Variation in hospital rates of induction of labour: a population-based record linkage study.
OBJECTIVE
To examine interhospital variation in rates of induction of labour (IOL) to identify potential targets to reduce high rates of practice variation.


METHODS
Population-based record linkage cohort study.


METHODS
New South Wales, Australia, 2010-2011.


METHODS
All women with live births of ≥24 weeks gestation in 72 hospitals.


METHODS
Variation in hospital IOL rates adjusted for differences in case-mix, according to 10 mutually exclusive groups derived from the Robson caesarean section classification; groups were categorised by parity, plurality, fetal presentation, prior caesarean section and gestational age.


RESULTS
The overall IOL rate was 26.7% (46,922 of 175,444 maternities were induced), ranging from 9.7% to 41.2% (IQR 21.8-29.8%) between hospitals. Nulliparous and multiparous women at 39-40 weeks gestation with a singleton cephalic birth were the greatest contributors to the overall IOL rate (23.5% and 20.2% of all IOL respectively), and had persisting high unexplained variation after adjustment for case-mix (adjusted hospital IOL rates ranging from 11.8% to 44.9% and 7.1% to 40.5%, respectively). In contrast, there was little variation in interhospital IOL rates among multiparous women with a singleton cephalic birth at ≥41 weeks gestation, women with singleton non-cephalic pregnancies and women with multifetal pregnancies.


CONCLUSIONS
7 of the 10 groups showed high or moderate unexplained variation in interhospital IOL rates, most pronounced for women at 39-40 weeks gestation with a singleton cephalic birth. Outcomes associated with divergent practice require determination, which may guide strategies to reduce practice variation.
Clinical and Population Perinatal Health, Kolling Institute, Northern Sydney Local Health District, St Leonards, New South Wales, Australia Sydney Medical School Northern, University of Sydney, St Leonards, New South Wales, Australia Department of Obstetrics and Gynaecology, Royal North Shore Hospital, Northern Sydney Local Health District, St Leonards, New South Wales, Australia.
Tanya A
TA
Nippita
Clinical and Population Perinatal Health, Kolling Institute, Northern Sydney Local Health District, St Leonards, New South Wales, Australia.
Judy A
JA
Trevena
Clinical and Population Perinatal Health, Kolling Institute, Northern Sydney Local Health District, St Leonards, New South Wales, Australia Sydney Medical School Northern, University of Sydney, St Leonards, New South Wales, Australia.
Jillian A
JA
Patterson
Clinical and Population Perinatal Health, Kolling Institute, Northern Sydney Local Health District, St Leonards, New South Wales, Australia Sydney Medical School Northern, University of Sydney, St Leonards, New South Wales, Australia.
Jane B
JB
Ford
Clinical and Population Perinatal Health, Kolling Institute, Northern Sydney Local Health District, St Leonards, New South Wales, Australia Sydney Medical School Northern, University of Sydney, St Leonards, New South Wales, Australia.
Jonathan M
JM
Morris
Clinical and Population Perinatal Health, Kolling Institute, Northern Sydney Local Health District, St Leonards, New South Wales, Australia Sydney Medical School Northern, University of Sydney, St Leonards, New South Wales, Australia.
Christine L
CL
Roberts
D000293:Adolescent; D000328:Adult; D001946:Breech Presentation; D002585:Cesarean Section / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D007231:Infant, Newborn; D007751:Labor, Induced / Q000706:statistics & numerical data; D009517:New South Wales; D007744:Obstetric Labor Complications; D010298:Parity; D036801:Parturition; D011247:Pregnancy; D055815:Young Adult
EPIDEMIOLOGY; OBSTETRICS