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Caesarean section is a procedure where a baby is delivered by cutting through the front wall of the abdomen to open the womb.
Approximately 20% of babies born in the UK are delivered by caesarean section because there may be an urgent or potential medical risk to mother or baby.
A caesarean section is indicated when there is a significant risk to the health of the mother or baby if the operation is not performed at a given time.
It may be performed as:
a planned procedure, where the medical need for the operation becomes apparent during pregnancy;
an emergency procedure, where a situation arises during labour that calls for urgent delivery of the baby; or
an elective procedure, on the basis of personal choice rather than as a result of medical risk.
The principal clinical reasons for the medical decision to perform Caesarean section are situations involving danger to the unborn baby, failure to progress with the labour, breech (bottom-first) presentation, and cases where the mother has had a previous Caesarean section.
A week-by-week guide to your pregnancy Why is it necessary?
In an emergency situation there may not be time to fully discuss the options for Caesarean section, and it may be necessary as a lifesaving procedure.
When a vaginal (normal) delivery would pose significant risks to the mother or baby, the midwife or doctor will discuss the option of a Caesarean for delivery and the reasoning behind it.
Medical circumstances for a Caesarean include:
Severe pre-eclampsia (pregnancy-related high blood pressure)
The unborn baby is not receiving enough oxygen, but a quick vaginal delivery is not possible at that time
Labour is not progressing. Sometimes, despite all efforts, labour fails to move the baby sufficiently quickly down the birth canal (the channel through the exit of the womb, through the pelvis and out through the vagina) and the mother or baby is in distress
Labour has been induced (brought on) for some medical reason but the methods used to induce labour are failing to produce contractions effective enough to lead to a vaginal delivery.
It has been found that it would be highly unlikely that the baby will fit through the normal birth canal. For instance, an x-ray or scan may have shown that the baby has a head larger than the space in the pelvis through which it needs to travel; or the baby is in an abnormal position inside the womb such that it is unlikely to fit through the birth canal.
The placenta (afterbirth) is blocking the exit to the womb. This is called placenta praevia.
Some types of infection are an indication for a planned Caesarean section. These include active genital herpes, where a normal delivery would risk transferring the virus to the baby, and HIV infection in the mother, where a Caesarean section reduces the chances of the baby becoming infected with the condition.
Premature labour; sometimes an emergency Caesarean section will prevent possible trauma to the delicate head of the premature baby as it travels through the birth canal.
Very small babies are especially at risk of brain haemorrhage if they have a normal delivery.
A medical condition such as a heart problem that would put the mother at risk during the efforts of a normal delivery.
How is it performed?
Caesarean sections are usually done by making a horizontal incision (cut) in the lower abdomen along the bikini line which allows another horizontal incision to be made in the wall of the womb to deliver the baby. The low incision avoids weakening the womb muscles unnecessarily and allows the operation to be performed more than once on the same woman, if necessary.
The operation is performed under a general, spinal or epidural anaesthetic; the last two of which involve the injection of local anaesthetic into the fluid that surrounds the spine (dura mater). Local anaesthetics numb the body from the waist down and allow the mother to stay awake, but free of pain, during the operation. In emergencies a vertical abdominal and womb incision may be used.
Once the baby has been delivered through the incision made into the womb, the placenta soon separates and is also removed. The wall of the womb is swabbed and closed with stitches that will later safely dissolve. The abdominal wound is then closed in layers.
This is much the same as for any other abdominal operation except that the mother will usually be in a healthier state. She should be able to get out of bed fairly soon after the operation, and the hospital will give instructions about how soon she can resume normal activities.
In general it will take about six weeks for all the tissues to heal completely. However, before this time the basic activities of life such as caring for the baby and for herself should be possible, but the mother should avoid heavy lifting and may need help especially in the days immediately after the birth.
If the operation was done for a reason that will not have changed for the next delivery (for instance, if the mother has a very narrow birth canal), a Caesarean section will be necessary for each childbirth.
Also, the scar left on the womb will mean that any future labours will not be allowed to go on for too long, since this may risk the scar opening up, which would be dangerous.
Women who have had a previous Caesarean section are usually offered what is called a trial of scar, where they are left to go into labour in the usual way but are closely monitored. Any sign of a hold-up in the progress of labour then leads to an emergency Caesarean section.
There are health risks associated with caesarean section. Although a common procedure, it still represents major abdominal surgery, and any operation carries a certain amount of risk.
The main risks include:
infection of the wound
thrombosis (clot) formation in the legs, which can be dangerous if part of the clot breaks off and lodges in the lungs
temporary problems with bladder control, and
temporary breathing difficulties for the baby.
There is a very small risk of death during delivery for mother or baby. This risk is three times greater for caesarean section than for vaginal delivery, and the recovery period is generally longer.
It is important to remember that this procedure has saved the lives of many women and babies over the years. Where a danger to health has been identified, the risks of the caesarean section are usually far outweighed by the risks of not doing it, particularly in an emergency situation.
Interventions for suspected placenta praevia (Cochrane Review). Neilson JP. The Cochrane Library, Issue 1, 2002. http://www.update-software.com/abstracts/ab001998.htm
Lateral tilt for caesarean section (Cochrane Review). Wilkinson C, Enkin MW. The Cochrane Library, Issue 1, 2002. http://www.update-software.com/abstracts/ab000120.htm
Planned caesarean section for term breech delivery (Cochrane Review). Hofmeyr GJ, Hannah ME. The Cochrane Library, Issue 1, 2002. http://www.update-software.com/abstracts/ab000166.htm
Manual removal of placenta at caesarean section (Cochrane Review). Wilkinson C, Enkin MW. The Cochrane Library, Issue 1, 2002. http://www.update-software.com/abstracts/ab000130.htm
Interventions for reducing the risk of mother-to-child transmission of HIV infection (Cochrane Review). Brocklehurst P. The Cochrane Library, Issue 1, 2002. http://www.update-software.com/abstracts/ab000102.htm
Elective delivery in diabetic pregnant women (Cochrane Review). Boulvain M et al. The Cochrane Library, Issue 1, 2002. http://www.update-software.com/abstracts/ab001997.htm
Epidurals and labour. Bandolier 1998, issue 68, page 7. http://www.jr2.ox.ac.uk/bandolier/band68/b68-7.html
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