Blood flow variations in internal carotid and middle cerebral arteries induced by postmenopausal hormone replacement therapy

Am J Obstet Gynecol. 1993 Nov;169(5):1226-32. doi: 10.1016/0002-9378(93)90287-s.


Objective: Our purpose was to clarify the mechanisms by which postmenopausal estrogen replacement therapy exerts its protective effect on cardiovascular risk.

Study design: By means of a bidirectional Doppler ultrasonographic system we measured pulsatility index variations the internal carotid artery and middle cerebral artery in 25 early postmenopausal women during a 6-month period of hormone replacement therapy. Transdermal estradiol (50 micrograms/day) was continuously administered. A 12-day course of medroxyprogesterone acetate (10 mg/day) was added every second month.

Results: The pulsatility index showed a significant (p = 0.0001) reduction in both arteries after 6 weeks. At 22 weeks a 25% reduction was measured. No variation of the estrogen-induced pulsatility index reduction was observed at the end of every cyclic progestogen supplementation.

Conclusions: In early postmenopausal women hormone replacement therapy causes a rapid reduction of pulsatility index in brain arteries. Cyclical progestational supplementation does not modify this positive effect on reactivity of the blood vessels.

MeSH terms

  • Administration, Cutaneous
  • Carotid Artery, Internal / diagnostic imaging
  • Carotid Artery, Internal / drug effects*
  • Cerebral Arteries / diagnostic imaging
  • Cerebral Arteries / drug effects*
  • Estradiol / therapeutic use
  • Estrogen Replacement Therapy*
  • Estrone / analogs & derivatives
  • Estrone / urine
  • Female
  • Humans
  • Medroxyprogesterone Acetate / therapeutic use
  • Middle Aged
  • Pulsatile Flow / drug effects
  • Regional Blood Flow / drug effects
  • Ultrasonography


  • estrone-3-glucuronide
  • Estrone
  • Estradiol
  • Medroxyprogesterone Acetate