Perimenopause is the hormonal transition that leads up to menopause. For most people, it starts in the mid-to-late 40s, but it can begin earlier. This phase ends when you have gone 12 months in a row without a period. At that point, you have reached menopause.
Perimenopause vs Menopause vs Postmenopause
You might hear these three terms used as if they mean the same thing, but they do not. Knowing the difference will help you understand what is happening in your body and what to expect next.
Perimenopause is the transition that starts with your first hormonal or cycle changes and lasts until you have gone 12 months without a period. Think of it as a phase, not a single moment. During this time, your hormones can fluctuate unpredictably. That is why your symptoms may feel so up and down. Perimenopause usually lasts between 4 and 8 years. Most symptoms you might link to menopause actually begin and peak during perimenopause.
Menopause is a single point in time. You reach menopause after you have gone 12 months in a row without a period. It is not a phase. In Singapore, the average age for menopause is about 49 years. You might expect to feel a big change at menopause, but most of the hormonal shifts have already happened during perimenopause.
Postmenopause is the stage that follows menopause. This is the rest of your life after menopause is confirmed. Some symptoms, especially those affecting the urinary and genital areas, can get worse without treatment. Hot flushes and night sweats usually improve over time, but not for everyone. During postmenopause, monitor your bone health, heart health, and metabolism. These become your main health priorities.
When Does Perimenopause Start?
You will usually notice perimenopause starting in your mid to late 40s. For most people, this happens around age 47 or 48. Some of you may see changes in your periods as early as your early 40s. If you notice signs of perimenopause before age 40, it is important to see your doctor. This could be a sign of premature ovarian insufficiency, which needs a different approach and care.
Several factors can influence the time at which you begin perimenopause. Smoking is one of the most significant. Women who smoke may experience both perimenopause and menopause 1 to 2 years earlier than those who do not smoke. Family history is also a factor since the age at which your mother went through menopause can indicate when your own menopause will occur. Body weight, stress, and ethnicity also play a role, but the connections are complex and not yet fully understood.
In Singapore, most women will likely reach menopause around age 49. This is a bit earlier than the global average of 51 to 52. For most women in Singapore, perimenopause starts in the mid to late 40s.
The Stages: Early vs Late Perimenopause
Perimenopause has two main stages. The STRAW+10 classification defines these stages and is the most widely used system for understanding the menopausal transition.
Early perimenopause starts when you first notice changes in your menstrual cycle. This usually means your periods vary by 7 days or more from one cycle to the next. Your oestrogen levels are starting to fluctuate, but they have not begun a steady decline. You might start to notice symptoms like hot flushes or night sweats. Most people in early perimenopause still ovulate and can become pregnant, so you still need contraception if you do not want to conceive.
Late perimenopause happens when your periods become much more irregular. You might skip two or more periods in a row, or go 60 days or longer between cycles. Your oestrogen levels are now dropping more steadily. Symptoms like hot flushes are often at their strongest. This stage ends with your final period, but you can only know for sure that it was your last period after 12 months without another one.
How Long Does It Last?
Most people experience perimenopause for 4 to 8 years, but it can be as short as 2 years or as long as 12. If you enter perimenopause earlier, your transition may last longer. Some symptoms, like hot flushes and night sweats, can continue for 7 to 11 years after menopause. This is longer than many people expect.
As you move into postmenopause, your long-term health risks change. Your risk of heart disease increases, especially in your fifties. This is about 10 years later than it happens for men. During this time, your cholesterol levels may change, your blood pressure can rise, and your body may become less sensitive to insulin. Even without symptoms, this is an important time to check in with your healthcare team and focus on prevention.
The Full Symptom Checklist
Perimenopause can bring more symptoms than you might expect, and many can start years before your periods stop. In a large study of over 145,000 symptom logs, fatigue, headache, anxiety, and brain fog were some of the most common symptoms at every stage of menopause- not just hot flushes.
