Short answer: For most women, only a little, if at all. Estrogen labels say a large placebo-controlled trial found no general effect on blood pressure, while a small number of case reports describe large rises as an individual reaction. In the Women's Health Initiative, women with high blood pressure who took hormone therapy had systolic readings about 1 to 2 mm Hg higher than on placebo. The labels say blood pressure should be checked at regular intervals.
The estradiol tablet label and the Premarin label carry the same paragraph on elevated blood pressure: in a small number of case reports, substantial increases have been attributed to idiosyncratic reactions to estrogens, meaning unusual reactions in particular people, while in a large randomized placebo-controlled trial a general effect of estrogen on blood pressure was not seen. The estradiol tablet label adds that blood pressure should be monitored at regular intervals with estrogen use.
The patient information for both lists high blood pressure among the possible side effects of estrogens.
| Trial | Women | Treatment | Blood pressure result |
|---|---|---|---|
| PEPI (1995) | 875 healthy postmenopausal women, 45 to 64, for 3 years | Premarin 0.625 mg alone or with a progestin, vs placebo | Systolic pressure rose during the trial, but did not differ by treatment |
| WHI secondary analysis (2023) | 9,332 women with high blood pressure, 50 to 79 | Premarin 0.625 mg alone | Systolic about 0.9 mm Hg higher than placebo |
| WHI secondary analysis (2023) | Same group | Premarin 0.625 mg plus MPA 2.5 mg | Systolic about 1.8 mm Hg higher than placebo |
PEPI was built to measure four heart risk factors: HDL cholesterol, systolic blood pressure, insulin and fibrinogen. Estrogen raised HDL and lowered LDL cholesterol in that trial, while blood pressure did not move differently from placebo. In the WHI analysis, the number of blood pressure medicines women took did not differ between hormone and placebo groups during the trial or across 16 years of follow-up. In the Premarin label's first-year trial table, hypertension was reported in 1 to 2% of women on Premarin and 2% on placebo.
The trials above used oral conjugated estrogens. The labels do not give separate blood pressure numbers for patches, gels or vaginal estrogen. See patch vs pill and blood clot risk for where the route of estrogen has been compared.
A rise of 1 to 2 mm Hg averaged across thousands of women can hide a larger change in one person, which is why the labels describe both. Home readings logged over time are easier to read than a single office visit. Dose Track can log blood pressure readings alongside each hormone dose to share with the prescriber, who decides whether anything needs to change.
Read more on Dose Track: Blood pressure · Estradiol tablet side effects · Women's Health Initiative · Menopause