Purpose: Intraovarian arterial blood flows before and after follicular rupture in ovulation induced cycles were examined by transvaginal color flow Doppler imaging. The changes observed in the intraovarian arterial resistance before and after ovulation in relation to the regularity of menstruation and several other parameters were analyzed.
Methods: In a prospective study, 22 patients undergoing infertility treatment in our center were recruited. Patients were divided into two subgroups, according to their menstrual regularity (regular menstrual group and oligomenorrheal group) and 42 cycles were studied. All patients received the same FSH low-dose stimulation treatment. The relationship between the post and preovulatory arterial pulsatility indexes (PI) was analyzed. Cycles that showed a decrease in their PI after ovulation of 10% or more were considered "profoundly decreased cycles." Cycles from the same patients without ovulatory stimulation (natural cycles) were used as control.
Results: In the regular menstrual group the rate of profoundly decreased cycles during FSH stimulation was 63.2%, which was similar to the rate observed in natural cycles. In the oligomenorrheal group the rate of profoundly decreased cycles during natural cycles was 14.3%, but in FSH ovulation induction cycles this rate was significantly increased (47.6%, p < 0.05). In addition, the pregnancy rate per cycle in the oligomenorrheal group was significantly higher than that in the regular menstrual group (p = 0.03).
Conclusions: Oligomenorrheal patients presented a higher rate in the decrease of their PI values after FSH stimulation, which is essential to achieve pregnancy. This elevated rate of reduction implies that oligomenorrheal patients have increased incidence of disturbance in their ovulatory process when compared to normal cycling patients. Thus, ovulation induction with FSH, in oligomenorrheal patients resulted in a higher pregnancy rate in this group.