Caesarean section rates in NSW

Towards Normal Birth (TNB, 2010), the major maternity policy in NSW, is currently being reviewed and work funded by the Population Health and Health Services Research Support (PHHSRS) Program is helping inform the development of a new maternity policy. Clinical and Population Perinatal Health Research has worked closely with NSW Kids and Families to ensure alignment between its research and these priorities and to feedback results of relevance to services and policies.

One specific area identified by NSW Kids and Families for evaluation was birth after caesarean section. The TNB policy identifies vaginal birth after caesarean section (VBAC) as one of 10 critical steps for providing woman-centred maternity care. For women who choose an elective repeat caesarean section, timing of delivery is critical to maximising infant outcomes. The 2007 Policy Directive: Maternity - Timing of elective or pre-labour caesarean section (also under review) recommends that, where there are no compelling medical indications, elective or pre-labour caesarean section should not occur prior to 39 completed weeks gestation due to increased risk of respiratory morbidity in infants born before 39 weeks.

A body of work examining variations in clinical practice completed by the biostatistics trainees funded through the PHHSRS Program (in addition to prior work) is informing the review and update of the above two policies. Using Perinatal Data Collection and Admitted Patient Data Collection data that were linked by the Centre for Health Record Linkage, multilevel modelling has been undertaken investigating the impact of patient, intervention and hospital factors on between-hospital variation in caesarean rates. Briefly, in three collaborative projects, and publications that were co-authored with care providers and NSW Ministry of Health staff, the following have been demonstrated:

• Wide variation in hospital VBAC rates (2%-49%). Only half of the between-hospital variation was explained by patient and hospital factors, and neither high nor low VBAC rates were associated with improved maternal or infant outcomes.
• Poor uptake of the policy regarding timing of pre-labour caesareans, with high rates of delivery prior to 39 weeks across hospitals (adjusted average 35%). Large between-hospital variation persisted despite adjustment for casemix and hospital characteristics, suggesting that non-medical factors are influencing the timing of low risk, pre-labour caesarean sections.
• Non-caesarean uterine scars have a prevalence of 3.0 - 3.4/1000 deliveries. Policies on caesarean section are relevant to women with uterine scars from surgery other than caesarean section but the population burden of illness was not previously known.
• The work is of relevance to clinicians, women and their families, maternity care providers as well as policy makers in the Ministry of Health, NSW Kids and Families and Local Health Districts. Processes to support translation into policy and practice have included: publication in peer-reviewed journals, presentations to local, state and national forums of researchers, clinicians and policymakers, a submission to the Australian Commission on Quality and Safety in Healthcare, and co-location of a researcher with policymakers at NSW Kids and Families.​