When expectant mothers go past their due date, doctors are often hesitant to induce, as induction comes with its own set of risks. However, a new study has found that induction at 41 weeks may be safer when compared to the “wait and see” approach.
Though halted early because of the high rate of stillbirths among overdue mothers, the Swedish study examined outcomes of late-term delivery from 14 random hospitals. More than 2,750 women with low-risk, uncomplicated but late-lasting pregnancies were followed. What they found was that morbidity risk increases as the pregnancy continues.
“Neonatal mortality and morbidity, as well as maternal morbidity, increase when the pregnancy lasts more than 40 weeks, and the risks increase further as the pregnancy advances,” said Ulla-Britt Wennerholm of Sahlgrenska University Hospital in Gothenburg, Sweden, who led the study. “There is still uncertainty about obstetric management of late-term pregnancies and the optimal time to induce labour,” she told Reuters Health by email.
Other adverse outcomes were also considered, including brain hemorrhaging, troubled breathing, convulsions that required medical intervention, oxygen deprivation, prolonged labor, cesarean deliveries, and maternal hemorrhaging, among others. Birth complications did not differ drastically between the groups, but the high rate of perinatal mortality forced the authors to cease the study early for ethical reasons.
“The routine at most Swedish clinics, and also in some other countries, is still to induce at 42 weeks, so it was unexpected that we had to stop the study early,” Wennerholm said. “The study was stopped for ethical reasons because of an unexpected higher rate of perinatal mortality.”
The authors say additional studies need to be done to confirm the findings and understand the reasons behind the high rate of mortality. Currently, they are analyzing individual patient data to determine if some of the women would have been predisposed to an increased risk. The hope is that mothers will have more knowledge to guide their choices about late-term birth.
“Choice is important with maternity care, and clear information about available options should be accessible to all pregnant women, enabling them to make fully informed and timely decisions,” said Sara Kenyon of the University of Birmingham in the UK, a professor of evidence-based maternity care who co-authored a commentary accompanying the study.
The authors also pointed out that late-term birth is usually relatively safe and straightforward.
“Pregnancies that continue past 41 weeks are usually safe and straightforward, but there is a small yet significant increase in stillbirth risk past this, so induction of labour at 41 weeks is a reasonable option for women,” Kenyon told Reuters Health by email. “We support the continual review of clinical guidelines as new evidence emerges to ensure best practice.”