Annual Report of the Perinatology Committee, Japan Society of Obstetrics and Gynecology, 2016: Overall report on a comprehensive retrospective study of obstetric management of preterm labor and preterm premature rupture of the membranes.

We conducted a questionnaire survey on the current obstetric management of preterm labor (PL) and preterm premature rupture of the membranes (pPROM). The questionnaire covered approximately a third of all preterm deliveries and nearly half of the preterm deliveries before 32 gestational weeks. The diagnostic criterion for PL was either painful uterine contractions or cervical dilatation. Tocolytic agents were primarily used as long-term maintenance therapy. Intrauterine infection was clinically diagnosed at most responding institutions. Amniocentesis was performed for PL or pPROM at only a small number (10%) of institutions. Prenatal steroids were administered for PL or pPROM, if indicated, at approximately 40-60% of responding institutions. Prophylactic antibiotics to maintain pregnancy were administered for pPROM at approximately 90% and for PL at approximately 20% of institutions. Maintenance therapy with a tocolytic agent was used for pPROM at approximately 90% of institutions.