Ultrasonographic examination was performed using the ALOKA prosound SSD-3500 (ALOKA, Wallingford, CT, USA) with a 7.5-MHz vaginal probe for color Doppler ultrasonography to assess the ovarian artery flow at the ovarian hilum. The pulsatile index (PI) and resistance index (RI) values were calculated according to the formula PI=[S-D]/mean and RI=[S-D]/S, where S was the peak systolic flow velocity; D was diastolic velocity; and the mean was the mean flow velocity. All examinations were conducted by the same investigator to minimize interobserver bias, and parameters were measured at least 3 times and the mean value was recorded.