Understanding the Risks & Side Effects of HRT: What You Need to Know

Hormone replacement therapy (HRT) can be life-changing for many women. From easing hot flushes and night sweats to improving mood, sleep, and overall quality of life, it’s one of the most effective treatments for menopause symptoms. It supports women’s long-term health when used appropriately.

But like any medical treatment, HRT is associated with potential risks and side effects. Knowing what to expect not only helps you make an informed decision but also brings peace of mind if certain symptoms arise along the way.

Common Side Effects (Usually Temporary)

Most side effects improve within a few weeks as your body adjusts.

Bleeding & Spotting

It’s normal to experience light bleeding or spotting when starting HRT or after changing the dose. This usually settles within 3–6 months. If bleeding is heavy or persistent, you need to speak to your doctor. 

Breast Tenderness

Some women notice breast pain, sensitivity, or a congested, “full” feeling. These often ease over time.

Mood changes

Mood swings or PMT-like symptoms may also happen, especially with the progesterone. If these are significant, then your doctor may recommend adjusting the type or dose.

Weight Changes: Myth vs Reality

Some women notice weight gain on HRT. But research shows most types of HRT are not directly linked to weight gain, which may be more related to menopause itself or midlife. In fact, by improving sleep, energy, and joint pain, HRT can help you stay active and maintain a healthy weight.

Other common side effects

Other side effects may include nausea, headache, fluid retention, heartburn, or bloating. These are again transient and usually improve with time. 

The More Serious (But Rare) Risks

It’s normal to feel concerned when you hear about the potential risks of HRT. The important thing to remember is that most of these risks are small and often comparable to everyday lifestyle factors such as drinking a glass of wine, being overweight, or not exercising regularly. 

The HRT types most often prescribed today, transdermal estradiol and micronised progesterone, were not included in the WHI at all, meaning those early numbers don’t directly apply to modern regimens.

"Much of the anxiety about HRT risks dates back to the Women’s Health Initiative (WHI), first published in 2002. Early reports painted a dramatic picture of harm, stating a significant increased risk of breast cancer, heart attacks and strokes. This resulted in worldwide panic and more than 70% drop in HRT prescribing and we are still trying to catch up. A follow-up analysis tells a very different story and the risks are much lower."

Breast cancer risk

Many of the women I meet are very worried about this risk. But the narrative is changing with more evidence based information available on breast cancer risk. 

• With combined HRT (estrogen plus natural progesterone), there is a very small increase in risk, around 1 extra case per 1,000 women over five years. To put that in perspective, drinking two glasses of wine most nights or being overweight after menopause increases breast cancer risk more than HRT does. This risk may be slightly higher with synthetic hormones. 

• Estrogen-only HRT: For women who’ve had a hysterectomy and need estrogen-only HRT, it does not carry the same breast cancer risk and may even slightly reduce it.

  
  

Blood Clots and Stroke

Oral estrogen ( taken in tablet form) can raise the chance of blood clots and stroke. But estrogen in the form of patches, gels, or sprays does not increase the risk. Similarly, synthetic progestogens can increase the risk of thrombosis, but using natural progesterone does not increase the risk.  

Why Timing Matters

Starting HRT before age 60 or within 10 years of menopause appears to tip the balance in your favour. At this stage, evidence suggests that HRT reduces the risk of heart disease and supports overall longevity.

Cognitive Health & Dementia

Timing is again the key. Early use (around perimenopause) may help protect brain health. However, some studies have shown that starting HRT after age 60 may slightly increase dementia risk, but this is still quite controversial.

Putting It All in Perspective

Your HRT journey should be as unique as you are.

Personalised approach wins

The type of hormone (e.g., body-identical versus synthetic), dosage, administration route (oral vs transdermal), your age, your personal and family risk factors, and how far into menopause you are can all shape your risk profile. Risks can be minimised by tailoring the HRT to your personal circumstances. Keep up with regular screenings, like mammograms, blood pressure, cholesterol, diabetes checks also help. 

Real benefits

HRT remains the most effective treatment for menopausal symptoms (hot flashes, vaginal dryness, mood issues) and reduces the risk of osteoporosis, heart disease, and protects the brain. 

The key is timing, personalisation, and regular medical guidance.

If you’re wondering whether HRT is right for you, the best next step is a personalised consultation. A conversation with your GP or a menopause specialist can help you weigh up your own individual risks and benefits with confidence.

Book your consultation with me today