Inducing labour at 41 weeks in low risk pregnancies is associated with a lower risk of newborn death compared with a "wait and see" approach until 42 weeks, a trial published in the British Medical Journal suggests.
Although the overall risk of death at 42 weeks is low, the researchers say induction of labour should be offered to women no later than 41 full weeks.
It is generally accepted there is an increased risk of problems for both mother and baby at or beyond 42 weeks of pregnancy.
Some studies have suggested that inducing labour from 41 weeks onwards improves these outcomes, but there is no international consensus on how to manage healthy pregnancies lasting more than 41 weeks.
Current practice in the UK and Scandinavia is to induce delivery for all women who have not gone into labour by 42 weeks.
Researchers in Sweden set out to compare induction of labour at 41 weeks with 42 weeks in low risk pregnancies.
The trial involved 2,760 women at an average age of 31-years-old with an uncomplicated, single pregnancy recruited from 14 Swedish hospitals between 2016 and 2018.
Women were randomly assigned to induction of labour at 41 weeks (1,381) or to the wait and see approach (1,379) until induction at 42 weeks if necessary.
For the main outcome measure, the researchers found no difference between the groups (2.4 per cent of women in the induction group had an adverse perinatal outcome compared with 2.2 per cent in the wait and see group).
Other outcomes, such as caesarean sections and mothers’ health after giving birth, also did not differ between the groups.
However, six babies in the wait and see group died compared with none in the induction group and the trial was stopped early. The researchers estimate that, for every 230 women induced at 41 weeks, one perinatal death would be prevented.
They pointed to some limitations, such as differences in hospital policies and practices that could have affected the results.
But they said women with low risk pregnancies “should be informed of the risk profile of induction of labour versus expectant management and offered induction of labour no later than at 41 full weeks”.
“This could be one of few interventions that reduces stillbirth,” they concluded.
The view is supported in a linked editorial by Prof Sara Kenyon and colleagues, who said induction at 41 weeks “looks like the safer option for women and their babies”.
They stressed that choice is important within maternity care, and said “clear information about available options should be accessible to all pregnant women, enabling them to make fully informed and timely decisions”.
