DEVELOPMENT OF A NORMAL RANGE FOR FIRST TRIMESTER PREGNANCY INTRACRANIAL TRANSLUCENCY MEASUREMENTS

Abstract

Intracranial translucency (IT) by ultrasound in the first trimester is used in screening for open spina bifida, which is predominantly seen in the second trimester morphology ultrasound. IT has been used in many countries, including Asian and European countries. The aim of this study is to generate an IT normal range and to correlate IT measurements and neurological system abnormalities identified during second trimester ultrasound scan. A retrospective cohort study was performed using 199 foetal records taken from nuchal translucency (NT) clinic, from 1 June 2016 to 30 November 2019. Intracranial translucency (IT) measurements were assessed using existing nuchal translucency (NT) images of the foetuses aged 11 weeks to 13 weeks and 6 days of gestational age, where the foetal measurements taken for this study were between 45 and 84 mm. Eighteen samples were excluded, leaving only 181 samples that met the set criteria were used to establish the IT normal range. Inclusion criteria for this study involved all pregnant women with singleton pregnancies who had undergone NT scan with gestational ages ranging from 11 to 13 + 6 days. Based on the normal range value created, a total of 144 samples were normal foetuses, while the other 37 foetuses had various ultrasound abnormalities in the second trimester of pregnancy with no open spina bifida found. The results obtained exhibit linearly increased IT measurements with increasing crown-rump length (CRL), gestational age (GA), and nuchal translucency (NT).