Womens Health

Does Estrogen Replacement Therapy Cause High Blood Pressure?

Frederick R. Jelovsek MD, MS

"Does taking estrogen (alone) elevate blood pressure in some women? I am 69, have taken estrogen for 15 (or more) years after a hysterectomy. Have had hypertension most of that time controlled with medication. One year ago I discontinued Ogen® after blood pressure was very high. Since then blood pressure is down and normal. Any connection?" Elise

There is generally considered to be an age related rise in blood pressure in women. It does not happen with everyone however. One study compared lay women with nuns over a 30 year time period with regard to how their blood pressure did (1). None of the women in either group were smokers and none took birth control pills nor did they use estrogen replacement therapy. They found that the group of nuns did not have the expected rise in blood pressure with age compared to the lay women. They attributed this to the lower stress level in the nunnerlie. It would also be possible that diets were different but in either case this is quite interesting.

Oral contraceptives which contain estrogen and progestin are known to sometimes raise blood pressure. Therefore many people assume that estrogen replacement therapy (ERT) or hormone replacement therapy (HRT) also increases blood pressure, however, this does not seem to be the case at all (2). Most of the evidence points to a lowering of blood pressure from ERT.

This is not to say that in your case the ERT did not raise your blood pressure. The coincidence of the blood pressure returning to normal when you discontinued it is too much to ignore. You may have had a hypertensive reaction to the specific estrogen formulation you were on or if you were taking any other medications during that time, there may have been interactions. If you stopped the ERT because of another problem, it is possible that the other problem actually lowered your blood pressure. You need to look at many different changes over that time period that may have influenced your blood pressure. Finally, in the late age 60's, your estrogen dose should have been at the level of 0.3 mg - 0.625 mg of conjugated estrogen equivalent (0.05 mg - 0.1mg estradiol). If you were on higher doses that could be the explanation.

Does estrogen replacement after menopause raise blood pressure?

In healthy post menopausal women, both ERT and HRT lower blood pressure compared with placebo (3). The average reduction is systolic pressure is 7% and the reduction of diastolic pressure is 16%.

In women who have hypertension, does ERT make the blood pressure worse?

No. In fact it seems the opposite. Several studies found that estrogen replacement actually lowers the blood pressure in women with hypertension who were on antihypertensive medicines. Interestingly, in women who were on calcium channel blockers for their hypertension, the blood pressure reduction was only half that of women on other types of antihypertensives suggesting that estrogen may function like a calcium channel blocker in lowering hypertension. Another randomized trial testing HRT and placebo found a reduction in the thickness of the heart wall (a long term effect of high blood pressure) in women taking HRT versus placebo. While HRT decreases blood pressure on the average in women with hypertension, not all women respond. About 40-45% of hypertensive women will have a lowering of blood pressure with HRT.

One study examined using injectable shots for ERT and HRT in a group of women who had moderate hypertension and who had discontinued their anti hypertensive medication. They found that the ERT and HRT did not raise blood pressure but also, the group of women receiving the inactive placebo medication had a decrease in blood pressure over the ninety day follow-up period. This may have been the same phenomenum that happened in your case, i.e., the hypertension itself improved perhaps with the lower stress and strain of worry about taking medications or other stress producing life circumstances.

Are there other effects of ERT on the cardiovascular system?

Hormone replacement has been found to decrease the incidence of calcium deposition in the blood vessels of the heart. In addition to the previously mentioned decrease in heart wall thickness, it also appears that ERT improves cardiac output and function both at rest and with exercise. Improved cholesterol levels are well documented from ERT with a lowering of the low density lipids (LDL) and a raising of the high density lipids (HDL) which is the good cholesterol.

These benefits must be weighed against a possible small increase in the incidence of thrombosis in women who already have vascular disease. The large randomized trial of HRT in women who already had coronary artery disease suggests so far that there may be an early adverse effect (? thrombosis) and then a later beneficial effect of HRT on heart attacks and death. We will have to see further data on the HERS study to know for sure.

Is there a soy substitute for Premarin® or Ogen® that would be as beneficial or nearly so as the estrogen?

Plant estrogens such as those derived from soy and red clover have effects somewhat like prescription estrogens although not as much. Phytoestrogens commercially available are mostly isoflavones in soy and a product called Promensil®. Isoflavones (40 mg/day) have a significant positive vascular effect like estrogens but they do not improve the lipid profile as do pharmaceutical estrogens. Athough they help the ability of the blood vessels to remain elastic and not hardened, isoflavones do not lower blood pressure in hypertensive patients.

My overall conceptual model of the plant estrogens is that they definitely have a beneficial effect on the cardiovascular system as well as osteoporosis but it is just not as much as HRT or ERT; I would assess them as about 50% effective. I would recommend taking a supplement of plant estrogens containing at least 40 mg of isoflavones if you are not taking ERT or HRT.


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