- This study was undertaken to investigate intraovarian blood flow during the early follicular, periovulatory and mid-luteal phases, during spontaneous and stimulated ovarian cycles. Transvaginal ultrasonography with colour flow imaging was used to measure the pulsatility index in eight patients with spontaneous cycles, 20 patients undergoing induction of ovulation with clomiphene citrate and 11 patients undergoing controlled ovarian hyperstimulation for in-vitro fertilization (IVF)-embryo transfer with gonadotrophin-releasing hormone analogue, human menopausal gonadotrophin, human chorionic gonadotrophin. All patients were studied during the early follicular, periovulatory and mid-luteal phase. Intraovarian blood flow velocity waveforms were found in 20% of cases at the early follicular phase, in 56% during the periovulatory phase and in 85% during the mid-luteal phase (P < 0.001). Pulsatility index at the early follicular phase was found to be 1.05 +/- 0.22, during the periovulatory phase 0.99 +/- 0.22 and during the mid-luteal phase 0.85 +/- 0.22. The appearance of intraovarian flow velocity waveforms may suggest either ovarian neovascularization or final follicular maturation or luteinization, which can be detected or measured by Doppler technology.