Irregular Periods Causes: 10 Common Reasons Your Cycle Is Late or Early

Part 1 of 7

What is a normal menstrual cycle, and what counts as irregular?

Your cycle runs from the first day of one period to the first day of the next. The NHS says the average is about 28 days, but anywhere from 21 to 35 days is normal for adults, and a period usually lasts 2 to 7 days. Periods are irregular when the gap is often shorter than 21 or longer than 35 days.

A little change from month to month is normal. A cycle of 27 days one month and 31 the next is not irregular. What matters is a pattern: cycles that keep swinging widely, periods that go missing for months, or bleeding that turns up at unexpected times.

Part 2 of 7

Irregular periods causes: 10 common reasons

The most common irregular periods causes are pregnancy, stress, big weight changes, intense exercise, hormonal contraception, breastfeeding, PCOS, thyroid problems, and the natural changes of puberty and perimenopause. Often more than one is involved, for example stress plus weight change during exams or a new job.

1. 1

   Step 1: 1. Pregnancy

   A missed period is often the first sign. If you have had sex, do a home pregnancy test; most are accurate from around the day your period was due.
2. 2

   Step 2: 2. Stress

   Exams, a wedding, a move, a death in the family or work pressure can delay ovulation, and so your period. The NHS lists stress and anxiety among the common causes.
3. 3

   Step 3: 3. Weight loss or gain

   Losing or gaining a lot of weight, crash dieting or eating too little for your activity can all disturb the hormones that trigger ovulation.
4. 4

   Step 4: 4. Too much exercise

   Very intense training, especially with low food intake, can make periods irregular or stop them. This is common in athletes and dancers.
5. 5

   Step 5: 5. Hormonal contraception

   Pills, injections, implants and hormonal coils often change bleeding patterns. Spotting in the first few months is expected; ask your doctor if it continues.
6. 6

   Step 6: 6. Breastfeeding

   Periods can stay away for months while you breastfeed. You can still ovulate before your first period returns, so talk to a doctor about contraception.
7. 7

   Step 7: 7. PCOS

   One of the commonest causes in India. Periods may be far apart or absent, then heavy. Read our guide to PCOS symptoms.
8. 8

   Step 8: 8. Thyroid problems

   Both an underactive and an overactive thyroid can change your cycle. A blood test checks it; see our guide to thyroid and periods.
9. 9

   Step 9: 9. Puberty

   Cycles are often irregular for the first year or two after periods start. Our first period guide explains what is normal for teens.
10. 10

    Step 10: 10. Perimenopause

    In your 40s, cycles often get shorter, longer or unpredictable as hormones shift. Our guide to perimenopause symptoms covers the signs.

Less common causes include raised prolactin, some medicines, long-term illnesses such as diabetes, and problems in the womb such as fibroids or polyps, which tend to cause bleeding between periods or heavier periods rather than late ones. Only a doctor can work out which applies to you.

Part 3 of 7

Why is my period late if I am not pregnant?

If a pregnancy test is negative, the most likely reasons for a late period are stress, illness, travel, a change in weight or exercise, or a cycle that simply ran long this month. If you are still worried, repeat the test after a few days or a week, because a test taken too early can miss a pregnancy.

• Count from the first day of your last period, not the last day.
• Think back: a fever, a long trip, exam season or a big diet change in the last month often explains a late period.
• If the period still has not come and the test stays negative, see a doctor, especially if you have missed three in a row.

Part 4 of 7

Why am I getting periods twice a month?

A period twice in one calendar month can be normal if your cycle is 21 to 24 days long, because the dates simply fall that way. But bleeding that is often less than 21 days apart, or bleeding between your normal periods, needs a doctor's check. Causes include hormone changes, contraception, polyps, fibroids and infections.

Bleeding after sex or between periods is never something to wait out, even if it is light. It is usually caused by something small and fixable, but only an examination can tell.

Part 5 of 7

How to regulate periods naturally: what actually helps

If there is no medical condition behind it, steady routines help your cycle most: regular meals with enough food for your activity, consistent sleep, moderate exercise and ways to manage stress. No single food, herb or kadha has been shown to fix irregular periods, so treat WhatsApp "period regulating" remedies with caution.

If a condition such as PCOS or a thyroid problem is found, your doctor may suggest treatment as well. Do not take hormone tablets or "period pills" from a chemist to bring on a period without a doctor's advice.

Part 6 of 7

How to track an irregular cycle (and be ready for surprises)

Tracking turns a vague worry into facts you can act on. Log the first day of every period, how long it lasted, how heavy it was, and anything unusual such as spotting or pain. After three to six months you, and your doctor, will see whether there is a real pattern.

Our free period tracker has an Irregular or PCOS mode that shows your next period as a range rather than a single date, keeps everything on your own phone, and can print a doctor report. Answers to common questions about it are in our FAQ.

When your cycle is unpredictable, keep a couple of pads in your bag at all times, and a liner for days when you think a period might start.

From Potent Hygiene

Potent Hygiene Daily Panty Liners

Potent Hygiene Daily Panty Liners are thin and breathable for spotting and the days a period might be on its way. They are for light spotting and discharge, not a full flow.

Part 7 of 7

When should you see a doctor about irregular periods?

See a doctor if you miss three periods in a row and are not pregnant, if your cycles are often shorter than 21 or longer than 35 days, if you bleed between periods or after sex, or if irregular periods come with weight change, extra hair, acne or tiredness. Also see one if you are trying to get pregnant.

1. 1Very heavy bleeding: soaking through an XL+ pad (or a period panty) in under 2 hours for several hours in a row, or passing clots bigger than a ₹5 coin.
2. 2Periods that last longer than 7 days, or that come less than 21 or more than 35 days apart once your cycle has settled.
3. 3Severe period pain that stops you from your day, or that doesn't ease with the usual measures.
4. 4Bleeding between periods, after sex, or ANY bleeding after menopause.
5. 5Periods that stop for 3 months or more when you are not pregnant.
6. 6Signs of infection: unusual discharge, a strong smell, itching, or burning when you pee.
7. 7After childbirth: a fever, foul-smelling discharge, or very heavy bleeding that does not ease after the first week.
8. 8No period by age 15, or no signs of puberty by age 13.

If your periods stop before the age of 40 and you are not pregnant, see a doctor rather than assuming it is early menopause. It can affect your bone and heart health and deserves proper attention.

This is guidance, not a diagnosis. If something feels off, trust yourself and see a doctor or gynaecologist. Most causes are common and treatable.