This sometimes occurs as a result of imperfect involution after the physiological enlargement of pregnancy, and in this case the increase in size is from excess in the muscular substance mainly. Hypertrophy of a similar kind occurs from the presence of tumours in the wall of the uterus. There may be hypertrophy from congestion and chronic inflammation, however caused.

A special Hypertrophy of the cervix has been observed in many cases. It occurs as a result of imperfect involution after pregnancy, but also as a consequence of prolapse of the vagina, the cervix being dragged down and greatly elongated. With very little descent of the uterus the cervix may be so elongated as to present externally.