What is the impact of bringing birth forward?

When it comes to giving birth, intervention is on the rise.
 
In 2020, around one in three (35%) of all labouring mothers and 46% of first-time mothers in Australia had an induced labour. That is up from around 26% of first-time mothers in 2010.
 
If an induction is being planned, evidence indicates that if there are no medical or obstetric reasons for an earlier birth, then waiting until at least 39 weeks is best for the baby, with the last few weeks of pregnancy important for brain and lung development.
 
But what is best for mothers?
 
A new study has provided further reassurance for those electing to be induced at 39 weeks gestation, as it is found to be associated with better health outcomes for women.
 
Researchers from the University of Melbourne Department of Obstetrics and Gynaecology analysed data from 14 studies, including the experiences of more than 1.6 million women, to examine the impact of an elective induction at 39 weeks.
 
They found that inducing labour at that gestation is associated with a 37% decreased risk of perineal injury.
 
Study co-lead Dr Roxanne Hastie told newsGP it is the first metanalysis of this size to confirm that inducing labour protects labouring mothers, as well as being safe for their babies.
 
‘Our findings reported that there is almost a 40% reduction in perineal injury for mothers, so third- or fourth-degree tears, which are a consequence for a lot of women,’ she said.
 
In Australia, severe perineal injury affects up to one in 20 women who have a vaginal birth. These injuries often require surgery and can take many months to heal.
 
As a result, Dr Hastie said that perineal injury is ‘definitely a concern for a lot of women’.
 
She said the findings are ‘reassuring’ and that they can now be used by clinicians, including GPs in a shared care arrangement, to assist pregnant patients when creating a suitable birth plan.
 
‘It’s important that women do have this information so that they can make informed decisions with their healthcare providers when they are deciding how and when to birth their babies,’ Dr Hastie said.
 
Meanwhile, the study also found that the benefits for women electing to be induced at 39 weeks extend beyond avoiding serious perineal injury.
 
‘We also found a reduction in emergency caesarean sections and also the need for assisted births – so vacuum or forceps,’ Dr Hastie said.
 
This is contrary to what the Australian Institute and Welfare states on its website. Drawing on research from 2012, it claims that while most women who have induced labour do well, as do their babies, that induction of labour ‘does increase the risk of emergency caesarean section’ compared to spontaneous labour.
 
However, Dr Hastie says this is a misconception from inaccurate research conducted in the 1970s that persisted until the 2000s.
 
‘They compared women having an induction of labour to those who gave birth spontaneously at the same gestation. But it’s not the appropriate group given you can’t really determine who is going to have a spontaneous birth,’ she said.
 
‘The ARRIVE Trial in 2018 really solidified that; it was a very well-designed clinical trial that showed quite clearly that induction of labour was not associated with an emergency caesarean section.’
 
In the decade since 2010, the rate of spontaneous labour fell from 56% to 41%, corresponding with increases in the rates of induced labour and no labour. In 2020, the main reasons for inducing labour were diabetes (15%), prolonged pregnancy (12%) and pre-labour rupture of membranes (11%).
 
While the study did find that labour at 39 weeks was associated with improved maternal labour-related and neonatal outcomes, among nulliparous women, induction was associated with shoulder dystocia, with the authors noting that this potential risk ‘should be discussed’ with the relevant patient cohort.

Though Dr Hastie says she is a proponent of evidence as power, she notes that elective induction will not be suitable for all women who have yet to go into spontaneous labour at 39 weeks.
 
‘We’re not saying that all women should have an induction, but that this is the evidence so that people can feel informed when they make decisions around birthing,’ she said.
 
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antenatal care induction labour mothers perineal injury pregnancy