The association of choroid plexus cysts with fetal aneuploidy, particularly trisomy 18, was first noted in 1986. Through the years there have been numerous reports on this subject, but no consensus has been reached with regard to chromosomal risk. In this review, we attempt to summarise published reports on second trimester choroid plexus cysts, with an emphasis on the strengths and weaknesses of each report. Based on these reports, additional malformations are a significant risk factor for aneuploidy and an indication for determination of fetal karyotype. The management of isolated choroid plexus cysts remains controversial.