Cycle Changes
For many women, the first indication of perimenopause is a change in their cycle. You could find that your cycles have become shorter, that you are bleeding more or less than normal, that periods have been missed, or that you are experiencing spotting between periods. Early signs of perimenopause include cycles that are shorter than 21 days, longer than 35 days, or a difference of 7 days or more between cycles. You should see your doctor immediately if you have any bleeding after menopause.
Vasomotor Symptoms
Hot flushes and night sweats affect most women during menopause. These symptoms happen when falling oestrogen levels disrupt the hypothalamus, your brain’s temperature control centre. You might feel sudden waves of heat lasting 2 to 10 minutes. Night sweats are the same thing at night, often waking you up drenched and making it hard to sleep well. These symptoms can start years before your periods stop and are a clear reason to talk to your doctor about treatment.
Sleep
Night sweats don’t merely cause sleep difficulties during perimenopause. Progesterone calms the nervous system because it converts into a substance called allopregnanolone, a neurosteroid that promotes deep, restful sleep. When progesterone levels fall, this effect diminishes, and you might have more trouble falling asleep, wake up more frequently, or get less deep sleep. These changes result from hormonal fluctuations, not simply stress or ageing.
Mood and Cognitive
Mood changes in perimenopause are caused by hormones, not by weakness. Oestrogen affects brain chemicals like serotonin, dopamine, and noradrenaline, which help regulate your mood. When oestrogen levels swing up and down, these brain chemicals do too. This can make you feel irritable, low, anxious, or more emotional than usual, even if nothing major has changed in your life.
Since you have never had any mental health problems before, perimenopause can increase your risk of developing depression or anxiety, and you may first notice these symptoms at this stage. This is a known result of hormonal changes and doesn’t reflect poorly on you.
Perimenopause can also increase your risk of Premenstrual dysphoric disorder (PMDD), which is more severe than PMS. If you notice your mood symptoms are much worse in the week before your period and improve once your period starts, talk to your doctor about PMDD. It is different from general anxiety or depression and needs specific care.
Physical
You may notice joint pain, muscle aches, or more morning stiffness during perimenopause. These symptoms are linked to lower oestrogen, which normally helps reduce inflammation. Headaches and migraines can also get worse. Palpitations, or a racing or irregular heartbeat, are common and usually harmless at this stage. Many people also feel tired, even if they are sleeping well.
Genitourinary
Genitourinary syndrome of menopause, or GSM, is the term for symptoms caused by lower oestrogen in your urogenital tissues. You might notice vaginal dryness, pain or discomfort during sex, itching, irritation, needing to urinate urgently or often, or more urinary tract infections. Unlike hot flushes, GSM does not get better on its own and can worsen without treatment. About half of postmenopausal women experience GSM, but local vaginal oestrogen is a safe and effective long-term treatment.
The Ones Nobody Warns You About
You may notice some perimenopause symptoms that are clinically recognised but rarely talked about.
Joint pain: The fact is that oestrogen has anti-inflammatory properties; when its levels fall, inflammation increases, which leads to joint stiffness and pain, a condition that is frequently mistaken for being due to ageing or arthritis.
Heart palpitations result from hormonal fluctuations that affect the autonomic nervous system, causing the heart to beat quickly, flutter, or beat irregularly. Although they are almost always harmless during the perimenopause period, it is still worthwhile discussing them with a doctor if they occur frequently or are accompanied by chest pain or shortness of breath.
Electric shock sensation: these are short, sharp sensations felt under the skin or in the head, usually happening just before a hot flush or while asleep. They are recognised but not well understood, and are believed to be caused by neurological changes resulting from oestrogen withdrawal.
Ringing or buzzing in the ears, which can worsen during perimenopause, is linked to oestrogen receptors in the inner ear and auditory cortex; a decline in these receptors may play a role.
Dry eyes and dry skin result from oestrogen helping retain collagen and moisture; when its levels decline, this is directly noticeable in the texture, elasticity, and comfort of the eyes.
Formication, which is a feeling of crawling or tingling on the skin, has been reported by some women during perimenopause and is regarded as being due to hormonal effects on the nervous system.
