The third stage of labour commences with the completed delivery of the fetus and ends with the completed delivery of the placenta and its attached membranes. The length of the third stage itself is usually 5-15 minutes. The absolute time limit for delivery of the placenta, without evidence of significant bleeding, remains unclear. Periods ranging from 30-60 minutes have been suggested.
Retained placenta is said to have occurred when the placenta remains in the uterus for more than 1 hour.
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 vary 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. Retained placenta was identified as the cause of 18% of severe obstetric haemorrhages in one American series.
If the labour has progressed normally and the mother wishes it, the third stage can be allowed to progress physiologically - without active management. However, if there has been significant haemorrhage, try to discover if the placenta has separated - as indicated by:
- A sudden rush of blood.
- Fundus moves higher and becomes rounded.
- Increase in length of part of the umbilical cord visible at the vulva.
- Raising of fundus does not cause the cord to decrease in length.
If the placenta has separated:
- Try to deliver the placenta by 'rubbing up' the uterus or giving IM synthetic oxytocin to produce a contraction.
- Then push it towards the vagina to help with expulsion of the placenta and membranes.
- These are held and twisted whilst pulling constantly so that membranes are kept intact.
If the placenta has not detached, it needs to be removed manually under anaesthetic:
- Place a gloved hand into the uterus, with the other hand on the fundus to control it.
- Follow the umbilical cord until you find the lower edge of the placenta.
- Push the hand between the placenta and the body of the uterus and ease the placenta away with a sawing action (NB: in cases of placenta accreta, the placenta will not detach easily and use of excessive force can result in life-threatening haemorrhage which may require hysterectomy).
- When fully detached, explore the uterine cavity for damage and for other pieces of placenta.
- Massage the fundus with one hand whilst extracting the placenta and membranes with the hand in the uterine cavity.
- Look carefully at the placenta to be sure that it is complete.
- Inject ergometrine IV and IM.
- A trapped placenta may respond to glyceryl trinitrate (500 micrograms sublingually).
The Release Trial found no significant difference in the need for manual removal of the placenta when umbilical vein oxytocin was compared to placebo.
- Retained placenta is, in itself, life-threatening because of its association with postpartum haemorrhage.
- Manual removal carries the risk of damage to the genital tract and of puerperal infection. It also increases the likelihood of bacterial contamination in the uterine cavity. However, there are no randomised controlled trials to evaluate the effectiveness of antibiotic prophylaxis to prevent endometritis after manual removal of placenta in vaginal birth.
Sulprostone is a potent stimulator of uterine smooth muscle contractions with high abortifacient activity. It is not licensed in the UK but has been shown to reduce the need for the manual removal of the placenta by 49%.
Further reading & references
- Smith JR et al; Management of the Third Stage of Labour, eMedicine, Sep 2010
- Saving Mothers' Lives. Reviewing maternal deaths to make motherhood safer: 2006-2008; Centre for Maternal and Child Enquiries (CMACE), BJOG. Mar 2011
- Weeks AD; The retained placenta. Best Pract Res Clin Obstet Gynaecol. 2008 Sep 13.
- Al-Zirqi I, Vangen S, Forsen L, et al; Prevalence and risk factors of severe obstetric haemorrhage. BJOG. 2008 Sep;115(10):1265-72.
- Intrapartum care, NICE Clinical Guideline (2007)
- Antenatal care: routine care for the healthy pregnant woman, NICE Clinical Guideline (March 2008)
- Ekerhovd E, Bullarbo M; Sublingual nitroglycerin seems to be effective in the management of retained placenta. Acta Obstet Gynecol Scand. 2008;87(2):222-5.
- Weeks AD, Alia G, Vernon G, et al; Umbilical vein oxytocin for the treatment of retained placenta (Release Study): a Lancet. 2010 Jan 9;375(9709):141-7. Epub 2009 Dec 7.
- Chhabra S, Dhorey M; Retained placenta continues to be fatal but frequency can be reduced. J Obstet Gynaecol. 2002 Nov;22(6):630-3.
- Chongsomchai C, Lumbiganon P, Laopaiboon M; Prophylactic antibiotics for manual removal of retained placenta in vaginal birth. Cochrane Database Syst Rev. 2006 Apr 19;(2):CD004904.
- van Beekhuizen HJ, de Groot AN, De Boo T, et al; Sulprostone reduces the need for the manual removal of the placenta in patients with retained placenta: a randomized controlled trial. Am J Obstet Gynecol. 2006 Feb;194(2):446-50.
|Original Author: Dr Hayley Willacy||Current Version: Dr Hayley Willacy|
|Last Checked: 18/03/2011||Document ID: 1724 Version: 22||© EMIS|
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