**9. Proposed guideline of MCH (Obstetrics division) for VBAC**

### **10. Intra partum monitoring of VBAC**

Intrapartum monitoring for women undergoing TOLAC required a concise and structured plan to increase success rates, reduce morbidity and litigation from possible omission and lack of recognition of potential or actual uterine rupture. The maternity unit should be equipped with a standby 24-hour readiness for caesarean delivery with access to immediate neonatal care. The Obstetric team and the team leader preferably the unit consultant/the consultant on call should be notified immediately when a woman presents for a planned VBAC. All effort should be made to review all her case notes and the birth plan as documented during the antenatal care and allow the woman to reaffirm her decision to continue with the original plan or opt out for caesarean section [21–23]. It is appropriate to put in an intravenous canula and collect blood for a full blood count and blood group with the serum saved for access to immediate crossmatch if needed and oral intake should be restricted to clear fluid. The woman should be placed on continuous electronic fetal monitoring because an abnormal fetal rate is the most consistent finding in women who have uterine rupture [22, 51]. A one-to-one midwifery support and continuous care is associated with improve birth outcome and this should be the norm in all facilities that allow women to attempt vaginal delivery with prior caesarean. It is recommended to perform another vaginal examination once the woman is in active phase, open a labour care guide and repeat vaginal examinations every 4 hours. It is important to note that uterine rupture, which is the disruption of the uterine muscle, with or without the serosa [52] can occur at any stage of labour and they are no reliable clinical markers for early detection [22, 51, 52]. A prolonged and profound bradycardia correlates with more than 80% of uterine rupture. A classic triad of pain, vaginal bleeding and fetal heart abnormalities may only be present in about 10% of women and most likely a late sign. Nonspecific heart rate abnormalities might need to be interpreted in the context of the woman and other obstetrics conditions. However, the following nonspecific signs should be closely monitored. These are abdominal pain in-between contractions, acute onset of uterine scar tenderness, caseation of previously efficient uterine contractions, prolonged first or second stage of labour, haematuria, loss of station, easier palpation of fetal parts, shoulder tip or chest pain in absent of vaginal bleeding and evidence of maternal tachycardia and shock [22]. Where uterine rupture is suspected, the obstetrics team should aim at category 1 caesarean section. The third stage of labour should be managed based on local guideline for active management of the 3rd stage of labour. There are no contraindications to use of analgesia both systemic and regional in women during TOLAC [51].

### **11. VBAC in special clinical scenarios**

Some clinical scenarios are a source of potential debate and management may vary according to local protocols, health workers experience, litigation climate and most importantly the women's preferences to mode of delivery.

#### **11.1 Twin gestation**

Uncomplicated twin gestation with the cephalic presentation in the leading twin has been found to have similar successful VBAC rates compared with singleton

pregnancy [53–55]. However, caution should be taken for mother with twin gestation requesting for VBAC because of uncertainty regarding the safety of planned VBAC in these group of women. Ford et al. showed an increase (0.9%) scar rupture compared with the lower value in singleton with one previous lower segment scar [51, 55]. In a recent multicenter retrospective cohort study with a sample size of 160 women with twin A in vertex position with a single previous lower segment caesarean section, Peled et al. [56] stated that successful VBAC in selected twin was achieved in 86.3% while Levin et al. [41] reported a success VBAC rate of 31.3% in women with twins who attempted VBAC with no prior vaginal delivery.

#### **11.2 Augmentation and induction of labour**

Several studies [57, 58] have reported increased risk of uterine rupture in women who had either augmentation or induction of labour. However, there are inadequate and underpowered studies from randomised controlled trials concerning these clinical dilemmas. Therefore, when considering augmentation or induction of labour in patients with one prior lower segment caesarean section, the risks and benefits should be borne in mind by the clinician and discussed with the woman [51]. In an observational metanalysis of 14 studies [42] and a total of 48,457 women that underwent TOLAC, the rate of uterine rupture after induction was estimated to be about 2.2% which is which is a more than 4-fold increase in rate of uterine rupture when compared to an unstimulated uterus. Prostaglandins carry the greatest risk of rupture in comparison to mechanical methods and oxytocin augmentation. In a recent randomised trial to compare controlled release dinoprostone vaginal insert and foley's catheter for labour induction after one previous caesarean delivery, the induction delivery interval was shortened with dinoprostone, however, the rate of similar maternal satisfaction is similar [59]. The decision to stimulate the uterus either by artificial initiation or enhanced weak contraction in a patient undergoing TOLAC should be taken at the highest level of seniority, preferably by a specialist obstetrician.

