True ovarian volume is underestimated by two-dimensional transvaginal ultrasound measurement

Objective: To investigate a possible difference between true ovarian volume and ovarian volume estimated with two-dimensional (2D) transvaginal ultrasound. Design: Prospective clinical and laboratory study. Setting: University hospital research laboratory. Patient(s): Premenopausal girls and women from three Danish national fertility centers (A: n = 42; B: n = 6; C: n = 18), who had one entire ovary removed for cryopreservation of ovarian cortex. Intervention(S): Transvaginal 2D ultrasound measurement of ovarian Volume before oophorectomy. True ovarian volume was obtained by weighing the ovary. Main Outcome Measure(s): Ovarian Volume estimated by weight and ultrasound. Result(s): Ovarian tissue density was 1.00 g/mL. Mean ovarian volume by ultrasound vs. weight in the three groups was as follows: A: 6.3 mL vs. 7.8 mL; 13: 5.4 mL vs. 6.8 mL; and C: 2.8 mL vs. 6.1 ml. Ovarian volume obtained by ultrasound was at least 27% smaller than the true ovarian Volume. Conclusion(s): Ovarian Volume was severely underestimated by transvaginal 2D ultrasound measurement. (Fertil Steril (R) 2010;93:995-8. (C)2010 by American Society for Reproductive Medicine.)