Chapter 23: Trial of Labor After Previous Cesarean Section

INTRODUCTION

Vaginal birth after cesarean (VBAC) was first reported in 1923 when Schell described the successful vaginal delivery of 34 infants to 23 mothers who had previous cesarean sections. A trial of labor (TOL) after cesarean section should be considered in every woman presenting for care, discussing the risks and benefits of VBAC while planning the birth. The success rate of TOL ranges from 50 to 86 percent.

The decision for a TOL after cesarean section is made together by the patient and her care provider, given appropriate setting for trial of VBAC. This discussion based on the indications should be well documented in the prenatal record.

PREREQUISITES

1. A previous lower segment transverse incision with no extension as documented by the hospital record and the operative note

2. The previous indication for cesarean section no longer exists

3. Cephalic presentation

4. No disproportion

5. No previous uterine rupture

6. Expectation of a normal labor and delivery

7. No medical or obstetric complications

8. Readily available blood, operating facilities, and in-house anesthesia

9. Patient understands and accepts the risks

CONTRAINDICATIONS

1. More than one previous cesarean section

2. Previous fundal or lower segment vertical incision or a T-shaped extension

3. Previous hysterotomy or myomectomy entering the uterine cavity

4. Previous uterine rupture

5. Unknown incision

6. Advice by the surgeon who did the first operation against a TOL

7. Abnormal presentation, such as brow, breech, or transverse lie

8. Placenta previa

9. Contracted pelvis or disproportion

10. Recurring indication

11. Urgent medical or obstetric indication for delivery

12. Unavailability of blood or refusal of patient to accept blood transfusion

13. Operating room away from the delivery suite; inability to perform immediate cesarean section

14. Patient's refusal to undergo a TOL

GUIDELINES FOR MANAGEMENT

1. Ideally, the onset of labor is spontaneous

2. The patient should come to hospital immediately if:

   1. She thinks that labor has begun

   2. The membranes have ruptured

   3. There is vaginal bleeding

3. Upon admission to the hospital:

   1. The maternal–fetal status is evaluated

   2. An intravenous infusion is set up

   3. Blood is cross-matched and available

   4. Electronic fetal monitoring is established

4. During labor:

   1. The fetal heart is monitored by continuous electronic fetal monitoring

   2. The uterine contractions are assessed by an electronic system or by a hand on the abdomen almost continually. Placement of an intrauterine pressure catheter can also be considered

   3. Maternal vital signs are checked every 15 minutes

   4. The patient is never left unattended

   5. The physician must be on the labor floor at all times

   6. Labor should progress normally

5. Although the use of oxytocin to stimulate labor is not contraindicated, it must be used with great care and only in selected cases. There is insufficient evidence about the safety of prostaglandins in TOL after cesarean section

6. If labor induction is indicated, mechanical methods using amniotomy or Foley catheters are preferable

7. Misoprostol is contraindicated for cervical ripening with previous cesarean section. All prostaglandin agents are associated with an increased risk of ...