title: [Seasonal influences on the duration of pregnancy and prolonged pregnancy].
mesh_terms: D002031:Bulgaria; D002980:Climate; D005260:Female; D006801:Humans; D011247:Pregnancy; D011273:Pregnancy, Prolonged; D012621:Seasons; D013997:Time Factors
vernacular_title: Sezonni vliianiia vurkhu produlzhitelnostta na bremennostta i prenosenata bremennost