Symptoms That Affect Daily Life Most: What Is Actually Happening
Why You Feel Mentally Slower and Why It Is Not Dementia
If you are finding it harder to concentrate, forgetting words, or losing your train of thought, you are not alone. Many people experience brain fog during perimenopause. Recent research confirms that small but real changes in memory can happen as you move through this stage. These changes are not just due to ageing.
You may notice that you forget names, words, or what you were about to say. Your attention and processing speed might feel slower too. The good news is that these changes are normal for most people and do not mean you have early dementia. In fact, memory and focus usually improve after menopause.
Hormones are the main reason for these changes. Oestrogen helps keep your brain cells healthy, supports blood flow in your brain, and helps make important brain chemicals. When oestrogen levels fluctuate during perimenopause, these systems can be disrupted, especially in the part of your brain that forms memories. Poor sleep and anxiety, which are also linked to hormones, can make these symptoms worse.
Why Your Body Shape Is Changing and What Is Actually Driving It
The weight changes that occur during perimenopause are real, well documented, and driven by specific hormonal mechanisms rather than ageing or lifestyle changes alone. If we understand the mechanism involved, we can tell what is within our control and what is not.
Decreased oestrogen reallocates fat from peripheral stores, such as the hips, thighs, and under-the-skin layers, to deposits in the abdominal area. This reallocation occurs regardless of total calorie intake. A longitudinal study of perimenopausal women showed that visceral adipose tissue increases significantly during the menopause transition, even in women who do not gain weight overall. The shift of fat to the abdomen has consequences beyond changes in appearance, since visceral fat is metabolically active and contributes to insulin resistance, dyslipidaemia, and increased cardiovascular risk.
During perimenopause, the metabolic rate also falls – energy expenditure decreases so that, with the same amount of food intake, there is greater fat accumulation than had been the case before. Along with oestrogen, muscle mass decreases, which in turn lowers the metabolic rate. Resistance training is the most well-supported intervention for maintaining muscle mass and countering this metabolic change – it is not enough merely to increase aerobic activity or to reduce calorie intake.
Loss of Sexual Desire in Perimenopause: What Is Behind It
It is common for women going through perimenopause to have a low libido, and this condition is due to several factors while often receiving inadequate treatment. The hormonal causes involve a falling level of oestrogen; this affects vaginal lubrication, genital sensitivity and blood flow to the pelvic area and a reduction in testosterone, which in turn affects sexual desire, energy levels and mood.
Testosterone levels decrease gradually during a woman’s reproductive years and keep dropping during perimenopause; by the time menopause is reached, they are about half of what they were in the mid-20s. Low levels of testosterone in women are linked to a decreased sex drive, fatigue, and a low mood. This pattern closely overlaps with other symptoms of perimenopause and is often overlooked in standard consultations.
Other factors such as hormones, sleep deprivation, anxiety, relationship issues, and concerns about body image all play a role. The genitourinary syndrome of menopause, which involves vaginal dryness and discomfort, can make sex physically unpleasant for many women and thus decrease their desire. Local vaginal oestrogen is often the most effective immediate treatment when dealing with this part of low libido.
How Is Perimenopause Diagnosed? Why a Single Blood Test Is Not Enough
Perimenopause is mainly diagnosed by looking at your age, symptoms, and menstrual pattern. No single blood test can confirm or rule it out. This is because your hormones change a lot during perimenopause. It is not a gap in medical knowledge.
During perimenopause, your oestrogen and FSH levels can change a lot from week to week and cycle to cycle. Research shows that FSH and oestradiol tests alone are not reliable for diagnosing perimenopause. Even if your test results are normal, you could still be in late perimenopause. According to the latest NICE guidelines, if you are over 45 and have typical symptoms, you do not need blood tests to confirm perimenopause. Your doctor can diagnose it based on your symptoms and history.
Blood tests are most useful in three specific situations:
- If you are under 45 and your doctor suspects perimenopause, blood tests can help rule out other causes of changes in your cycle.
