Starting HRT: what to expect in the first months

The first few months on HRT (hormone replacement therapy) are often the most unsettled. Side effects are common early on, and NHS advice is that they usually improve over time, so it’s a good idea to carry on for at least 3 months if you can. It’s also common to have no side effects, or only mild ones.

Some of what you notice may not be the HRT at all. The NHS points out that side effects of HRT can be similar to menopause symptoms, which makes the early weeks hard to read. Keeping track helps.

The side effects people notice first

NHS information lists headaches, breast pain or tenderness, feeling sick, mood changes (including low mood or depression), leg cramps and a mild rash or itching among the side effects of oestrogen. Progestogen, the second hormone in combined HRT, can bring changes in bleeding, tiredness or dizziness, mood changes (again including low mood or depression) and acne. ACOG’s list for US readers is shorter: temporary breast soreness, bloating (fluid retention) and headaches.

The NHS describes a rough pattern for several of these:

• headaches usually last only a few days after you start
• breast tenderness usually improves after 4 to 6 weeks
• feeling sick should wear off after a few days
• leg cramps usually last only for the first few weeks
• mood changes may last for the first few months

Treat these as rough guides. None of the sources puts a date on when your hot flushes, sleep or mood will improve, and that varies from person to person. Whether the treatment is working for you is one of the things the first review looks at.

Weight is a common worry. The NHS says there’s little evidence that most types of HRT make you put on weight, and that weight gain around menopause often happens whether or not you take HRT.

When not to wait for the review

Speak to a GP (UK) or your doctor (US and elsewhere) if a side effect is severe or carries on for longer than 3 months. NHS medicine pages also suggest speaking to your doctor sooner if a headache lasts longer than a week or is severe, if feeling sick lasts more than a week, or if mood changes become too difficult to cope with. If low mood ever turns into thoughts of harming yourself or ending your life, get help straight away. The numbers are in the last section. ACOG’s advice is to talk with your ob-gyn if side effects trouble you or last longer than expected.

If something isn’t settling, there are usually options. A GP might suggest changing the type of HRT or how you take it, for example switching from tablets to patches, and that it can take time to find the right HRT for you. Those decisions belong with your prescriber. Don’t stop or change prescribed HRT without talking to them first.

What the 3-month review is for

NICE recommends reviewing each menopause treatment at 3 months, to see how well it’s working and how you’re getting on with it. After that, it recommends a review once a year, unless there’s a reason to look sooner, such as side effects or the treatment not helping. If treatment doesn’t improve your symptoms, or side effects carry on, NICE recommends referral to a healthcare professional with expertise in menopause.

US practice is less fixed on timings. ACOG suggests talking with your ob-gyn every year about whether to continue. Ask when your first follow-up will be.

The review goes better with specifics. NICE says people with a womb will be asked about bleeding at the 3-month review. Useful things to bring:

• the names of your products and the date you started each one
• which symptoms have changed, and which haven’t
• any side effects, when they started and whether they’ve eased
• the dates of any bleeding or spotting, and how heavy it was

A simple log, kept in Ruva or on paper, saves you trying to remember three months of detail in a ten-minute appointment.

Bleeding you can expect

If you have a womb, some bleeding in the early months is common. NICE says vaginal bleeding is a common side effect during the first 6 months of systemic HRT, and within any 3 months of changing your systemic HRT. What’s expected after that depends on the type you take.

Type of HRT	What’s common early on	Tell your prescriber about
Sequential (cyclical) combined HRT, usually started while you still have periods	A regular monthly withdrawal bleed at the end of each course of progestogen. Irregular bleeding is also common in the first few months.	Heavy bleeding, or unexpected bleeding after 6 months on it
Continuous combined HRT, usually started after periods have stopped	It aims to be bleed-free, but irregular bleeding or spotting is common in the first 4 to 6 months.	Heavy bleeding, or unexpected bleeding after 6 months on it
Oestrogen-only HRT after a hysterectomy	Bleeding isn’t expected.	Any vaginal bleeding

This advice has changed recently. In April 2026 NICE amended its recommendation on bleeding and pointed to the British Menopause Society’s guidance on unscheduled bleeding on HRT. Women’s Health Concern, the BMS’s patient arm, says you should be told what bleeding to expect for the type of HRT you use. If nobody has told you, ask.

When bleeding needs a prompt check

Bleeding outside the expected pattern for your HRT is called unscheduled bleeding. Women’s Health Concern says it’s a common side effect and unlikely to point to a serious problem, but it should always be reported. It won’t always need tests. Sometimes a change to your HRT is enough, and that’s for your prescriber to decide with you.

Get in touch with your GP or prescriber soon, rather than waiting for a review, if:

• you have unscheduled bleeding more than 6 months after starting HRT, or more than 3 months after a change to it
• bleeding is heavy or goes on for a long time, however long you’ve been taking HRT
• bleeding becomes heavier
• you get bleeding after you hadn’t had periods for a while

NICE’s advice is to get medical help promptly for unscheduled bleeding beyond those early timeframes. Under the BMS guideline, bleeding within the settling-in period may be managed by adjusting your HRT for up to 6 months. A quicker internal ultrasound scan, usually booked within 6 weeks, may be recommended if bleeding starts more than 6 months after starting or changing HRT, if it’s heavy or prolonged, or if you have some risk factors for womb cancer. For people at higher personal risk, a more urgent referral is recommended, usually within two weeks.

Risk factors your clinician will ask about include obesity, diabetes, polycystic ovary syndrome and family history. A referral to a gynaecologist doesn’t mean cancer has been found. It’s a way of getting you to the right clinic at the right time. The article on bleeding after menopause covers the checks in more detail.

Getting help, and how quickly

Call 999 now (UK), or 911 (US), or your local emergency number, if you have chest pain and breathlessness, difficulty speaking or moving your arm or leg, or your face has dropped on one side. The NHS lists these as possible signs of a blood clot in the lungs, heart problems or a stroke. Call 999 now too if your lips, mouth, throat or tongue suddenly swell, or you’re struggling to breathe or swallow, which can be a serious allergic reaction. Don’t drive yourself to A&E. Ask someone to drive you, or call for an ambulance.

If you feel you may be about to harm yourself, call 999 or go to A&E now (UK), or call 911 (US). If you’re having thoughts of ending your life, you can call Samaritans free on 116 123 (UK), or call or text 988 (US).

Call a doctor or NHS 111 now (UK), or contact your doctor or an urgent care clinic (US and elsewhere), if you have pain, redness or swelling in one leg, usually in the calf. This can be a sign of a blood clot in the leg.

Contact your doctor soon if you notice a lump or changes in your breasts, or any of the bleeding changes above. Mention any risk factors for womb cancer, such as diabetes or a family history, as they can mean you’re seen more quickly. Keep going to breast screening appointments while you take HRT. For side effects that are hanging on rather than worrying, the 3-month review is the place to talk them through.