Amniotomy
Although every woman's, pregnancy and birth is unique there are certain things that women say during their labour that makes us think “I wish I had a pound for every time I have heard that”. Some things make us smile inwardly in anticipation such as when she says, “I can’t do this”. We gently explain that it is normal to feel this way and that maybe she is going through the transition stage.
However one thing we often hear that does not make us smile quite so much is “they had to break my waters for me last time”. This is often said as if she had been done a great service, that somehow her body was unable to do its job properly and needed assistance
Women’s knowledge around this intervention seems somewhat dubious. They have heard about “having your waters broken” and appear to understand that it will “speed it up a bit”.
The Evidence
In normal labour the force and pressure of contractions will at some point cause the bag of amniotic fluid around the baby to burst, very often at full dilatation, (10cms). Rarely the baby will be born with the bag intact. With the medicalisation of childbirth the routine breaking of waters, (amniotomy) became accepted practice. This was done in order to speed up labour and studies have shown that in first labours this can reduce the length of labour by 60-120 minutes. In subsequent labours this time may be less.
However if some women perceive this as a benefit it must be considered whether there is a price to pay? It appears that pain is increased following amniotomy that may lead to a higher uptake of analgesia including epidural with its added risks of instrumental delivery and caesarean section.
Evidence indicates that baby heart rate abnormalities in labour may be increased following amniotomy even when the baby is healthy. This also could lead to unnecessary caesarean sections.
The bag or membrane is a barrier to infection while intact. Let us not forget the procedure itself. A long crochet like hook is passed through the cervix to “pop” the bag. The hook on the end is in close proximity to the baby’s head. Sadly newborn babies have been born with the scratches to prove that this was a difficult procedure for that particular woman!
Recommendations following many studies are that this intervention should be reserved for abnormal labours only.
Copyright (c) V Howes
Kent Midwifery Practice 2002