- If you are under 40, blood tests can check for premature ovarian insufficiency. This diagnosis needs two FSH results above 25 IU/L, taken at least four weeks apart.
- Before you start HRT, your doctor may order blood tests to set a baseline and help guide your treatment.
In Singapore, a basic hormone panel (FSH, LH, oestradiol, and TSH) usually costs between SGD $80 and $200, depending on the clinic and the number of tests. It is a good idea to include thyroid testing (TSH) because thyroid problems can cause symptoms very similar to perimenopause. Thyroid issues are one of the most commonly missed alternative diagnoses.
What to Track Before Seeing a Doctor
If you keep a symptom diary for 2 to 4 weeks before your appointment, you will give your doctor a much clearer picture of what is going on. This helps your doctor see real patterns instead of relying on memory.
Track the following:
Your menstrual pattern: note your cycle length, flow, spotting, and any missed periods.
Hot flushes and night sweats: record how often they happen, how severe they are, and what time of day they occur.
Sleep: track how many hours you sleep, how well you sleep, and if night sweats wake you up.
Mood: watch for anxiety, low mood, or irritability, and note when these feelings are strongest in your cycle.
Cognitive symptoms: look out for brain fog, trouble finding words, or difficulty concentrating.
Physical symptoms: note any joint pain, headaches, palpitations, or fatigue.
Genitourinary symptoms: record any vaginal dryness, discomfort, or urgent need to urinate.
Medications and supplements: make a list of everything you are currently taking, including contraception.
You do not need a formal template. Simple notes on your phone are enough. Focus on spotting patterns, not making a perfect record.
When to Seek Help
You do not have to wait until your symptoms feel overwhelming to ask for help. You can see your doctor if any of the following apply to you:
- Your symptoms are making it hard for you to sleep, affecting your mood, work, or relationships
- Your periods have become much heavier, more irregular, or have stopped before you turn 45
- You notice bleeding after sex, between periods, or after 12 months without a period. These symptoms should always be checked promptly.
- Your mood changes are severe, last a long time, or come with thoughts of harming yourself.
- You are under 40 and have noticed changes in your cycle. It is important to get checked for premature ovarian insufficiency as soon as possible.
- You want to learn about your options before your symptoms become more noticeable.
Frequently Asked Questions
References:
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- Fenton, A. (2021). Weight, Shape, and Body Composition Changes at Menopause. Journal of Mid-Life Health, 12(3), 187–192. https://doi.org/10.4103/jmh.jmh_123_21
- Maki, P. M., & Jaff, N. G. (2024). Menopause and brain fog: How to counsel and treat midlife women. Menopause, 31(7), 647–649. https://doi.org/10.1097/GME.0000000000002382
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- Pyne, Y., Burgin, J., & Hickey, M. (2024). Towards a more accurate global picture of perimenopause. Bulletin of the World Health Organization, 102(12), 922–924. https://doi.org/10.2471/BLT.24.292659
- Uddenberg, E. R., Safwan, N., Saadedine, M., Hurtado, M. D., Faubion, S. S., & Shufelt, C. L. (2024). Menopause transition and cardiovascular disease risk. Maturitas, 185, 107974. https://doi.org/10.1016/j.maturitas.2024.107974
- Yu, Y., Yapeng, H., Liu, Z., Fang, L., Li, J., Luan, Y., Li, W., Cong, H., & Wu, X. (2025). Mitochondrial dysfunction in perimenopausal mood disorders: From hormonal shifts to neuroenergetic failure (Review). International Journal of Molecular Medicine, 56(6), 215. https://doi.org/10.3892/ijmm.2025.5656
Anna Haotanto is the Founder of Zora Health and a passionate advocate for women’s empowerment. Anna’s personal experiences with egg-freezing, PCOS, perimenopause and the challenges of fertility have fueled her mission to provide high-quality information, financing, and support to help women and couples navigate their fertility journeys with confidence. She is also recognised for her achievements in finance, entrepreneurship, and women’s empowerment, and has been featured in various media outlets. You can also follow her on Linkedin or Instagram.
