Side effects of hormone therapy in menopause

Side effects of hormone therapy in menopause are usually mild and temporary. The complaints you may notice in the first months, such as nausea, tender breasts, headache and irregular bleeding, are often part of adjusting to a new hormone level and tend to ease for many women after that. This article explains which effects you can expect, how long they usually last, why the way the hormones are delivered matters, and when a complaint is instead a reason to seek medical help straight away.

In short

• The most commonly reported side effects are nausea, tender or swollen breasts, headache, a bloated feeling and irregular bleeding. They are usually mild.
• For most women these complaints ease during the first months as the body adjusts. Irregular bleeding can continue for the first three to six months.
• Estrogen delivered through a patch or gel carries a lower risk of blood clots than estrogen in tablet form.
• Persistent complaints are more often a reason to review the dose or delivery method with your doctor than to stop on your own.
• Some signals, such as sudden calf pain, breathlessness or chest pain, call for immediate medical contact.

Which side effects of hormone therapy are most common?

The complaints most often reported in the first weeks are nausea, tender or swollen breasts, headache, a bloated feeling and irregular bleeding. The NHG Standard on menopause describes that roughly 1 to 10 percent of users experience such non-serious complaints, including irregular bleeding, headache, gastrointestinal complaints and painful or tense breasts.

These complaints usually point to the body adjusting to the new hormone level rather than to a wrong treatment. For many women they are mild and temporary. Even so, it differs from person to person: one woman barely notices anything, while another has clear complaints in the first weeks.

How long do the side effects usually last?

Most side effects ease during the first months after you start, as your body adjusts to the hormone level. Irregular bleeding, also called breakthrough bleeding, is the exception: it occurs in many women during the first three to six months and can lessen with a small adjustment to the dose. If irregular bleeding continues beyond six months, further investigation is needed to rule out other causes (NICE, menopause guideline).

If your complaints do not lessen after a few months, in practice that is more often a reason to review the dose or the delivery method with your doctor than to stop. Women who stop too early often see complaints such as hot flashes and night sweats return.

Not sure whether your complaint is part of adjusting or a reason to act? A broader view of menopause can help you put side effects in perspective. Download the free guide →

Why does the method of delivery make a difference?

Estrogen can be delivered in different ways, and that difference matters. With estrogen in tablet form (oral), the active substance first passes through the liver, which influences the production of clotting factors. With a patch or gel (transdermal), the estrogen enters the blood through the skin and largely bypasses the liver.

Research shows that transdermal estrogen goes together with a lower risk of blood clots (venous thrombosis) than oral estrogen. A meta-analysis in the Journal of Clinical Endocrinology & Metabolism found an increased thrombosis risk with oral delivery, while transdermal delivery did not show that risk. The NICE menopause guideline points in the same direction. In practice, switching from a tablet to a patch or gel is therefore, for some women, the first adjustment a doctor suggests when nausea or headache persists, and it can be a consideration where there is a higher risk of thrombosis.

What does the WHI study mean for the risk of hormone therapy?

Many worries about hormone therapy stem from the WHI study in the early 2000s. That study looked mainly at older women, on average around 63 years old, who used a combination of conjugated equine estrogen and a synthetic progestogen (MPA). That is not the same treatment as the bio-identical hormones often prescribed now, and the age at which someone starts matters for the balance between benefits and drawbacks.

Observational research suggests that the type of progestogen can make a difference. In the French E3N cohort study, the breast cancer risk with estrogen combined with micronized progesterone was not significantly increased, while combinations with synthetic progestogens did show an increased risk. It is important to note here: this is observational research and not proof that bio-identical hormones are free of risk. Hormone therapy has real benefits and drawbacks, and whether it suits you is a decision a doctor makes together with you, based on your personal situation and history.

What can you do yourself about side effects?

You are not powerless against side effects. A few things help to keep them manageable:

• Treatment usually starts with a low dose, so your body can adjust. Complaints such as nausea or tender breasts are then often milder.
• Keep track of which complaints you notice in the first weeks, so your conversation with your doctor is based on what you actually experience rather than on memory.
• Take a tablet with some food if it makes you nauseous, and discuss a patch or gel if the complaint persists.
• Do not stop on your own, but talk with your doctor about a dose adjustment or a different delivery method.

At Menovia we review your complaints and blood values at set moments, so that a temporary adjustment complaint is distinguished from a dose that is not yet well tuned. Bio-identical hormones form the core of the treatment, while lifestyle is an important addition. If you want to know what to look for when choosing care, read more about a hormone therapy menopause clinic.

When to see a doctor

Most side effects are harmless, but a number of signals call for immediate action. Contact your doctor straight away or call the emergency number if you have:

• sudden, severe pain or swelling in a calf or leg;
• unexpected breathlessness;
• chest pain;
• sudden weakness, or problems with speech or vision.

These can be signs of a blood clot (thrombosis or pulmonary embolism), which is an emergency. Also make contact, though less urgently, if irregular bleeding continues beyond six months, if you have severe or persistent headache, or if complaints do not lessen after a few months. If you are unsure about heart palpitations that seem unrelated to a hot flash, read more about heart palpitations in menopause.

Frequently asked questions

What are the most common side effects of hormone therapy in menopause? Nausea, tender or swollen breasts, headache, a bloated feeling and irregular bleeding are the most common in the first weeks. They are usually an adjustment reaction and ease for most women during the first months.

How long do side effects of hormone therapy usually last? Most complaints lessen during the first months after you start. Irregular bleeding can continue for the first three to six months. If complaints persist after a few months, a dose adjustment or a different delivery method arranged by your doctor is the logical next step.

What is the difference between oral and transdermal hormone therapy in terms of side effects? Estrogen through a patch or gel carries a lower risk of blood clots than estrogen in tablet form, because it largely bypasses the liver. If a tablet causes nausea or headache, switching to a patch or gel is often the first adjustment a doctor considers.

Is hormone therapy safe after the WHI study? The WHI study looked at a specific combination, conjugated equine estrogen with a synthetic progestogen, in mainly older women. Those outcomes do not translate one to one to bio-identical hormones in women who start around menopause. Hormone therapy has benefits and risks. Whether it is a sound choice for you depends on your age, health and history, and is something you discuss with a doctor.

Should I stop if I get side effects? Usually not. Persistent complaints are more often a reason to review the dose or the delivery method than to stop. Do not stop on your own, but talk with your doctor. For warning signals such as sudden calf pain, breathlessness or chest pain, do seek immediate contact.

Can I combine hormone therapy with medication for weight gain? For women who, alongside menopause complaints, also struggle with weight gain, GLP-1 medication can in some cases be considered as an addition, always alongside bio-identical hormone therapy and lifestyle and never as a replacement. Whether this is suitable is assessed by a doctor. Read more about weight gain during menopause.

Sources

• NHG. NHG Standard on menopause (M73). Dutch College of General Practitioners. richtlijnen.nhg.org
• NICE. Menopause: identification and management (NG23). National Institute for Health and Care Excellence. nice.org.uk
• Mohammed K, et al. Oral vs Transdermal Estrogen Therapy and Vascular Events: A Systematic Review and Meta-Analysis. Journal of Clinical Endocrinology & Metabolism, 2015. academic.oup.com
• Fournier A, et al. Unequal risks for breast cancer associated with different hormone replacement therapies: results from the E3N cohort study. Breast Cancer Research and Treatment, 2008. pmc.ncbi.nlm.nih.gov

This information is intended as an educational resource and does not replace medical advice, diagnosis, or treatment. For complaints or questions about your personal situation, we recommend consulting a doctor.