# Gestational Age-Specific Reference Ranges for Fetal Cavum Septum Pellucidum Width in an Iranian Population: Gestational Age-Specific Reference Ranges for Fetal Cavum Septum Pellucidum Width

## TL;DR

This study establishes gestational age-specific reference ranges for fetal CSP width in an Iranian population using ultrasound measurements from 1000 normal fetuses.

## Contribution

The study provides population-specific normative data for CSP width in Iranian fetuses across gestational ages.

## Key findings

- CSP width increased from 18 to 33 weeks, plateaued at 33–37 weeks, and slightly declined near term.
- Strong correlations were found between CSP width and head circumference (r=0.644) and biparietal diameter (r=0.631).
- Normative values were defined using percentile distributions with a 5th percentile length-to-width ratio of 1.06.

## Abstract

Cavum septum pellucidum (CSP) is a critical anatomical land mark of normal
midline development of brain and its absent is associated with brain
anomalies. On the other hand, the size of CSP differs among different
populations. The aim of this study was the evaluation of the size (width) of
CSP at various gestation age (18 to 40 weeks’ pregnancy) in Isfahan, Iran
population.

This cross-sectional study was performed at Isfahan hospitals (Al-Zahra and
Shahid Beheshti) from December 2022 until December 2023. The CSP was
measured in 1000 normal fetuses at trans-ventricular plane by
trans-abdominal ultrasound by two expert operators. In these fetuses the HC
and BPD were measured. Regression analysis revealed significant relationship
between CSP width and gestational age, also between CSP width and HC and
BPD.

The mean CSP width was 5.3 ± 2.08 mm, ranging from 2.15 mm to 8.85 mm. CSP
width increased progressively from 18 to 33 weeks, plateaued at 33–37 weeks,
and slightly declined near term. Strong correlations were found between CSP
width and head circumference (HC) (r=0.644, P0.01) and biparietal diameter
(BPD) (r=0.631, P0.01). The study defined normative fetal CSP development
values using percentile distributions with a 5th percentile length-to-width
ratio of 1.06.

The present study provides normative data for fetal CSP width and useful
information about the development of the CSP based on gestational age.