What is acute uterine inversion, how is it classified, and how does it present?

Uterine inversion is the uterus turning inside-out, usually from cord traction on a fundal/unseparated placenta. Classified: 1st degree (fundus to cervix), 2nd degree (uterus through cervix into vagina), 3rd degree (prolapse outside the vulva).

Presentation: profound (neurogenic/vasovagal) shock disproportionate to blood loss, haemorrhage, severe abdominal pain, an absent uterine fundus abdominally, and a fleshy mass at/outside the introitus.

Clinical relevance. Recognising the disproportionate shock and absent fundus allows prompt diagnosis of uterine inversion.

More Detail

Acute uterine inversion

A rare but life-threatening third-stage emergency.

Cause

Usually excessive controlled cord traction on a fundal placenta before separation. Higher risk with multiparity, connective tissue disorders (Marfan, Ehlers-Danlos), and it may occur with placenta accreta.

Classification

• 1st degree - the inverted fundus reaches up to the cervix.
• 2nd degree - the body of the uterus protrudes through the cervix into the vagina.
• 3rd degree - complete prolapse of the inverted uterus outside the vulva.

Presentation

• Profound shock - a neurogenic (vasovagal) response to traction on the uterus/ligaments, out of proportion to blood loss.
• Haemorrhage and severe abdominal pain.
• Absent uterine fundus abdominally (a depression where the fundus should be).
• A fleshy, dark red-blue mass at or outside the introitus.