Premature rupture of the fetal membranes, the phases of the moon and barometer readings.

Over a 2-year period, 1,516 births were investigated to determine whether the onset of parturition could be correlated with the phases of the moon or to barometric height. 1,269 births started spontaneously, and of these, 254 (20%) started with premature rupture of the fetal membranes (PROM). No association was observed between the phases of the moon and deliveries beginning with PROM or with deliveries beginning without PROM. 1,302 of the women had regular menstrual cycles before pregnancy, and among these no specific relationship was found between the phases of the moon and the first day of the last menstruation before pregnancy. No relationship was found between the frequency of PROM and the barometric height. Variations in barometric height up to 9 h before the fetal membranes ruptured did not influence the frequency of PROM. Deliveries with PROM occurred significantly more often among primipara than among multipara. PROM occurred more frequently during night-time in the 8-hour period between 10 p.m. and 6 a.m. These results suggest that the causes of PROM are not correlated to the phases of the moon or to meteorological variations.