1. Cytomegalovirus Infection and Pregnancy
Max Brinsmead MB BS PhD
May 2015

2. 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

4. 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

5. 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

6. 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

7. 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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