Why did my period stop?
The most common reason a period stops is pregnancy, so take a test first. If it's negative, common causes include stress, losing weight or eating too little, intense exercise, hormonal birth control, breastfeeding, PCOS, thyroid problems and perimenopause. If you've missed three periods in a row, or you're under 15 and haven't started, see a doctor.
First: could you be pregnant?
If you've had sex since your last period, a pregnancy test is the first step. Tests are most reliable from the day your period was due. If it's negative and your period still hasn't come, test again in a few days. Our pregnancy test calculator shows the best day.
Common reasons a period stops
| Cause | Why it stops periods | Clues |
|---|---|---|
| Stress | The brain turns down the hormones that trigger ovulation | A hard few weeks, poor sleep, big life change |
| Low weight or eating too little | The body saves energy by pausing ovulation | Dieting, weight loss, eating disorder |
| Intense exercise | Same energy-saving switch, especially with low food intake | Training hard, endurance sports |
| Hormonal birth control | Some methods thin the lining so periods stop | Hormonal IUD, implant, injection, continuous pill |
| Breastfeeding | Prolactin keeps ovulation switched off | Recent baby |
| PCOS | Ovulation happens rarely or irregularly | Long cycles, acne, extra hair |
| Thyroid problems | Thyroid hormones affect the cycle | Tiredness, weight or temperature changes |
| High prolactin | Blocks ovulation | Sometimes milky nipple discharge, headaches |
| Perimenopause | Ovulation becomes less regular | Age 40s, hot flashes, sleep changes |
Less often, periods stop because of conditions like early menopause (before 40), scarring inside the uterus after surgery, or certain medicines, including some antipsychotics and chemotherapy. A doctor can sort these out with a few simple tests.
How long is too long?
Missing a single period after a stressful month is common, and one late period isn't usually a cause for worry. Doctors call it amenorrhea when periods stop for 3 months in a row in someone who had regular cycles, or 6 months in someone with irregular cycles. Read more in what amenorrhea is.
You've missed 3 periods in a row and aren't pregnant, you haven't had a first period by 15, your periods stopped and you're under 40, or you also have headaches, vision changes, milky nipple discharge, excess hair growth, or you've lost a lot of weight. If you're struggling with food or exercise, please reach out: it's common and help works.
Why it's worth getting checked
A missing period is a signal, not just an inconvenience. Low estrogen over a long time can weaken bones, and some causes, like thyroid problems or PCOS, are easier to manage when caught early. If stress or under-eating is behind it, getting support often brings periods back.
Stress, mood and a missing period
Stress and missed periods can feed each other: worry delays the period, and the late period causes more worry. Logging your mood alongside your cycle can show whether a rough patch lines up with a late or missing period. See can stress delay your period and can anxiety cause a late period.
Frequently asked questions
Can your period stop for no reason?
It can feel that way, but there's usually a cause, often stress, weight change or exercise. If it doesn't come back within 3 months, a doctor can help find it.
Is it bad if my period stopped on birth control?
Usually not. Some methods, like the hormonal IUD, implant and injection, often make periods light or stop them, and that's expected.
Can weight gain stop your period?
It can. Weight gain, especially with PCOS or insulin resistance, can make ovulation irregular and periods stop.
Will my period come back on its own?
Often, once the cause settles, such as stress easing or eating enough again. If it hasn't returned in 3 months, see a doctor.
Sources
- NHS: Missed or late periods
- Cleveland Clinic: Amenorrhea
- MedlinePlus: Absent menstrual periods, secondary
- Gordon CM et al. Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab (2017)
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
What is amenorrhea?Amenorrhea means absent periods: no period by 15, or no period for 3 months or more. The types, common causes from stress to PCOS, and how it's treated.
Why is my period late? 10 common reasonsWhy is my period late if you're not pregnant? Stress, late ovulation, weight change, PCOS, perimenopause and more, plus when a late period needs a doctor.
Late period but a negative pregnancy test?Late period but a negative pregnancy test? You may have tested early or ovulated late. Other common causes, when to retest, and when to see a doctor.
PCOS (now also called PMOS) and your cyclePCOS, now also called PMOS, explained: the common signs, how doctors diagnose it, what it does to your cycle and mood, and what helps day to day.How late is my period? Check in secondsHow late is my period? Enter your last period and cycle length to see exactly how many days late you are, whether that's normal, and what to do next.