If you’re in your 40s and your periods have started arriving late, perimenopause is one of the most likely reasons. It’s the stage before menopause when hormone levels start to change, and a change in your periods is usually the first thing people notice. But it isn’t the only possible cause, and pregnancy is still possible.
What perimenopause is
Menopause is when your periods stop for good because of lower hormone levels. You’ve reached it when you haven’t had a period for 12 months. For most people it happens between the ages of 45 and 55.
Perimenopause is the time leading up to that. It can last several years. During it, your ovaries don’t release an egg as reliably, and hormone levels rise and fall less predictably than before.
How your periods may change
Because ovulation becomes less regular, so do your periods. The NHS describes changes such as:
- periods coming less often, so some are late or skipped
- periods coming more often, with shorter cycles
- bleeding that’s heavier or lighter than you’re used to
Many people notice a mix. A run of shorter cycles might be followed by a long gap, then a heavy period. Over time, the gaps usually get longer until periods stop altogether.
This makes predictions harder. The period calculator gives date ranges rather than a single date, and logging your cycles in the period tracker shows how your pattern is changing.
Other signs of perimenopause
Changes to your periods often come with other symptoms. You may have few of these, or many:
- hot flushes and night sweats
- difficulty sleeping
- mood swings, low mood or anxiety
- problems with memory or concentration, sometimes called brain fog
- vaginal dryness, itching or discomfort, which can make sex painful
- needing to pee more often, or more urinary infections
- headaches, muscle aches and joint pain
- palpitations, when your heartbeat feels faster or more noticeable
If you recognise several of these alongside changes to your periods, perimenopause is a likely explanation. But a GP can confirm it and talk you through your options.
Don’t rule out pregnancy
It’s a common mistake to assume that late periods in your 40s can’t mean pregnancy. You can still ovulate during perimenopause, even when your periods are irregular. If you’ve had sex without contraception, take a pregnancy test when your period is late.
Keep using contraception until you’re advised you no longer need it. Guidance is usually to continue for a while after your last period, and a GP or sexual health clinic can tell you how long applies to you.
Get urgent help if you could be pregnant and have severe pain on one side of your tummy, pain in the tip of your shoulder, or feel faint.
Other causes to consider
Perimenopause is common in your 40s, but other causes of late periods still apply at any age:
- stress, illness or a big life change
- weight loss or weight gain
- intense exercise
- hormonal contraception
- thyroid problems
- polyendocrine metabolic ovarian syndrome (PMOS, formerly called PCOS)
If your periods have changed suddenly, or you have symptoms that don’t fit, it’s worth getting checked rather than assuming it’s perimenopause.
If you’re under 45
Periods that become irregular or stop before the age of 45 can be a sign of early menopause, or premature menopause if it happens before 40. It’s more likely if it runs in your family, if you smoke, or if you’ve had certain treatments such as chemotherapy or surgery on your ovaries.
It’s important to see a GP if you think this might be happening. Starting menopause early raises the risk of problems with your bones and heart, and hormone treatment can help protect them. A GP may do blood tests if you’re under 45.
When to see a GP
The NHS suggests contacting a GP if:
- you think you have symptoms of perimenopause or menopause and want to know your options
- you have symptoms like palpitations
- your bleeding has changed and you’re bleeding more, not less, than before
- you’ve had no period for 12 months or more and then have any vaginal bleeding
Heavy bleeding and bleeding after menopause are worth checking promptly, because they can have causes other than hormone changes.
You don’t have to put up with symptoms that affect your sleep, work or relationships. Treatments such as hormone replacement therapy (HRT) and other options can help, and early advice can make a real difference.