Incompetent cervical os as a factor in habitual abortion. The value of Shirodkar operation.
D000026:Abortion, Habitual; D000028:Abortion, Induced / Q000209:etiology*; D002584:Cervix Uteri / Q000737:chemistry*; D005260:Female; D006801:Humans; D008910:Minnesota; D011247:Pregnancy
ABORTION/etiology; CERVIX UTERI/chemistry