1. Vaginal Birth after C-section
Dr M.Rashidi

2. History of C-section in U.S.
1916: “Once a cesarean, always a cesarean”

3. History of VBAC
1980: NIH panel begins to encourage trial of labor (TOL) for women with h/o C-section
1981 VBAC rate: 3%
1990: US Public Health Service propose goal of C-section rate of 15% (and VBAC rate of 35%)

4. Early data: Pro-Trial of labor (TOL)
Rosen (1991): No significant difference in maternal mortality rate found for ERCS vs. TOL. Failed TOL results in no major risk.
Flamm (1994): TOL pts shown to have shorter hospitalizations, fewer postpartum transfusions, and fewer postpartum fevers.
Hook (1997): Infants born after TOL developed fewer neonatal respiratory problems (ie: TTN) compared to those born by elective repeat C-section (ERCS)

5. More recent concerns about VBAC
1999: NEJM editorial pointed out increasing rates of uterine rupture as VBAC rates have increased
1999: Use of Misoprostol for cervical ripening/labor induction (vs spontaneous labor) found to bring almost 30-fold increase in uterine rupture rate
2001: Use of prostaglandins for cervical ripening/labor induction (vs spontaneous labor) found to carry 5-fold increased risk of uterine rupture

6. Paradigm shift on C-sections
Some OB/Gyns and patients are now questioning whether vaginal births should always be the goal
- Some advocate elective C-section as better in long run, with decreased rates of pelvic dysfunction and urinary & fecal incontinence

7. New attitudes toward C-section
Extreme example: Brazil - where the C-section rate is currently around 25% in public hospitals and around 98% for women who have access to private medicine
- Sign of status (Middle class & up)
- More convenient for MDs (quicker)
- MDs receive little training in difficult vaginal delivery

8. Advantages of VBAC Lower rates of maternal morbidity
Postpartum fever
Wound infection
Blood transfusion
Hysterectomy
Maternal discomfort
Length of stay
Fewer cases of neonatal respiratory distress

9. Disadvantages of attempting VBAC
Increased rates of uterine rupture
- 0.2% for ERCS vs 0.4% for TOL
Increased rates of perinatal death
- 0.3% for ERCS vs 0.6% for TOL
Induction with prostaglandins or misoprostol contraindicated

10. Uterine rupture
Nonsurgical complete disruption of all uterine layers which usually leads to bleeding and extrusion of all or part of the fetal-placental unit.

11. Risk factors for uterine rupture during TOL
Maternal age > 30
Fetal weight > 4000 grams
Induction of labor
No previous h/o vaginal delivery

12. Risk factors for uterine rupture during TOL
Previous C-section due to dystocia
Type of C-section
Classical incision (4 - 9%)
T-shaped incision (4 - 9%)
Low vertical incision (1 - 7%)
Low transverse incision ( %)

13. Clinical manifestations of uterine rupture
Fetal bradycardia
Variable or late decelerations
Maternal hypotension/shock
Vaginal bleeding
Cessation of contractions
Loss of station/fetal presenting part
Abdominal pain

14. Complications of uterine rupture
Maternal mortality very rare
Fetal morbidity/mortality more common
- Fetal asphyxia occurs in 5%
- Perinatal morbidity/mortality highest when fetus extruded into abdomen or when interval between bradycardia & delivery exceeded 18 minutes

15. ACOG-approved VBAC candidates
Maximum of 2 previous LTCS
Vertex fetal presentation
No other uterine scars
No history of previous uterine rupture
Clinically adequate pelvis
Ability to perform emergency C-section

16. Absolute contraindications to VBAC
Prior transfundal myomectomy
Prior classical or T-shaped uterine incision
Inability to perform emergency C-section

17. Relative contraindications to VBAC (more research needed)
Unknown uterine scar (most will be LTCS)
Low-vertical uterine incision
Breech presentation
Twin gestation
Postterm pregnancy
Suspected macrosomia

18. Success rates for attempted VBAC
50-70% of attempted VBACs result in successful vaginal birth
Factors making VBAC success more likely:
- Previous vaginal delivery
- Favorable cervix/Bishop score
- Spontaneous onset of labor
- Breech presentation as reason for previous C-section (85% success)

19. Induction of labor in attempted VBAC
Spontaneous labor is most successful & has lowest rate of uterine rupture
Misoprostol should never be used
Rates of rupture shown in U.W. study (2001 NEJM) differed by method of induction:
Spontaneous labor %
Induction without prostaglandins %
Induction with prostaglandins – 2.45%

20. Other issues in attempted VBAC
Amnioinfusion considered safe
Epidural anesthesia is considered safe
Continuous EFM recommended throughout labor
Ultrasound or MR imaging of lower uterine segment may prove helpful in predicting risk of uterine rupture

21. Conclusions At least 50% of attempted VBACs are successful
Absolute risk from TOL is small
Uterine rupture 0.2 – 1.5%
Hysterectomy 0.1 – 0.2%
Perinatal death 0.2%