Bleeding between periods: causes, when to see a GP and what tests to expect

The NHS says bleeding between periods or after sex can have lots of possible causes. Common causes of bleeding between periods include hormonal contraception such as the contraceptive pill, small growths in and around the womb such as polyps or fibroids, and sexually transmitted infections (STIs) such as chlamydia.

The NHS lists other causes of irregular periods that can disturb your cycle: puberty, the start of menopause (usually between the ages of 45 and 55), pregnancy (a missed period is often an early sign), losing or gaining a lot of weight, stress and anxiety, and exercising too much. It says conditions such as polyendocrine metabolic ovarian syndrome (PMOS), which used to be called polycystic ovary syndrome, or thyroid problems can also cause irregular periods.

The NHS says that pelvic inflammatory disease, which is usually caused by an infection spreading from the vagina, can cause bleeding between periods or after sex, along with pelvic pain, unusual discharge and pain during sex.

The NHS says to see a GP or go to a sexual health clinic if you are bleeding between periods or after sex. Its irregular periods advice also lists bleeding between periods among the reasons to see a GP, along with periods lasting longer than 7 days, irregular periods with other symptoms such as weight gain, tiredness or excess facial hair, or struggling to get pregnant.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you have recently missed a period, have unusual vaginal bleeding, and have pain anywhere in your tummy, including your lower tummy (pelvic pain). This could be a sign of an ectopic pregnancy and needs to be checked as soon as possible.

For pelvic inflammatory disease, the NHS says to call 999 or go straight to A&E if you have pelvic pain that is severe, getting worse or hurts when you move or touch the area; pelvic pain with heavy bleeding from your vagina; a sharp, sudden and intense pain in your lower tummy; pain under your ribs on the right side and in your right shoulder; or you feel dizzy or faint, have a very high temperature, or feel very unwell. Do not drive yourself.

The NHS says a doctor or nurse will ask questions about your symptoms and medical history. You may have a pregnancy test, a blood test, a test for sexually transmitted infections (which may be a urine test or a swab of fluid from your vagina), and an examination of your vagina and cervix. If further tests are needed, you may be referred for an ultrasound scan, colposcopy or hysteroscopy.

NICE's heavy menstrual bleeding guideline gives more detail on hysteroscopy. It says outpatient hysteroscopy should be offered to women with heavy menstrual bleeding if their history suggests submucosal fibroids, polyps or endometrial pathology, for example because they have symptoms such as persistent intermenstrual bleeding. It says women should be advised to take oral pain relief before the procedure, and that endometrial biopsy may be considered at the time of hysteroscopy for women at high risk, such as those with persistent intermenstrual or irregular bleeding or who take tamoxifen.

It helps to keep a record before your appointment: the dates of bleeding, how heavy it was, whether it is linked to sex, any pain or discharge, your contraception, and whether a period has been missed. The NHS suggests using an app or a diary to keep track of your periods.

The NHS says any treatment you need will depend on what is causing the bleeding. Treatment is not always needed for irregular periods, and if it is, it depends on the cause. For example, if PMOS is causing irregular periods, the combined pill may help make periods more regular, and medicines can help if thyroid problems are the cause.

If hormonal contraception is the cause, NICE says anticipated changes in bleeding pattern with a levonorgestrel-releasing intrauterine system are particularly likely in the first few cycles and may last longer than 6 months, and it is advisable to wait for at least 6 cycles to see the benefits. Infections such as chlamydia are treated with antibiotics.

The NHS lists causes of bleeding after sex as changes to the surface of the cervix (cervical ectropion), small growths on the cervix (polyps), vaginal dryness and sexually transmitted infections such as chlamydia. As with bleeding between periods, it should always be checked by a GP or sexual health clinic because it can sometimes be a sign of cancer.

Bleeding after the menopause is treated differently. The NHS says that if you have noticed bleeding from your vagina after your menopause, even if it is only a small amount or it has only happened once, you should see a GP. A GP should refer you to hospital or a special postmenopausal bleeding clinic, and you should not have to wait more than 2 weeks to see a specialist.

You can start with a GP or a sexual health clinic on the NHS. If a cause is not found, the GP may refer you to a gynaecology service for a scan or hysteroscopy, with waiting times that vary by area.

Some people choose a private gynaecology appointment, scan or hysteroscopy for an earlier answer. The investigations are the same in either setting. Whichever route you use, persistent bleeding needs a defined explanation, and results should be shared with your GP.