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Vaginal Birth after Caesarean (VBAC)

Vaginal Birth after Caesarean (VBAC). Max Brinsmead PhD FRANZCOG September 2010. VBAC – The Controversy. “Once a Caesarean always a Caesarean” Edwin Cragin – 1916 In an era of classical CS Designed to prevent unnecessary primary CS

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Vaginal Birth after Caesarean (VBAC)

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  1. Vaginal Birth after Caesarean(VBAC) Max Brinsmead PhD FRANZCOG September 2010

  2. VBAC – The Controversy • “Once a Caesarean always a Caesarean” • Edwin Cragin – 1916 • In an era of classical CS • Designed to prevent unnecessary primary CS • For 60 years “Trial of (lower segment) scar” was standard British practice • But repeat CS more common in the US • Controversy broke out again in 2000 • And it was all about fetal risks

  3. VBAC – The Controversy Smith et al from Cambridge UK in JAMA 2002 Reviewed 313, 238 singleton births, 37 - 43w, cephalic presentation in the Scottish Morbidity Register 1992 -1997 excluding congenital malformations and found… 1. Rate of perinatal death 11 times higher for VBAC compared to elective CS 2. This is 2 times higher than for multiparas having a vaginal birth

  4. VBAC – The Controversy Guise et al from Portland Oregan in BMJ July 2004 Reviewed 568 publications on VBAC vs elective CS but found only 71 had useful data Concluded that the additional risk of perinatal death from attempted VBAC was 1.4 per 10,000 (95 percent confidence limits 0 - 9.8) In only 5% of uterine ruptures did the baby die This means that one has to perform 7142 elective CS to prevent one baby death

  5. This presentation will: • Examine the advantages and disadvantages of VBAC • Evaluate the risks to mother & baby • Provide an evidence base for the safe practice of VBAC... • Patient selection • Preparation of patients • Guidelines for intrapartum care

  6. Advantages of VBAC • Greater maternal satisfaction • But it’s not all about “me” • Quicker recovery • But not always • Cheaper • But not much cheaper than elective CS and can be much more costly • Less RDS for babies • But greater risk of death & disability • Less maternal morbidity and mortality • But these are rare with elective CS

  7. Advantages of VBAC - 2 • More vaginal births in the future • But what’s the point if there’s only to be two kids! • Less maternal depression • But there is no evidence that this is so • Breast feeding more likely to succeed • Occurs in the delivery room • Easier for mothers without wound pain • Avoids risks unique to CS • But these are rare

  8. Advantages of Elective CS • Certainty of timing • That’s the modern way! • Certainty of outcome • If I have a 30 – 50% chance of CS just do one! • Emergency CS more dangerous • It’s Pain-free • More or less guaranteed! • Often preferred by fathers & obstetricians • That’s a male thing

  9. Advantages of Elective CS • Protects the pelvic floor • Controversial because • Some risk arises from the pregnancy itself • And CS may not be protective • Safer for babies • But the absolute risk of VBAC is small • Avoids the risk of scar rupture • But there is much uncertainty about the frequency of this • and the maternal and fetal risks

  10. VBAC Risk to the Fetus • The rate of perinatal death is 11 x higher than for elective CS • BUT… • This risk is equivalent to that of being a fetus to a Primigravida • The absolute risk is only 4.5 per 10,000 births • Confidence limits are wide • In the 2002 UK publication all emergency CS were classified as attempted VBAC

  11. Maternal Risk from VBAC • Meta analysis of risk of death • 2.8 per 10,000 with trial of scar • 2.4 per 10,000 for elective CS • No maternal death ever attributed to scar rupture • Scar rupture • Much confusion in the literature over the definition • Rate of asymptomatic scar rupture the same whether VBAC or elect CS • Overall rate approx. 0.5% or 1:200 • Was 0.35% in the largest combined contemporary study • Hysterectomy • Additional risk from trial of scar is 3.4 per 10,000 • Requires 2941 elective CS to prevent one hysterectomy

  12. Patient selection for VBAC • Type of previous CS • "10% " risk of rupture from classical and T incisions • Myomectomy and Hysterotomy • Indication for Previous CS • But 50-75% of patients can VBAC after previous CS for CPD! • Previous obstetric history • VBAC success >90% if there has been prior vaginal birth • Dilatation at the time of previous CS • Gestation at previous CS – was there a lower segment? • Number of previous CS • Increasing risk with increasing number

