Winter is gradually receding, and right on cue in February, they appear: the heart decorations for Valentine's Day. Plump red hearts hang everywhere, stare at you from shop windows, pulsate across the internet.
Their image has prompted me to write something about the often-neglected topic of endo and heart problems—or more precisely, "heart palpitations."
Because as much as research points to the connection between endo and cardiovascular risks, the unpleasant arrhythmia symptoms seem to remain partly invisible when it comes to women's health education around endometriosis.
And yet, upon closer inspection, there are several scientific publications that address the topic of arrhythmia more closely.
A 2025 review on endometriosis and cardiovascular disease summarizes various cohorts and states, among other things, that endometriosis is associated with an approximately 26% increased risk of arrhythmias (according to a British study). Generally, an elevated overall cardiovascular risk in endometriosis is considered plausible, although individual studies find varying effect sizes.
Another research gap arises from the fact that there are currently hardly any published specific studies primarily focused on clinical heart symptoms (palpitations, skipped beats, etc.) in the form of symptom diaries or Holter monitoring in endometriosis patients. The focus is usually on diagnosed cardiovascular events and arrhythmic diagnoses in registries, not on subjective symptoms.
And yet many of us know them: those unpleasant skipped heartbeats. Whether caused by increased inflammatory activity, general exhaustion, or hidden iron deficiency due to heavy blood loss (e.g., in adenomyosis).
Since endometriosis is now considered a systemic disease, it makes sense that cardiac arrhythmias can be promoted through multiple pathways. The mechanisms can be roughly divided into vascular/cardiac structure, inflammation/stress, and neuro-hormonal regulation.
In the following, it's worth looking at the biological levels where these connections can mechanistically unfold.
Chronic Inflammation and Vascular Damage
Reviews show increased endothelial dysfunction and arterial stiffness in endometriosis, which can promote electrical instability and ischemic micro-damage to the myocardium—a breeding ground for arrhythmias.
Low-grade systemic inflammation and oxidative stress additionally lead to impaired endothelial function and disrupted vascular tone.
Hormonal Factors (Estrogen/Progesterone)
Endometriosis typically involves estrogen excess and progesterone resistance. Estrogen, in turn, affects ion channels, conduction, and the QT interval. Cyclic hormone level fluctuations can thus modulate susceptibility to supraventricular and ventricular arrhythmias.
Autonomic Nervous System
Studies show reduced vagal activity (heart rate variability markers) in women with endometriosis, indicating a disturbed autonomic balance.
Additionally, chronic pain, stress, and sleep disturbances often amplify this sympathetic overactivity, which can promote tachycardias and rhythm instability.
This bundle of conditions, risk factors, and dysregulations is assumed in most analyses to be the reason for the increased arrhythmia risk in endometriosis.
If such a risk appears plausible, the question inevitably arises whether and where gentle therapeutic approaches might exist.
Leonurus cardiaca – Motherwort
In recent years, motherwort—known in European traditional medicine—has finally carved out its place as an over-the-counter remedy for palpitations, independent of endometriosis, for cardiac patients who, according to cardiological assessment, don't (yet) need strong medications. For the cardiac indication (extrasystoles, functional tachycardias with nervousness), the traditional use is now well established.
The botanical name of a species widespread in Eurasia: Leonurus cardiaca—where Leonurus refers to the lion's tail and points to the shape of its clustered labiate flowers, which hang densely and shaggily like a lion's tail tuft.
Cardiaca refers, as does everything in cardiology, to the heart.
But is there research on Leonurus and endometriosis? Does the lion's tail have potential to address rogue endo cells?
Not really.
To be brief upfront: There is experimental evidence that components of motherwort (especially from the related species Leonurus japonicus) have anti-inflammatory effects on uterine/endometrial tissue. However, direct, well-documented research specifically on endometriosis in humans remains very limited and rather indirect.
Interestingly, traditional medicine does attribute effects on "women's ailments" to motherwort. There is a known uterine connection, with the herb cited as an effective helper for menstrual cramps, PMS, and menopausal complaints. Naturopathic approaches therefore often use motherwort to relieve dysmenorrhea, cycle irregularities, anxiety/tension, and various climacteric symptoms. These symptoms may partially overlap with endometriosis, but not necessarily.
In scientific reviews, Leonurus cardiaca is found in connection with cardioprotective, anti-inflammatory, analgesic, and uterotonic effects, but endometriosis is not listed as a clearly studied clinical application. As a side effect, it can increase bleeding tendency (antithrombotic/antiplatelet effects), which is relevant for heavy menstrual bleeding or concurrent use of anticoagulants/platelet aggregation inhibitors.
Relevant Active Compounds and Uterine Effects
Important constituents of motherwort include alkaloids such as stachydrine and leonurine, as well as certain coumarin derivatives. They show vasodilating, anti-inflammatory, and smooth muscle-modulating effects.
A 2025 animal study on "motherwort total alkaloids" (from Leonurus japonicus) showed that the 39 identified alkaloids significantly attenuate experimentally induced endometritis (inflammation of the uterine lining) through inhibition of the PI3K/AKT/NF-κB signaling pathway and reduction of inflammatory mediators.(1)
The same study also states that these alkaloids show "anti-endometriosis effects" in vitro through downregulation of the PI3K/AKT/NF-κB signaling pathway in endometrial cells.
However, human studies are still pending in this context, and this involves a related species, not our European motherwort.
Yet it wouldn't be the first time that traditional European medicine, through decades of application reports, provides clues to potential future active compounds that could be useful in the search for an endometriosis medication.
The lion's heart of us endo patients therefore needs, besides courage, above all one thing: patience for the science.
Find studies on comorbidities and endo on the Studies page →
(1) Effect of Leonurus japonicus alkaloids on endometrial inflammation and its mechanisms