Analysis of multiple birth rates in Japan. VI. Quadruplets: birth and stillbirth rates.
D000328:Adult; D001723:Birth Rate; D005260:Female; D005313:Fetal Death / Q000453:epidemiology*; D005865:Gestational Age; D006801:Humans; D007564:Japan; D008297:Male; D008423:Maternal Age; D011247:Pregnancy; D011783:Quadruplets