Unadjusted and customised weight centiles in the identification of growth restriction among stillborn infants

The study aims to compare the utility of unadjusted with customised weight standards in the identification of intrauterine growth restriction (IUGR) among unexplained stillborn infants undergoing postmortem examination. Unadjusted and customised birthweight centiles were determined for 51 unexplained stillborn infants undergoing perinatal autopsy. Unadjusted centiles were calculated from an ultrasonically derived fetal weight standard. Customised centiles were calculated from an online calculator which adjusts the standard to account for important physiological variables. IUGR was defined as moderate or severe according to brain/liver ratios of > 3 and > 5, respectively. The relationship between the weight centiles and abnormal brain/liver weight ratios was explored. Neither unadjusted nor customised standards identify stillborn infants with brain/liver ratios > 3:1. Both unadjusted and customised weight standards identify stillborn infants with brain/liver ratios > 5 equally well with high sensitivity (95%) but low specificities (63% and 66%, respectively). Customising weight standards to account for physiological variables does not identify growth restricted stillborn infants more usefully than an unadjusted fetal weight standard.