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.
PIP: The purpose of this study was to determine cyclical patterns of free fluid in the pelvis of asymptomatic premenopausal women. A total of 254 pelvic sonograms were performed on 40 volunteers 17-47 years of age. 114 of these sonograms were performed midcycle, 70 were preperiod, 42 were within 5 days after cessation of menses, and 28 occurred during menstruation. Free fluid in the pelvis was observed during all phases of the menstrual cycle. The highest percentage of positive-for-fluid sonograms occurred within 5 days preceding the onset of menstruation, both in oral contraceptive (OC) users (26%) and nonovulatin women (30%). This finding is attributed to increased fluid production related to an estradiol-induced increase in capillary permeability. In the non-OC users, free fluid in the pelvis was also often (26%) observed in the period immediately after ovulation. Overall, 38% of non-OC users and 36% of OC users demostrated cul-de-sac fluid at some point in the menstrual cycle. This study demonstrates that free pelvic fluid can be a normal finding in asymptomatic women without known gynecologic disease.