#### **11.3 Two or more previous CS**

The outcome of planned VBAC in two or more prior caesarean sections is associated with low success rates and high rates of uterine rupture and greater catastrophic morbidity compared with women with one prior lower segment caesarean section [51]. The Royal College of Obstetricians and Gynaecologists cautiously states that VBAC can be considered in a pregnant woman at term with 2 previous uncomplicated lower segment caesarean sections after detailed informed consent by the consultant obstetrician but is contraindicated in a patient with 3 previous caesarean sections [22]. A case–controlled study that compared TOLAC and ERSC after 2 prior caesarean section found similar maternal and neonatal morbidity, however the uterine rupture rate was 1.16% compared with none in the ERSC group [60].

#### **11.4 Preterm pregnancy**

Preterm delivery in patients with prior caesarean section has been associated with lower success rates as reported in a multicenter trial retrospective study in preterm deliveries [61]. In patients with either fetal abnormalities or fetal demise in the mid trimester and prior caesarean section, options of hysterotomy, dilatation and curettage and medical induction of labour have not been randomised in any study [51].

Misoprostol has been reported to be successful in mid trimester termination of pregnancy for both women with and without previous caesarean section [62, 63]. A reasonable option is to use misoprostol and mifepristone, or a combination with intracervical balloon catheter can be carefully tailored to achieve vaginal delivery [51, 63].

#### **11.5 Post date**

There is evidence that the still birth rate at or after 39 weeks is higher (1.5–2-fold) in women with previous caesarean delivery compared to women with unscarred uterus. Data are not adequate to recommend delivery at this gestational age, more so that induction of labour is associated with reduced VBAC success rate and increased complications [22, 51]. If spontaneous labour has not occurred at 41 weeks, the RCOG recommends that the woman is reviewed by the senior obstetrician to reassess her options for membrane sweep, induction of labour or ERSC and provisional date for ERSC offered at 40 + 10 weeks. ACOG recognises that the likelihood of success VBAC may be less beyond 4o weeks but that should not be sole indication to preclude TOLAC [22, 23]. In a close analysis of gestational age and association with successful VBAC, Hackler et al. [64] found a bimodal distribution of high success rate between late preterm (34–36 weeks) and late term (41–42 weeks). The proportion of women that will experience spontaneous labour between 40 – 40 weeks +6 day is quoted to be more than 32% and 16% between 41 – 41 weeks +6 days [65]. Therefore, it would be reasonable to allow more than 40% of women to present in spontaneous labour if they desire to have a VBAC.

## **12. Contraindications to VBAC**

Careful review of patient history, case notes, surgical notes, delivery plan and meticulous evaluation from prenatal care and at labour ward suit will help clinicians to tease out women that are not suitable for VBAC. Contraindications to VBAC are previous uterine rupture, classical caesarean section, and other contraindications to vaginal delivery like major degree placenta previa [21–23].

In a previous uterine rupture, there is a 5% or more recurrent rupture if vaginal delivery is attempted. There is insufficient evidence on the safety of VBAC in women who had a history of complicated scars like inverted T and J incisions and inadvertent uterine extension at primary incision, significant uterine surgery like myomectomy or any unification procedure, fetal macrosomia (estimated fetal weight > 3.8 kg) and breech presentation [21–23]. These complicated scars should be documented in the woman surgical notes and handcard and should be regarded as a contraindication to VBAC in future pregnancy. Maternal refusal should be considered an absolute contraindication to VBAC, and the prospective mother has the right to refuse VBAC during antenatal and intrapartum care. Epidural anaesthesia is not contraindicated in women with planned VBAC and should be offered to women on request where feasible [51].
