Cytomegalovirus Infection in Pregnancy

Question 1

What is CMV?

Answer 1

A member of the herpesvirus family (herpesvirus 5)

Question 2

How common is CMV, in relation to other infections transmitted to the fetus during pregnancy?

Answer 2

It is the most common virus transmitted to the fetus during pregnancy

Question 3

What proportion of women become infected with CMV during pregnancy?

Answer 3

Approx 1 in 100

Question 4

What proportion of maternal CMV infections are vertically transmitted to the fetus?

Answer 4

Around 1/3

Question 5

What % of fetal CMV infections will cause damage to the fetus?

Answer 5

5%

Question 6

When is the highest risk of a fetal CMV infection causing damage to the fetus?

Answer 6

In the first trimester

Question 7

How can maternal acquisition of CMV infection occur?

Answer 7

• Close contact, including household contacts and occupational exposure
• Sexual exposure
• Transfusion
• Organ transplantation

Question 8

Is CMV always active?

Answer 8

No, it can cycle through periods where it lies dormant and then reactivates

Question 9

When can CMV be passed onto other people, including the baby?

Answer 9

During activation

Question 10

What is the most common presentation of CMV infection?

Answer 10

It is usually asymptomatic in immunocompetent individuals

Question 11

If symptomatic, how might CMV present?

Answer 11

Can cause mild flu-like illness, or in some patients a mononucleosis syndrome

Question 12

What can a mononucleosis syndrome-type presentation of CMV cause?

Answer 12

• Fever
• Splenomegaly
• Impaired liver function

Question 13

What investigations are done if maternal CMV is suspected?

Answer 13

Viral serology for CMV specific IgM and IgG

Question 14

What is a positive test for viral serology in suspected maternal CMV?

Answer 14

• Presence of CMV specific IgG in mother that was previously seronegative
• Presence of CMV IgM and low IgG avidity

Question 15

What is meant by avidity?

Answer 15

The strength with which the antibody binds to the antigen

Question 16

What management is required in immunocompetent women?

Answer 16

No treatment is required

Question 17

What anti-CMV drugs are available?

Answer 17

• Gangciclovir

- Forscarnet

Question 18

Should anti-CMV drugs be used in pregnancy?

Answer 18

No

Question 19

Why should anti-CMV drugs not be used in pregnancy?

Answer 19

Because they have potential teratogenic effects, and can cause haematological and renal toxicity

Question 20

How can fetal CMV infection be diagnosed prenatally?

Answer 20

Via amniocentesis and PCR of the amniotic sample

Question 21

When can prenatal testing for fetal CMV infection be carried out?

Answer 21

After 21 weeks gestation

Question 22

Why can prenatal testing for fetal CMV infection only be carried out after 21 weeks gestation

Answer 22

Because functioning fetal kidneys are required for the virus to be excreted into the amniotic fluid

Question 23

What should be done if fetal CMV infection is confirmed?

Answer 23

There is no effective therapy, and termination of the pregnancy should be offered

Question 24

What should be done if a woman with fetal CMV infection wants to continue with the pregnancy?

Answer 24

Serial ultrasound scanning should be performed

Question 25

What is the purpose of serial ultrasound scanning when there is confirmed fetal CMV infection?

Answer 25

To assess for the manifestations of congenital CMV