Caesarean Section

Caesarean section (CS) is the delivery of a foetus, placenta and membranes through incisions in the abdominal wall (laparotomy) and uterine wall (hysterotomy) after the age of viability. It is among the commonest major operations performed on women worldwide, and for NEET PG the high-yield zones are the type of uterine incision (classical vs lower-segment), abdominal incisions (Pfannenstiel vs Joel-Cohen), indications, VBAC/trial of scar criteria, and antibiotic prophylaxis.

Definition and terminology

The term derives most likely from the Latin caedere ("to cut"), not from Julius Caesar (who could not have been delivered abdominally as his mother survived). Key terms:

• Primary CS – first caesarean in a woman.
• Repeat CS – CS in a woman with a previous caesarean.
• Elective (planned) CS – done before onset of labour for a known indication.
• Emergency CS – done after labour begins or when an acute maternal/foetal indication arises.
• Perimortem (resuscitative) CS – done within ~4–5 minutes of maternal cardiac arrest to aid maternal resuscitation by relieving aortocaval compression.

High-yield: The optimal time to deliver in a perimortem caesarean is within 4 minutes of maternal cardiac arrest, with delivery completed by 5 minutes ("4-minute rule") to maximise both maternal and neonatal survival.

Classification of urgency (RCOG / NICE categories)

The RCOG four-category classification is frequently tested as it standardises the decision-to-delivery interval (DDI).

Category	Definition	Target decision-to-delivery interval
1	Immediate threat to life of woman or foetus (e.g. cord prolapse, uterine rupture, prolonged bradycardia)	≤ 30 minutes
2	Maternal/foetal compromise, not immediately life-threatening	~ 30–75 minutes
3	No compromise but needs early delivery	Planned, no urgency
4	Elective – at a time to suit woman/team	Scheduled

High-yield: Category-1 CS target DDI is 30 minutes; this is a classic single-best-answer recall.

Types of uterine incision (classical vs lower-segment)

This is the single most examined comparison.

Feature	Lower-segment CS (LSCS)	Classical CS
Incision site	Transverse, in lower uterine segment	Vertical, in upper (contractile) segment of body
Frequency	Operation of choice (>95%)	Rare, reserved
Blood loss	Less	More (vascular upper segment)
Healing & scar strength	Strong, heals well	Weaker scar
Risk of scar rupture in next pregnancy	~0.2–0.7% (silent dehiscence, usually in labour)	~4–9% (can rupture before labour, in 3rd trimester)
Peritonisation / adhesions	Covered by visceral peritoneum; fewer adhesions	More adhesions, bowel/omentum
VBAC allowed later?	Yes (eligible)	No (contraindicated)
Post-op ileus / morbidity	Lower	Higher

Indications for a CLASSICAL caesarean (must-know)

A classical (upper-segment vertical) incision is chosen when access to the lower segment is poor or dangerous:

1. Lower segment poorly formed / inaccessible – very preterm delivery, lower-segment fibroid, dense adhesions.
2. Anterior placenta praevia with large vessels over the lower segment (to avoid cutting through the placenta).
3. Transverse lie with back down (impacted shoulder) / abnormal lie where lower-segment delivery is unsafe.
4. Constriction ring / Bandl's ring or contracted lower segment.
5. Postmortem / perimortem CS – speed of access.
6. Some cases of cervical carcinoma (to avoid the friable lower segment), conjoined twins, certain fetal anomalies.
7. Densely adherent bladder from previous surgery.

High-yield: A previous classical scar is an absolute contraindication to VBAC and is an indication for elective repeat CS at ~36–37 weeks because of the risk of rupture before labour.

Abdominal (skin) incisions — Pfannenstiel vs Joel-Cohen

Feature	Pfannenstiel	Joel-Cohen (used in Misgav-Ladach)
Level	~2–3 cm above pubic symphysis, curved	~3 cm higher, straight transverse
Rectus sheath	Opened separately, sheath dissected off recti	Minimal sharp dissection; mostly blunt finger separation
Tissue handling	More sharp dissection	Blunt, "tear" technique → less bleeding
Speed	Slower	Faster (shorter operating & delivery time)
Outcomes	More post-op analgesia needs	Less febrile morbidity, less blood loss, quicker recovery

High-yield: The Joel-Cohen incision (core of the Misgav-Ladach method) is associated with shorter operating time, less blood loss, less postoperative fever and faster recovery than Pfannenstiel.

High-yield: A midline vertical (sub-umbilical) skin incision is used when speed is paramount (category-1 emergency), gross obesity, or when wide access is needed (e.g. suspected malignancy, classical CS).

