SPTB and infection: Preterm birth could afflict 10% of children born worldwide, and 2 in 3 preterm births occur spontaneously.[29] Acute or chronic intrauterine inflammation or infection are common obstetric complications, which increase the risk of sPTB.[13] Local inflammatory processes have been considered to be the most important pathogenesis of sPTB, and the distinct inflammatory nature of sPTB has been a focus of researchers.