Evaluation of Prenatal Central Nervous System Anomalies: Obstetric Management, Fetal Outcomes and Chromosome Abnormalities

Abstract

\n Objective: To study the prognostic outcomes of fetuses with prenatally diagnosed central nervous system (CNS) anomalies and describe the obstetric management for those fetuses.Methods: In this retrospective study, fetuses who were detected to have central nervous system by prenatal ultrasound from January 2010 to December 2019 were recruited. Data regarding prenatal diagnosis and obstetric outcome were retrieved from maternal and paediatric records. Prognosis of children who survived till delivery was classified based on their neurodevelopmental outcome within 2 years of life.Results: 365 fetuses were prenatally diagnosed with CNS malformations within the 10-year study period, at a mean gestational age of 24.65±7.37 weeks at diagnosis. Ventriculomegaly (23.36%) was the commonest CNS anomalies diagnosed antenatally. 198 (54.20%) fetuses has associated extra-CNS anomalies, with cardiovascular system being the most common organ system involved with CNS anomalies. Karyotyping was performed in 111 pregnancies, with chromosomal aberrations detected in 53 (49.07%) cases and culture failure in 3 cases. Edward syndrome and Patau syndrome were commonly associated with CNS anomalies. Fetuses with congenital CNS anomalies and abnormal chromosomal karyotyping more likely to be diagnosed earlier by prenatal ultrasound and tend to have poorer obstetric and neurocognitive prognosis. Among the 279 cases whom their pregnancy outcomes were available, 105 (37.63%) pregnancies were electively terminated, 35 (12.54%) pregnancies ended in spontaneous loss while the remaining 139 (49.82%) cases resulted in live births. The decision of TOP largely depends on mean diagnostic gestational age, presence of chromosomal aberrations and abnormal amniotic fluid volume in those fetuses. Ruling out 21 (15.11%) cases which were lost to 2-year follow-up, only 75 (53.96%) infants were still alive by the age of 2 years. Only 32 (23.02%) children with prenatally diagnosed CNS anomalies had normal neurodevelopmental outcome. The presence of multiple CNS anomalies and involvement of extra-CNS anomalies indicated a poorer neurodevelopmental prognosis.Conclusion: Less than 50% of fetuses with prenatally diagnosed CNS anomalies resulted in live births. Even if they survive till delivery, majority passed away within 2 years or had neurodevelopmental disability.