Objectives: To identify and evaluate the congenital central nervous system (CNS) malformations and its associated anomalies. To identify any existing risk factors.

Methods: All confirmed cases of congenital cranial nerve system (CNS) anomalies from 2006-2015 from the database of the Ultrasound Unit in University Malaya Medical Centre were analysed. The medical records were obtained from the Medical Records Department.  The demographic and pregnancy data were collected including antenatal and delivery data, age, race, history of smoking and co-morbid factors such as diabetes and pregnancy-induced hypertension (PIH). All the collected data were analyzed using SPSS version 21 and the study is using Pearson Chi-Square test (p-value). In all cases, p value < 0.05 was considered statistically significant.

Results: There were 298 (27%) confirmed cases of CNS anomalies from 2006-2015 out of 1099 all congenital malformations. Statistical analysis shows the mean maternal group age is 30.84 with highest age of 45 and lowest age of 19. The population race in this study consist of 222 Malay (74.5%), 37 Chinese (12.4%), 28 Indian (9.4%) and 11 others (3.7%). There were 220 cases with single congenital CNS anomaly (73.8%) and 77 cases with multiple congenital CNS anomaly (25.8%). The types of diagnosis of the congenital CNS anomaly include 110 ventriculomegaly (28.1%), 45 anencephaly (11.5%), 9 fetal acrania (2.3%), 15 microcephaly (3.8%), 37 holoprosencephaly (9.4%), 36 cisterna magna anomalies (9.2%), 29 spina bifida (7.4%), 20 encephalocoele (5.1%), 17 agenesis of corpus callosum (4.3%), 21 Dandy-Walker variant (5.4%), 6 posterior fossa cyst (1.5%), 15 choroid plexus cyst (3.8%), 2 arachnoid cyst (0.5%), 2 hydrocephalus (0.5%), 8 hypoplastic cerebellum (2.0%), and 17 others CNS anomaly (4.3%).

Conclusions: Congenital cranial nervous system anomalies are one of the commonest congenital malformations and ultrasound is a useful tool for diagnosis.