Are hormone replacement therapy (HRT) patches less likely to cause hypertension than oral contraceptives in peri- or post-menopausal women?

HRT Patches vs Birth Control Pills: Blood Pressure Risk Comparison

HRT patches are substantially less likely to cause elevated blood pressure than oral contraceptives, making them the safer choice for blood pressure management in appropriate candidates.

Direct Evidence on Blood Pressure Effects

Oral Contraceptives and Hypertension Risk

Oral contraceptives consistently cause detectable blood pressure increases and frank hypertension in a significant proportion of users, even with modern low-dose formulations. 1

• Current users of oral contraceptives have an 80% increased risk of hypertension (RR 1.8; 95% CI 1.5 to 2.3) compared with never users 1
• The absolute risk translates to 41.5 cases of hypertension per 10,000 person-years attributable to oral contraceptive use 1
• Many women taking oral contraceptives experience a small but detectable increase in BP, with a small percentage developing frank hypertension—this occurs even with modern preparations containing only 30 µg estrogen 1
• The hypertensive effect is readily reversible, with BP returning to pretreatment levels within 3 months of discontinuation 1
• Oral contraceptives occasionally precipitate accelerated or malignant hypertension 1
• The contraceptive-induced hypertension appears related to the progestogenic, not estrogenic, potency of the preparation 1

HRT and Blood Pressure Effects

HRT produces minimal blood pressure changes that should not preclude hormone use in normotensive or hypertensive women. 1

• The Women's Health Initiative (WHI), the largest longitudinal study, found only an average 1 mm Hg increase in SBP over 5.6 years among 8,506 postmenopausal women randomized to conjugated equine estrogen and medroxyprogesterone acetate compared with placebo 1
• There was no difference in DBP between hormone treatment groups 1
• The Baltimore Longitudinal Study on Aging showed women receiving HRT had a significantly smaller increase in SBP over time than nonusers 1
• The Postmenopausal Estrogen/Progestin Intervention trial showed no effect of HRT on SBP or DBP 1
• Several studies using 24-hour ambulatory monitoring suggest HRT improves or restores normal nighttime BP "dipping" that may be diminished in postmenopausal women, potentially reducing total BP load and target organ damage 1
• Overall, HRT-related change in BP is likely to be modest and should not preclude hormone use in normotensive or hypertensive women 1

Route of Administration Matters for HRT

Transdermal HRT patches have additional advantages over oral HRT formulations regarding cardiovascular and thrombotic risk. 2, 3, 4

• Transdermal estradiol patches avoid first-pass hepatic metabolism, resulting in a more favorable cardiovascular and thrombotic risk profile compared to oral formulations 2
• Transdermal routes have lower rates of venous thromboembolism and stroke compared to oral estrogen 2
• Systolic blood pressure was actually reduced with the transdermal route in controlled studies 4
• Transdermal oestrogens have a lower risk of thrombosis compared with oral regimens 3

Clinical Algorithm for Decision-Making

When Comparing HRT Patches to Birth Control Pills for BP Risk:

1. For perimenopausal/postmenopausal women with vasomotor symptoms:

   • Choose transdermal HRT patches as first-line (50 μg estradiol daily, changed twice weekly) 2
   • Expected BP effect: minimal (≤1 mm Hg increase in SBP) 1
   • May actually improve nocturnal BP dipping 1

2. For reproductive-age women needing contraception:

   • Oral contraceptives carry 80% increased hypertension risk 1
   • Expect 41.5 additional hypertension cases per 10,000 person-years 1
   • Monitor BP closely with 6-month prescription limits recommended 1

3. For women with existing hypertension or cardiovascular risk factors:

   • HRT patches are acceptable with close BP monitoring initially, then at 6-month intervals 1
   • Oral contraceptives require careful risk assessment and may necessitate discontinuation if hypertension develops 1

Critical Caveats

Risk factors that increase susceptibility to contraceptive-induced hypertension include: family history of hypertension, pregnancy-induced hypertension, occult renal disease, obesity, age ≥35 years, and duration of oral contraceptive use 1

Regular BP monitoring is essential: throughout contraceptive therapy, with semiannual reevaluations recommended 1, while hypertensive women on HRT should have BP monitored closely at first and then at 6-month intervals 1

The hypertensive effect of oral contraceptives is reversible within 3 months of discontinuation, but withdrawal may be necessary if hypertension develops 1