Uterine Inversion

Uterine inversion is turning of the uterus inside out, with the fundus passing through the cervix into the vagina or outside the vulva. It is classed by degree (first: fundus reaches the cervical ring; second: through the cervix; third: to the introitus; fourth: outside the vulva) and by timing (acute: within 24 hours; subacute: 24 hours to 4 weeks; chronic: after 4 weeks). It is rare, at 1 in 2000 to 1 in 20,000 births, and matters because it causes severe haemorrhage and neurogenic shock.

• Risk factors: fundal placenta, excessive cord traction, fundal pressure, short cord, uterine atony, placenta accreta spectrum, precipitate labour, magnesium sulphate, previous inversion, uterine anomaly or fibroid.
• A smooth round mass in the vagina after birth is inversion until proved otherwise.
• Nonpuerperal inversion is caused by a submucous fibroid or uterine tumour.

After birth, women have sudden severe lower abdominal pain, heavy bleeding, profound shock out of proportion to blood loss (vagal), a mass in the vagina or at the vulva, and no palpable fundus on the abdomen or a dimple in the fundus. Chronic inversion presents with bleeding, discharge and a mass.

• Reddish or bluish mass with the placenta attached in acute inversion.
• Absent uterus on abdominal palpation or a cup-shaped fundus.
• Differential diagnosis: prolapsed submucous fibroid, vaginal haematoma, retained placenta in the vagina, cervical prolapse, uterine tumour, uterine rupture.
• Complications: haemorrhagic and neurogenic shock, infection, uterine necrosis, coagulopathy, recurrence, hysterectomy, maternal death.

The diagnosis is clinical, with ultrasound for doubtful or delayed cases.

• Abdominal palpation for loss of the fundus or an indentation; vaginal examination for a smooth mass through the cervical ring, with the cervical ring around the neck of the mass.
• Pulse, blood pressure, blood loss, level of consciousness.
• Ultrasound: indented (U-shaped) or absent fundus and a mass in the vagina; MRI for chronic inversion.
• Haemoglobin, clotting screen, group and cross-match 4 units.

The principle is immediate replacement before the cervix tightens, with shock resuscitation, and surgery only if manual replacement fails.

• Supportive: call for help; two large-bore cannulae; Ringer's lactate 1 to 2 litres rapidly; oxygen; stop the oxytocin infusion and avoid fundal pressure; leave the placenta attached if not yet delivered, until the fundus is replaced; replace the uterus at once, then remove the placenta; blood transfusion for shock.
• Pharmacological: glyceryl trinitrate 400 to 800 micrograms sublingual or 50 to 200 micrograms IV, or terbutaline 0.25 mg subcutaneous, for uterine relaxation before replacement; spinal anaesthesia or general anaesthesia with sevoflurane if relaxation is not enough; after replacement: oxytocin 10 IU IM and infusion of 40 IU in 1 litre Ringer's lactate at 250 mL per hour, ergometrine 0.2 mg IM (not in hypertension), misoprostol 800 micrograms sublingual; cefazolin 2 g IV plus metronidazole 500 mg IV, then amoxicillin-clavulanate 625 mg oral 8-hourly for 5 days; tranexamic acid 1 g IV over 10 minutes.
• Procedures: manual replacement (Johnson manoeuvre): push the fundus up through the cervix with the flat of the hand toward the umbilicus, fingers pointing to the posterior fornix, and hold for 3 to 5 minutes until the uterus contracts; hydrostatic replacement (O'Sullivan): warm sodium chloride 0.9 percent 2 to 3 litres infused into the posterior fornix with the hand sealing the introitus; surgical replacement at laparotomy by traction on the round ligaments (Huntington) or incision of the posterior ring (Haultain), or vaginal incision of the cervical ring (Spinelli); hysterectomy for necrosis, infection or failure; for chronic inversion, surgical replacement or hysterectomy; for fibroid related inversion, removal of the fibroid or hysterectomy.
• Red flags: shock out of proportion to blood loss, bradycardia, a mass at the vulva, absent fundus, bleeding, fever above 38 degrees Celsius, foul discharge.
• Follow-up: observation of bleeding and pulse every 15 minutes for 2 hours then 4-hourly for 24 hours; haemoglobin at 24 hours; ultrasound at 1 week; review at 6 weeks; counselling about recurrence risk and delivery with a prepared third stage.