Cohort study of the incidence of spontaneous preterm birth and septic abortion referred by pathological examination in Gifu prefecture in Japan.

Aims: To clarify the incidence of spontaneous preterm birth (PB) and septic abortion (sab) in Gifu prefecture in Japan.

Study Design: This prospective, population-based cohort study was approved by our hospital's Institutional Review Board. All 36 hospitals (100%) in Gifu prefecture offering obstetrical services participated in the study.