5 Red Flag Signs That You Could Be Entering Perimenopause

While it’s not as commonly spoken about as menopause is, perimenopause can be a huge transitionary experience for many people.

In fact, according to the gynaecological health experts at Clue:  “Early perimenopause typically starts when someone is in their mid-40s, but it can also start earlier or later. In early perimenopause, cycle length typically varies by around seven days or more.

“This increases as someone goes through perimenopause. The early perimenopause phase can last between one and eight years.” 

So, what are the signs of perimenopause?

Emma Bardwell, a registered nutritionist and women’s health and menopause expert for Active Iron, explained to HuffPost UK that there are five lesser-known symptoms you should look out for - and when you need to contact your GP.

Irregular or heavy periods

“The early signs of perimenopause can be subtle and easy to miss,” explained Bardwell, a registered nutritionist, health writer, and author of The Perimenopause Solution. “One of the first warning signs is a shift in the regularity of your periods or heavier menstrual bleeding than usual. Typically, this is when your cycle length starts to vary by seven or more days. You may also go from having predictable menstrual cycles to spotting randomly or missing periods altogether.

“Menorrhagia, or heavy periods, is a common side effect of fluctuating hormone levels - often due to unopposed oestrogen building up in the uterine lining - and frequently coexists alongside anovulatory cycles and irregular menstrual bleeding. Prolonged or heavy bleeding (flooding) can lead to iron loss, potentially resulting in low iron over time.”

One thing that can help is actually period trackers. There help you learn more about your body, how your menstrual cycle is from one month to another and the resulting impacts. 

They can also be ideal for spotting irregularities in bleeding and symptoms.

“Tracking physical and mental changes throughout your cycle can be a powerful tool to help visualise and draw connections between symptom patterns – making them easier to anticipate and manage.

“Having data and insight about your own body and cycle helps you to feel more in control of your health and wellbeing as you navigate the changes that come with perimenopause,” said Rhiannon White, Chief Product Officer from the female health app Clue.

Feeling fatigued

A 2024 survey conducted by Active Iron found tiredness and fatigue to be the second most common symptom of perimenopause, with 63 per cent of women struggling with it and 80 per cent reporting feeling tired all the time. “During perimenopause, your body’s oestrogen and progesterone levels begin to fluctuate. These fluctuations cause symptoms that can lead to perimenopause fatigue,” explained Bardwell.

“Interrupted sleep often accompanies perimenopause, leaving many women waking up exhausted. This fatigue can lead to physical impacts and cognitive challenges, such as difficulty with thinking, concentration, memory, or decision-making. It’s easy to see how these symptoms can affect a woman’s quality of life, making daily activities like work, relationships, and exercise increasingly difficult.”

Pain in the muscles and joints

“During perimenopause and menopause, levels of hormones like oestrogen, progesterone, and testosterone decline and then stay low forever. These three hormones have numerous beneficial effects throughout your body. They reduce inflammation everywhere, including in the musculoskeletal system,” said Bardwell.

“This means that when women have low levels of these hormones, there is often more inflammation in the muscles, joints, and soft tissues, leading to symptoms of muscle and joint pain and stiffness. Some women may also experience conditions such as plantar fasciitis (pain on the bottom of your foot, around your heel and arch), carpal tunnel syndrome, frozen shoulder, or more generalised arthritis.”

Reduced thyroid function

During perimenopause, declining oestrogen and progesterone levels can reduce thyroid function, as these hormones help regulate thyroid balance. Since thyroid disorders are ten times more common in women and increase with age, it’s not unusual for perimenopausal women to also develop thyroid conditions.

Bardwell explained that thyroid conditions can impact perimenopausal women both physically and mentally. In particular, you might experience weight gain, tiredness, and a reduction in the body’s metabolic rate, among other symptoms. “If thyroid function is disrupted during perimenopause, it can affect the body’s ability to metabolise nutrients. It can also impact your ability to absorb iron efficiently, potentially leading to iron deficiency and wider health impacts,” Bardwell adds.

Low iron levels

Low iron as a result of heavy menstrual bleeding can be common but if it’s left unaddressed, it can lead to difficult health consequences.

According to the NHS, these can include: tiredness and lack of energy, shortness of breath. heart palpitations, paler than usual skin and headaches.

“While increasingly common in perimenopausal women, low iron levels can be surprisingly difficult for women to identify because the symptoms - such as fatigue, weakness, and dizziness - are often subtle and often overlap those attributed to the hormonal changes of perimenopause,” said Bardwell.

“Many women adapt to these symptoms over time, not realising that their energy levels and overall wellbeing have gradually declined. Given how common this is, it’s crucial for women, especially those at higher risk, to stay aware and consider getting their iron levels checked if they experience persistent symptoms.”

How can you manage low iron levels? Bardwell explained that while diet can help, it may not be enough. Supplements are an option, but they often cause side effects like nausea and constipation, leading many women to stop taking them. She advises choosing an iron supplement that is clinically proven to boost iron levels with minimal side effects for better energy and long-term health.

“Of course, when it comes to perimenopause symptoms can vary widely from person to person, so it’s always a good idea to consult with a healthcare provider for personalised advice and management.”