EP05.16: Narrow CSP in second trimester and its implications for prenatal counselling

To identify the incidence of narrow CSP and establish its implications as a helpful tool in prenatal counselling. This is a retrospective study carried out between November 2022 to June 2023. Among the patients attending for second trimester scans, patients with narrow CSP were identified (CSP width less than -2 SD). Extended neurosonogram and detailed anatomical assessment was done for the presence of associated cranial and extracranial anomalies. The genetic testing results were studied and perinatal outcomes correlated. Total number of patients were 10812. Out of these 115 had narrow CSP (1.06%). It was an isolated finding in 73 cases (63%) and associated with other abnormalities in 42 cases (36%). Aneuploidy markers coexisting with narrow CSP: 3 cases of renal pelviectasis (2.6%), 9 cases of echogenic foci in left ventricle (7.8%), 5 cases of choroid plexus cysts (4.3%) and 1 case of echogenic foci in rectosigmoid. 3 patients underwent direct testing for genetic anomalies and all of them had normal karyotype. Abnormal CSP is an important marker of major intracranial anomalies. In case of narrow CSP, an extended neurosonogram and a thorough anatomical survey is essential to detect associated abnormalities. Presence or absence of these abnormalities decides the need for genetic testing and gives invaluable guidance in prenatal counselling. Narrow CSP if isolated is associated with favourable outcome.