[Effect of the Yom Kippur fast on parturition]

Food-withdrawal has been proposed as a possible mechanism for initiating the onset of labor in animals and humans. The hypothesis was based upon the reported increase in deliveries of infants during the Yom Kippur fast. We studied the effect of the fast on full term deliveries of Jewish women, with non-fasting Bedouin women as controls (1988-1995, 1,313 Jewish and 1,091 Bedouin deliveries). To determine the effect of Yom Kippur itself, delivery rates on Sukkot and Yom Kippur were compared in both groups. The mean delivery rate in the Jewish population was significantly higher during Yom Kippur and the day after, than during the 7 days before Yom Kippur (15.1 +/- 5.1 and 14.6 +/- 4.7 vs 10.7 +/- 3.5, p < 0.04 and p < 0.01, respectively). There was an increase in delivery rate during the 6 hours before the end of the fast. In the Bedouin women there were no changes in delivery rate during any of these periods. There were no significant differences in the rates of deliveries during the Sukkot festival between Jewish and Bedouin women. We conclude that fasting is associated with a significant increase in the rate of deliveries at term.