Middle cerebral artery blood velocity during controlled ovarian hyperstimulation

Objective: To measure cerebral blood flow velocities using transcranial Doppler during ovulation induction after pituitary suppression. Design: Women undergoing controlled ovarian hyperstimulation after pituitary suppression were prospectively studied. Setting: Tertiary institution. Patients: A microprocessor-controlled directional pulsed-wave adjustable hand held probe (2 MHz) was used to measure blood flow velocities and pulsatility indices in the right and left middle cerebral arteries (middle cerebral artery) in nine patients. Measurements of peak middle cerebral artery velocities (cm/s) and pulsatility index were obtained after achieving pituitary suppression with leuprolide acetate and repeated over several days after treatment with human menopausal gonadotropin (225 IU/d). Results: There was a significant increase in the peak middle cerebral artery velocities (cm/s) of the patients measured at the time of pituitary suppression when compared with those obtained at the time of maximal estradiol (E₂) (98 ± 12 versus 105 ± 12, P < 0.03). The pulsatility index also showed a significant increase from 0.72 ± 0.08 at the time of pituitary suppression to 0.82 ± 0.04 at the time of maximal hyperestrogenism, P < 0.002. Estradiol values obtained at the time of the transcranial Doppler examinations were normalized by transformation to their natural logarithms (LnE₂). The middle cerebral artery velocities were significantly correlated with LnE₂ levels (P < 0.0001 and r = 0.93). Conclusion: Estrogen levels appear to be directly correlated with cerebral blood flow velocity and pulsatility index, implying an effect of ovarian steroids on cerebrovascular hemodynamics.