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What causes bleeding between periods?

There are many different causes of bleeding between periods. Some may not be anything to worry about, but seek medical advice if you're concerned.  

Hormonal contraceptives

Irregular bleeding, such as bleeding between periods, is common during the first three months of starting hormonal contraception, such as the:

If you're concerned about bleeding or it lasts longer than three months, you should seek medical advice.

You may also bleed between periods if you:

Other causes

Some other causes of bleeding between periods include:   

  • taking the emergency contraceptive pill  
  • injury of the vagina – for example, from having rough sex 
  • having a recent abortion – seek medical advice if you're bleeding heavily 
  • sexually transmitted infections (STIs) such as chlamydia – it's a good idea to get tested if you've recently had unprotected sex with a new partner    
  • reproductive hormones not working normally – this is common in women approaching the menopause or in women with polycystic ovary syndrome (PCOS)
  • stress
  • vaginal dryness
  • harmless changes to the neck of the womb (cervix) – this may be called cervical ectropion or cervical erosion
  • cervical cancer – if you're aged 25 to 64, you should be having regular cervical screening tests to detect any changes to your cervix; even if you're up-to-date with screening tests, you should seek advice about irregular bleeding, particularly bleeding after sex, to eliminate the possibility of cervical cancer 
  • womb (uterus or uterine) cancer – this is more common in post-menopausal women, and most cases of endometrial cancer are diagnosed in women over the age of 50; see your GP if you're over 40 and have bleeding between periods to eliminate the possibility of uterine cancer
  • cervical or endometrial polyps – benign or non-cancerous growths in the womb or the lining of the cervix

When to seek medical advice

If you're concerned about your bleeding, you should:

A healthcare professional will talk to you about your symptoms. Depending on your situation, they may suggest carrying out some tests, such as:

  • tests for STIs, which may include an examination of your genitals
  • a pregnancy test
  • a cervical screening test, if you're aged 25 to 64 and not up-to-date with these 
  • a pelvic ultrasound scan 

To diagnose some conditions, you may need an examination, such as: 

  • a speculum examination – a speculum is a medical instrument that's inserted into your vagina to examine your vagina and cervix
  • an internal examination of your vagina with the fingers (bimanual examination)  

Read the answers to more questions about women's health

Further information:

Menstrual cycle: animation

This animation explains in detail how the menstrual cycle works.

Media last reviewed: 21/02/2015

Next review due: 21/02/2017

Page last reviewed: 03/11/2016

Next review due: 03/11/2019