Why is my period early? Common causes of an early period

A ‘normal’ menstrual cycle can vary with cycles lasting anywhere from 21 to 35 days with an average of 28 days.

This means a period that arrives earlier than expected isn’t always a cause for concern. There are many factors that can shift the timing of a period, including changes to hormones, lifestyle, or other temporary fluctuations.

Table of content:

• My period has arrived a week early. Is that normal?
• Causes of an early period
  1. You’ve changed your diet or exercise regime
  2. You’re stressed
  3. Your routine has changed
  4. Your period isn’t regular yet
  5. It’s actually spotting
  6. Hormonal contraception
  7. Polycystic ovary syndrome (PCOS)
  8. Thyroid diseases
  9. Uterus conditions
  10. Perimenopause
  11. Other health conditions
• What does an early period mean?
• How to avoid being surprised by early period symptoms
• When should you see a doctor about an early period?
• What you can do when your period comes early

My period has arrived a week early. Is that normal?

It might be – having occasional early periods can be normal. For example if you are young and have only recently started your periods they can be irregular for a couple of years. If the change is occasional and there are no other worrying signs, it often isn’t a problem but if there is a consistent change, or if there is bleeding in between your periods please see your doctor.

Causes of an early period

You’ve been to the loo and noticed that tell-tale spot of blood on your underwear what could be going on? There are lots of causes of early periods including:

1. You’ve changed your diet or exercise regime

Diet and exercise affect your hormones, and hormones control your menstrual cycle. Sudden weight gain or loss, dieting, or starting a very intense exercise routine can affect hormone levels and disrupt the menstrual cycle timing

2. You’re stressed

Feeling stressed comes with a whole lot of changes in your body, and whether that stress is short term or ongoing, it can interfere with the hormones that regulate the menstrual cycle, potentially causing earlier or irregular periods.

3. Your routine has changed

Any major change in your regular schedule such as sleep disruption, travel, shift work, or irregular daily cycles can affect the hormonal regulation of the menstrual cycle leading to changes in when your period arrives. In general these fluctuations will balance themselves out as soon as your schedule settles down.

4. Your period isn’t regular yet

If you’ve recently started getting your period, you’re more likely to experience irregular cycles – which might mean you get your period before you were expecting it! That’s because the hormones that control your menstrual cycle are a new thing for your body, and it hasn’t quite got the hang of them yet.

5. It’s actually spotting

Sometimes what feels like an “early period” is really light bleeding or spotting for example, mid-cycle ovulation spotting or breakthrough bleeding from hormonal contraception and this can make your cycle appear “shorter.”. Here the bleeding is often very light, perhaps it only shows up on the toilet paper when you wipe, or you may notice heavier bleeding. If though you think you are having bleeding in between your periods or after sex, this should always be assessed by a doctor.

6. Hormonal contraception

Starting, stopping or switching hormonal contraception (pill, IUD/IUS, injection) can change cycle length, cause early or late bleeding, spotting, or irregular cycles.

7. Polycystic ovary syndrome (PCOS)

PCOS is a condition that can affect hormones and disrupt regular ovulation, leading to irregular cycles with early, late or missed periods. Other symptoms may include weight gain, acne or excessive hair growth.

8. Thyroid diseases

Both having an underactive or overactive thyroid gland can impact your menstrual cycle, affecting when the period arrives.

9. Uterus conditions

Conditions affecting theuterus such as endometriosis, fibroids, a polyp, or infection can cause irregular bleeding.

10. Perimenopause

The menopause defined as the last period and is diagnosed after you haven’t had a period for 12 months. However just as starting your period was just one point in puberty, there is a period of years of hormonal change which leads up to the menopause, known as the perimenopause. In this time the menstrual cycle can become shorter, periods can even become heavier and longer, or the cycle can become irregular. Although the average age of the menopause in the UK is 51, the perimenopause can last about a decade before that. Early menopause affects 1 in 20 women where there is menopause under the age of 45, and a premature menopause, which occurs under the age of 40 affects 1 in 100 women, becoming less common the younger the age. What this means though is that changes to your cycle might be related to the perimenopause at a much earlier age than you might have thought!

11. Other health conditions

Even if it isn’t directly a gynaecological health problem, any severe illness or chronic disease, significant changes in overall health or certain medications can all affect the menstrual cycle.

What does an early period mean?

Getting your period early usually that the regulation of your cycle has been disrupted, generally temporarily.. Fluctuations in your hormones from month to month are common and are typically nothing to worry about, especially if you’ve only just started menstruating. It may be triggered by stress, lifestyle changes, or hormonal fluctuations, and most of the time it resolves without any medical intervention if things return to normal.

However, if early or irregular periods become frequent, or are accompanied by other symptoms (heavy bleeding, pain, very irregular cycles, other health changes), this could point to a medical condition such as PCOS, thyroid imbalance, uterine fibroids, endometriosis or other disorders.

How to avoid being surprised by early period symptoms

To avoid stained underwear from an unexpected period or spotting, a lot of girls wear pantyliners a few days before they’re scheduled to get their period. This way, if your period is a little early, you’re still protected. Also watch your body – you might notice early period symptoms. If your breasts become tender, you will have mood swings, a feeling of water retention in your body. This is a sign that the early period symptoms.

Don’t wear a tampon, menstrual cup or disc just in case your period starts early. Instead, keep pads or tampons on hand means you’ll be prepared if your period sneaks up on you.

When should you see a doctor about an early period?

It’s usually fine to wait a cycle or two if your period is slightly early or irregular, though if there is any risk of pregnancy do take a pregnancy test.

If you experience any of the following please see your doctor:

• Your periods become regularly irregular (very early, very late, or unpredictable).
• You have heavy, prolonged or painful periods.
• You have spotting between periods or bleeding that is unusual for you.
• You have symptoms such as unexpected hair growth, acne, tiredness, weight changes, or mood changes, which might suggest conditions like PCOS or thyroid disorders.
• Bleeding occurs after sex, or you have pelvic pain, discomfort, or signs of infection.

What you can do when your period comes early

If an early period or irregular cycle is likely caused by lifestyle changes such as weight changes diet, exercise, trying to stabilise those areas may help bring cycle timing back to normal, though if you need help and support with those please see your doctor. Good general health, balanced nutrition, moderate exercise, good sleep, and stress management can all support your hormones.

If you are using hormonal contraception and you think it might be contributing to early or irregular bleeding, speak to a doctor about whether a different method might work better for you.

If you are concerned about conditions such as PCOS, thyroid problems, or uterine conditions, a doctor may investigate with hormone tests, ultrasound, or other diagnostics, and then recommend suitable treatment or lifestyle changes.

This is generalised advice and isn't personalised nor to replace the advice of your doctor and other health care professionals.