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Cesarean Section

Most common obstetrical operation – Episiotomy

Most often the incision is made in the lower uterine segment transversely, as described by Kerr. Occasionally, a low segment vertical incision, as described by low vertical, may be used. The classical incision is a vertical incision into the body of the uterus above the lower uterine segment and reaching the uterine fundus. This incision is seldom used today.





Central placenta previa


Adherent placenta

Previous LSCS

Severe degree of contracted pelvis


Previous two LSCS


Classical CS


Fetal distress (Most common)


Transverse/ oblique lie

Elderly primi/ grand multipara

Advanced carcinoma cervix



Preeclampsia / severe eclampsia


Indications for Classical Cesarean Section

  1. Lower segment fibroid
  2. Cervical cancer
  3. Placenta percreta
  4. Dense adhesions in lower pelvis
  5. Severe kyphoscoliotic pelvis

Establishment of Fetal Maturity Prior to Elective Repeat Cesarean Delivery

Fetal maturity may be assumed if one of the following criteria is met:

  1. Fetal heart sounds have been documented for 20 weeks by nonelectronic fetoscope or for 30 weeks by Doppler ultrasound.
  2. It has been 36 weeks since a positive serum or urine chorionic gonadotropin pregnancy test was performed by a reliable laboratory.
  3. An ultrasound measurement of crown-rump length, obtained at 6-11 weeks, supports current gestational age of 39 weeks or more.
  4. Clinical history and physical and ultrasound examination performed at 12-20 weeks support current gestational age of 39 weeks or more.

Merits and Demerits of Lower Segment Operation over Classical


Lower Segment



Operative field less bloody because of less vascularity

The wall is thin, and as such apposition is perfect lie

More bloody because of increased vascularity

The wall is thick, and coaptation of the margins is not perfect


Hemorrhage and shock-less

Peritonitis is less even in infected uterus because of perfect peritonization and, if occurs, localized to pelvis

Peritoneal adhesions and intestinal obstruction are less

Convalescence is better

Mortality is much lower


Chance of peritonitis is more in presence of

uterine sepsis

More because of imperfect peritonization

Relatively poor

Mortality is high

Wound healing

The scar is better healed because:

Perfect apposition of the thin margins

Chance of blood collecting in the

wound is less

The wound remains quiescent during

healing process

The scar is weak because:

Imperfect apposition because of thick margins

Chance of blood collection in the wound is

more, which hinders union

The wound is in a state of tension and due to

contraction and relaxation of the upper segment. As a result, the knots may slip or the

sutures may become lax


Chance of gutter formation is unlikely

as placental implantation is usually


Chance of gutter formation on the inner aspect

is likely because of (a) inclusion of the deciduas or (b) inadequate coaptation of the friable

inner part when the placenta is anteriorly


During future


Scar rupture is less (mainly in labor):


More risk of rupture (mainly in third

trimester): 4-9%


  1. Trial of scar is different from trial of labor.
  2. A patient of previous LSCS attempting a vaginal delivery is called a trial of scar (as the previous scar is put to trial).
  3. Trial of labor is indicated in mild-to-moderate CPD (with no prior uterine scar) and if it fails then the patient is delivered by LSCS, whereas trial of scar is absolutely contraindicated in CPD.
  4. The absolute risk of uterine rupture attributable to a trial of scar resulting in death or injury to the fetus is about 1 per 1000.

Recommendations of the ACOG Useful for the Selection of Candidates for Vaginal Birth after Cesarean Delivery

  1. No more than one prior low-transverse cesarean delivery
  2. Clinically adequate pelvis (no CPD)
  3. No other uterine scars or previous rupture
  4. Physician immediately available throughout active labor who is capable of monitoring labor and performing emergency cesarean delivery
  5. Availability of anesthesia and personnel for emergency cesarean delivery

Estimated Risks for Uterine Rupture in Women with a Prior Cesarean Delivery


Prior Uterine Incision

Estimated Rupture (%)


T shaped

Low vertical

Low transverse


4 – 9


0.2 - 1.5

  1. In women with uterine malformations who have undergone cesarean delivery, the risks for uterine rupture in a subsequent pregnancy may be as high as with a classical incision.
  2. Women who have previously sustained a uterine rupture are at increased risk of recurrence. Those with a rupture confined to the lower segment have been reported to have a 6% recurrence risk in subsequent labor, whereas those whose prior rupture included the upper uterus have a 32% recurrence risk.
  3. The rate of uterine rupture is increased nearly fivefold in women with two previous cesarean deliveries compared with that in those only with one-3.7% versus 0.8%.
  4. Any previous vaginal delivery, either before or following a cesarean birth, significantly improves the prognosis for a subsequent successful vaginal birth after cesarean delivery (VBAC).
  5. The success rate for a trial of scar depends to some extent on the indication for the previous cesarean delivery.
  6. Generally, about 60-80% of trials after prior cesarean birth result in vaginal delivery, with success being maximum if previous cesarean section was because of breech presentation.
  7. Women attempting VBAC who had no previous vaginal deliveries, the relative risk of uterine rupture is more than doubled when the birth weight is at least 4000 g.
  8. As maternal weight increases, the rate of VBAC success decreases.
  9. Any attempt to induce cervical ripening or to induce or augment labor increases the risk of uterine rupture in women undergoing a trial of scar.
  10. Use of oxytocin to induce or augment labor has been implicated in uterine ruptures in women attempting VBAC.
  11. The American Academy of Pediatrics and the ACOG have concluded that oxytocin may be used for both labor induction and augmentation with close patient monitoring, in women with a prior cesarean delivery undergoing a trial of scar.
  12. Several prostaglandin preparations commonly are employed for cervical ripening or labor induction. Recent evidence indicates that their use in women attempting VBAC substantively increases the risk of uterine rupture.
  13. The ACOG discourages the use of prostaglandin cervical ripening agents for the induction of labor in women with previous LSCS.

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