  13. Patient selection for VBAC -2 • Time since previous CS • Risk of scar rupture is 2 – 3x greater if <18m • Maternal weight • Miserable rates of VBAC for women >135 Kg • Lower uterine segment thickness • No uterine ruptures if >4.5 mm • Maternal Age • Clear evidence for declining uterine performance with age at first labour • Family history of labour performance • A field ripe for study

  14. Patient selection for VBAC - 3 • Size of the mother and baby • But we are very bad at estimating this • Other pregnancy problems • Should be assessed according to obstetric principles • Engagement and cervical ripening • Best assessed at the onset of labour • Labour performance • That’s why it’s called trial of scar • Dilatation and descent • Progress rather than arbitrary time limits • Psychological Factors • The patient’s willingness and drive • The support provided

  15. More than one previous CS? Tahseen & Griffith BJOG Jan 2010 in a systematic analysis of available data and meta analysis concluded: • Overall success 71.1% • Risk of scar rupture 1.36% (this is 3x greater than for one CS) • Perinatal risk is 0.09% (this is 3x greater than for one CS) • The overall maternal morbidity was the same as that for elective CS Hysterectomy, transfusion, febrile morbidity etc

  16. More than two previous CS? Cahill et al BJOG 2010 in a retrospective cohort study 89 women with >2 previous CS concluded: • Overall success 79.8% • No cases of uterine rupture • The overall maternal morbidity was the same as that for elective CS Hysterectomy, transfusion, febrile morbidity etc

  17. Lower segment thickness and risk of scar rupture Rozenberg et al Lancet 1996 studied 642 women with ultrasound , measured the thinnest point of the lower segment against a filled bladder, then attempted VBAC: >4.5 mm - no ruptures or dehiscence (278) 3.6 - 4.5 mm 2% rate of scar rupture (177) 2.6 - 3.5 mm 10% rate of scar rupture (136) <2.6 mm 16% rate of scar rupture (51) Can be technically difficult particularly in obese woman Vaginal and 3-dimensional measures promising

  18. VBAC for the Obese? Carrel et al (Am J OG in 2003) studied 70 women >200 lb, 70 who were 200-300 lb and 69 >300 lb 81.8% success for those <200 lb 57.1% success for those 200-300 lb 13.3% success for those >300 lb Infection rate was: 5.7% group 1 11.4% group 2 39% group 3 (Very similar results published in 2001)

  19. VBAC for Older Women? Byfield et al Am J OG in 2004 studied 659 women <30 years age, 721 who were 30-35 years age and 370 >35 years age 72% success for those <30 71% success for those 30-35 65% success for those >35 Scar rupture rate was: 2.0% group 1 1.1% group 2 1.4% group 3

  20. Pregnancy Interval and Risk of Scar Rupture Byfield et al Am J OG in 2002 studied 1527 women who attempted VBAC at <12 to >36 months after previous CS: 4.8% ruptured for those <12m 2.7% ruptured for those 13-24m 0.9% ruptured for those 25-36m 0.9% ruptured for those >36m

  21. Pregnancy Interval and Risk of Scar Rupture Bujold & Gauthier Obstet Gynec in 2010 studied 1768 women who attempted VBAC after one previous CS: 4.8% ruptured for those <18m 1.9% ruptured for those 18-24m 1.3% ruptured for those >24m Also noted 7-fold increased rate of rupture when the previous CS was a single layer closure

  22. Single vs Double-layer closure at prior CS Blumenfeld et al BJOG in 2010 studied 127 women undergoing primary CS. At subsequent CS those who had a single layer closure had a 7-fold increased risk of bladder adhesions (RR=6.96, CI 1.72 – 28.1) Regardless of any other variation in surgical technique

  23. Induction of Labour for VBAC? Ravasia et al Am JOG 2000 studied 2119 women attempting VBAC between 1992 and 1998 of whom 27% had an induction of labour Spontaneous labour 0.45% scar rupture rate Induced labour 1.4% Cx ripening c PGs 2.9% Cx ripening c Foley 0.7% IOL not using PGs 0.7%

  24. Induction of Labour for VBAC -2? Lyndan-Rochelle et al NEJM 2001 studied all women attempting VBAC between 1987 and 1996 in Washington state Rate of Scar Rupture No labour 1.6 per 1000 Spontaneous labour 5.2 " " Induced labour (not PGs) 7.7 " " Induced with PGs 24.5 " " However this study used ICD9 codes for identifying scar rupture and these are only 40% accurate

