In vitro maturation and fertilization of oocytes from unstimulated ovaries: Predicting the number of immature oocytes retrieved by early follicular phase ultrasonography

OBJECTIVE: To select women who will benefit most from in vitro maturation (IVM) of oocytes treatment, this study was undertaken to examine the ability of a transvaginal ultrasonography to predict the number of immature oocytes collected from unstimulated ovaries. STUDY DESIGN: The relationship between the number of immature oocytes retrieved and the pregnancy rate was assessed in 189 IVM treatment cycles. In 96 consecutive cycles, an early follicular phase transvaginal ultrasonographic measurement of the antral follicle count (AFC), ovarian volume, and peak ovarian stromal blood flow velocity (Vmax) was performed, and the results were correlated with the number of immature oocytes. RESULTS: The clinical pregnancy rate increased significantly with the number of oocytes retrieved (P = .02) and was 26.8% (15/56) in those with >10 immature oocytes. The AFC, ovarian volume, and ovarian stromal Vmax were all predictive of the number of oocytes retrieved, but when the other factors were controlled by multiple regression analysis the AFC was the only significant predictor (P < .001). CONCLUSIONS: Pregnancy rates after IVM correlate with the number of immature oocytes retrieved. This is best predicted by an ultrasonographic assessment of the AFC.