birth has 11 distinct synonyms spread across 4 of its 6 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is death.
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 baby born; an offspring
“the overall rate of incidence of Down's syndrome is one in every 800 births”
Synonyms, antonyms and the broader and narrower relations for birth come from Princeton University’s WordNet. Full sources and licences.