Vaginal Birth after C-sectionVaginal Birth after C-section
Dr M.Rashidi
History of C-section in U.S.History of C-section in U.S.
1916: “Once a cesarean, always a cesarean”
History of VBACHistory 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%)
Early data: Pro-Trial of laborEarly data: Pro-Trial of labor (TOL) (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)
More recent concerns about VBACMore 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
Paradigm shift on C-sectionsParadigm 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
New attitudes toward C-sectionNew 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
Advantages of VBACAdvantages 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
Disadvantages of attempting VBACDisadvantages 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
Uterine ruptureUterine rupture
Nonsurgical complete disruption of all uterine layers which usually leads to bleeding and extrusion of all or part of the fetal-placental unit.
Risk factors for uterine rupture Risk factors for uterine rupture during TOLduring TOL
• Maternal age > 30• Fetal weight > 4000 grams• Induction of labor• No previous h/o vaginal delivery
Risk factors for uterine rupture Risk factors for uterine rupture during TOLduring 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 (0.2 - 1.5%)
Clinical manifestations of Clinical manifestations of uterine ruptureuterine rupture
• Fetal bradycardia• Variable or late decelerations• Maternal hypotension/shock• Vaginal bleeding• Cessation of contractions• Loss of station/fetal presenting part• Abdominal pain
Complications of uterine ruptureComplications 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
ACOG-approved VBAC candidatesACOG-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
Absolute contraindications Absolute contraindications to VBACto VBAC
• Prior transfundal myomectomy • Prior classical or T-shaped uterine
incision• Inability to perform emergency C-section
Relative contraindications to VBAC Relative contraindications to VBAC (more research needed)(more research needed)
• Unknown uterine scar (most will be LTCS)• Low-vertical uterine incision• Breech presentation• Twin gestation• Postterm pregnancy• Suspected macrosomia
Success rates for attempted VBACSuccess 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)
Induction of labor in Induction of labor in attempted VBACattempted 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 - 0.52%• Induction without prostaglandins - 0.72%• Induction with prostaglandins – 2.45%
Other issues in attempted VBACOther 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
ConclusionsConclusions
• 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%
