A caesarean section involves a surgical operation to deliver the baby via an incision in the abdomen and uterus. It can be a planned procedure (elective caesarean) or performed where there are acute problems during the antenatal period or labour (emergency caesarean).
Elective caesarean section involves a planned date on which a woman will come in for delivery. It is usually performed under a spinal anaesthetic, and is considered generally a very safe and routine procedure. Usually these are performed after 39 weeks gestation.
Indications for elective caesarean include:
- Previous caesarean
- Symptomatic after a previous significant perineal tear
- Placenta praevia
- Vasa praevia
- Breech presentation
- Multiple pregnancy
- Uncontrolled HIV infection
- Cervical cancer
There are four categories of emergency caesarean section:
- Category 1: There is an immediate threat to the life of the mother or baby. Decision to delivery time is 30 minutes.
- Category 2: There is not an imminent threat to life, but caesarean is required urgently due to compromise of the mother or baby. Decision to delivery time is 75 minutes.
- Category 3: Delivery is required, but mother and baby are stable.
- Category 4: This is an elective caesarean, as described above.
The most commonly used skin incision is a transverse lower uterine segment incision. There are two possible incisions:
- Pfannenstiel incision is a curved incision two fingers width above the pubic symphysis
- Joel-cohen incision is a straight incision that is slightly higher (this is the recommended incision)
A vertical incision down the middle of the abdomen is also possible, but this is rarely used. It may be used in certain circumstances, such as very premature deliveries and anterior placenta praevia.
Blunt dissection is used, after the initial incision with a scalpel, to separate the remaining layers of the abdominal wall and uterus. Blunt dissection involves using fingers, blunt instruments and traction to tear the tissues apart, rather than to cut them with sharp tools such as a scalpel. This results in less bleeding, shorter operating times and less risk of injury to the baby.
The layers of the abdomen that need to be dissected during a caesarean are:
- Subcutaneous tissue
- Fascia / rectus sheath (the aponeurosis of the transversus abdominis and external and internal oblique muscles)
- Rectus abdominis muscles (separated vertically)
- Vesicouterine peritoneum (and bladder) – the bladder is separated from the uterus with a bladder flap
- Uterus (perimetrium, myometrium and endometrium)
- Amniotic sac
The baby is delivered by hand with the assistance of pressure on the fundus. Forceps may be used if necessary.
The uterus is closed inside the abdomen using two layers of sutures. Exteriorisation (taking the uterus out of the abdomen) is avoided if possible. The abdomen and skin are then closed.
A spinal anaesthetic involves giving an injection of a local anaesthetic (such as lidocaine) into the cerebrospinal fluid at the lower back. This blocks the nerves from the abdomen downwards.
A spinal anaesthetic is safer, and leads to fewer complications and a faster recovery than a general anaesthetic. The potential problems are that the patient remains awake (most patients tolerate this well, but some prefer to be asleep), and it takes longer to initiate than a general anaesthetic.
Risks associated with having an anaesthetic:
- Allergic reactions or anaphylaxis
- Urinary retention
- Nerve damage (spinal anaesthetic)
- Haematoma (spinal anaesthetic)
- Sore throat (general anaesthetic)
- Damage to the teeth or mouth (general anaesthetic)
Elective caesarean sections are generally considered a very safe and routine procedure. Emergency caesarean sections have a higher risk of complications, as they are usually performed in less controlled settings and for more acute indications (e.g. fetal distress). There are a long list of potential complications, as with any surgery.
Measures to reduce the risks during caesarean section are:
- H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) before the procedure
- Prophylactic antibiotics during the procedure to reduce the risk of infection
- Oxytocin during the procedure to reduce the risk of postpartum haemorrhage
- Venous thromboembolism (VTE) prophylaxis with low molecular weight heparin
There is a risk of aspiration pneumonitis during caesarean section, caused by acid reflux and aspiration during the prolonged period lying flat. H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) are given before the procedure to reduce the risk of this happening.
Generic surgical risks:
- Venous thromboembolism
Complications in the postpartum period:
- Postpartum haemorrhage
- Wound infection
- Wound dehiscence
Damage to local structures:
- Blood vessels
Effects on the abdominal organs:
Effects on future pregnancies:
- Increased risk of repeat caesarean
- Increased risk of uterine rupture
- Increased risk of placenta praevia
- Increased risk of stillbirth
Effects on the baby:
- Risk of lacerations (about 2%)
- Increased incidence of transient tachypnoea of the newborn
Vaginal Birth After Caesarean (VBAC)
It is possible to have a vaginal birth after a previous caesarean section, provided the cause of the caesarean is unlikely to recur. An assessment of the likelihood of success should be made in each case. Success rate of VBAC is around 75%. Uterine rupture risk in VBAC is about 0.5%.
- Previous uterine rupture
- Classical caesarean scar (a vertical incision)
- Other usual contraindications to vaginal delivery (e.g. placenta praevia)
Having a caesarean section is likely to lead to a period of reduced mobility. Women should have a VTE risk assessment performed to determine the type and duration of VTE prophylaxis (follow local guidelines). Prophylaxis for VTE involves:
- Early mobilisation
- Anti-embolism stockings or intermittent pneumatic compression of the legs
- Low molecular weight heparin (e.g. enoxaparin)
Last updated September 2020