10.1  Predisposing factors for a ruptured uterus

The uterus of a woman in labour may rupture if the delivery is obstructed (for any reason) while the uterus continues contracting until it tears or bursts. You already know a lot about the complications of labour and delivery from Study Sessions 8 and 9, so you should be well prepared to answer the following question.

  • What factors can you suggest that would increase the risk of a ruptured uterus occurring?

  • Uterine rupture may occur if the labour is obstructed due to:

    • Cephalopelvic disproportion (the fetal head is too large or the mother’s pelvis is too small to allow the baby to descend down the birth canal).
    • Persistent malpresentation or malposition of the fetus (e.g. breech, face, brow or shoulder presentation, or the baby is head down (vertex presentation) but in the occipito-posterior position (with the back of its skull towards the mother’s back).
    • Multiple pregnancy (twins or more babies, especially if they are ‘locked’ at the neck or conjoined/fused together).
    • Physical obstruction preventing the baby from descending (e.g. a tumour in the abdomen or uterus).
    • Scarring of the uterus (which we referred to in the introduction to this study session).

The first four causes have already been covered in detail in earlier study sessions, but there is more to be said about uterine scarring and some other reasons why uterine rupture may occur.

Learning Outcomes for Study Session 10

10.1.1  Uterine scarring