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About the Authors:
Hannah E. Knight
Roles Conceptualization, Formal analysis, Methodology, Writing - original draft, Writing - review & editing
* E-mail: [email protected]
Affiliations Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, United Kingdom, Royal College of Obstetricians and Gynaecologists, London, United Kingdom
ORCID http://orcid.org/0000-0002-6809-2517
David A. Cromwell
Roles Conceptualization, Formal analysis, Writing - review & editing
Affiliation: Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, United Kingdom
ORCID http://orcid.org/0000-0002-6516-8125
Ipek Gurol-Urganci
Roles Formal analysis, Writing - review & editing
Affiliation: Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, United Kingdom
Katie Harron
Roles Formal analysis, Methodology, Writing - review & editing
Affiliation: Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, United Kingdom
ORCID http://orcid.org/0000-0002-3418-2856
Jan H. van der Meulen
Roles Methodology, Writing - review & editing
Affiliation: Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, United Kingdom
ORCID http://orcid.org/0000-0002-9451-2335
Gordon C. S. Smith
Roles Conceptualization, Writing - review & editing
Affiliation: Department of Obstetrics and Gynaecology, University of Cambridge, NIHR Cambridge Comprehensive Biomedical Research Centre, Cambridge, United Kingdom
ORCID http://orcid.org/0000-0003-2124-0997Abstract
Background
A recent randomised controlled trial (RCT) demonstrated that induction of labour at 39 weeks of gestational age has no short-term adverse effect on the mother or infant among nulliparous women aged ≥35 years. However, the trial was underpowered to address the effect of routine induction of labour on the risk of perinatal death. We aimed to determine the association between induction of labour at ≥39 weeks and the risk of perinatal mortality among nulliparous women aged ≥35 years.
Methods and findings
We used English Hospital Episode Statistics (HES) data collected between April 2009 and March 2014 to compare perinatal mortality between induction of labour at 39, 40, and 41 weeks of gestation and expectant management (continuation of pregnancy to either spontaneous labour, induction of labour, or caesarean section at a later gestation). Analysis was by multivariable Poisson regression with adjustment for maternal characteristics and pregnancy-related conditions. Among the cohort of 77,327 nulliparous women aged 35 to 50 years delivering a singleton infant, 33.1% had labour induced: these women...