Vaginal Estradiol Cardiovascular Impact: Long-Term Safety Evidence

What is known about vaginal estradiol and cardiovascular risk?

The long-term cardiovascular evidence is observational. The main outcome data come from the Nurses' Health Study, which followed postmenopausal women who were not using systemic hormone therapy from 1982 to 2012, with vaginal estrogen use self-reported on biennial questionnaires and outcomes confirmed from medical records [1]. Over 18 years of follow-up, after adjustment for covariates, the risks of cardiovascular disease, cancer and hip fracture were not different between users and non-users of vaginal estrogen, and no health outcome examined showed a statistically significant increase in risk [1]. Its cardiovascular outcomes were total myocardial infarction, stroke and pulmonary embolism or deep vein thrombosis [1]. The report describes vaginal estrogen use in general and does not identify a specific vaginal estrogen formulation [1]. The authors say their findings lend support to the safety of vaginal estrogen use [1].

How much estradiol actually reaches the blood?

A 2020 systematic review summarized systemic estradiol levels across low-dose vaginal products using sensitive mass spectrometry assays [2]. Untreated postmenopausal women averaged 3.1 to 4.9 pg/mL, and the authors proposed a normal untreated range of undetectable to 10.7 pg/mL [2]. Against that background:

• A 10 mcg tablet insert produced 6.6 to 14.8 pg/mL [2].
• A 10 mcg softgel capsule insert produced 4.6 to 7.4 pg/mL [2].
• A 4 mcg softgel capsule insert produced 3.6 to 3.9 pg/mL [2].
• A 25 mcg tablet insert produced 16.7 to 22.7 pg/mL, and a 25 mcg softgel capsule 7.1 to 9.1 pg/mL [2].

Absorption was dose-dependent and varied by formulation, and the review notes it may also be influenced by how high in the vagina the product is placed [2]. The authors conclude that very low systemic estradiol absorption with low and ultralow-dose vaginal estrogens may potentially decrease any adverse events associated with estrogen [2]. That is a pharmacokinetic argument, not an outcome finding.

What the 0.01% estradiol vaginal cream label says

The estradiol vaginal cream, 0.01% label (effective 2026-04-13) opens with a boxed warning titled endometrial cancer, cardiovascular disorders, breast cancer and probable dementia [3]. It states that estrogen-alone therapy should not be used for the prevention of cardiovascular disease or dementia, and describes the Women's Health Initiative estrogen-alone substudy, in which daily oral conjugated estrogens 0.625 mg was associated with increased risks of stroke and deep vein thrombosis in women aged 50 to 79 over 7.1 years [3]. It also states that in the absence of comparable data, these risks should be assumed to be similar for other doses of conjugated estrogens and other dosage forms of estrogens [3].

The warnings section adds a point specific to this product: systemic absorption may occur with estradiol vaginal cream, 0.01%, and the warnings, precautions and adverse reactions associated with oral estrogen treatment should be taken into account [3]. The cream's contraindications include undiagnosed abnormal genital bleeding, known or suspected breast cancer or a history of it, estrogen-dependent neoplasia, active DVT or PE or a history of these conditions, active arterial thromboembolic disease such as stroke or MI or a history of these conditions, known liver dysfunction or disease, and known protein C, protein S or antithrombin deficiency or other thrombophilic disorders [3].

The label says that if a stroke, DVT, PE or MI occurs or is suspected, estrogen therapy should be discontinued immediately, and that where feasible estrogens should be discontinued at least 4 to 6 weeks before surgery of a type associated with increased thromboembolism risk, or during prolonged immobilization [3].

Where the boxed-warning cardiovascular findings come from

The cardiovascular findings cited in that boxed warning come from trials of oral conjugated equine estrogens [3]. In the Women's Health Initiative estrogen-alone substudy, 10,739 women aged 50 to 79 with prior hysterectomy received 0.625 mg/day oral conjugated equine estrogens or placebo, and the trial was stopped early after an average of 6.8 years, with hazard ratios of 0.91 for coronary heart disease and 1.39 for stroke [6]. The companion trial of 16,608 women with a uterus tested conjugated equine estrogens 0.625 mg plus medroxyprogesterone acetate 2.5 mg and reported hazard ratios of 1.29 for coronary heart disease, 1.41 for stroke and 2.13 for pulmonary embolism [7]. Neither trial tested estradiol, and neither tested a vaginal product.

The Climara transdermal estradiol label handles this differently, stating that only daily oral conjugated estrogens 0.625 mg were studied in the WHI estrogen-alone substudy, so the relevance of those findings to lower doses and other routes of administration is not known [8]. The vaginal cream label instead says similar risks should be assumed in the absence of comparable data [3].

Route of administration and clot risk

The strongest human data separating routes concern venous thromboembolism, and they compare oral with transdermal delivery. The ESTHER case-control study, conducted in France between 1999 and 2005, matched 271 women with a first idiopathic venous thromboembolism against 610 controls [5]. The adjusted odds ratio for venous thromboembolism in current users versus non-users was 4.2 (95% CI 1.5 to 11.6) for oral estrogen and 0.9 (95% CI 0.4 to 2.1) for transdermal estrogen [5]. A 2008 meta-analysis of eight observational studies and nine randomized trials found a pooled odds ratio for first venous thromboembolism of 2.5 (1.9 to 3.4) for oral estrogen and 1.2 (0.9 to 1.7) for transdermal estrogen, with a pooled randomized estimate of 2.1 (1.4 to 3.1) for oral estrogen [9].

Neither analysis examined vaginal estradiol, and the transdermal comparisons are non-randomized [5][9]. The Climara label still lists clot warnings and contraindications [8].

What the Cochrane review of vaginal estrogens covers

The 2016 Cochrane review compared intravaginal estrogen preparations for vaginal atrophy in postmenopausal women, including creams, pessaries, tablets and the estradiol-releasing ring, with a minimum of 12 weeks of treatment [4]. Its primary outcomes were participant-assessed symptom improvement and the adverse event of endometrial thickness; secondary outcomes were clinician-assessed symptom improvement, other adverse events such as breast disorders, total adverse events, and adherence [4]. The outcomes listed in its abstract are symptom and local safety measures; cardiovascular events are not among them [4].

What has changed in FDA labeling

On 2025-11-10 the FDA asked makers of menopausal hormone therapy products to remove boxed-warning language on cardiovascular disease, breast cancer and probable dementia, remove the recommendation to use the lowest effective dose for the shortest time, and add consideration of starting therapy for moderate to severe vasomotor symptoms in women under 60 or within 10 years of menopause [10]. The agency noted that it had received questions about whether the boxed warnings were warranted, particularly for local vaginal estrogen-only products, and said cardiovascular and breast cancer information stays elsewhere in the labeling [10].

On 2026-02-12 the FDA approved updated labels for six products, including one topical vaginal estrogen [11]. That topical vaginal product is Estring [12]. The estradiol vaginal cream, 0.01% label in DailyMed, effective 2026-04-13, still carries the longer boxed warning described above [3]. Label changes are rolling out product by product, so what a given vaginal estradiol product's label says depends on which product it is.