Abstract
The objective is to evaluate the tidal level’s relationships to the onset of labor and the premature rupture of the fetal membranes (PROMs) in pregnant women. This study is a retrospective analysis of 313 spontaneous full-term deliveries over a one-year period at the Department of Obstetrics and Gynecology, T Hospital, Ibaraki, Japan. The average of the tidal level at onset of labor is significantly higher than the average tidal levels over the whole of 2010 (p=0.006). We did not find any significant relationship between the average of the tidal level at PROMs and the average tidal levels over the whole of 2010, between the number of the onset of labor and changes in the tide level, or between the number of PROMs and changes in the tide level. We concluded that when the tidal level is high, the onset of labor tends to occur more frequently. Therefore, we can presume that the gravitational pull of the Moon influences the onset of labor in pregnant women on the Earth.
