A. The assessment would include review of the previous surgical notes regarding the indication for the caesarean sections , the uterine incisions and any associated complications. History of the gestational age during caesarean sections and the interval from the last childbirth needs to be enquired into. Classical caesarean section is associated with a risk of scar rupture of 200-900 in 10,000 deliveries and is a contraindication for Vaginal birth after caesarean. A history of scar rupture too is a contraindication. J shaped and Inverted T incisions are associated with higher rupture rates. Caesarean section for dystocia and preterm caesarean are associated with lower success rates of vaginal birth . A shorter inter pregnancy interval of less than two years is also associated with increased failure rates..
Any complication in the present pregnancy should be taken into account. Multiple pregnancy , Placenta praevia are contraindications to vaginal birth.. Obesity is also associated with higher failure rates. The location of placenta, if Low lying or anterior during the anomaly scan needs to be reconfirmed at 32 weeks. Placenta praevia accreta is a contraindication for vaginal birth after caesarean , is associated with major obstetric haemorrhage and needs repeat caesarean section with additional preparations.
The woman should be counselled that if she has 2 previous uncomplicated caesarean sections, she may be allowed a vaginal birth trial after detailed risk assessment by the consultant obstetrician and informed consent . Delivery would be in a consultant led unit with facilities for emergency caesarean sections, blood transfusion and neonatal intensive care unit.. Any other previous uterine scar or history of rupture mandates a planned repeat caesarean section at 39 weeks.
She should also be informed that the rate of uterine rupture is not significantly increased compared to one previous section but there is higher risk of blood transfusion and hysterectomy compared to a single transverse section. The success rate of VBAC is 72-76%. The risk of uterine rupture is 2-8 in 1000 births. There is also an additional 1% risk of endometritis and blood transfusion compared to ERCS. There is also an increase in the risk of birth related perinatal deaths by an additional 2-3/10,000 births compared to elective section .The risk of antepartum stillbirths beyond 37 weeks is increased in the VBAC patients and so is the risk of Hypoxic ischaemic encephalopathy of 8/10,000.
Vaginal birth is associated with a decreased risk of transient tachypnoea of the newborn by 2 % compared with repeat caesarean section delivery. Failed VBAC is associated with a poorer outcome of uterine scar dehiscence or rupture, blood transfusion, hysterectomy and birth asphyxia of the neonate. The patient should be provided information leaflets regarding risks and benefits and the discussion should be documented in the hand held notes.
B. The woman should be asked about the duration of rupture of membranes, associated pain abdomen, bleeding and about fetal movements. The pulse rate , temperature, BP should be checked and per abdominal examination done to assess presentation, uterine size, uterine contractions ,and auscultate the FHR. An admission CTG would be done as she is a high risk patient. Per speculum examination to document ruptured membranes, colour of liquor and digital examination to assess cervical dilatation, effacement, position is done. Prior to vaginal examination placental localization should be confirmed by review of the antenatal notes.. Expectant management for 24 hours is associated with spontaneous onset of labour in 60% cases.. Induction of labour in this patient with previous two sections is associated with 2-3 fold higher risk of uterine rupture and needs counselling and evaluation by the consultant. Unfavourable features for vaginal delivery would necessitate a caesarean section.
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