Prediction of Large-for-Gestational-Age Neonates by Different Growth Standards.

OBJECTIVE

Compare the accuracy of the Hadlock, the NICHD, and the Fetal Medicine Foundation (FMF) charts to detect large-for-gestational-age (LGA) and adverse neonatal outcomes (as a secondary outcome).

METHODS

This is a secondary analysis from a prospective study that included singleton non-anomalous gestations with growth ultrasound at 26-36 weeks. LGA was suspected with estimated fetal weight > 90th percentile by the NICHD, FMF, and Hadlock charts. LGA was diagnosed with birth weight > 90th percentile. We tested the performance of these charts to detect LGA and adverse neonatal outcomes (neonatal intensive care unit admission, Ph < 7.1, Apgar <7 at 5 minutes, seizures, and neonatal death) by calculating the area under the curve, sensitivity, specificity, positive predictive value, and negative predictive value.

RESULTS

Of 1054 pregnancies, 123 neonates (12%) developed LGA. LGA was suspected in 58 (5.5%) by Hadlock, 229 (21.7%) by NICHD standard, and 231 (22%) by FMF chart. The NICHD standard (AUC: .79; 95% CI: .75-.83 vs. AUC .64; 95%CI: .6-.68; p = < .001) and FMF chart (AUC: .81 95% CI: .77-.85 vs. AUC .64; 95%CI: .6-.68; p = < .001) were more accurate than Hadlock. The FMF and NICHD had higher sensitivity (77.2 vs. 72.4 vs. 30.1%) but Hadlock had higher specificity for LGA (97.5 vs. 88.5 vs. 85.4%). All standards were poor predictors for adverse neonatal outcomes.

CONCLUSIONS

The NICHD and the FMF standards may increase the detection rate of LGA in comparison to the Hadlock chart. However, this may increase obstetrical interventions.