Overview

Postural orthostatic tachycardia syndrome (PoTS) is a condition that results in a sudden, increased heart rate when you stand up from lying down or sitting down. 

The words in the syndrome stand for:

• Postural: It involves body posture
• Orthostatic: It involves the body being in an upright position
• Tachycardia: When the heart beats rapidly
• Syndrome: A combination of symptoms
  

Symptoms of PoTS may include vertigo, tiredness, brain fog, heart palpitations, shortness of breath, and fainting. This varies from mild to severe between individuals, which can significantly impact their quality of life.¹

Women aged 15-50 years are more likely to experience PoTS, as the condition is heavily influenced by hormonal activity. Women of childbearing age experience intense hormone fluctuations due to menstrual cycles and pregnancy, which makes them more prone to PoTS. 

By understanding the role of hormones, particularly during the menstrual cycle and pregnancy, patients can better understand and manage their symptoms. 

Diagnosis of PoTS

Healthcare providers diagnose PoTS after taking the patient’s medical history and performing physical examinations,¹ which include:

Electrocardiography (ECG)

This examination is performed to better understand the heart’s electrical conductivity, rate, and rhythm, and to exclude any other conditions with overlapping symptoms.

Head-up tilt table test

The examination is performed by lying on a tiltable surface for about 5 to 20 minutes. Afterwards, the table tilts slowly to 60-70 degrees, and the patient remains in an upright position for 10 to 45 minutes. Blood pressure and heart rate are constantly monitored, and the patient is asked how they are feeling during the examination. 

Heart rate monitor

A heart rate monitor is patched onto the patient’s chest and records heart activity for 24 hours, while the patient is asked to go on with their normal day-to-day activities. 

Blood and urine tests

A routine blood test may be performed to understand the patient’s health profile and rule out other conditions. Additionally, the patient may be asked to provide a urine sample to test for sodium levels. In PoTS, sodium levels are typically less than 170 millimoles per litre of blood. 

Understanding hormones

What are hormones?

Hormones are the body’s message carriers. They transfer chemical information that controls many body functions.

Key hormones involved in the menstrual cycle and pregnancy

• Oestrogen: It helps grow the uterine lining and regulates other hormones.
• Progesterone: It prepares the body for a potential pregnancy.

The menstrual cycle

There are 4 phases of the menstrual cycle.

• Phase 1 — Menstruation: The uterine lining sheds and blood flows out of the vagina
• Phase 2 — Follicular: The lining of the uterus thickens again, and follicles start to grow
• Phase 3 — Ovulation: One grown follicle contains a mature egg, which is released from one ovary
• Phase 4 — Luteal: The mature egg travels through the fallopian tube to the uterus. If fertilisation does not occur during the egg’s journey to the uterus, the menstrual cycle will resume from phase 1 

During the 4 phases of the menstrual cycle, hormone levels rise and drop to facilitate each phase.²

Menstrual cycle and PoTS

Just before the period starts (during the transition from the late luteal phase to the menstrual phase), oestrogen and progesterone levels are low. This is because fertilisation did not occur in the preceding ovulation to luteal phase, and therefore high levels of these hormones are not needed to sustain an early pregnancy. 

Symptoms of PoTS tend to worsen when oestrogen levels are low, and women are more likely to experience increased heart rate, dizziness, and fatigue. 

Oestrogen is a hormone that has various functions — apart from its important role in reproductive health, it is also a vasodilator, affecting the width of blood vessels. When oestrogen levels are low, there is less space for blood to flow within the blood vessels. This can result in less blood reaching the brain, and therefore an increased heart rate in an attempt to pump more blood to the brain.³

Some PoTS symptoms, such as lightheadedness, have been reported to be less intense during the follicular phase, which is when oestrogen levels rise again.⁴

Pregnancy and PoTS

Over the course of a pregnancy, there are major hormonal changes, with oestrogen and progesterone levels being the most affected. In the first 8 weeks of pregnancy, the amount of blood pumping from the heart to the rest of the body increases by 20%, and by 20-28 weeks, it increases by 40%. This increase in cardiac output is caused by increased oestrogen levels and other factors.⁵ 

This mainly happens because increased blood volume and heart activity are needed to maintain the increased function of all organ systems to accommodate a growing fetus.

Symptoms of PoTS during pregnancy vary depending on the individual and the trimester. 

