What are the operative steps and relevant anatomy for performing a lower‑segment caesarean section (LSCS) in a term pregnant woman?

Lower Segment Caesarean Section (LSCS): Operative Steps and Anatomy

Pre-operative Preparation

Administer intravenous first-generation cephalosporin within 60 minutes before skin incision, and add azithromycin if the patient is in labor or has ruptured membranes. 1

• Prepare the abdominal skin with chlorhexidine-alcohol solution, which is superior to aqueous povidone-iodine. 1
• Apply povidone-iodine vaginal preparation to reduce post-cesarean infection rates. 1
• Give oral paracetamol pre-operatively for multimodal analgesia. 1
• Position the patient supine with left uterine displacement after 20 weeks gestation to prevent aortocaval compression. 1
• Use forced-air warming devices, warm intravenous fluids, and raise operating room temperature to prevent peri-operative hypothermia. 1

Anesthesia

Regional anesthesia (spinal or epidural) is strongly preferred over general anesthesia for LSCS. 1

• Add 50–100 µg intrathecal morphine (or up to 300 µg diamorphine) to the spinal anesthetic for optimal postoperative pain control. 1
• Ensure adequate maternal oxygenation and optimal uteroplacental perfusion throughout the procedure. 2
• If general anesthesia is required, use rapid sequence induction with the patient in the "ramped" position to optimize laryngoscopic view. 3

Surgical Steps and Anatomical Considerations

1. Abdominal Incision

Perform a Joel-Cohen (modified Misgav-Ladach) transverse incision, which reduces postoperative pain and improves outcomes compared with a Pfannenstiel incision. 1

• Make a straight transverse skin incision 3 cm below the line joining the anterior superior iliac spines. 1
• The incision is placed in the suprapubic region, typically at the level of the pubic hairline. 1

2. Fascial and Muscle Layer

Use blunt dissection to open the fascia transversely; this technique is associated with less postoperative pain. 1

• After opening the fascia, separate the rectus muscles bluntly in the midline. 1
• The rectus abdominis muscles are separated rather than cut, preserving their integrity. 1

3. Peritoneal Entry

• Enter the peritoneal cavity bluntly or sharply. 1
• Do not create a bladder flap when possible; its omission improves postoperative pain scores. 1
• The bladder lies anteriorly and inferiorly; if a bladder flap is created, the vesicouterine peritoneum is incised and the bladder is dissected downward. 1

4. Uterine Incision (Hysterotomy)

Make a transverse incision in the lower uterine segment and expand it bluntly to lessen intra-operative blood loss. 1

• The lower uterine segment is the non-contractile portion of the uterus between the bladder reflection and the upper contractile corpus. 4
• Make a small transverse incision (approximately 2-3 cm) in the lower segment with a scalpel. 1
• Extend the incision laterally using blunt dissection (fingers or scissors) in a curved fashion to avoid the uterine vessels at the lateral margins. 1
• Avoid vertical extensions (T or J extensions) when possible, as they are associated with excessive blood loss, broad ligament hematomas, cervical lacerations, and uterine artery lacerations. 5

5. Delivery of the Infant

• Deliver the infant's head through the hysterotomy, applying gentle fundal pressure if needed. 1
• Suction the infant's mouth and nose after delivery of the head. 2
• Delay cord clamping for at least 1 minute at term delivery (at least 30 seconds for preterm delivery). 2, 1
• Routine suctioning of the airway or gastric aspiration should be avoided unless there are symptoms of an obstructed airway. 2

6. Intra-operative Medications (After Delivery)

• Administer intravenous paracetamol if not given pre-operatively. 1
• Give intravenous NSAIDs for multimodal analgesia. 1
• Administer intravenous dexamethasone for pain control and anti-emetic prophylaxis (use caution in patients with glucose intolerance). 1

7. Uterine Closure

Close the hysterotomy in two continuous layers in situ (without exteriorizing the uterus); this lowers the risk of uterine rupture in later pregnancies and reduces postoperative pain. 1

• The first layer incorporates the full thickness of the myometrium. 1
• The second layer provides hemostasis and inverts the first layer. 1
• Exteriorization of the uterus increases postoperative pain and should be avoided. 1
• Two-layer closure is associated with lower rates of uterine rupture in subsequent pregnancies compared to single-layer closure. 1

8. Peritoneal and Fascial Closure

Do not close the peritoneum (visceral or parietal); high-quality evidence shows no benefit and a reduction in postoperative pain and operative time. 1

• Peritoneal non-closure does not increase adhesion formation or other complications. 1
• Do not re-approximate the rectus muscles; this further decreases postoperative pain. 1
• Close the fascial layer with a continuous absorbable suture. 1

9. Subcutaneous Tissue and Skin

• In women with ≥2 cm of subcutaneous tissue, reapproximate that tissue layer to reduce wound infection and separation. 2, 1, 3
• Close the skin with subcuticular suture rather than staples; this reduces wound separation compared to staples removed at 4 days. 1

Post-operative Analgesia

Continue regular oral or intravenous paracetamol and NSAIDs; they act synergistically with intrathecal morphine and should not be omitted. 1

• Reserve opioid administration for rescue analgesia when other modalities fail or are contraindicated. 1
• Apply abdominal binders to improve comfort and support. 1
• Consider transcutaneous electrical nerve stimulation (TENS) as an adjunctive analgesic technique. 1

Critical Pitfalls to Avoid

• Never delay antibiotic administration until after cord clamping—this outdated practice increases maternal infection risk. 1
• Avoid closing the peritoneum—this increases operative time without any benefit and may increase postoperative pain. 1
• Do not use staples for skin closure if they will be removed at 4 days—subcuticular sutures reduce wound complications. 1
• Avoid gabapentinoids, intravenous ketamine, and neuraxial clonidine/dexmedetomidine—these have limited evidence and concerning side-effect profiles. 1
• Do not omit basic analgesics (paracetamol and NSAIDs) when using intrathecal morphine—they work synergistically and provide superior pain control. 1
• Avoid vertical (classical) uterine incisions unless absolutely necessary (e.g., poorly developed lower segment, dense adhesions, placenta previa/accreta)—they are associated with higher risk of uterine rupture in subsequent pregnancies and contraindicate trial of labor after cesarean. 4, 5

Special Considerations for High-Risk Patients

• In women with BMI >40, establish intravenous access early and alert operating room staff if weight exceeds 120 kg to ensure adequate staffing and equipment. 2, 3
• Apply mechanical thromboprophylaxis using pneumatic compression devices before cesarean section when possible, and consider weight-based dosing of pharmacologic thromboprophylaxis in women with class III obesity. 2, 3
• All women with BMI ≥30 should have active management of the third stage of labor due to increased risk of postpartum hemorrhage. 2