Is amniotic fluid volume influenced by a 24-hour fast?

OBJECTIVE: To assess the influence of fasting for 24 hours on the amniotic fluid index (AFI). STUDY DESIGN: The AFI of 22 parturients in the second trimester of uncomplicated pregnancy was evaluated on the morning after a 24-hour fast. Patients were prospectively matched to another group of 25 patients who did not fast. Both groups were reevaluated after one week. Two different observers, blind to each other's results, performed the examinations. RESULTS: A statistically significant difference was found in the AFI between the two groups on the day after fasting (11.73 ± 2.12 versus 15.4 ± 1.2, respectively; P < .01). After one week there was no difference in AFI between the two groups (15.35 ±1.2 and 15.42 ± 1.2, respectively; P > .01). CONCLUSION: Fasting may reduce the amniotic fluid volume as shown by the AFI, and fluid intake may restore the normal amount of amniotic fluid volume.