Aetiology of PMB

The causes of PMB can be considered anatomically¹⁵ with those in bold being most common.

Table 2 – Causes of PMB

	Location	Cause
1	Vulva	Trauma*, vulvitis, benign and malignant lesions
2	Vagina	Foreign body irritation (e.g. ring pessary for prolapse), vaginitis (including atrophic vaginitis or post-radiotherapy), vaginal tumours
3	Cervix	Cervical erosion, cervicitis, polyps, decubitus ulcers secondary to prolapse, malignancy
4	Uterus	Endometrial atrophy and inflammation, endometritis, endometrial hyperplasia due to HRT or excessive oestrogen, polyps, endometrial carcinoma, sarcoma, mixed mesodermal tumour
5	Fallopian tube	Fallopian tube malignancy
6	Ovary	Benign or malignant ovarian tumours (including Brenner tumours, granulosa and theca cell tumours)
7	Urinary tract**	UTI, urethral caruncle (vascular growth at the end of the urethra), papilloma, carcinoma of the bladder
8	Bowel**	Haemorrhoids, anal fissures, diverticular bleed, bowel or rectal cancer
9	Systemic	Increased bleeding risk (anticoagulation, thrombocytopenia) Secondary to medications including exogenous oestrogen and HRT (16) Non-prescription medications including phytoestrogens

*In vulnerable patients ensure trauma is not abusive or a safeguarding concern.

** It is not uncommon for bleeding from the urethra or rectum to be mistaken for genital tract bleeding.

Malignancy is a cause of PMB that must not be missed. Risk factors for endometrial cancer include:

• Endogenous oestrogen exposure
  • Nulliparity, low parity
  • Polycystic ovarian syndrome
  • Early menarche, late menopause
  • Functional ovarian tumours
  • Obesity, diabetes, hyperlipidaemia

• Exogenous oestrogen exposure
  • Unopposed oestrogen therapy
  • Tamoxifen

• Hereditary

Learning Bite

A first step in the assessment of PMB is to make sure the bleeding actually comes from the genital tract, and not the urethra or rectum.