A classic teaching mnemonic for the layers traversed in a Pfannenstiel-LSCS, outside-in: "Skin → Superficial fascia (Camper + Scarpa) → Rectus sheath → Recti (separated) → Transversalis fascia → Parietal peritoneum → Uterovesical fold → Lower uterine segment."

Indications for caesarean section

Broadly grouped (the examiner usually wants you to separate absolute from relative):

Maternal/absolute & strong indications

• Central placenta praevia (major-degree, especially type III/IV)
• Cephalopelvic disproportion / contracted pelvis
• Obstructed labour, prior classical CS, ≥2 previous LSCS
• Active genital herpes, HIV with high viral load (to reduce vertical transmission)
• Vaginal/cervical obstruction (large fibroid, carcinoma cervix)
• Previous reconstructive pelvic/perineal surgery, vesicovaginal fistula repair

Foetal

• Non-reassuring foetal status (pathological CTG, abnormal Doppler)
• Cord prolapse with live foetus, not delivering vaginally soon
• Malpresentations: transverse lie, brow, breech (selected), footling breech
• Severe growth restriction with compromise

Combined / obstetric

• Abruptio placentae with live foetus and no imminent vaginal delivery
• Failed induction, failure to progress (commonest indication overall)
• Two or more previous caesareans, prior uterine rupture

High-yield: Worldwide, the commonest indications grouped are (1) previous CS, (2) dystocia/failure to progress, (3) malpresentation (mainly breech), (4) non-reassuring foetal status. "Failure to progress" is the most common primary indication.

Trial of labour after caesarean (TOLAC) / VBAC

VBAC = vaginal birth after caesarean. TOLAC is the attempt; VBAC is a successful vaginal birth.

Selection criteria favouring VBAC

1. One (occasionally two, with counselling) prior LSCS (transverse).
2. Prior non-recurrent indication (e.g. breech, foetal distress) rather than recurrent (e.g. contracted pelvis).
3. Singleton, cephalic presentation.
4. Spontaneous onset of labour at term.
5. Adequate clinical pelvis, estimated foetal weight not excessive.
6. Previous successful vaginal delivery (strongest predictor of success).
7. Facilities for immediate emergency CS (anaesthesia, theatre, blood) available.
8. Inter-delivery interval ≥ 18–24 months.

Contraindications to VBAC

• Previous classical / inverted-T / J incision or extensive uterine surgery (e.g. myomectomy entering cavity).
• Previous uterine rupture.
• Two or more prior CS where individual unit policy disallows, or any usual CS indication still present (praevia, CPD).
• Patient declines / no facility for emergency CS.

High-yield: The single best predictor of successful VBAC is a prior successful vaginal delivery. Overall VBAC success in well-selected women is ~60–80%.

High-yield: Prostaglandins (especially misoprostol) are avoided for induction in a scarred uterus because they markedly increase rupture risk. Mechanical methods/oxytocin with caution are preferred if induction is needed.

Sign of impending/established scar rupture flow: Scar tenderness / pain → fetal heart rate abnormality (commonest first sign) → loss of station / receding presenting part → vaginal bleeding & maternal tachycardia, hypotension → cessation of contractions.

High-yield: Abnormal CTG / sudden foetal bradycardia is the most common and earliest reliable sign of uterine scar rupture — not pain, not bleeding.

Anaesthesia

• Regional (spinal or epidural) is preferred for most caesareans — safer than general anaesthesia, avoids failed intubation/aspiration, allows maternal bonding.
• Spinal is the commonest for elective CS (rapid, dense block).
• General anaesthesia reserved for true emergencies needing immediate delivery, regional contraindication (coagulopathy, refusal, sepsis at site), or failed regional.

High-yield: The leading anaesthetic causes of maternal death historically are failed intubation and aspiration (Mendelson's syndrome) under GA — hence the strong shift to regional anaesthesia. Give antacid prophylaxis (sodium citrate ± H₂-blocker/PPI, metoclopramide).

Surgical technique — stepwise approach

1. Consent, group & save/cross-match, IV access, antacid prophylaxis, indwelling catheter.
2. Antibiotic prophylaxis BEFORE skin incision (see below).
3. Position with 15° left lateral tilt to avoid aortocaval compression.
4. Abdominal incision (Pfannenstiel/Joel-Cohen, or midline).
5. Open layers down to peritoneum; deflect bladder via uterovesical fold.
6. Transverse lower-segment uterine incision, extended by blunt (finger) traction (less bleeding than sharp extension).
7. Deliver head/breech; deliver placenta — spontaneous delivery with cord traction preferred over manual removal (less blood loss/endometritis).
8. Uterotonics: oxytocin bolus (slow IV) ± infusion to contract the uterus.
9. Close uterus in two layers (single-layer closure debated for scar integrity).
10. Check haemostasis, swab/instrument count, close sheath, skin.

