WordNet records no synonym and no antonym for tubal ligation. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a sterilization procedure with women; both Fallopian tubes are tied in two places and the tubes removed in between the ligations
Synonyms, antonyms and the broader and narrower relations for tubal ligation come from Princeton University’s WordNet. Full sources and licences.