Objective:

Determine the prevalence of congenital malformations of the central nervous system, diagnosed by prenatal ultrasound, in the “Dr. Freddy Guevara Zuloaga” from the University Hospital of Caracas, Venezuela, in the period between 2015 and 2023. Methods: Retrospective, descriptive, cross-sectional study. The statistical records of the Unit were reviewed, with a population of 77 534 patients evaluated, of which 3 075 were pathological cases and 775 patients with an ultrasound diagnosis of congenital malformation of the central nervous system were included.

Results:

Among the congenital malformations detected, a prevalence of congenital malformations of the central nervous system of 25,20% was obtained over a period of 9 years. The largest number of studies was carried out in 2016 (12,781). The most frequent congenital central nervous system malformations were: ventriculomegaly (190/24,7%), Arnold Chiari type II (114/14,8%), acrania-exencephaly sequence (96/12,47%).

Conclusion:

Major brain structures can be identified by ultrasound at the end of the first trimester, allowing early diagnosis of major defects such as acrania, anencephaly, and holoprosencephaly. As brain development progresses, some defects in brain growth and differentiation may be detected during routine second trimester anatomical scans.