Cytomegalovirus Infection and Pregnancy Max Brinsmead MB BS PhD May 2015

Cytomegalovirus Proper name is Human Herpesvirus 5 1:100 babies are born with this congenital infection 1:10 of those infected will show some effect 1:10 of those will have severe mental retardation CMV is a common cause of mental retardation And causes 30% of congenital neural deafness ~40% of women are non immune when pregnant Health workers and women with children who bring home CMV are most at risk Vaccination is not possible But trials are currently in progress

Neonatal CMV Syndrome Small for dates Failure to thrive Hepatospenomegaly Microcephaly Cerebral calcifications Chorioretinitis Hearing deficits (may occur later in life) The virus can be detected in urine and saliva

Vertical CMV Transmission 1-4% of women seroconvert during pregnancy 90% of congenital CMV is due to primary maternal infection Risk to the fetus with CMV reinfection is 0.5 – 2% Reinfection with another strain is also possible The earlier the infection in pregnancy the greater the risk Can cause miscarriage in the 1st trimester Risk to the fetus is small if infection is acquired prior to pregnancy Fetal infection cannot be predicted by maternal testing but IgG avidity testing emerging as a pointer

Diagnosis of Intrauterine CMV Maternal infection commonly asymptomatic but 5% have an illness that resembles glandular fever Requires identification of both IgM and IgG in a previously seronegative woman Or IgM alone when reactivation from latency occurs IgM can persist for months after primary infection False positive IgM can occur by cross reaction with other Herpes viruses The virus can be detected by amniocentesis – refer to a major perinatal centre Serial USS, amniocentesis and cordocentesis Viral DNA by PCR etc. emerging methods

Treatment of Intrauterine CMV Termination of pregnancy is really the only option Should respond to anti viral agents such as Ganciclovir and Valganciclovir but their role in pregnant women and the neonate is unproven Trials are underway Likewise little data on the role of prophylactic immune gamma globulin One non-RCT trial showed it to reduce fetal risk by ≈60%

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