Cytomegalovirus (CMV) poses a risk to fetal development only when contracted during the first half of pregnancy. Only 40% of these fetuses will develop the infection and of those, only 5 to 15% will have symptoms at birth. In a severely affected fetus, CMV may result in intrauterine growth restriction (IUGR), microcephaly, calcification in the brain, cognitive disabilities, hearing loss, low blood platelet count and liver enlargement.
Recurrent maternal CMV infection (a CMV infection contracted before the pregnancy) does not pose serious risks to the fetus.
Centers for Disease Control – CMV Congential Infection
Perinatology – Diagnosis & Management of CMV Infection in Pregnancy
Mother-to-Baby – Cytomegalovirus (CMV) & Pregnancy PDF