A federal judge has blocked a regulation that could have permanently closed Alabama’s busiest abortion clinic, saying the rule was unnecessary to protect women. Judge Myron Thompson of Federal District Court issued a temporary restraining order blocking the rule last week and followed up with an opinion issued Thursday. The 2007 regulation requires clinics to hire a physician with hospital-admitting privileges to handle patient complications. The West Alabama Women’s Center in Tuscaloosa, one of five abortion providers in Alabama, sued. The clinic complied with the regulation for years, but said it was unable to meet the requirement after its longtime doctor retired. The court case applies only to the Tuscaloosa clinic. Judge Thompson said the clinic has few cases with complications and that protests by abortion opponents had made physicians hesitant to work with abortion providers.