The presence of an IUD does not interfere with the vascular resistance of the uterine arteries that can be shown by Doppler flow assessments 1 month after insertion.

Our study demonstrates that estrogen reduces the vascular resistance of the central retinal artery in postmenopausal women because of a vasodilatory effect.

Our results demonstrate the existence of a progestogenic vasoconstrictive effect in the ophthalmic and central retinal arteries. As this study provides new data, the observed effect needs further investigations to better elucidate its extent. Moreover, our findings may be particularly useful to others interested in understanding the vascular dynamics of the cerebral vessels and to researchers running clinical trials related to hormone replacement therapy.

Our study demonstrates that tibolone administration to healthy postmenopausal women does not affect the resistance of small-caliber cerebral arteries.

Resumo de tese Palavras-chave Tibolona Artéria oftálmica Artéria retiniana Ultra-sonografia Doppler Ensaio clínico Aleatório Controlado com placebo Keywords Tibolone Ophthalmic artery Central retinal artery Doppler analyzes randomized clinical trail Placebo controlled Efeito da tibolona sobre artérias oftálmica e retiniana avaliados pela ultra-sonografia Doppler Effect Tibone's use on retinal and ophthalmic arteries evaluated by Doppler ultrasound