Transperineal use of a pocket‐sized ultrasound machine vs conventional transvaginal ultrasound: a blinded comparison of cervical length in pregnancy

Abstract

Transperineal use of a pocket-sized ultrasound machine versus conventional transvaginal ultrasound: A blinded comparison of cervical length in pregnancySpontaneous preterm birth is a leading cause of neonatal mortality and morbidity and remains a particular challenge in obstetrics 1 . Sonographic cervical length (CL) is useful to aid in managing women at risk of preterm labour and assist in effective use of healthcare resources. We present our study, evaluating the feasibility and accuracy of measuring CL with a PUM, in a blinded comparison with conventional HSUM TV ultrasound. PUM shows promise as a point of care ultrasound device for measuring CL.The PUM used has a 1.7 -3.8 MHz phased array transducer with a 13 x 19mm footprint and fixed sector angle of 75 0 (GE VScan). A TV probe is not currently provided for PUM units.This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/uog.15861This article is protected by copyright. All rights reserved. Accepted ArticleWe performed a prospective, observational cohort study of 113 non-consecutive pregnant women, 11-40 weeks gestation, who required a transvaginal scan as part of their clinical management and gave consent. Conventional HSUM TV scan of CL was performed by qualified sonographers and PUM TP scan was performed by one of the study investigators, also a qualified sonographer or sonologist, blinded to ultrasound indication and TV scan result.Identical scan techniques were used with the shortest straight line measurement of internal os, cervical canal and external os, recorded for analysis (Figure 1).Paired measurements were obtained in 99/113 patients giving a PUM TP feasibility rate of 88% (95% CI: 81% to 94%). The mean CL using conventional HSUM TV was 32.5mm (SD=9.6, range Ultimately, the accuracy and performance of a new machine is dependent on the users' experience. The PUM TP technique is feasible and for trained operators, accuracy improves with experience. It shows promise as a point of care ultrasound device for measuring cervical length.