Irregular Vaginal Bleeding

Irregular vaginal bleeding presents commonly in primary care – particularly to female GPs, as the patient will often anticipate a pelvic examination. This chapter covers all causes of this symptom throughout life including prepubertal, causes in early pregnancy and post-menopausal (causes in late pregnancy are not covered as they constitute a quite different clinical scenario). The key to appropriate management usually lies in a careful history

Published: 2nd August 2022 | Updated: 15th August 2022

Differential diagnosis

Common Diagnoses

  • Dysfunctional Uterine Bleeding (DUB)
  • Breakthrough Bleeding (BTB) on Contraceptive Pills and Long-Acting Reversible Contraception; also HRT
  • Cervical Polyp or Erosion
  • Cervicitis and PID
  • Post-Menopausal Atrophic Vaginitis

Occasional Diagnoses

  • Endometrial Polyps
  • Ovulatory Bleeding (Associated with Mittelschmerz)
  • Hypothyroidism (and Less Commonly Hyperthyroidism)
  • Perimenopause
  • Bleeding During Early Pregnancy (20% of all Pregnancies in First Trimester); Also Miscarriage, Ectopic Pregnancy

Rare Diagnoses

  • Uterine Bleeding in the Newborn
  • Carcinoma (Ovary, Fallopian Tube, Uterus, Cervix and Vagina)
  • Cystic Glandular Hyperplasia (Metropathia Haemorrhagica)
  • Pyometra
  • Hydatidiform Mole (5% Go on to Chorionic Carcinoma)

Ready reckoner

Key distinguishing features of the most common diagnoses

DUBBTBPolyp/ErosionCervicitis/PIDAtrophic Vaginitis
Profuse BleedingPossibleNoNoPossibleNo
Painful PeriodsPossibleNoNoYesNo
Discomfort PVNoNoNoPossibleYes
Post-Coital BleedingNoNoYesPossiblePossible

Possible investigations

Likely: FBC, specialised gynaecological investigation (see the following list) for post-menopausal or intermenstrual bleeding

Possible: HVS and endocervical swab, colposcopy, transvaginal ultrasound

Small Print: TFT

  • FBC to check for anaemia in heavy bleeding. Raised WCC in PID.
  • TFT: To check for possible thyroid dysfunction
  • HVS and endocervical swab: To attempt to establish pathogen in cervicitis and PID.
  • Transvaginal ultrasound: To detect uterine and ovarian pathology, hydatidiform mole and to establish nature of problem in early pregnancy
  • Colposcopy: If significant cervical pathology suspected
  • Specialised gynaecological investigation (e.g. hysteroscopy and endometrial sampling): Performed in secondary care, particularly for intermenstrual and post-menopausal bleeding

Top Tips

  • Try to distinguish between intermenstrual bleeding and irregular periods, as the likely causes are different (the former suggests a structural lesion, the latter is likely to be DUB). Simply asking the patient if the bleed feels like a period, with associated period-type symptoms, may help.
  • Consider asking the patient to keep a menstrual diary. Very slight bleeding occurring consistently in mid-cycle with a slight pain and with no other worrying features suggests an ovulatory bleed.
  • Remember that missed doses, diarrhoea and vomiting, and the first few months of treatment can cause breakthrough bleeding when using oral hormonal preparations. It is worth waiting a few more cycles before changing treatment.

Red Flags

  • Post-menopausal bleeding is always abnormal. Even if atrophic vaginitis is present, do not assume this is the cause – this symptom requires a full assessment.
  • A very inflamed-looking cervix with a purulent discharge is likely to be caused by Chlamydia infection – consider referral to the local GUM clinic for further investigation and contact tracing.
  • A ‘recent’ normal cervical smear can provide false reassurance; if the cervix looks suspicious, do not take another smear – remember, this is a screening, rather than diagnostic, test. Instead, refer urgently for colposcopy.
  • Beware of ‘breakthrough bleeding’ in patients on hormonal contraception or HRT. If it persists, consider other causes and investigate or refer.
  • Unilateral pelvic pain with vaginal bleeding within a fortnight of a missed period suggests an ectopic pregnancy. Admit urgently
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Website disclaimer

Pulse Reference is based on the best-selling book Symptom Sorter.

The experts behind Pulse Reference are Dr Keith Hopcroft who is the co-author of Symptom Sorter, a GP in Essex and Pulse’s editorial advisor and Dr Poppy Freeman, a GP in Camden and also a clinical advisor to Pulse.

This website is for clinical guidance only and cannot give definitive diagnostic information. Practitioners should work within the limits of their individual professional practice, seek guidance when necessary and refer appropriately.