Prediction of macrosomia by serial sonographic measurements of fetal soft-tissues and the liver in women with pregestational diabetes.

OBJECTIVES

This study aimed to determine whether antenatal ultrasound measurements of fetal soft-tissues and liver can predict macrosomia in women with pregestational diabetes.

METHODS

Fetal biometry, soft-tissue thickness (anterior abdominal wall [STAW], thigh [STT], upper arm [STA], scapular [STS]) and liver size were measured sonographically at 23, 28, 31 and 34 weeks of gestation. Large for gestational age (LGA) was defined as a birth weight greater than 90th percentile for gestational age on standard curves adjusted for maternal height and weight, parity and fetal gender. The area (±standard error) under receiver operating characteristic (AUROC) curves were also calculated.

RESULTS

A total of 29 pregnant women with pregestational diabetes were included, and a total of 663 measurements taken. Fifteen neonates were LGA. There was no significant difference in fetal soft-tissue thickness at 23, 28 and 31 weeks between the LGA and non-LGA neonates. In contrast, at 34 weeks, fetal soft-tissues were significantly thicker in LGA neonates (P<0.05), but with no difference in liver surface area between the two groups. The specificity and sensitivity of 34-week ultrasonography to detect macrosomia was 78.6% and 66.7%, respectively, for abdominal circumference (AC), 71.4% and 93.3% for STT, 85.7% and 80.0% for STA, and 71.4% and 86.7% for STAW. No parameter was more powerful than the others. The best AUROC curves were found for AC (0.807), STT (0.821), STA (0.855) and STAW (0.821).

CONCLUSION

Third-trimester sonographic measurements of fetal soft-tissue may help to detect macrosomia in pregnancies complicated by pregestational diabetes.