Using inter‐institutional practice variation to understand the risks and benefits of routine labour induction at 41+0 weeks. (14th July 2014)

• Record Type: Journal Article
• Authors: Hutcheon, JA; Harper, S; Strumpf, EC; Lee, L; Marquette, G
• Is Part Of: BJOG. Volume 122:Number 7(2015:Jul.)
• Page Start: 973
• Page End: 981
• Publication Date: 2014-07-14
• Subjects: Obstetrics -- Periodicals; Gynecology -- Periodicals; 618
• DOI: 10.1111/1471-0528.13007
• Languages: English
• ISSNs: 1470-0328

Abstract

<abstract abstract-type="main" id="bjo13007-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="bjo13007-sec-0001" sec-type="section"> <title>Objective</title> <p>To evaluate the risks and benefits of routine labour induction at 41<sup>+0</sup> weeks' gestation for mother and newborn.</p> </sec> <sec id="bjo13007-sec-0002" sec-type="section"> <title>Design</title> <p>Population‐based retrospective cohort study of inter‐institutional variation in labour induction practices for women at or beyond 41<sup>+0</sup> weeks' gestation.</p> </sec> <sec id="bjo13007-sec-0003" sec-type="section"> <title>Population</title> <p>Women in British Columbia, Canada, who remained pregnant ≥41<sup>+0</sup> weeks and delivered at one of the province's 42 hospitals with >50 annual deliveries, 2008–2012 (<italic>n</italic> = 14 627).</p> </sec> <sec id="bjo13007-sec-0004" sec-type="section"> <title>Methods</title> <p>The proportion of women remaining pregnant a week or more past the expected delivery date who were induced at 41<sup>+0</sup> or 41<sup>+1</sup> weeks' gestation for an indication of 'post‐dates' was calculated for each institution. We used instrumental variable analysis (using the institutional rate of labour induction at 41<sup>+0</sup> weeks as the instrument) to estimate the effect of labour induction on maternal and neonatal health outcomes.</p> </sec> <sec id="bjo13007-sec-0005" sec-type="section"> <title>Main outcome measures</title> <p>Caesarean delivery, instrumental delivery, post‐partum haemorrhage, 3rd or 4th degree lacerations, macrosomia, neonatal intensive care unit admission, and 5‐minute Apgar score <7.</p> </sec> <sec id="bjo13007-sec-0006" sec-type="section"> <title>Results</title> <p>Institutional rates of labour induction at 41<sup>+0</sup> weeks ranged from 14.3 to 46%. Institutions with higher (≥30%) and average (20–29.9%) induction rates did not have significantly different rates of caesarean delivery, instrumental delivery, or other maternal or neonatal outcomes than institutions with lower induction rates (<20%). Instrumental variable analyses also demonstrated no significantly increased (or decreased) risk of caesarean delivery (0.69 excess cases per 100 pregnancies [95% CI −10.1, 11.5]), instrumental delivery (8.9 per 100 [95% CI −2.3, 20.2]), or other maternal or neonatal outcomes in women who were induced (versus not induced).</p> </sec> <sec id="bjo13007-sec-0007" sec-type="section"> <title>Conclusions</title> <p>Within the current range of clinical practice, there was no evidence that differential use of routine induction at 41<sup>+0</sup> weeks affected maternal or neonatal health outcomes.</p> </sec> </abstract>