Management of vaginal birth after caesarean

Management of vaginal birth after caesarean (VBAC)

Table of Content

1. Introduction

2. Successful and unsuccessful planned VBAC/Incidence

3. Antenatal Care

4. Caution

5. Contraindications to VBAC

6. Risks and benefits of VBAC

7. Induction and augmentation

8.Intrapartum care

9. Indicators of scar dehiscence/ rupture

10. Postnatal review

10. References

Introduction

• Vaginal Birth After Caesarean section refers to any woman who has experienced a prior caesarean birth who plans to deliver vaginally rather than by repeat caesarean section.

Successful and unsuccessful planned VBAC/Incidence

• A vaginal birth (spontaneous or assisted) in a woman undergoing planned VBAC indicates a successful VBAC.
• Birth by emergency caesarean section during the labour indicates an unsuccessful VBAC.
• Overall chances of successful planned VBAC after a single previous caesarean is 72–75%.
• Previous vaginal delivery particularly previous VBAC is the single best predictor of successful VBAC and is associated with a planned VBAC success rate of 85-90%. Previous vaginal delivery is also independently associated with a reduced risk of uterine rupture.

Antenatal care

• Women with a prior history of one uncomplicated lower-segment transverse caesarean section, in an otherwise uncomplicated pregnancy at term, with no contraindication to vaginal birth, should be able to discuss the option of planned VBAC and the alternative of a repeat caesarean section.
• At booking visit, detailed events of the previous birth and postnatal period should be taken into consideration
• A final decision for mode of birth should be agreed between the woman and her Consultant or senior middle-grade doctor at booking first visit to the hospital (usually around 20 weeks) unless woman is undecided. In this case, decision should be documented by 36 weeks gestation or earlier.
• If a consultant is unavailable in clinic, the completed notes should be left for review later
• There should be documented individual management plan for labour for the woman
• Prior plan for VBAC may change in light of evolving problems during pregnancy that may preclude VBAC.
• A plan for the event of labour starting prior to term (< 37 weeks) should be documented.
• Plan and method of induction should be clearly documented should pregnancy continue beyond 40 weeks. This may be planned at clinic visit at 40+ weeks by the consultant or senior middle-grade doctor.
• The antenatal counselling of all women with one previous caesarean birth should be documented
• A patient information leaflet which highlights the risk and benefit of VBAC should be provided with the consultation
• Women with 2 or more Caesarean section who request VBAC may be cautiously offered only after counselling by a consultant. This should include the risk of uterine rupture and maternal morbidity, and the individual likelihood of successful VBAC (e.g. given a history of prior vaginal delivery). Success rate 62-75%, uterine rupture rate from systematic review 1.36%.
• An individualized assessment of the suitability for VBAC should be made in women with factors that increase the risk of uterine rupture.
• The routine use of VBAC checklists during antenatal counselling should be considered, as they would ensure informed consent and shared decision making in women undergoing VBAC.

Caution

• Post dates
• Obesity
• women with twin gestation
• fetal macrosomia
• short inter-delivery interval (less than 12 months since last delivery)
• PPROM/ SROM in current pregnancy
• Still birth
• Maternal age of 40years or more
• Other associated obstetric /medical / surgical conditions
• Lower pre-labour bishop score
• Deceased ultrasonography lower segment myometrial thickness
• Plan for induction/ augmentation in above cases should be made by a senior clinician

Contraindications to VBAC

• Women with a prior history of one classical caesarean section.
• Women with previous uterine rupture
• Women who have other absolute contraindications to vaginal birth that apply irrespective of the presence or absence of a scar (e.g. major placenta praevia.)
• Women with a previous uterine incision other than an uncomplicated low transverse caesarean section incision who wish to consider vaginal birth should be assessed by a consultant or senior middle-grade doctor with full access to the details of the previous surgery.
• NB: There is insufficient evidence to support the safety of VBAC in women with previous inverted T or J incision, low vertical uterine incision or significant inadvertent uterine extension at the time of primary caesarean; hence caution should be exercised in these women and decisions should be made by a senior obstetrician on a case by case basis

Risks and benefits of VBAC (points for counselling

Induction and augmentation

• • Senior clinician should discuss the following with the woman: decision to induce labour, the proposed method of induction, the decision to augment labour with oxytocin, the time intervals for serial vaginal examination and the selected parameters of progress that would necessitate discontinuing VBAC
  • There is 2-3-fold increased risk of uterine rupture and around 1.5-fold increased risk of caesarean section in induced and/or augmented labour compared with spontaneous labour
  • There is a higher risk of uterine rupture with induction of labour with prostaglandins.
  • Risk of uterine rupture with prostaglandin induction: 87/ 10,000
  • Risk of uterine rupture with non- prostaglandin induction (balloon): 29/10,000

• Preference should be given to induction of labour using mechanical methods as it is associated with a lower risk of scar rupture compared with prostaglandins.

Intrapartum care

• Planned VBAC should be conducted in CDS, with continuous electronic monitoring.
• In labour, plan of management should be documented and regularly updated throughout labour in consultation with the on-call Consultant/ Consultant-of-the-week
• IV access and FBC, G&S
• Epidural anaesthesia is not contraindicated in planned VBAC.
• Women insisting on home birth should be carefully counselled by the consultant.
• Women should have supportive one to one care
• Arrange appointments with Community midwife matron for organizing support and drawing detailed plan of limiting factors for referral to CDS.

Indicators of scar dehiscence/ rupture

• abnormal CTG
• severe abdominal pain, especially if persisting between contractions
• chest pain or shoulder tip pain
• sudden onset of shortness of breath
• acute onset scar tenderness despite good epidural
• abnormal vaginal bleeding or haematuria
• cessation of previously efficient uterine activity
• maternal tachycardia, hypotension or shock

• loss of station of the presenting part
• Change in abdominal contour and inability to pick up fetal heart rate at the old transducer site.

• NB: The classic triad of a complete uterine rupture (pain, vaginal bleeding, fetal heart rate abnormalities) may present in less than 10% of cases. This is an acute emergency which warrants triggering the emergency buzzer, summoning the on-call consultant, simultaneously resuscitating mother as necessary and delivering as soon as possible by caesarean section.

Postnatal review

• Postnatal review should include discussion regarding circumstances relating to the delivery and plan for future birth

References

1.Royal College of Obstetricians and Gynaecologists. (2015). Birth after Previous Caesarean Section. London: RCOG.  Available at: www.rcog.org.uk