If a woman at risk of congenital CMV chooses to have an amniocentesis for diagnosis of fetal infection, this sampling provides an opportunity to collect an aliquot of AF for RNA analysis. RNA sequencing (RNAseq) is a relatively new technology that enables detailed analysis of the genes that are actively expressed ('switched on') during a particular disease state. The investigators will apply RNAsequencing methods to amniotic fluid to search for potential gene expression differences that may assist in understanding the disease through functional analysis and identifying candidate biomarkers for future studies.