Early Fetal Growth Rate Helps Predict Macrosomia


SAN FRANCISCO — Accelerated fetal growth in the midtrimester, as assessed by individualized growth potentials and ultrasound imaging, helped predict macrosomia in a study of 70 women who developed gestational diabetes.

“Early suggestion of accelerated fetal growth offers a window of opportunity to optimize glycemic management” of the mother and potentially prevent macrosomic stillbirth and perinatal morbidity, Dr. Anita Manogura reported in a poster presentation at the annual meeting of the Society for Maternal-Fetal Medicine.

She and her colleagues prospectively followed 70 women who went on to develop gestational diabetes. The women underwent serial assessments, including standardized ultrasound exams for nuchal translucency screening (11–14 weeks' gestation), detailed evaluation of anatomy (18–20 weeks' gestation), and formal fetal echocardiogram (22–24 weeks' gestation and then every 4 weeks thereafter), wrote Dr. Manogura of the University of Maryland, Baltimore, and her associates.

They used the Gardosi method to predict individual fetal growth potentials based on fetal gender and the mother's height, weight, parity, ethnicity, and other characteristics. Estimated fetal weights from imaging were converted to percentiles, with large for gestational age (LGA) defined as above the 90th percentile.

Early differences were seen between the 27 LGA infants and infants born at normal weights. By 24 weeks' gestation, LGA infants had a median estimated fetal weight in the 54th percentile, significantly higher than the 48th percentile for normal-weight neonates. At 24 weeks, an estimated weight that was above the 58th percentile predicted an LGA baby with a sensitivity of 30% and specificity of 84%.

If this trend continued at 28 weeks, then the odds of having an LGA baby were four times higher. At 28 weeks, future LGA babies were at a median 72nd percentile of estimated fetal weight, compared with the 51st percentile for normal-weight infants. An estimated fetal weight of greater than the 58th percentile at 28 weeks increased the sensitivity of predicting macrosomia to 63%, with a specificity of 87%.

“The potential to interrupt this progression by intensive midtrimester glycemic management deserves further study,” the investigators concluded.

Elevated estimated fetal weight percentiles on ultrasound did not predict adverse perinatal outcomes such as shoulder dystocia, cesarean delivery, or neonatal complications.

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