Sensitivity and specificity of ultrasound indices of ovulation in spontaneous cycles

Objective: Evaluation of sensitivity and specificity of 4 ultrasound indices of ovulation. Study design: Multicenter collaborative study of 794 abdominal and transvaginal ultrasound scanning of ovaries performed during 271 cycles in 107 normally fertile women. Comparison of sensitivities and specificities of indices using McNemar test. Results: The sensitivity and specificity of the indices were 84 and 89.2, respectively, for disappearance or sudden decrease in follicle size; 38.4 and 79.7 for appearance of ultrasonic echoes in the follicle; 61.6 and 87.1 for irregularity of follicular walls; 71.0 and 88.2 for appearance of free fluid in the cul-de-sac of Douglas. Conclusion: Ultrasonic echoes had a significantly lower sensitivity (P<0.001) and specificity (P<0.01) than other indices. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.