Social Conditions; D044465:White People