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The temporal effect of progestogen on uterine artery pulsatility index in postmenopausal women receiving sequential
M S Marsh1, T H Bourne, M I Whitehead
1Academic Department of Obstetrics and Gynaecology, King's College School of Medicine and Dentistry, London, United Kingdom.
Objective:
To determine the time relationship between the ingestion of progestogen during sequential hormone replacement therapy (HRT) and impedance to blood flow in the uterine arteries.
Design:
Nine postmenopausal women who had already received HRT for at least 6 months were treated with either transdermal 17 beta-E2, 0.1 mg/d, or conjugated equine estrogens (Es), 1.25 mg/d, to which norethindrone, 0.7 mg/d, was added for 12 days in a single 28-day cycle of therapy. Transvaginal ultrasonography with color flow imaging was used to measure the pulsatility index (PI) in the uterine arteries every 3 to 5 days over one 28-day treatment cycle.
Results:
The ingestion of norethindrone increased the mean uterine artery PI by 30% (SE 16.4%). The PI fell significantly within 4 days of ceasing norethindrone.
Conclusion:
Progestogen addition in sequential HRT causes changes in the uterine arterial tone, but the effect subsides within 4 days of progestogen withdrawal.