The proposed constitutional amendment would allow licensed physicians to perform abortions on demand if the period of gestation has not exceeded 20 weeks.
Description of ballot proposal accessed via: http://ballotpedia.org/wiki/index.php/Michigan_Abortion_Legalization_Initiative,_Proposal_B_(1972)
Source for Popular Vote data: Michigan Department of Administration, comp., "Official Canvass of Votes, General Election November 7, 1972," Michigan Manual, 1973-1974 (Lansing: Michigan Department of Administration, 1973)