Dependence of the in-vitro fertilization capacity of the oocyte on perifollicular flow in the preovulatory period of unstimulated cycles

BACKGROUND: One method to economize on monitoring cycles for IVF and improving its outcome is follicular selection. The purpose of our study was to determine whether quantitative indices of perifollicular blood flow allow the prediction which follicles contain a fertilizable oocyte and which do not. METHODS: This prospective study included 178 unstimulated cycles for IVF in patients treated for tubal infertility, endometriosis and unknown causes of infertility that ended with follicular aspiration. All male partners had a normal spermiogram. Cycles were monitored using ultrasound folliculometry and estimation of serum estradiol concentrations. On the day of hCG administration (day 0), day +1 and prior to follicular aspiration (day +2), perifollicular blood flow was measured using color and pulsed Doppler. The pulsatility index (PI), resistance index (RI) and peak systolic velocity (PSV) between the group in which fertilization occurred (group A) and that in which no fertilization occurred (group B) were compared. Student's t-test and ANOVA were used for statistical analysis. RESULTS: The oocyte recovery rate was 71.5% and the fertilization rate 74.8%. Comparison of RI and PI between group A (N = 95) and group B (N = 32) revealed a decline in PI and RI after hCG administration in both groups. Only on day 0 was PI in group A significantly lower than that in group B. The difference in RI and PSV between the two groups was not statistically significant. ANOVA showed that there was no significant difference in serial Doppler measurements between the two groups. CONCLUSION: We confirmed an increased perifollicular blood flow in the preovulatory period. Quantitative indices of perifollicular blood flow are of limited value as parameters for cycle monitoring and decision-making in unstimulated cycles for IVF.