VBAC Risks: New research intensifies debate?

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The controversy over vaginal birth after caesarean (known as VBAC) has been given fresh impetus by a new study highlighting the VBAC risks.

VBAC Risks: New research intensifies debate?

The controversy over vaginal birth after caesarean (known as VBAC) has been given fresh impetus by a new study highlighting the VBAC risks.

The risk of complications during vaginal birth is higher for mothers and infants following a previous caesarean, Canadian researchers have found – although it is important to stress that the overall risk of a complication remains low.

There are strong opinions for and against VBAC (pronounced vee-bac), and my own view is that women need to make their own informed decision and be supported in whatever birth they decide to have.

VBAC or ERCS?

The options are VBAC or another caesarean, known as ‘Elective Repeat Caesarean Section’ (ERCS).

A VBAC Conference 2018 held in the autumn took as its starting point the belief that mothers are not given a full right to choose. “Why are women still denied the right to have a VBAC? Why are mothers forcefully attacked and bullied because they have too much of a voice?” its website asked.

However, guidance in the British Medical Journal states: “An exploration of the woman’s wishes and shared decision making is vital.”

The new research

So, what does the Canadian research say?

The new findings were unexpected. They have come after an analysis of data from nearly 200,000 Canadian women who had a prior caesarean and then gave birth between 2003 and 2014.

Reporting in the Canadian Medical Association Journal, the researchers said that attempted VBAC is associated with higher rates of adverse effects or death for mothers and infants. But Dr. Carmen Young from the University of Alberta stressed: "The absolute rates of adverse maternal and neonatal outcomes are low with both attempted VBAC and elective repeat caesarean delivery." Further study is needed to help explain the findings, she said.

What are the risks of VBAC and ERCS?

Attempted VBAC is associated with a higher risk of uterine rupture, haemorrhage and other maternal and infant complications.

Repeat caesarean sections are associated with an increased risk of surgical complications and placental complications in subsequent pregnancies.

It is also difficult to predict which patients will have a successful VBAC, so planning is a challenge.

But if this sounds alarming, the advice to doctors in the BMJ points out how there is every chance that all will be well. It says:

  • Either vaginal birth or elective repeat caesarean section are reasonable options, and adverse outcomes are rare in most uncomplicated pregnancies in women with a previous caesarean section.
  • Around 50% of women with one previous caesarean section attempt a vaginal birth in their second pregnancy, and of these nearly two thirds are successful.

Asking mothers what they want

The BMJ advises doctors to “explore the woman’s concerns, preferences, reasons for previous caesarean section, and plans for future pregnancies to inform the choice of mode of delivery.” It also notes that women attribute different values to the benefits and risks of either approach, and I agree wholeheartedly with this insight.

Key points

To help mothers put the arguments for and against into proportion, the Royal College of Gynaecologists has issued the following key points:

  • If you are fit and healthy, both VBAC and ERCS are safe choices with very small risks.
  • 3 out of 4 women who have had one caesarean section and then have a straightforward pregnancy and go into labour naturally give birth vaginally.
  • 9 out of 10 women will have a successful VBAC if they have ever given birth vaginally. Successful VBAC has the fewest complications
  • Giving birth vaginally carries small risks for you and your baby but, if you have a successful vaginal birth, future labours are less complicated with fewer risks for you and your baby.
  • Having a caesarean section makes future births more complicated.
  • Most women who have a planned caesarean section recover well and have healthy babies, but it takes longer to get back to normal after your baby is born.


Further reading

To find out more about this complex topic, you can read the full Canadian research study here.

Consult the BMJ guidance here

Read the full Royal College of Gynaecologists information page here

And learn more about the VBAC Conference here

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