Background: Many pregnant Muslim women choose to fast during Ramadan every year worldwide. This study aimed to examine the effect of Ramadan fasting on serum leptin, neuropeptide Y and insulin in pregnant women and find whether fasting during pregnancy could have a negative effect on the health of mothers and fetuses. Methods: This cross-sectional study was conducted on 39 healthy volunteer fasting pregnant women. Serum leptin, neuropeptide Y, insulin levels, body mass index and weight were measured five times on 0, 7th, 14th and 28th days of Ramadan and on the 14th day post-Ramadan. The data were analyzed by SPSS software (version 11.5) using repeated measures ANOVA to find whether any changes occurred in the variables of interest during the study, and Pearson correlation coefficient was used to examine the relations among the variables. Results: A significant change in fasting blood sugar, neuropeptide Y and leptin was observed during the study (p0.05). Conclusion: The result of this study revealed the important role of leptin and neuropeptide Y in the long term regulation of energy balance in pregnant women with chronic diurnal fasting, and it further revealed that Ramadan fasting did not significantly change the serum insulin level
