Predicting periviable birthweight and survival: bedside ultrasound versus anatomy scan gestational adjusted age projection

Abstract

Objective: Two methods of birthweight (BW) prediction in the periviable period: bedside ultrasound proximate to delivery versus gestation-adjusted-projection (GAP) method was compared.

Methods: Periviable births were identified over a 6-year period. The GAP method was applied to the estimated fetal weight (EFW) from anatomy scans and the gestational age at delivery to predict BW, designated EFW_GAP. EFW from the bedside ultrasound (EFW_US), and the EFW_GAP were compared to actual BW to calculate absolute values of error in BW estimates. Neonatal survival estimates were made utilizing a National Institute of Child Health and Human Development calculator.

Results: EFW_US was more accurate than EFW_GAP in predicting BW as the mean absolute value of error with bedside ultrasound ǀEFW_US-BWǀ was significantly lower than mean absolute value of error with GAP method ǀEFW_GAP-BWǀ, 75.32 ± 74.64 g versus 125.68 ± 130.62 g, p = 0.01. Predicted neonatal survival based on EBW_US was closer to reference than predicted survival based on EBW_GAP 9.66% ± 9.43% versus 7.76% ± 7.78% p = 0.26.

Conclusions: EFW_US is more accurate than EFW_GAP for predicting BW in this period. However, the GAP technique could have utility in survival predictions when timely performance of ultrasound is not feasible.

Keywords:

• Periviable period
• gestation-adjusted projection
• ultrasound competency
• hadlock
• fetal weight ratio

Acknowledgements

The authors would like to acknowledge the Perinatal Outreach Center at Albany Medical Center for their assistance in identifying study subjects. There was no grant support received.

Disclosure statement

The authors have no conflicts of interest to disclose in relevance to this study.

Additional information

Funding

No funding was utilized in the production of this research.