Are customised birth weight centiles of any value in women with diabetes of pregnancy?

Abstract

A birth weight centile can be calculated by correcting for non-pathological factors such as gestational age, maternal height and booking weight, parity and ethnicity. Fetal macrosomia is associated with diabetes of pregnancy and arbitrarily defined as a birth weight above the 90th centile for gestational age. It is an important diagnosis to make due to its inherent risks in the intrapartum and neonatal period. The aim of this study was to determine if a customised birth weight centile was associated more closely with adverse outcome than birth weight corrected for gestational age only in women with diabetes of pregnancy. Customised birth weight centiles and birth weight for gestational age centiles were calculated on 271 women with impaired glucose tolerance/gestational diabetes. Pregnancy outcomes included caesarean delivery, shoulder dystocia and neonatal complications. The caesarean section rate was 34% and neonatal complications affected 21% of all deliveries. Birth weight >4 kg occurred in 21% of pregnancies. ROC curves were generated for each outcome measure. Shoulder dystocia and RDS were associated closely with both customised and non-customised birth weight centiles. There was no significant difference between the two birth weight centiles and outcome measures.