Abstract: Fetal choroid plexus cysts (CPCs) are a common central nervous system malformation, with 1%~4% of all fetus suffering. They can be diagnosed by routine ultrasound examination during the first or second trimester pregnancy，and be associated with fetal chromosomal abnormalities and nervous system abnormalities especially with regard to trisomy 18 and Aicardi syndrome. This association is also influenced by many factors. So physicians should consider these factors first, such as isolated CPCs or CPCs associated with other fetal abnormalities, the risk of trisomy based on mother’s serum screening, the characteristics of CPCs and so on. Then, physicians can predict the individual risk and provide accurate genetic counseling.

Key words: Choroid plexus cysts, Prenatal diagnosis, Trisomy 18, Aicardi syndrome