Fluid in the female pelvis: cyclic patterns

A total of 254 pelvic sonograms were performed on 40 volunteers in order to determine a cyclic pattern, if any, of free fluid in the pelvis in asymptomatic premenopausal women. Free fluid was observed during all phases of the menstrual cycle. The highest percentage of positive-for-fluid sonograms was observed within 5 days preceding onset of menses in both oral contraceptive users and non-oral contraceptive users. The second highest percentage was observed between days 13 and 21 in non-oral contraceptive users.