Fetal anterior abdominal wall thickness in diabetic pregnancy

The purpose of this study was to investigate whether third trimester fetal anterior abdominal wall (AAW) thickness in diabetic pregnancy reflects glycaemic control and predicts macrosomia.

Prospective cohort study in a tertiary level maternity unit. One hundred and twenty-five diabetic mothers (71 pre-gestational and 54 gestational diabetics on insulin) underwent routine serial third trimester ultrasound examination with the additional measurement of AAW thickness. Pregnancy outcome was obtained.

335 fetal AAW measurements were recorded in diabetic pregnancy from 30 to 38 weeks gestation. Third trimester AAW was significantly higher in macrosomic babies (5.4+/-1.4 mm vs. 4.7+/-1.4 mm, p<0.05). ROC derived cut off for AAW in the prediction of macrosomia was 3.5 mm at 30 weeks, 4.5 mm at 33 weeks and 5.5 mm at 36 weeks gestation. Using either a raised AAW measurement or an AC>90th centile, the prediction of birth weight greater than the 90th centile was better (88%) than with AC alone (70%). This improvement in sensitivity held even at earlier gestations in the third trimester.

Measurement of AAW in diabetic pregnancy may have a role in the prediction of macrosomia.