Preterm birth is the single greatest cause of perinatal morbidity andmortality in nonanomalous infants, responsible for 70 percent of fetal,neonatal, and infant deaths. The outcome for premature and low birth weightinfants is better than most medical professionals believe it to be. Spontaneous preterm birth is a syndrome in which multiple riskfactors operate collaboratively via injury to the maternal fetal interface toproduce several related clinical disorders. Preterm labor may be initiated by infection, ischemia, hemorrhage,uterine distension, or endocrine factors.