The Noto Peninsula earthquake struck the coast of the Noto Peninsula, Japan on March 25, 2007, resulting in the death of one woman and injury to 356 people. A total of 684 houses were totally destroyed by this earthquake, and more than 2,500 people were forced to live at shelters. In this study, we have evaluated the association between the incidence of peripartum abnormalities and seismic intensity of the Noto Peninsula earthquake.

Demographic data, births, seismic intensity of the earthquake and the incidence of peripartum abnormalities between June 25, 2007 and January 31, 2008 were surveyed. The dataset included 126 pregnant women who lived in the disaster area. The seismic intensity of the earthquake was expressed on the scale (0–7, with 7 being the strongest measure) used by the Japan Meteorological Agency. The subjects of the analysis included 19.7% of the pregnant women affected by the disaster.

Of the pregnant women included in this study, 7.9% had a premature rupture of membranes (PROM), with the percentage being significantly higher in the group that experienced a seismic intensity of 6 than in that experienced a seismic intensity of 5.

Our epidemiologic study shows that the PROM among our study cohort was associated with seismic intensity, suggesting that the physical outcome was due to aftershocks of the earthquake at a seismic intensity ≥6. This outcome may result from the psychological stress caused by the earthquakes.