What is perimenopause, and how do I know it has started?
Understand the changes that can happen before your periods stop, what to have handy for a GP discussion and where to find more focused guidance.
What is perimenopause, and how do I know it has started?
Perimenopause is the transition leading up to menopause and ending 12 months after the final period. It often starts in the 40s, but timing and symptoms vary. Changing periods are often an early sign, alongside hot flushes, sleep, mood or concentration changes. Age, symptoms and period history usually guide assessment; a GP can help rule out other causes and plan support.
What is perimenopause?
Perimenopause is the phase when ovarian hormone levels fluctuate before the final period and through the following 12 months. Menopause is the final period itself, confirmed after 12 months without another period when contraception, pregnancy or another cause does not explain the change. Premenopause means the reproductive years before perimenopause.
You do not need to wait until periods stop to ask for help. Symptoms can begin while periods still look fairly regular, and support or treatment can be discussed before menopause is confirmed.
When does it start, and what are the first signs?
Perimenopause commonly starts in the 40s, although it can begin earlier or later. A change in the usual period pattern is often an early sign: cycles may become shorter or longer, bleeding may become lighter or heavier, or some periods may be missed.
Other early changes can include hot flushes, night sweats, broken sleep, anxiety or mood changes, brain fog, vaginal dryness, bladder changes, joint or muscle symptoms and changes in sexual desire. There is no required order and some people have few symptoms. A new symptom in midlife should not automatically be attributed to perimenopause.
If periods become irregular or stop before 45, ask for assessment rather than waiting 12 months. The early menopause and premature ovarian insufficiency guide explains why the assessment and longer-term care may differ.
Are there stages, and how long can it last?
The transition is gradual rather than a fixed sequence. Earlier in perimenopause, cycle length may start to vary. Later, longer gaps between periods are more common. These patterns can help a clinician understand where you may be in the transition, but they do not predict an exact final-period date or symptom timeline.
Perimenopause lasts about 4 to 6 years on average and can last from 2 to 10 years. Individual symptoms may come and go, overlap, improve or continue after the final period. The perimenopause symptoms guide helps group changes by their pattern and impact rather than treating a symptom list as a diagnosis.
Do I need a blood test?
For most people over 45 with a typical pattern, perimenopause is identified from age, symptoms and period history rather than one hormone result. Hormone levels fluctuate, so a single result can be difficult to interpret and is not needed before discussing symptom support.
Testing may be useful when periods change before 45, the pattern is unclear, pregnancy is possible, medicines or contraception affect bleeding, or another cause needs to be checked. Depending on the history, that might include pregnancy testing or tests for thyroid problems, low iron or another condition. Do not stop contraception or prescribed hormones just to arrange a test without advice from the clinician interpreting it. The menopause blood-tests guide explains these limits in more detail.
Can I still become pregnant?
Ovulation can still occur during perimenopause, even when periods are irregular. Menopausal hormone therapy is not contraception. If pregnancy is possible and not wanted, discuss how long to continue contraception and which option suits your health and preferences rather than relying only on an irregular or absent period.
If a period is late or pregnancy symptoms occur, take a pregnancy test or seek advice. The choosing contraception guide can help prepare the questions to ask.
What can I do next?
Record changes that matter to you: period dates and flow, the symptom causing the most disruption, sleep, medicines, contraception and the effect on work, relationships or daily life. Choose one or two outcomes you want help with, such as fewer night sweats, more reliable sleep, less anxiety or a plan for heavy bleeding.
A GP can assess whether the pattern fits perimenopause, consider other causes and discuss practical changes, psychological support, hormonal or non-hormonal treatment where appropriate. You can ask for another review if symptoms change, the first plan does not help or treatment causes problems. The menopause treatment guide explains how to compare options around your main concern.
Sources and further reading
Sources supporting this guide. Source organisations have not reviewed or endorsed HerDoc.
When to seek urgent care
Arrange prompt medical assessment for very heavy or persistent bleeding, bleeding between periods or after sex, or bleeding after 12 months without a natural period. A scheduled withdrawal bleed can be expected with some prescribed hormonal plans; ask what pattern is expected for yours. Seek urgent care for severe or rapidly worsening pelvic or abdominal pain or symptoms that make you acutely unwell. If pregnancy is possible, one-sided pelvic pain, shoulder-tip pain, bleeding, dizziness or fainting needs urgent in-person assessment. Call 000 for collapse, severe bleeding, chest pain, severe breathing difficulty, sudden confusion, facial droop, sudden weakness or speech difficulty.
- Very heavy or persistent bleeding
- Bleeding between periods, after sex or after 12 months without a natural period
- Severe or rapidly worsening pelvic or abdominal pain
- Possible pregnancy with pain, bleeding, dizziness or fainting
Related pages
FAQs
How is perimenopause different from menopause?
Perimenopause is the transition that begins before the final period and includes the first year afterwards. Natural menopause is recognised after 12 months without periods when there is no other explanation. Hormonal contraception or treatments and procedures that affect periods can make the timing harder to identify.
Can I seek help if only one symptom bothers me?
Yes. You can focus the conversation on one concern and how it affects your life. You do not need a long symptom list before asking for help.
What history is useful for a first perimenopause discussion?
Have your period pattern, symptom timing, medicines, contraception and relevant personal or family history handy. Previous results and what you have already tried can also help.
What if I cannot tell when the changes started?
An approximate timeline is useful. Describe what is different now and the concern you most want help with; you do not need a complete diary before the appointment.