You’ve laboured, you’ve birthed and you’re finally holding your baby in your arms. But wait, there’s more.
Known as the ‘third stage of labour’ delivering the placenta is something most mums-to-be spend little time thinking about. The placenta is the only organ that is created and expelled – and our specialist obstetrician Dr Gary Sykes explains how it happens.
The third stage of labour starts after baby is born and ends when the placenta is delivered. The uterus continues to contract after delivery of the baby and these ongoing contractions cause the placenta to separate from the uterine wall and be expelled through the birth canal.
Different approaches to the third stage
There are a two different ways that the third stage of labour can be managed.
The ‘expectant’ approach to third stage management is waiting without any encouragement of the placenta to deliver. The expectant management approach has been shown, in studies, to be associated with a greater likelihood of excessive maternal bleeding and a longer duration third stage.
The primary reason for ‘active’ management of the third stage is to minimise the maternal blood loss. Active management usually results in a much shorter duration of the third stage. It involves administering an intramuscular injection to the new mum (usually at the time of delivery of baby’s shoulders) to cause the uterus to contract.
It also involves early cord clamping (though some mothers now request delayed cord clamping) and controlled traction on the umbilical cord to deliver the placenta.
Length of the third stage
The usual duration of the third stage, even with active management, varies considerably. Sometimes it is less than one minute and sometimes it is over 30 minutes. It is usually about five to 10 minutes. The longer the duration of the third stage the greater the risk of significant haemorrhage. Hence it’s usually considered the third stage is prolonged if it is greater than 30 minutes. If it is prolonged, a manual removal of the placenta is done.
What is more significant than the duration of the third stage, is the amount of haemorrhage. If there is severe haemorrhage, then there should be active intervention irrespective of the duration. If the third stage is more than 30 minutes duration and there are no bleeding issues, then there is no immediate clinical need for intervention.
What is a retained placenta?
A placenta is retained because it is still adherent to the uterine wall, it is trapped behind a closing cervix or there is a ‘placenta accreta’ problem. This means the placental tissue has invaded the uterine wall in pregnancy and so the placenta is morbidly adherent to the uterus.
A manual removal procedure is done for a retained placenta. This can be done with the mother breathing on nitrous oxide gas, but it is very painful. It is best done under a regional block (epidural or spinal anaesthetic) or under a general anaesthetic.
For a placenta accreta problem other measures are needed.
What happens to a placenta?
The placenta is disposed of by the hospital in the same way as other human tissue items are disposed of. You can take the placenta home if you wish, though this is a request that is very infrequently made.
After completing all the stages of childbirth, you will be checked for the next few hours to make sure that the uterus continues to remain well contracted (by checking the location of the fundus of your uterus by abdominal palpation), your bleeding is not excessive and your ‘obs’ (blood pressure, pulse and temperature) are normal and stable.