Irregular Vaginal Bleeding

Differential Diagnosis

Common Diagnoses

Occasional Diagnoses

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

Published: 2nd August 2022 Updated: 10th April 2024

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