High-yield: Routine closure of the parietal and visceral peritoneum is NOT recommended (no peritonisation) — it reduces operating time and post-operative pain without increasing adhesions.

Antibiotic prophylaxis (high-yield)

• A single dose of a first-generation cephalosporin (e.g. cefazolin 1–2 g IV) is the drug of choice.
• Timing: 15–60 minutes BEFORE skin incision (not after cord clamping) — reduces maternal infectious morbidity (endometritis, wound infection) without harming the neonate.
• Add azithromycin to cefazolin for women in labour or with ruptured membranes undergoing CS (reduces endometritis further).
• Penicillin-allergic: clindamycin + gentamicin.

High-yield: Pre-incision prophylactic antibiotics (cefazolin) given before skin incision are superior to post-cord-clamp dosing — a frequently tested NEET PG fact.

Complications

Intra-operative

• Haemorrhage (atony, extension of incision into uterine vessels/broad ligament).
• Bladder, ureteric or bowel injury (higher with previous CS/adhesions).
• Difficult delivery of impacted head; extension of incision (T/J) → weak scar.

Immediate post-operative

• Primary postpartum haemorrhage, anaesthetic complications.
• Venous thromboembolism (CS is a major VTE risk → thromboprophylaxis).
• Paralytic ileus, atelectasis.

Late / infective

• Endometritis (commonest infectious complication), wound infection, UTI.
• Wound dehiscence, scar haematoma.

Future-pregnancy / long-term

• Scar rupture / dehiscence, increased repeat CS.
• Placenta praevia and placenta accreta spectrum — risk rises with each successive CS; the combination "previous CS + anterior placenta praevia" strongly predicts accreta.
• Caesarean scar (niche/isthmocele) → abnormal bleeding, scar ectopic pregnancy, secondary infertility.
• Adhesions, chronic pain.

High-yield: The risk of placenta accreta spectrum rises steeply with the number of prior caesareans, especially when a placenta praevia overlies the previous scar — a favourite linkage question.

Key differentials / decision contrasts

The "differentials" here are decision points the examiner contrasts:

• CS vs instrumental vaginal delivery in second stage with foetal distress (station, dilatation, operator skill decide).
• Classical vs LSCS (table above) — choice driven by access to lower segment.
• Elective repeat CS vs TOLAC — based on type of prior scar, indication, patient preference, facilities.
• Placenta praevia vs abruptio as the haemorrhagic indication (painless vs painful bleeding).

Recently asked / exam angle

• "Earliest sign of uterine scar rupture?" → Abnormal CTG / foetal bradycardia.
• "Absolute contraindication to VBAC?" → Previous classical caesarean (or prior rupture).
• "Best predictor of successful VBAC?" → Previous successful vaginal delivery.
• "Timing of prophylactic antibiotic in CS?" → 15–60 min before skin incision; cefazolin.
• "Incision in Misgav-Ladach technique?" → Joel-Cohen.
• "Drug avoided for induction in scarred uterus?" → Misoprostol/prostaglandins.
• "Target decision-to-delivery interval in category-1 CS?" → 30 minutes.
• "Layer NOT closed routinely in CS?" → Peritoneum (no peritonisation).
• "Most common infectious complication after CS?" → Endometritis.
• "Which placental complication increases with number of CS?" → Placenta accreta spectrum.
• "Uterotonic of choice immediately after delivery of baby in CS?" → Oxytocin.
• "Perimortem CS time limit?" → Within 4–5 minutes of maternal arrest.

Rapid revision

1. LSCS = operation of choice; transverse lower-segment incision, strong scar, VBAC-eligible.
2. Classical CS = vertical upper-segment, higher rupture risk before labour, contraindicates VBAC.
3. Joel-Cohen (Misgav-Ladach) incision → faster, less bleeding, less fever than Pfannenstiel.
4. Midline vertical skin incision for speed/obesity/wide access.
5. Cefazolin 15–60 min before skin incision; add azithromycin if in labour/ROM.
6. Earliest sign of scar rupture = foetal heart abnormality/bradycardia, not pain.
7. Best VBAC predictor = prior successful vaginal delivery; success ~60–80%.
8. Misoprostol contraindicated for induction in a scarred uterus.
9. Regional > general anaesthesia; GA deaths from failed intubation & Mendelson's aspiration.
10. Peritoneum is NOT re-approximated (no peritonisation) — saves time, less pain.
11. Placenta accreta risk rises with each CS, especially praevia over old scar.
12. Category-1 CS decision-to-delivery target = 30 minutes; perimortem CS within 4 minutes.