Why is my period late? 10 common reasons
Your period is usually late because ovulation happened later than usual. Pregnancy is the first thing to rule out with a test, but stress, illness, travel, weight change, intense exercise, coming off the pill, breastfeeding, PCOS, thyroid problems and perimenopause can all delay ovulation and push your period back by days or weeks.
When does a period count as late?
A normal adult cycle is anywhere from 21 to 35 days, and it's normal for it to move by a few days from month to month. So a period that arrives two days after your app said it would isn't really late. Most doctors start calling a period late when it's 5 or more days past the day you expected it, and missed when you go six weeks or more without bleeding. Read more in how late a period can be.
The usual reasons your period is late
Your period comes about 12 to 14 days after you ovulate. That second half of the cycle, the luteal phase, is fairly steady. The first half is not: anything that delays ovulation delays your period by the same number of days.
| Reason | Why it delays your period | What to look for |
|---|---|---|
| Pregnancy | Hormones from the pregnancy stop the lining from shedding | Sore breasts, nausea, tiredness; take a test |
| Stress | Stress hormones can quiet the brain signals that trigger ovulation | A hard month, a move, exams, grief |
| Illness or travel | Fever, jet lag and disrupted sleep can postpone ovulation | A cold, flu or a big trip mid-cycle |
| Weight change or under-eating | The body pauses ovulation when energy is low | Dieting, sudden weight loss, eating disorders |
| Intense exercise | Heavy training without enough fuel can switch cycles off | Training for a race, new hard routine |
| Coming off the pill | Your own cycle can take a few months to settle | Stopped hormonal contraception recently |
| Breastfeeding | Prolactin keeps ovulation low | Periods may stay away for months |
| PCOS | Ovulation happens rarely or irregularly | Long cycles, acne, extra hair growth |
| Thyroid problems | Both under- and overactive thyroid affect the cycle | Tiredness, weight change, feeling cold or hot |
| Perimenopause | Ovulation becomes less regular in your 40s | Cycles getting shorter, longer or skipped |
What to do when your period is late
- If you could be pregnant, take a test. Most home tests are reliable from the first day of your missed period. Our pregnancy test calculator shows the best day.
- If the test is negative, wait a few days and test again. If you ovulated late, hCG may not show yet. See late period, negative test.
- Look back at the month. Were you ill, stressed, traveling or training hard around two weeks before your period was due? That's when a delay usually starts.
- Check your history. If your cycles always vary, a late period may just be your normal range. The period late checker compares today with your usual cycle.
When ovulation is late, the luteal phase is late too, so PMS can feel like it drags on. If you feel teary or tense for longer than usual, that's often the same delay showing up in your mood.
Why tracking makes a late period less scary
A late period feels very different when you know your real range. If your cycles run from 27 to 33 days, day 31 isn't late at all. Logging a few months shows you that range, and logging how you feel shows whether stress or illness lined up with the delay.
When to see a doctor about a late period
See a doctor if you've missed three periods in a row, if you're pregnant and have pain on one side or bleeding (to rule out an ectopic pregnancy), if your period is late along with weight change, extra hair growth or very tired feelings, or if your periods haven't started by age 15. Get urgent help for severe tummy pain or fainting.
Frequently asked questions
How late can a period be without being pregnant?
A period can be a week or more late without pregnancy, usually because ovulation came late. If you've had a negative test and still no period after two weeks, test again and consider seeing a doctor.
Can stress really make my period late?
Yes. Stress can delay ovulation, which pushes your period back. Read more in can stress delay your period.
Is it normal for my period to be late one month?
An occasional late period is common and usually nothing to worry about. A pattern of long or missed cycles is worth tracking and discussing with a doctor.
Can a late period mean perimenopause?
In your 40s, yes, it can be one of the first signs. See first signs of perimenopause.
Sources
- NHS: Missed or late periods
- NHS: Periods
- Cleveland Clinic: Amenorrhea
- Bull JR et al. Real-world menstrual cycle characteristics of more than 600,000 menstrual cycles. npj Digital Medicine (2019)
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
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