Objective: To present updated national birthweight percentiles for gestational age by sex for singletons born in Australia.Design and setting: Cross-sectional population-based study of 2.53 million singleton live births of infants born in Australia between 1998 and 2007.Main outcome measures: Birthweight percentiles by gestational age and sex.Results: Between 1998 and 2007 women in Australia gave birth to 2,539,237 live singleton births. Of these, 2,537,627 had gestational age between 20 and 44 weeks and non-missing sex and birthweight. Birthweight percentiles are presented by sex and gestational age for a total of 2,528,641 births after excluding 8,986 births for having outlying birthweight. Since the publication of the previous Australian birthweight percentiles in 1999, median birthweight for term babies has increased between 0 and 25g for boys and between 5 and 45g for girls.Conclusions: There has been only a small increase in birthweight percentiles for babies of both sexes and most gestational ages since 1991-1994. These national percentiles will provide a current Australian reference for clinicians and researchers assessing size at birth.3

Background Interrupted time series analysis is increasingly used to evaluate the impact of large-scale health interventions. While segmented regression is a common approach, it is not always adequate, especially in the presence of seasonality and autocorrelation. An Autoregressive Integrated Moving Average (ARIMA) model is an alternative method that can accommodate these issues. Methods We describe the underlying theory behind ARIMA models and how they can be used to evaluate population-level interventions, such as the introduction of health policies. We discuss how to select the shape of the impact, the model selection process, transfer functions, checking model fit, and interpretation of findings. We also provide R and SAS code to replicate our results. Results We illustrate ARIMA modelling using the example of a policy intervention to reduce inappropriate prescribing. In January 2014, the Australian government eliminated prescription refills for the 25 mg tablet strength of quetiapine, an antipsychotic, to deter its prescribing for non-approved indications. We examine the impact of this policy intervention on dispensing of quetiapine using dispensing claims data. Conclusions ARIMA modelling is a useful tool to evaluate the impact of large-scale interventions when other approaches are not suitable, as it can account for underlying trends, autocorrelation and seasonality and allows for flexible modelling of different types of impacts.

ObjectiveTo determine trends in pregnancy-associated cancer and associations between maternal cancer and pregnancy outcomes.DesignPopulation-based cohort study.SettingNew South Wales, Australia, 1994–2008.PopulationA total of 781 907 women and their 1 309 501 maternities.MethodsCancer and maternal information were obtained from linked cancer registry, birth and hospital records for the entire population. Generalised estimating equations with a logit link were used to examine associations between cancer risk factors and pregnancy outcomes.Main outcome measuresIncidence of pregnancy-associated cancer (diagnosis during pregnancy or within 12 months of delivery), maternal morbidities, preterm birth, and small- and large-for-gestational-age (LGA).ResultsA total of 1798 new cancer diagnoses were identified, including 499 during pregnancy and 1299 postpartum. From 1994 to 2007, the crude incidence rate of pregnancy-associated cancer increased from 112.3 to 191.5 per 100 000 maternities (P < 0.001), and only 14% of the increase was explained by increasing maternal age. Cancer diagnosis was more common than expected in women aged 15–44 years (observed-to-expected ratio 1.49; 95% CI 1.42–1.56). Cancers were predominantly melanoma (33.3%) and breast cancer (21.0%). Women with cancer diagnosed during pregnancy had high rates of labour induction (28.5%), caesarean section (40.0%) and planned preterm birth (19.7%). Novel findings included a cancer association with multiple pregnancies (adjusted odds ratio 1.52, 95% CI 1.13–2.05) and LGA (aOR 1.47, 95% CI 1.14–1.89).ConclusionsPregnancy-associated cancers have increased, and this increase is only partially explained by increasing maternal age. Pregnancy increases women’s interaction with health services and the possibility for diagnosis, but may also influence tumour growth.

Depression and anxiety (internalizing disorders) are the largest contributors to the non-fatal health burden among young people. This is the first meta-analysis to examine the joint efficacy of universal, selective, and indicated preventive interventions upon both depression and anxiety among children and adolescents (5-18 years) while accounting for their co-morbidity. We conducted a systematic review of reviews in Medline, PsycINFO and the Cochrane Library of Systematic Reviews, from 1980 to August 2014. Multivariate meta-analysis examined the efficacy of preventive interventions on depression and anxiety outcomes separately, and the joint efficacy on both disorders combined. Meta-regressions examined heterogeneity of effect according to a range of study variables. Outcomes were relative risks (RR) for disorder, and standardized mean differences (Cohen's d) for symptoms. One hundred and forty-six randomized controlled trials (46 072 participants) evaluated universal (children with no identified risk, n = 54) selective (population subgroups of children who have an increased risk of developing internalizing disorders due to shared risk factors, n = 45) and indicated prevention (children with minimal but detectable symptoms of an internalizing disorder, n = 47), mostly using psychological-only strategies (n = 105). Reductions in internalizing disorder onset occurred up to 9 months post-intervention, whether universal [RR 0.47, 95% confidence interval (CI) 0.37-0.60], selective (RR 0.61, 95% CI 0.43-0.85) or indicated (RR 0.48, 95% CI 0.29-0.78). Reductions in internalizing symptoms occurred up to 12 months post-intervention for universal prevention; however, reductions only occurred in the shorter term for selective and indicated prevention. Universal, selective and indicated prevention interventions are efficacious in reducing internalizing disorders and symptoms in the short term. They might be considered as repeated exposures in school settings across childhood and adolescence. (PROSPERO registration: CRD42014013990.).