# Late period? The common reasons > From pregnancy to stress to switching your pill. Category: Cycle basics · 4 min read · Written by the Splash team · Sources checked October 2026 URL: https://splash.care/learn/cycle-basics/late-period ## Quick answer A period is usually called late when it is more than a few days past when you expected it. If there is any chance you are pregnant, take a test first. If not, stress, illness, travel, weight change, exercise, contraception, breastfeeding, PCOS and perimenopause are the common reasons. Three missed periods in a row is worth a GP visit. - If you have had sex, a pregnancy test is the first step. - A negative test early on is less reliable, so repeat it in a few days if your period still has not come. - Stress, weight changes, exercise and contraception are common causes. - Three missed periods in a row means it is time to see a GP. ## Key facts - The NHS describes a normal cycle as 21 to 35 days, so a “late” period depends on your own usual length. - Most pregnancy tests work from the first day of a missed period (NHS). - Missing three periods in a row when not pregnant is a reason to see a GP (NHS). A late period can send your brain into overdrive. Breathe. There are lots of possible reasons, and most are not serious. Many people have a late or missed period at some point. ## Could I be pregnant? Rule it out first If you have had sex, take a [pregnancy test](https://splash.care/tools/pregnancy-test-timing). The NHS says most tests can be used from the first day of a missed period. If you are not sure when your period was due, test at least 21 days after you last had unprotected sex. Home tests are accurate if you follow the instructions, and a positive result is almost certainly right. A negative result is less reliable, especially if you test early. If you still think you could be [pregnant](https://splash.care/learn/fertility-ttc/early-pregnancy-signs), wait a few days and test again. [See a GP](https://splash.care/learn/conditions/talk-to-your-doctor) if you get a negative result on a second test but your period still has not arrived. The NHS says you can use a wee collected at any time of day, but always check the instructions on your test. ## Why is my period late if I’m not pregnant? - [Stress](https://splash.care/learn/cycle-basics/stress-travel-illness). - Sudden weight loss, or being overweight. - Doing too much [exercise](https://splash.care/learn/period-care/exercise-on-period). - Hormonal contraception (the pill, injection or coil), including after stopping it. - Breastfeeding. - The start of [perimenopause](https://splash.care/learn/glossary/perimenopause) (usually between 45 and 55). - [PCOS](https://splash.care/learn/glossary/pcos) (now also called [PMOS](https://splash.care/learn/glossary/pmos)), thyroid problems, or other conditions such as diabetes. > **Splash says:** if your period is very late, add a note about anything unusual, such as stress, illness, travel or a new medicine. That is useful for you and any doctor. ### When to see a doctor See a GP if you have missed 3 periods in a row, your periods have not started by 15, your periods have become irregular, or you have missed a period along with symptoms like weight gain or loss, tiredness, thick hair on your face, or dry or oily skin. Ask for an urgent appointment or call NHS 111 if you have recently missed a period and have unusual bleeding with pain anywhere in your tummy or pelvis, as this can be a sign of ectopic pregnancy. Call 999 for sudden, severe tummy pain with fainting, dizziness or looking very pale. ## Questions people ask ### How late can a period be before I should worry? A few days either way is normal because cycles vary. If you could be pregnant, test once your period is late. If you are not pregnant, see a GP if you miss three periods in a row, or sooner if you are worried or have other symptoms. ### Can stress make my period late? Yes. Stress can delay ovulation, and when ovulation is late, the period is late too. Illness, travel and big changes in sleep, weight or exercise can do the same. ### My test is negative but my period is still late. What now? If you tested early, test again in a few days. If tests stay negative and your period does not come, common causes include stress, weight change and PCOS. See a GP after three missed periods, or sooner if you are worried. ## Sources 1. [NHS: Missed or late periods](https://www.nhs.uk/symptoms/missed-or-late-periods/) 2. [NHS: Doing a pregnancy test](https://www.nhs.uk/pregnancy/trying-for-a-baby/doing-a-pregnancy-test/) 3. [NHS: Vaginal bleeding between periods or after sex](https://www.nhs.uk/symptoms/vaginal-bleeding-between-periods-or-after-sex/) 4. [NHS: Periods](https://www.nhs.uk/conditions/periods/) This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).