• First trimester: The severity of PoTS symptoms during the first trimester may serve as an indicator of what the symptoms will look like for the rest of the pregnancy; however, improvements or worsening remain a possibility.
  During the first trimester, the body undergoes major hormonal and blood pressure changes, and some women report worsening PoTS symptoms
• Second trimester: As the pregnancy proceeds, the body adapts to the major changes from the first trimester, and some women experience improved symptoms
• Third trimester: Symptoms can return, especially in the last phase of the third trimester, as the body prepares for birth⁶

After birth, some women report worsening symptoms. This may be due to the oestrogen levels dropping in the postpartum period and remaining low until the menstrual cycle and ovulation resume.⁷

Why hormones matter in managing PoTS

The majority of women will experience menstrual cycles in their lifetime, and some women will also experience a pregnancy. When dealing with PoTS, it is important to understand the way hormones work during these phases in order to manage symptoms. 

Awareness about symptoms and when they happen can help patients better communicate their experience with PoTS to healthcare providers. 

This way, professionals can come up with a treatment that supports individuals during their menstrual cycle phases and pregnancy. 

Management tips for hormone-related PoTS fluctuations

Depending on the severity of PoTS and how much the symptoms affect an individual's life, management of the condition involves therapies with or without medication.

PoTS symptoms during the menstrual cycle

During the menstrual cycle, lifestyle changes are the first-line treatment for PoTS symptoms. Some of these include: 

1. Drinking more water and including electrolytes (hydration is key)
2. Eating more salt to help with blood volume; however, it is important to first consult a doctor regarding salt intake
3. Tracking your cycle to understand when symptoms get better and when there is a flare-up.
4. Using compression garments to relieve symptoms
5. Resting more, especially if you get more easily fatigued and dizzy

If the symptoms do not get better, you can discuss with your doctor about hormone-related therapies, such as birth control pills and hormone injections. The latter method, however, remains unclear as to whether it helps manage PoTS symptoms, and further research is required to draw conclusions.^4,8 

PoTS symptoms during pregnancy

Pregnancy affects blood volume and circulation, which can both improve or worsen PoTS depending on the stage. Medication-free ways of managing PoTS include:

1. Staying hydrated
2. Eating more salt to maintain blood pressure; again, it is important to consult with a doctor first
3. Using compression garments to relieve symptoms
4. Light exercises such as prenatal yoga can help with symptoms; consult a doctor before taking up exercising to minimise risks

As of 2024, there is no approved medication for PoTS. For pregnant women, healthcare providers may prescribe off-label beta-blockers and clonidine to slow down the heart rate and regulate blood pressure. Other treatment options include fludrocortisone and midodrine. Additionally, anti-vomiting medication or admission of intravenous fluids may be recommended, if vomiting is part of PoTS or pregnancy symptoms. Vomiting can lead to dehydration and low blood volume, increasing the severity of symptoms like dizziness and fainting. 

Approximately 60% of women receiving medication for PoTs have improved symptoms during pregnancy.⁹ 

However, it is important to know that the medication mentioned is not proven to treat symptoms of PoTS, but healthcare providers might recommend the medication route to investigate the different effects medicine has on the individual. 

Treatments should always be individualised, and in the context of pregnancy, it is crucial to consult with an expert team such as gynaecologists to confirm the safety of certain medications during pregnancy and help manage symptoms. 

FAQs

Does PoTS affect more females or males?

While people assigned male at birth can also experience PoTS, the condition is more prominent in women. 

How do menstrual cycles and pregnancies affect PoTS?

During these events, hormone levels rise and drop really quickly. This can worsen symptoms of PoTS. 

How do I manage PoTS?

Hormone-related symptoms of PoTS can be managed with lifestyle changes or certain medications. Always consult a healthcare provider regarding managing PoTS with medication. 

Summary

PoTS is a condition prominent in women of reproductive age (aged 15 to 50 years). During these ages, hormone levels fluctuate constantly either due to menstrual cycles, or potential pregnancies. Hormonal activity is strongly linked to the severity of PoTS symptoms, impacting patients’ daily activities and overall quality of life. 

While medication can be provided to alleviate symptoms, it is important to pay attention to body signs and understand hormonal patterns that may cause flare-ups, in order to adapt your lifestyle in a way that decreases the severity of symptoms and benefits your health.

More research is ongoing to understand how to better support patients and relieve symptoms, but in the meantime, awareness of your symptoms and expert input can positively affect your life.