Retained Placenta

There are three main types of retained placenta following the vagina delivery:

• Placenta adherens (when there is failed contraction of the myometrium behind the placenta)
• Trapped placenta (a detached placenta trapped behind a closed cervix)
• Partial accreta (Rarely the placenta invades the myometrium deeply - placenta increta - even to the external serosa - placenta percreta - preventing detachment)

The incidence and importance of retained placenta varies greatly around the world. In less developed countries, it affects about 0.1% of deliveries but has up to 10% case fatality rate. In more developed countries, it is more common (about 3% of vaginal deliveries) but very rarely associated with mortality.¹

• Placenta accreta - 1/2,500 deliveries.
• After 2 caesarean sections for placenta praevia, there is approximately 40% risk of placenta accreta.²

If the labour has progressed normally and the mother wishes it, the third stage can be allowed to progress physiologically - without active management.³ However, if there has been significant haemorrhage, try to discover if placenta has separated - as indicated by:

• A sudden rush of blood
• Fundus moves higher and becomes rounded
• Increase in length of part of umbilical cord visible at vulva
• Raising of fundus does not cause cord to decrease in length

If placenta has separated:

• Try to deliver the placenta by 'rubbing up' uterus or giving IM synthetic oxytocin to produce a contraction.
• Then push it towards the vagina to help with expulsion of placenta and membranes.
• These are held and twisted whilst pulling constantly so that membranes are kept intact.

If placenta has not detached, it needs to be removed manually under anaesthetic:

• Place gloved hand into uterus with other hand on fundus to control it
• Follow umbilical cord until find lower edge of placenta
• Push the hand between the placenta and the body of the uterus and ease placenta away with a sawing action (N.B. in cases of placenta accreta the placenta will not detach easily and use of excess force can result in life-threatening haemorrhage which may require hysterectomy)
• When fully detached, explore the uterine cavity for damage and other pieces of placenta
• Massage fundus with one hand whilst extracting placenta and membranes with hand in uterine cavity
• Look carefully at placenta to be sure that it is complete
• Inject ergometrine IV and IM
• The need for manual removal can be reduced by 20% by the use of intraumbilical oxytocin (30 i.u. in 30 mL saline).^1,4
• A trapped placenta may respond to glyceryl trinitrate (500 mcg sublingually)⁵

The Release Trial, which commenced in 2005, is an on-going randomised controlled trial of umbilical vein oxytocin versus placebo for the treatment of retained placenta.⁶

Retained placenta is in itself life threatening because of its association with postpartum haemorrhage.⁷
Manual removal carries the risk of damage to genital tract and puerperal infection. Manual removal of placenta increases the likelihood of bacterial contamination in the uterine cavity. There are no randomised controlled trials to evaluate the effectiveness of antibiotic prophylaxis to prevent endometritis after manual removal of placenta in vaginal birth.⁸

Sulprostone is a potent stimulator of uterine smooth muscle contractions with high abortifacient activity. It reduces the need for the manual removal of the placenta by 49%.⁹