CMV in Pregnancy: Exposure Concerns & Antibody Timing

Question
Dear Doc-
I never had heard of cmv till mid second trimester. i have a son in preschool he is 3 and 4 months. I am worried about an exposure as i am not immune. Is this common to occur in pregnancy? on occasion i have kissed my son on cheek hand shared drink exc.. also after a possible exposure how long woulkd it take for antibodies to show up? thanks again.

Answer
You certainly should continue to hold your son and kiss him. You do not have to be that compulsive. CMV infection is the most common congenital infection, affecting 0.4-2.3% of babies.  It is a DNA herpesvirus. In the United States, approximately half of the population is CMV seropositive. The virus has been isolated from saliva, cervical secretions, semen, and urine. Infection can also be contracted by exposure to infected breast milk or blood products. Transmission can occur from mother to child both in utero and postpartum. An estimated 40,000 infants are born infected with CMV infection in the U.S. annually. By school age, 30-60% of children are infected.Most women with CMV are asymptomatic. These symptoms include low grade fever, malaise, arthralgias, and pharyngitis. Maternal infection currently can be detected reliably only by documenting maternal seroconversion using serial immunoglobulin G measurements during pregnancy. If seropositivity is detected at least several months before conception, symptomatic fetal infection is unlikely. In practice, this testing does not occur. Most primary infections are clinically silent, so the majority are undiagnosed.  Screening is not recommended. All babies are evaluated upon delivery. I do not think you should worry about it because there is really nothing you can do about it.