Background: Severe growth restriction (SGR, birthweight below the 3rd percentile) is a risk factor for poor perinatal outcomes. The rate of severe of SGR undelivered at 40 weeks (SGR40+) has been adopted as a health system performance indicator in Victoria since 2010, but this is not routinely reported in Western Australia (WA).
Aims: To investigate trends in the proportion of SGR40+ singletons in WA, the morbidity and mortality patterns of these babies and maternal characteristics.
Methods: Using data extracted from core population health datasets and linked by the Data Linkage Branch of the WA Department of Health, we report the proportion of SGR40+ singletons between 2006-2015. Using 2014-15 data, we describe their outcomes and maternal characteristics compared to 1) all babies born 37 or more weeks with no SGR and 2) SGR babies born at 37-39 weeks (SGR37). Logistic regression was used to identify associated factors.
Results: Between 2006-2015 the proportion of SGR 40+ singletons decreased from 40.2% to 30.9%. The maternal factors associated with SGR40+ (e.g. 1st birth, smoking, having Aboriginal, Asian or African ethnicity, low BMI, delayed ante-natal care) are all known risk factors. Compared to non- SGR births, SGR40+ births had higher stillbirth and mortality rates, although these estimates were imprecise as based on small numbers. SGR40+ babies were also more likely to have qualified newborn care days than those without SGR but less likely than SGR37 babies.
Conclusion: Routinely collected data is a useful tool for monitoring trends in SGR40+ births and their outcomes.