Vaginal delivery after previous caesarean section

Vaginal delivery after previous caesarean section

The rising incidence of caesarean section in present day practice has come to stay, the safety of the operation for the mother has led to the expansion of its scope for foetal interests. Present day investigations for foetal wellbeing during pregnancy help to identify the foetus at risk. Advances in neonatal care have made it possible to salvage many preterm babies. If therefore, during pregnancy, foetal growth retardation and compromise is suspected, induction of preterm labour/termination of pregnancy by caesarean section are alternatives that need consideration. However, beyond a point, further resort to caesarean section becomes counterproductive. Also, the present day practice of eschewing difficult and traumatic vaginal instrumental assisted deliveries in favour of caesarean section has also contributed substantially to the rising incidence. In present day practice, an incidence of caesarean deliveries of 15-20% seems acceptable. However, any unbridled rise should be curbed.

Worldwide the rising incidence of caesarean section has become a matter of concern to the obstetrician, the patients and the health care providers. Whilst it is true that many caesarean sections are being undertaken in foetal interests, and there is no doubt that caesarean section has helped to salvage many compromised babies, and thereby lowered perinatal morbidity and mortality. It is important that the decision for caesarean section should be made after weighing all available options.

The dictum 'Once a caesarean, always a caesarean' is no longer tenable. Numerous studies have established the ability of the lower segment transverse uterine scar to withstand future childbirth and the safety of attempting vaginal delivery in a well-supervised institutional environment is no longer disputed. However, the decision to give a trial of labour in women with a previous caesarean scar should be judicious and well planned.

Before subjecting a woman with a previous caesarean to a trial of the scar and attempting a vaginal delivery, the safety and rationale for the decision require to be scrutinized.

Prerequisites and contraindications to vaginal birth after previous caesarean section

Prerequisites to attempting vaginal delivery after previous caesarean section

Hospital records should establish that there were no complications during previous surgery like extension of incision, haematoma formation, postoperative febrile morbidity which would impair the integrity of the previous uterine scar.

The previous indication for caesarean section no longer exists (non-recurrent).

The foetal presentation is cephalic.

There is no cephalopelvic disproportion, an X-ray pelvimetry may help.

The baby is not too large.

There is no history of previous scar rupture.

There is a reasonable expectation of a vaginal delivery.

No medical or obstetric complications are present.

Blood transfusion facilities are easily available.

Facilities to undertake emergency surgery at short notice are available.

Neonatal care facilities are available.

The patient understands and accepts these risks.

Contraindications to vaginal delivery after previous caesarean section

More than one previous caesarean section (some consider this a relative contraindication).

Previous classical or T-shaped incision.

Opinion of the previous surgeon against future trial of scar.

Abnormal presentation.

Antepartum haemorrhage.

Recurring indication.

Suspicion of disproportion or midpelvic and/or outlet contraction.

Institutional facilities not available.

Patient's refusal to undergo trial.

Management of trial of vaginal delivery after previous caesarean section and the results expected after such trial.

Management of trial of caesarean scar

Ideally the onset of labour should be spontaneous (pain, draining, show).

On admission, evaluate maternal and foetal conditions, these should be satisfactory. Exclude cephalopelvic disproportion. Send patient's blood for group and cross-match. Set up an infusion line and restrict oral intake.

During labour monitor maternal vital parameters every half hourly. After she progresses to established labour, check maternal condition every 15 minutes. Monitor labour contractions and record electronic FHR continuously. In absence of this facility, intermittent auscultation of the foetal heart sounds half hourly in early labour, every 15 minutes during advanced first stage of labour and after each pain during the second stage of labour is recommended.

Record progress of labour on a partogram.

The patient should not be left unattended at any time.

Judicious use of oxytocin to mimic normal pains is permissible.

Use labour analgesia—drugs/epidural with great care, these may mask signs.

Unexplained or persisting maternal tachycardia, suprapubic persistent discomfort, blood-stained urine, vaginal bleeding, unsatisfactory partographic progress, evidence of foetal distress or passage of meconium, and an unsatisfactory FHR tracing constitute indications to intervene in time.

She should be allowed a spontaneous vaginal delivery with an episiotomy if required or assistance with an outlet forceps/ventouse when the head comes down onto the perineum.

After delivery of the placenta, you may explore the lower uterine segment for evidence of scar rupture. This assessment is not easy and needs practice, sometimes the thinned-out lower uterine segment is thrown into a fold giving the false impression of scar dehiscence. Lastly overenthusiastic digital probing may cause the scar to give way and thereby precipitate a crisis.

Watch the maternal parameters closely for the next few hours before transfer to the room.

Results

Almost 50-60% of patients with previous caesarean section are eligible for vaginal delivery after previous caesarean section.

Almost 60-75% of these patients can be successfully delivered by the vaginal route.

The average incidence of scar rupture ranges between 0.5-2.0%.

Perinatal mortality is comparable to the average for normal patients.

Classical scars are more prone to rupture, hence such patients should be preferably considered for elective caesarean section.