London - Pregnant women should be induced at 41 weeks instead of adopting a "wait-and-see" approach, a study suggests.
Researchers found women with low-risk pregnancies who are overdue are less likely to have a stillbirth if they are induced.
A pregnancy is considered full-term when it reaches 37 weeks and most pregnancies last around 40 weeks.
It is not unusual for women to be up to two weeks late, but the chances of stillbirth increase the longer the wait goes on. Current practice is only to induce delivery for women who have failed to go into labour by 42 weeks.
However a trial, published in the British Medical Journal, found there was a lower risk of death when babies were induced at 41 weeks.
The researchers estimate that, for every 230 women induced at 41 weeks, one perinatal death would be prevented.
Researchers at Gothenburg University in Sweden compared the wait-and-see "expectant management" approach with inductions offered at 41 weeks.
The trial involved 2 760 women with an uncomplicated, single pregnancy who were admitted to 14 Swedish hospitals between 2016 and 2018.
The researchers measured factors such as stillbirth, deaths in the first days of life, low oxygen levels, and breathing problems in both groups of babies.
They found these health factors were experienced at a similar rate – by the babies of 33 women induced at 41 weeks and 31 women in the waiting group.
But six babies in the expectant management group died against none in the induction group, so the trial was stopped early.These were five stillbirths and one early neonatal death. There was also a lower admittance to a neonatal intensive care unit in the group induced at 41 weeks.
The authors say differences in hospital policies and practices could have affected the results.
But they say women with low-risk pregnancies should be offered inductions "no later" than at 41 weeks and that "this could be one (of few) interventions that reduces stillbirth".
In an editorial, Professor Sara Kenyon, professor of evidence based maternity care at the University of Birmingham, and colleagues say induction at 41 weeks "looks like the safer option for women and their babies".
They add: "Choice is important within maternity care, and clear information about available options should be accessible to all pregnant women, enabling them to make fully informed and timely decisions."
The World Health Organisation recommends inducing labour at 41 weeks and many countries offer induction between 41 and 42 weeks.
Professor Alexander Heazell, of the Royal College of Obstetricians and Gynaecologists, said: "We are saddened by reports of babies who died during a research trial in Sweden."
He added: "The findings of this Swedish trial are in line with what is already known – that pregnancies that continue to, or pass, 41 weeks are usually safe and straightforward, but there is a small yet significant increase in stillbirth risk."