Missed period and not pregnant: 10 possible causes
Short answer: a missing period when you're not pregnant is called secondary amenorrhoea. Doctors use that term after three months without a period (or six months if your cycle was always irregular). The most common causes are stress, weight or training changes, PCOS, thyroid problems, hormonal contraception and perimenopause.
One skipped cycle is usually harmless, your body isn't a clock. Persistently missing periods are worth taking seriously, even without a wish to conceive: prolonged low oestrogen isn't good for bone and heart health.
1. Pregnancy (rule it out)
The most common cause, and a test can be taken too early. Repeat after a week if unsure. See can you bleed while pregnant?
2. Stress
Sustained stress suppresses the hypothalamic signal that drives ovulation. No ovulation usually means no period. Read cortisol, stress and your cycle.
3. Low energy availability
Rapid weight loss, strict dieting, an eating disorder or heavy training without eating enough can pause your cycle. In athletes this is called RED-S. Common, treatable, and worth addressing.
4. Significant weight gain
A substantially higher weight can also disturb hormone balance and make ovulation irregular.
5. PCOS
Polycystic ovary syndrome is a leading cause of absent or very irregular cycles, often alongside acne, excess hair growth or difficulty losing weight. Read PCOS explained.
6. Thyroid
Both an underactive and overactive thyroid disrupt cycles. A simple TSH blood test clarifies this.
7. Raised prolactin
Excess prolactin can suppress ovulation. Signs: milky nipple discharge without breastfeeding, headaches or vision changes. Always worth investigating.
8. Contraception
With a hormonal IUD, injection, implant or continuous pill use, absent bleeding is often normal. After stopping the pill your cycle usually returns within a few months; longer than three months warrants a check. Read coming off the pill.
9. Breastfeeding and postpartum
Exclusive breastfeeding often suppresses cycles for months. See your cycle after birth.
10. Perimenopause or POI
From your late 30s and 40s cycles get more erratic. Periods stopping before 40 may indicate primary ovarian insufficiency, which should be investigated. Read perimenopause in your 30s.
When to see a doctor
- Three months without a period and no clear explanation
- You've never had a period and you're 15 or older
- Milky nipple discharge, headaches or vision changes
- Hot flushes, night sweats or vaginal dryness under 40
- Marked excess hair growth, acne or rapid weight change
- You're trying to conceive
Bring your cycle data. An overview of your last six to twelve cycles, symptoms included, makes the conversation concrete.
General information, not medical advice.
FAQ
How long can a period be late?
A single skipped cycle is common. After three months without one, get it checked.
Can stress really delay a period?
Yes. Stress can delay or block ovulation, so your period arrives late or not at all.
Does no period mean I'm not fertile?
Not necessarily. Ovulation can return before your first bleed, so pregnancy is possible without contraception.
Want to understand your cycle better?
