Vaginal birth after one previous caesarean section: VBAC | Catherine Elliot

Vaginal birth after one previous caesarean section: VBAC

The most important step in the planning of a subsequent delivery following a previous caesarean section (CS) is to take into consideration the wishes of the woman and her birth partner. It is vital to explore one’s own fears, wishes and hopes in preparation for the delivery.

When considering a vaginal birth after caesarean section (VBAC) it is a shared decision making process and it is important for both the birth attendant and the mother to be aware of the benefits and potential complications associated with this choice. It is appropriate to offer a planned VBAC to women with singleton pregnancies where they have had only one previous CS and the baby is assessed to be in the correct position (cephalic) and is not considered to be too big.

In addition there should be no contraindication to a vaginal delivery (such as a
low-lying placenta or breech presentation) and this would apply even in the absence of a previous CS.

In recent research, a successful vaginal birth after a caesarean section carries the least risk of complication, however an emergency caesarean section (in this case applies to a CS performed in labour because of labour complications) carries the most risk. In other words it is of vital importance to plan the delivery carefully.

The success rate of a VBAC is quoted as 70% and this is increased in women who have delivered vaginally before, and reduced in women who have previously experienced obstructed labour and an emergency caesarean section.

What are the potential complications that may occur during labour in women who has had a previous caesarean:
A vaginal birth following a caesarean section carries a 1:200 chance of uterine rupture, which is a very serious life threatening complication for both mother and baby. A uterine rupture is when the old scar (from the previous caesarean) on the uterus bursts open. This risk is all but avoided if a planned caesarean section is performed at 39 weeks gestation.

The labour may not progress as planned and an emergency caesarean would then need to be performed.

When considering the timing of a planned delivery it is advisable to preform a planned caesarean section at 39 weeks. There is good evidence to suggest that a delivering before 39 weeks may result in respiratory (breathing) difficulties in the baby as well as a negative influence on their school performance and ability in the early developmental years.
It may not be possible (due to medical conditions, or pregnancy complications) to continue the pregnancy until 39 weeks, and in these cases the benefits of delivery outweigh the above concerns.

What needs to happen in labour?

1) The labour would need to start on its own (spontaneous labour) at or before full term (40 weeks).
2) The labour and delivery should take place in a hospital where there are facilities for an emergency caesarean section and a pediatrician available.
3) Continuous fetal heart rate monitoring (CTG) is mandatory from the onset of uterine contractions.
4) An epidural can be administered, however the assessment should be made carefully on the day as this form of pain blocking may well mask the early signs of uterine rupture.
5) Medication to advance the labour, such as oxytocinon (Pitocin) should not be used, and the onset of labour cannot be induced with medication.

Areas to be cautious when assessing a woman for a planned VBAC are in the cases of a women being over the age of 40, large babies, or when the pregnancy extends over the due date in which case the labour should only be induced by an artificial rupture of membranes and not with the use of medication.

It is important to discuss all options with your health care provider, to be aware of the potential risks and benefits of your delivery choice and to feel comfortable with the birth plan set out for you and the new addition to your family.

Compiled by Dr Catherine Elliott and includes recommendations and guidelines form all relevant countries including the Royal College of Obstetricians (UK)