title: Bed rest did not prevent prematurity in twins because the etiology lies in the stretch and poor progesteronegenesis.
mesh_terms: D000328:Adult; D001510:Bed Rest; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011247:Pregnancy; D011374:Progesterone / Q000096:biosynthesis; D014427:Twins; D014599:Uterus / Q000502:physiology
chemical_list: D011374:Progesterone