Peer-reviewed article

Longitudinal Outcomes of Fetuses with an Isolated Narrow Cavum Septi Pellucidi: Prenatal Diagnosis to Early Childhood Neurodevelopment Assessment.

Bhatia A, Ng MY, Chu SH, Tan JVK, Chandran S · 15 Sept 2026

Abstract

Introduction The objective of this study was to evaluate prenatal and postnatal immediate and long-term outcomes of fetuses with an isolated narrow cavum septi pellucidi (CSP). Methods Single-center retrospective review of a cohort of fetuses with an isolated narrow CSP (below -2 standard deviations [SDs] for gestational age [GA]) identified on mid-trimester anomaly scan from 2017 to 2022. Results During the 6 years, 77,546 pregnant women underwent anomaly screening scan, and 228 were identified with an isolated narrow fetal CSP. A follow-up ultrasound at a mean GA of 28.9 weeks showed that CSP measurements were normalized in 58.5% of cases, while in the remaining cases, they were below -2 SD for the respective GA. There were no additional cerebral findings; however, three fetuses were growth-restricted. Among these, 130 mothers delivered at our institution, at a mean GA of 38.3 weeks, and were followed for perinatal and long-term neurodevelopmental outcomes. Clinical examination at birth was unremarkable for all neonates. For the majority of them (n = 105/130), cranial scan at 1 month was normal, and minor findings were noted in 18 cases. Neurodevelopmental outcomes were normal for 81.5% (n = 106) of infants at 2 years, while 24 (18.5%) were referred to the Child Development Unit with concerns regarding speech and language delay, behavioral issues, gross motor delay, and global developmental delay. Extended follow-up showed normal outcomes for 89.2% (n = 116) of cases, nine out of 15 children with speech-language delay had improved, while 5 (3.85%) were diagnosed with autism spectrum disorder. Conclusion An isolated narrow CSP is a benign, transitory subtle anatomical finding in prenatal brain. However, its identification should prompt detailed neuroimaging and evaluation to exclude associated abnormalities. The long-term neurodevelopmental outcome is overall good when the finding is isolated.