Objective: To evaluate the influence of three-week fasting on gonadotropin pulsatility in extremely obese women of reproductive age.
Design: Prospective study of 21-day fasting (400 kcal/day), under medical supervision.
Subjects: 20 females, average age of 35.1 +/- 5.9 y, and average BMI of 41.19 +/- 8.39 kg/m2, with regular menstrual cycles (26-34 days). The mean weight loss was 12.5 +/- 3.23 kg.
Measurements: Blood samples for LH and FSH were taken between 4th and 7th day of the menstrual cycle, before and in the first cycle immediately after weight reduction, for 6 h, starting at 09.00 with 10 min intersample intervals. Pulsatility analysis was done using Pulsar program. Statistical analysis was done using Wilcoxon's matched pairs signed ranking test and McNemar's test.
Results: There was no statistically significant difference (p > 0.05) in LH and FSH pulsatile secretion before and after diet including the number of pulses, amplitudes, interpulse intervals and peak lengths. There were no disturbances of menstrual cycle during or after the diet.
Conclusion: These results suggest that a 21-day fast, accompanied with significant weight loss, does not affect gonadotropin pulse pattern in follicular phase and normal menstrual cycle length in extremely obese females of reproductive age, compared with the pattern before diet.