The effect of a 25-hour fast during the Day of Atonement on preterm delivery

Objective: To determine the effect of the Day of Atonement fast (a 25-hour Jewish fast), on preterm delivery. Methods: A comprehensive analysis of all deliveries during the Day of Atonement and during the corresponding day a week earlier, between the years 1988 and 2011, was performed. Preterm delivery was defined as delivery before 37 completed weeks of gestation. Data on fasting status was deduced from the ethnicity (as only Jewish parturients fast during the Day of Atonement). Multivariable logistic regression model was used to control for confounders. Results: During the Day of Atonement in the studied period, 744 deliveries took place, out of which 52.1% (n = 388) were of Jewish patients (i.e. fasting group), and 47.9% (n = 357) were of non-Jewish patients. Out these, 6.3% (n = 47) were preterm deliveries. Jewish parturients were at significantly higher risk for preterm delivery during the Day of Atonement (adjusted OR = 2.0; 95% CI, 1.03-3.83; p = 0.041). In the corresponding day, a week before the Day of Atonement, Jewish ethnicity was not found to be a risk factor for preterm delivery (OR = 0.92; 95% CI, 0.50-1.69; p = 0.789). The model controlled for: previous preterm delivery, intrauterine growth restriction and placental abruption. Conclusions: A 25-hour fast is an independent risk factor for preterm delivery.