Endometrial and myometrial thickness and uterine blood flow in postmenopausal women: the influence of hormonal replacement therapy and age.

The aim of our study was to assess the age and hormonal influence on endometrial and myometrial thickness and uterine blood flow in postmenopausal women. One hundred and nine healthy postmenopausal women were examined by transvaginal ultrasonography and color Doppler ultrasonography. Twenty women (18.4%) were under continuous HRT for at least 1 year. In all patients, full thickness of the endometrium and half thickness of the myometrium was measured. Pulsed Doppler waveforms were used to calculate the RI for the left and right uterine arteries. Endometrium thickness in the groups without HRT did not change as the years of postmenopause progressed. This was also true for myometrial thickness. The resistance to blood flow in the uterine arteries remained the same as the postmenopause progressed, but with each 5 year analysis, the ability to see the uterine arteries decreased. The duration of the therapy did not affect the measured parameters. The thickness of the endometrium was larger in the groups with HRT in comparison with all groups without HRT (P < 0.01). Myometrial thickness and uterine blood flow are not affected and did not show any significant influence from HRT. In conclusion, continuous HRT significantly influences the thickness of the postmenopausal endometrium but not of the myometrium or the uterine artery blood flow.