Total RNA from AF samples from 10 CMV infected and 10 uninfected fetuses, matched for gestational age and fetal sex, will be analysed. Total RNA will be extracted from the AF supernatant samples will be performed using the Qiagen Circulating Nucleic Acid extraction kit. Whole transcriptome amplification and RNA-sequencing of the cell free RNA will be performed and the expression profiles of the case and control groups compared in a paired analysis as performed in previous studies of AF RNA. Pathway analysis of the differentially-regulated genes will be used for the biological interpretation. The investigators will employ both widely used commercial software (Ingenuity Pathway Analysis™) and a fetus-specific functional analysis tool developed by collaborators at Tufts University (DFLAT).