Multiple gestation.
D000649:Amniocentesis; D000013:Congenital Abnormalities / Q000175:diagnosis; D005260:Female; D005333:Fetus / Q000502:physiology; D006128:Growth; D006801:Humans; D011247:Pregnancy; D011272:Pregnancy, Multiple; D011295:Prenatal Care; D011296:Prenatal Diagnosis; D014427:Twins; D014428:Twins, Conjoined; D014463:Ultrasonography