Definition

Delivery of a fetus via the abdominal route (laparotomy) requiring an incision into the uterus (hysterotomy).

Incidence

Cesarean section delivery is the second most common surgical procedure (behind male circumcision), accounting for around 20–25% of all deliveries in the UK and 32% in the USA.

Indications (Figure 67.1)

• Most indications for cesarean section are relative and rely on the judgment of the obstetric care provider.
  
• The most common indication for a primary (first) cesarean section is failure to progress in labor.
  
• Absolute cephalopelvic disproportion (CPD) refers to the clinical setting in which the fetus is too large relative to the bony pelvis to allow for vaginal delivery even under optimal circumstances. Relative CPD is where the fetus is too large for the bony pelvis because of malpresentation (brow, compound presentation).

Technical considerations

• Elective cesarean section can be performed after 39 weeks’ gestation without documenting fetal lung maturity.
  
• Regional is preferred over general analgesia.
  
• Routine use of prophylactic antibiotics will decrease the incidence of postoperative febrile morbidity.
  
• Skin incision may be Pfannenstiel (low transverse incision, muscle separating, strong, but limited exposure), midline vertical (offers the best exposure, but is weak), or paramedian (vertical incision lateral to rectus muscles, rarely used). Pfannenstiel incisions may rarely be modified to improve exposure by dividing the rectus muscles horizontally (Maylard incision) or lifting the rectus off the pubic bone (Cherney incision).
  
• Types of hysterotomy are reviewed in Figure 67.1.
  
• Elective surgery (such as myomectomy) should not be performed at the time of cesarean section, because of the risk of bleeding.