Birth Before 29 Weeks: Interventions Leading to Better Outcomes for mothers and babies (BILBO)
In Canada, more than 350,000 babies are born each year. Preterm birth complicates 7.6% of births, with variations of ±15% between provinces. Preterm birth is the most important cause of perinatal mortality and morbidity, and is recognized to hold the greatest potential for improvement of health outcomes. The inaugural project of CPN, BILBO, built on a standardized national database of pregnancies at high risk of very preterm birth at 22 to 28+ weeks' gestation.
In women at risk of very preterm birth at 220 – 286 weeks' gestation, we sought to identify obstetric practices that may be associated with good maternal or perinatal outcomes. Our specific objectives were:
- To examine variations in outcomes and practices for the major causes of spontaneous and indicated very preterm birth among Canadian tertiary perinatal units;
- To identify obstetric practices that were associated with favourable and unfavourable outcomes for further intervention studies of the major causes of very preterm birth, after correction for pregnancy (maternal and fetal) characteristics [and for perinatal outcomes, also neonatal risk markers and neonatal intensive care practices]; and
- To study variations in resource use associated with obstetric practice and tertiary perinatal characteristics, after adjustment for baseline population risks.
In the setting of very preterm birth, our hypothesis was that variation in maternal and perinatal outcomes would not be fully explained by variability in patient mix. Rather, variability in clinical practice would further explain variations in outcomes. Also, variations in resource use would not be fully explained by variability in tertiary perinatal unit characteristics and patient mix, but further explained by variability in practice.
Our team included content and methods experts in each of the major causes of spontaneous or indicated very preterm birth, epidemiology, database design/maintenance, national networks, medical informatics, and statistical modelling. This project involved 16 of 22 tertiary perinatal units across Canada and focused on the major determinants of spontaneous and indicated very preterm birth (at 220–286 weeks): spontaneous preterm labour, preterm prelabour rupture of membranes, intrauterine growth restriction (abdominal circumference <3rd centile), gestational hypertension (with/without proteinuria), and antepartum haemorrhage. From August 2006 to March 2011, we enrolled almost 6,500 such women at risk of very preterm birth, who were admitted to a Canadian tertiary perinatal unit. Data was obtained from the maternal and neonatal/infant/paediatric records, and included adverse perinatal and maternal outcomes, patient mix (including maternal demographics, past medical/obstetric history, characteristics of current pregnancy), neonatal care (for perinatal outcomes), and specific key obstetric practices (including maternal transport, cervical cerclage, amnioinfusion, fetal and maternal surveillance, pharmacological and non-pharmacological therapy, and pregnancy prolongation). Analysis is ongoing, and we will: i) determine crude outcome incidence rates among centres, ii) examine variations in outcomes and practices among tertiary perinatal units, using staged multivariate logistic and linear regression analysis, iii) associate obstetric practice differences with outcomes variation, iv) compare crude measures of resource use, and v) analyze resource use variation among centres.
Relevance of this Research
For the major causes of very preterm birth, this study will determine whether there are inter-institutional variations in maternal or perinatal outcomes that can be accounted for by variability in obstetric practice, after correction for differences in patient mix. This information will be used to improve outcomes (for both mothers and babies) and reduce costs, by targeting practices for trials of effectiveness. This project formed the basis of the Canadian Perinatal Network (CPN), one of a number of national networks designed to cover maternal, fetal, newborn and paediatric health. Data collection for CPN is linked to the Canadian Neonatal Network that has been an effective vehicle for both the generation of new knowledge, and the translation of existing knowledge into clinical practice. The funding for CPN has been provided by CIHR (2002–8, Neonatal-perinatal Interdisciplinary Capacity Enhancement Grant and 2005–2009 Operating Grant) and the MSFHR (2003–8, through the Centre for Health Innovation and Improvement, Child and Family Research Institute of British Columbia).
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