Pelvic pain has many causes. Pelvic pain can arise from a number of different organs or from different medical problems within the pelvis.
The causes include:
Pain from the uterus – fibroid pain, prostaglandin pain, clot colic, adenomyosis
Pain from the ovaries – ovarian cysts, ovulation pain, ovarian remnant syndrome
Pain from the bowel – irritable bowel syndrome, bloating, food intolerance, constipation, inflammatory bowel disease
Pain from the bladder – interstitial cystitis
Pain from adhesions Pain from nerves – neuropathic pain Pain from veins – ovarian vein syndrome, pelvic congestion syndrome
Pain from muscles, joints or ligaments
Pain from the appendix
Pelvic infections – pelvic inflammatory disease
Pain arising from the uterus
Uterine pain occurs on the first one or two days of a menstrual period. The uterus is a hollow muscular organ and when the uterine muscle contracts during a period the result is a cramp-like pain that comes and goes every few minutes. Between the contractions there is little pain. The pain may be referred to the thigh (but not below the knee) or into the lower back when the pain is severe. Uterine pain is usually felt across a large area in the centre of the lower abdomen. If the pain is present in one small area or on one side of the pelvis then other reasons for the pain are more likely.
Pain during the month is less common but possible. If it is uterine pain then it typically worsens as a period becomes closer and eases off in the week after the period. Some women with bleeding between periods are aware that whenever they bleed they experience pain that feels like a period.
Prostaglandins are chemicals that cause the uterus to contract and therefore lead to a cramp-like pain. Prostaglandin pain is especially common in teenage girls and young women, and may cause pain in older women too, particularly if they have never had children. If the prostaglandins affect the nearby large bowel then they may cause diarrhoea and bowel cramps. If they spread to or affect the whole body then they lead to fainting, nausea or a slight rise in body temperature. Lesions of endometriosis can produce prostaglandins and this may be one way in which endometriosis causes pain. There is no specific test for prostaglandin pain. Prostaglandins do not alter the appearance of the pelvic organs, so no abnormalities are seen on an ultrasound scan or during a laparoscopy. Blood tests are unhelpful. The diagnosis is therefore made on the history of the symptoms. If pain is present on the first day of the menstrual cycle and improves or disappears with anti-prostaglandin medication such as NSAIDs then prostaglandin pain is the likely cause.
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