The accuracy of sonographic fetal weight in very preterm infants (≤32 weeks)

Inshirah Sgayer; Tala Barbara; Asal Darwish; Ala Aiob; Lior Lowenstein; Maya Frank Wolf; Marwan Odeh

doi:10.1016/j.jogoh.2024.102785

The accuracy of sonographic fetal weight in very preterm infants (≤32 weeks)

J Gynecol Obstet Hum Reprod. 2024 Apr 5;53(7):102785. doi: 10.1016/j.jogoh.2024.102785. Online ahead of print.

Authors

Inshirah Sgayer¹, Tala Barbara², Asal Darwish³, Ala Aiob⁴, Lior Lowenstein⁴, Maya Frank Wolf⁴, Marwan Odeh⁴

Affiliations

¹ Department of Obstetrics and Gynecology, Galilee Medical Center, Nahariya, Israel; Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel. Electronic address: inshirah.sg.sh@gmail.com.
² Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel.
³ Department of Obstetrics and Gynecology, Galilee Medical Center, Nahariya, Israel.
⁴ Department of Obstetrics and Gynecology, Galilee Medical Center, Nahariya, Israel; Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel.

PMID: 38583861
DOI: 10.1016/j.jogoh.2024.102785

Abstract

Objective: To examine the accuracy of sonographic fetal weight to predict birthweight in very preterm infants (<32 weeks), and to compare the accuracy of estimated fetal weight (EFW) between those small for gestational age (SGA) and those appropriate for gestational age (AGA).

Study design: A retrospective study was conducted of data recorded between January 2010 and March 2023. Included were women with singleton livebirths at 23+0-31+6 weeks who had an EFW within one week from delivery. Mean percentage error, mean absolute percentage error, and underestimation and overestimation rates were calculated. We compared the accuracy of EFW between SGA and AGA infants.

Results: In total, 360 women were included. The mean absolute percentage error was 7.8 % (range 0 %-68.9 %); for 207 (57.5 %) infants the percentage error was within ±10 %. Overestimation error >10 % was observed in 102 (28.3 %) infants and errors >20 % in 34 (9.4 %). Among infants born in the periviable period (23+0 - 25+6 weeks; N = 56), the mean absolute percentage error was 9.8 % (range: 0 %-40.3 %); the value was within ±10 % for only 28 periviable infants (50 %) and exceeded 20 % for 16.1 %. Among SGA compared to AGA infants, the mean absolute percentage error was higher (11.1% vs. 6.6 %, p = 0.035). Overestimation error >10 % was more frequent among SGA than AGA infants (55 (49.1 %) vs. 47 (19.0 %), p < 0.001). In a multivariate logistic regression analysis, SGA status was independently associated with a higher mean percentage error (beta = 0.260, p < 0.001) and an increased risk of an error >10 % (odds ratio = 2.1, 95 % confidence interval 1.2-3.5, p = 0.008).

Conclusions: Sonographic EFW is limited in assessing very preterm infants, particularly those who are SGA or born during the periviable period. These limitations should be considered regarding impending very preterm births and concerns about abnormal fetal growth.

Keywords: Fetal weight estimation; Overestimation; Periviable infants; Preterm delivery; Small for gestational age; Sonography.