Caesarean section is the commonest major operation performed on women worldwide. Operative techniques used for caesarean section vary and some of these techniques have been evaluated through randomised trials.

Various abdominal incisions have been used for caesarean delivery. These include vertical (midline and paramedian) incisions and transverse incisions (Pfannenstiel, Maylard, Cherney, Joel‐Cohen). The type of incision used may depend on many factors including the clinical situation and the preferences of the operator.

Traditionally, vertical incisions were used for caesarean delivery (Myerscough 1982). Here the skin is incised in the midline between the umbilicus and the pubic symphysis. The rectus sheath and the peritoneum are incised in the midline. This area is the least vascular. Vertical subumbilical midline incisions have the presumed advantage of speed of abdominal entry and less bleeding. A vertical midline incision may be extended upwards if more space is required for access. Moreover, this incision may be used if a caesarean delivery is planned under local anaesthesia (WHO 2000). The disadvantages of a vertical midline incision include the greater risk of postoperative wound dehiscence and development of incisional hernia. The scar is cosmetically less pleasing. In the paramedian incision, the skin incision is made to one side of the midline (usually right). The anterior rectus sheath is opened under the skin incision. The belly of the underlying rectus abdominus muscle is then retracted laterally and the posterior rectus sheath and peritoneum are opened. Because of a shutter‐like effect, the stress on the scar is presumed to be less. The paramedian incision is reportedly stronger (Kendall 1991) than the midline scar but has no cosmetic advantage.

The lower abdominal transverse incision is adequate for the vast majority of caesarean operations. It has the advantages of cosmetic approval and minimal risk of postoperative disruption. The risks of incisional hernia are less than those following vertical incisions. However, transverse abdominal incisions usually involve more dissection and may require more surgical skills. Blood loss following dissection may be more. Also, this incision may be difficult to make under local anaesthesia, though successful techniques have been described (Sreenivasan 2006). Transverse incisions are difficult to extend if increased access is required.

The traditional lower abdominal incision for caesarean delivery is the incision described in 1900 by Pfannenstiel. Classically, this incision is located two fingers‐breadth above the pubic symphysis. Here the skin may be entered via a low transverse incision that curves gently upward, placed in a natural fold of skin (the 'smile' incision). After the skin is entered, the incision is rapidly carried through subcutaneous tissue to the fascia, which is then nicked on either side of the midline. The subcutaneous tissue is incised sharply with a scalpel. Once the fascia is exposed, it is incised transversely with heavy curved Mayo scissors. In the standard technique, the upper and then the lower fascial edges are next grasped with a heavy toothed clamp, such as a Kocher, and elevated. Under continuous tension, the fascia is then separated from the underlying muscles by blunt and sharp dissection. Once the upper and lower fascia have been dissected free, and any perforating vessel sutured or electrocoagulated, the underlying rectus abdominus muscles are separated with finger dissection. If the muscles are adherent, sharp dissection is necessary to separate them. The peritoneum is then opened sharply in the midline. The initial entry is then widened sharply with fine scissors exposing intraperitoneal contents.

When exposure is limited and additional space is required, the Maylard or Cherney modification may be used. In the Maylard procedure, the rectus abdominus muscles are divided either sharply or by electrocautery to allow greater access to the abdomen. However, this may result in a good deal of tissue damage and the underlying artery may be entered (O'Grady 1995). The Maylard incision length is usually longer than the Pfannenstiel incision. However, difficulty in delivery of the fetus is minimal with Pfannenstiel incisions measuring at least 15 cm in length (Ayers 1987), the length of a standard Allis clamp ‐ the Allis clamp test (Finan 1991). Shorter incisions may lead to difficulty in general exposure or delivery of the baby's head, or both.

In the Cherney procedure, the lower fascia is reflected exposing the tendinous attachment of the rectus abdominus muscle bodies to the fascia of the pubis (O'Grady 1995). The muscle is severed as low as possible and the proximal and distal ends suture ligated. One or both muscle attachments may be divided as required.

The Mouchel incision is similar to the Maylard incision. This transverse incision runs at the upper limit of the pubic hair and is thus lower than the Maylard incision. The muscles are divided above the openings of the inguinal canals (Mouchel 1981).

In the Pelosi technique (Wood 1999) for caesarean delivery, the skin is cut in a low transverse fashion with a knife. The subcutaneous tissues and fascia are incised with electrocautery. The upper aspect of the fascial incision is elevated and the median raphe (line or ridge) is dissected cephalad (towards the head) 2 cm to 3 cm using electrocautery. The rectus muscles are separated bluntly with fingers to identify the underlying peritoneum, which is then entered by inserting the index finger inwards and upwards or sharply as required. The peritoneum and muscles are stretched to the full extent of the skin. In this technique, no bladder flap is created before incision of the uterus (hysterotomy). After delivery of the baby, the obstetrician awaits spontaneous placental expulsion before closing the hysterotomy in one layer. The fascia is closed and the skin edges are approximated with staples. The Pelosi technique was reported to be associated with decreased operative time, decreased blood loss, improved patient outcome and decreased overall cost (Wood 1999).

Joel‐Cohen (Joel‐Cohen 1977) described a transverse skin incision, which was subsequently adapted for caesarean sections. This modified incision is placed about 3 cm below the line joining the anterior superior iliac spines. This incision is higher than the traditional Pfannenstiel incision. Sharp dissection is minimised. After the skin is cut, the subcutaneous tissue and the anterior rectus sheath are opened a few centimetres only in the midline. The rectus sheath incision may be extended laterally by blunt finger dissection (Wallin 1999) or by pushing laterally with slightly opened scissor tips, deep to the subcutaneous tissues (Holmgren 1999). The rectus muscles are separated by finger traction. If exceptional speed is required in the transverse entry, the fascia may be incised in the midline and both the fascia and subcutaneous tissue are rapidly divided by blunt finger dissection (Joel‐Cohen 1977). Stark used this incision for caesarean delivery along with single layer closure of the exteriorised uterus and non‐closure of the peritoneum. This package of surgical techniques for caesarean section used at the Misgav‐Ladach hospital, Jerusalem, has been popularised by Stark and others (Holmgren 1999). The reported advantages include shorter operating time (Darj 1999; Franchi 1998; Mathai 2002; Wallin 1999), less use of suture material (Bjorklund 2000), less intraoperative blood loss (Bjorklund 2000; Darj 1999; Wallin 1999), less postoperative pain (Darj 1999; Mathai 2002) and less wound infection (Franchi 1998) in the group undergoing caesarean by these techniques.

There are other Cochrane reviews on surgical techniques used at caesarean section, for example, techniques of repair of the uterine incision (Jokhan‐Jacob 2004), techniques for closure of the abdominal wall (Anderson 2004) and skin (Alderdice 2003) after caesarean section. This review focuses specifically on abdominal surgical incisions for caesarean section.