  25. Induction of Labour for VBAC -3? Lin & Rayner Am JOG 2004 studied 3533 women attempting VBAC after one or more CS, 2523 in spontaneous labour, 438 by elective CS, 430 induced with oxytocin and 142 induced with Misoprostol Rate of scar rupture was significantly higher when labour was induced. No significant difference between oxytocin (0.8%) and Misoprostol (1.1%)

  26. Induction of Labour for VBAC -4? Dekkar et al studied 29,008 women attempting VBAC in Australia 1998 – 2000 BJOG 117:1358 2010 Rate of scar rupture (complete & partial ) was: No labour 0.01% Spontaneous labour with no augmentation 0.15% Labour augmented with oxytocin 1.91% Induced using oxytocin 0.54% Induced using prostaglandins (PG’s) 0.68% Induced with PG’s and oxytocin 0.88% Overall rate of successful VBAC 54.3%

  27. Canadian College Surgeons & Physicians Guidelines 1993 - 1 Trial of labour should be recommended to all women who have had only one previous CS. Except for: Previous classical, T or unknown uterine incision Previous hysterotomy or full thickness myomectomy Previous uterine rupture Any contraindication to labour in this pregnancy eg placenta previa, transverse lie etc. The wish of the patient is paramount (and the partner should ideally also be involved)

  28. Canadian College Surgeons & Physicians Guidelines 1993 - 2 The patient should be made aware of the hospital’s resources and any limitations The previous obstetric record should be consulted Consultation with a specialist obstetrician is not mandatory Induction of labour with oxytocin or Foley catheter is acceptable Augmentation with oxytocin is acceptable but caution required if arrest has occurred in the active phase of labour

  29. Canadian College Surgeons & Physicians Guidelines 1993 - 3 Continuous EFM required only when when induction or augmentation of labour is used The problem of false positives No evidence that it is a specific indicator of scar rupture Epidural anaesthesia not contraindicated Twins not contraindicated Suspected fetal macrosomia & diabetes not contraindicated

  30. My guidelines for VBAC - 1 • Patients are counselled that VBAC is not appropriate if: • There is a classical, T-shaped or unknown uterine incision • More than one CS has been performed • The previous CS was performed for failure to progress in the active phase of labour i.e. >4 cm dilated • Their BMI is >35 • Patients accepted outside of these guidelines on a case- by-case basis.

  31. My guidelines for VBAC - 2 • Patients who are suitable for a trial of scar should be told by their primary carer that elective CS and VBAC have risks and benefits. • They should: • Read on the subject – RCOG 2008 • Discuss it with an obstetrician • Their decision will be respected • Patients planning VBAC require one to one preparation

  32. My guidelines for VBAC - 3 • Any available record about the previous CS is scrutinized • The patient is provided with individualised chance of success with VBAC & maternal and fetal risks • Delivery in a place capable of emergency laparotomy is recommended • Any limitation in the patient’s chosen place of birth is discussed • The discussion is documented

  33. My guidelines for VBAC - 4 • Offer IOL by sweep membranes, ARM and oxytocin in safe working hours at 39 – 41w • Cervical ripening with Foley but not PGs • If admitted in spontaneous labour then review by obstetrician within 2 hrs is desirable • IV line, group and save • Epidural if required. • Monitor by continuous CTG only if oxytocin or epidural is in use

  34. My guidelines for VBAC - 5 • CS is recommended if there is failure to progress i.e. • <1 cm per hour dilatation over >4 hrs and >3 cm and good uterine activity • No head descent with >60 minutes active pushing in the 2nd stage • Assisted delivery may be attempted according to usual obstetric dictates • OR “Fetal Distress” i.e. • Scalp lactate >4.8 or CTG so abnormal as to warrant scalp sampling by RCOG guidelines

  35. My experience with VBAC - 1 • 330 private multigravid patients 2001 – 04 • 65 had undergone previous CS (20%) • 32 attempted VBAC (50%) • 21were successful (66%) • 12 by SVD and 9 assisted

  36. My experience with VBAC - 2 • Among the 32 VBACs there were: • 2 patients who had 2 previous CS (one with a “thin lower segment”) • 5 patients whose previous CS was for failure to progress and 2 of these had a bigger baby during VBAC • 1 patient who had a third degree tear in her first SVD, elective CS for the second and SVD with an intact perineum during VBAC

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