Wyoming becomes first US state to outlaw use of abortion pills

Violation of the ban is to be treated as a criminal misdemeanor, punishable by up to six months in jail and a fine of up to $9,000.

The governor said he was also allowing enactment, without his signature, of a separate bill passed by state lawmakers to prohibit conventional abortion procedures except when necessary to protect the health and life of the mother, or in case of rape or incest. Exception is also permitted to end a pregnancy if doctors determine there to be a lethal abnormality of the foetus.

A two pill combination of mifepristone and another drug is the most common form of abortion in the US.

Medication abortions were the preferred method for ending pregnancy in the US even before the supreme court overturned Roe v Wade, the ruling that protected the right to abortion for nearly five decades.

Courts have put on hold enforcement of abortion bans or deep restrictions in Arizona, Indiana, Montana, Ohio, South Carolina, Utah and Wyoming. Idaho courts have forced the state to allow abortions during medical emergencies.

Reuters and Associated Press contributed to this report