Prospective cohort study of three- versus two-dimensional ultrasound for prediction of oocyte maturity

OBJECTIVE: To determine whether three-dimensional follicular ultrasound (3-D) measurements are better predictors of optimal timing of hCG administration than two-dimensional (2-D) images, the current standard. DESIGN: Prospective, cohort study. SETTING: Tertiary referral center. PATIENT(S): Seventy-six patients undergoing IVF. INTERVENTION(S): Seventy-six consecutive patients undergoing serial follicular monitoring during IVF had an additional daily 3-D volume scan of their ovaries once lead follicles had reached 16 mm diameter. MAIN OUTCOME MEASURE(S): Number of mature oocytes retrieved. RESULT(S): The 2-D follicular diameter measurements predicted 25.4% of the observed variance in the number of mature oocytes retrieved. The 3-D follicular volume measurements were more predictive of outcome, accounting for 29.2% of the observed variance in number of mature oocytes retrieved. Follicles >22 mm diameter and 5 mL volume were associated with fewer mature oocytes reflecting an undesired postmature state. Follicles measuring 11 to 15 mm had a 50% chance of yielding a mature oocyte. CONCLUSION(S): Three-dimensional follicular volume measurements have a stronger correlation with the number of mature oocytes retrieved than 2-D measurements. As 3-D technology improves, this parameter may replace 2-D measurements in the optimal timing of hCG before oocyte retrieval.