Fetal measurements on ultrasound that are in the bottom 30% can be as concerning for adverse neonatal outcomes as macrosomia, according to the authors of a retrospective study.

Records for all women with gestational diabetes (GDM) or pre-existing type 2 diabetes (T2DM) who gave birth at a regional hospital during 2016 were examined in the study, led by researchers from the Menzies School of Health Research in Darwin.

A total of 275 pregnant women were included — 84% with GDM and 16% with T2DM — all of whom gave birth at 30 weeks’ gestation or later, the authors reported in the Australian and New Zealand Journal of Obstetrics and Gynaecology.

Fetuses whose abdominal circumference (AC) was at the 30th percentile or lower on the last ultrasound before delivery were nearly four times more likely to have an adverse neonatal outcome than those in the 31-70th percentile, which was used as a reference group, the authors reported.