Correlation between neonatal outcomes of twins depends on the outcome : Secondary analysis of twelve randomised controlled trials

ObjectiveTo estimate the magnitude of the correlation between neonatal outcomes of twins and demonstrate how this information can be used in the design of randomised controlled trials (RCTs) in women with twin pregnancies.DesignSecondary analysis of data from 12 RCTs.SettingObstetric care in multiple countries, 2004-2012.Population or sample4504 twin pairs born to women who participated in RCTs to assess treatments given during pregnancy.MethodsIntraclass correlation coefficients (ICCs) were estimated using log-binomial and linear models.Main outcome measuresPerinatal death, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular haemorrhage, necrotising enterocolitis, s…