The Karman cannula
is a soft, flexible cannula
(or curette) popularized by Harvey Karman
in the early 1970s. The flexibility of the Karman cannula was claimed to reduce the risk of perforating the uterus during vacuum aspiration
. Both Karman's procedure, menstrual extraction
, and his cannula were embraced by activists Carol Downer
and Lorraine Rothman
, who modified the technique in 1971
and promoted it.
The "self help" abortion movement envisioned by Downer and Rothman never entered the mainstream in the U.S. before or after Roe v. Wade
. Physicians sometimes use a Karman cannula in early induced surgical abortion, in treatment of incomplete abortion, and in endometrial biopsy. Physicians and other health care providers sometimes use a Karman cannula in "menstrual regulation" vacuum aspiration procedures in developing countries where abortion is illegal (e.g. Bangladesh
Although Karman aspiration is generally accepted as a "safe" method of surgical evacuation of the uterus, it is as dangerous as other sharp or steel gynecological surgical instruments at untrained hands. The surgical termination of pregnancy should be considered a serious intervention where bleeding, uterine and other vital organ perforations, serious pain and shock are -although rare - probable and serious complications.