Once baby has been born the placenta is no longer needed either by the maternal body or the baby. It is this process of being expelled that is called the third stage of labour. There are three ways in which this can be delivered: the physiological, the active or the expectant management.
A physiological – or natural – third stage means waiting for the body to resume a pattern of contractions by itself, causing the placenta to detach from the uterine wall and be delivered by the woman. This can take anywhere from around 10 to 60 minutes. The cord is left intact during this time, allowing all the blood from the placenta to transfer to the baby, and is only cut when the placenta has been delivered – the term delayed cord clamping is used to refer to this. Optimal cord clamping – to mean that the cord is cut only when it stops pulsating – is the WHO recommended practice to best supply the baby with iron supplies until around 6 months of age although any delay does pose an increased risk of jaundice needing treatment in the baby.
A physiological approach to the third stage occurs mostly in midwife-led units and home births, where continuity of care to women can be practised[1]. This is probably due to the birth being seen as a normal life event rather than a medical ‘problem’ that needs to be fixed; an attitude often seen in consultant-led units.
In comparison, an active third stage involves giving a prophylactic uterotonic, i.e. a drug that stimulates contractions of the uterus, cord clamping and controlled cord traction. The drug syntocinon or syntometrine will be injected as the baby is born or immediately after and the cord will be clamped and cut in order for the drug not to transfer to the baby. The midwife will keep a hand on the woman’s fundus to check that the placenta has detached and will either encourage the mother to push the placenta out or will carry out controlled cord traction to help it on its way out.
By cutting the cord of the baby at this stage the baby could be deprived of up to a third of its blood as it has not had chance to transfer from the placenta. On the other hand, there is evidence to suggest that active management decreases the risk of heavy blood loss immediately after the delivery of the placenta. For this reason, it is generally advised that women who have had interventions have an active managed third stage as these increase the risk of heavy blood loss[2].
For some mothers there will be a health risk associated with a decision to pursue a physiological third stage and these women will be offered active management as an alternative. However, if this is declined then ‘watching’ or expectant management may be suggested, which aims to start with a physiological delivery and switch to active management if needed. The main concern is for women for whom a large blood loss would be extremely detrimental, or where there is already an increased risk of heavy blood loss. This is because the drug used in active management reduces blood loss immediately after the delivery of the placenta[3]. However, this method also reduces the baby’s birthweight due to the non-transfer of blood from the placenta and further has been shown to increase the mother’s blood pressure, heighten the intensity of afterpains and cause vomiting and the readmission of the mother to hospital for the treatment of prolonged bleeding (Beglet 2015).
If the mother chooses a physiological third stage there are means of encouraging the placenta to detach in a timely manner and avoid the risk of having to resort to active management. Michel Odent[4] teaches that it is important to keep oxytocin levels up while the placenta is being delivered, to contract the uterus and push the placenta out and there are a number of ways this can be achieved. Keeping the birth environment calm, quiet, warm and dimly lit will inhibit the production of adrenaline and keep oxytocin flooding the body. Skin-to-skin contact[5] and breastfeeding the baby in the ‘golden hour’ post-birth will also help the woman’s body release oxytocin and shorten the length of the third stage. If a woman has received artificial oxytocin during the augmentation of labour it may be more difficult for her body to produce it naturally, making these actions really important for her to have a physiological third stage. If not enough oxytocin is naturally produced, then the injection would likely be necessary.
Being in an upright position may assist the expedition of the delivery of the placenta and without the need for intervention as gravity does its job of easing it out of the woman’s body. It is shortening the length of the third stage that may be the key to reducing the risk of severe post birth bleeding[6].
.
[1]Blackburn S. (2008) Physiological third stage of labour and birth at home: In: Edwins J. (Ed.). Community midwifery practice. Blackwell: Oxford.
[2] https://www.nct.org.uk/birth/third-stage-labour
[3] Begley, CM, et al (2015) Delivering the placenta with active, expectant or mixed management in the third stage of labour Cochrane Database of Systematic Review
[4] Odent M, (2001) New reasons and new ways to study birth physiology. Int J Gynaecol Obstet
[5] Marin GMA, LLana MI, Lopez EA, et al. (2010) Randomizd controlled trial of early skin-to-skin contact: effects on the mother and the newborn. Acta Paediatrica
[6] Magann EF, Evans S, Chauhan SP et al. (2005). The length of the third stage of labor and the risk of postpartum hemorrhage. Obstetrics and Gynecology