Classification of puerperal uterine inversion

(A) 1st. degree (incomplete) inversion: the fundus is within the endometrial cavity.
(B) 2nd. degree (complete) inversion: the fundus protrudes through the cervical os.
(C) 3rd. degree inversion (uterine prolapse): the fundus protrudes to or beyond the introitus.
(D) 4th. degree (total uterine and vaginal) inversion: both the uterus and vagina are inverted.