Published: 21 July 2023
Artificially starting labour at 39 weeks of pregnancy has the greatest benefit for reducing risks for women from more socioeconomically deprived areas, compared with waiting for labour to begin naturally, according to new evidence from researchers at St George’s, University of London and partners.
The team analysed more than half a million births in England to probe the effects of inducing labour at 39 weeks of pregnancy. Their findings suggest that an increased uptake of induction of labour at this time may help reduce inequities in harmful perinatal outcomes – the period of time between the start of pregnancy and up to a year after giving birth.
However, the authors highlight the need for more research to dig further into this evidence to guide clinical policy on induction and women’s choices at an individual level.
Adverse perinatal outcomes— which include stillbirths, neonatal deaths, pre-term births, and other birth complications— are more common amongst women from deprived areas and ethnic minorities in England.
There is ongoing debate about whether starting labour artificially at 39 weeks, instead of once they are overdue at 41-42 weeks, should be offered in low-risk pregnancies based on ethnicity or socioeconomic status.
Over half a million births analysed
In the new study, published in Plos Medicine, researchers analysed a database of all maternal admissions in the NHS between January 2018 and March 2021. The research was carried out as part of the National Maternity and Perinatal Audit, evaluating maternity services across England, Scotland and Wales.
A total of 501,072 women with low-risk pregnancies who had not yet given birth at 39 weeks were included in the analysis, of which 47,352 (9.5%) were induced at 39 weeks.
Data revealed that an adverse perinatal outcome affected 3.3% (1,555 out of 47,352) of births in the labour-induced group and 3.6% (16,525 out of 453,720) of births in the expectant management group (women who were monitored while waiting for labour to start naturally).
Small but important benefit
After adjusting for factors including ethnicity, socioeconomic background, maternal age, parity, year of birth, and birthweight centile, the team found a small but important benefit from inducing labour in low-risk pregnancies, with 360 inductions associated with avoiding one adverse outcome. These benefits were mainly seen in women from more socioeconomically deprived areas and women with no previous pregnancies.
“Improved collection of routine data on the indication for induction and the presence of risk factors is required to corroborate the role that induction of labour at 39 weeks in women with a low-risk pregnancy can play in reducing inequalities in risk of adverse perinatal outcomes.”
- Professor Asma Khalil, Professor of Obstetrics and Maternal Fetal Medicine at St George’s, University of London -
"Our study highlighted that we urgently need detailed, accurate and complete data from each maternity unit, collected at national level, especially about the indications of induction of labour, so that we get an even better understanding of the role that induction of labour can play in improving perinatal outcomes."
- Dr. Ipek Gurol-Urganci, co-author of the study at London School of Hygiene & Tropical Medicine -