Rates of trisomy 18 in livebirths, stillbirths, and at amniocentesis.
D000022:Abortion, Spontaneous / Q000235:genetics*; D000328:Adult; D000649:Amniocentesis; D002170:Canada; D002901:Chromosomes, Human, 13-15; D002902:Chromosomes, Human, 16-18; D004314:Down Syndrome / Q000235:genetics; D005260:Female; D005313:Fetal Death / Q000235:genetics; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D011247:Pregnancy; D014314:Trisomy; D014481:United States