CMV In Pregnancy

Question 1

What is the incidence of Congenital CMV ?

Answer 1

0.5 - 2 %
One of the most common congenital infections

Question 2

What is the leading cause of childhood deafness?

Answer 2

Congenital CMV

Question 3

What is the risk of vertical transmission of CMV in each trimester?

Answer 3

*In PRIMARY infection
1st & 2nd trimester 40%
3rd trimester 80%
*In RECURRENT infection
1 - 2 %

Question 4

What is the risky period for congenital CMV ?

Answer 4

Primary infection
Before 14 w 👉 severe infection
3rd trimester 👉 highest risk of transmission

Question 5

What is the risk of damage if the fetus is infected as a result of primary maternal infection with CMV ?

Answer 5

25 % if the fetus is infected
- 10 % of them are symptomatic at birth
- 10 % of those asymptomatic at birth will devlop Long term hearing loss

Question 6

What are the ways of transmission in CMV infection?

Answer 6

Respiratory - food sharing - breastfeeding - kissing - vertical infection - sexual intercourse…
( by body fluids)

Question 7

What are the maternal symptoms of CMV infection?

Answer 7

90 % asymptomatic
Pharyngitis - rhinitis - arthralgia
Headache - myalgia - fatigue

Question 8

What are the features of congenital CMV ?

Answer 8

1-📌 Ocular defects : chorioretinitis - cataracts - optic atrophy - microphthalmos - visual impairment
2-📌 sensorineural : deafness 12 %
3-📌 hepatospleenomegaly: jaundice - thrombocytopenia purpura
4-📌 pneumonitis
5-📌 microcephaly
6-📌 cerebral palsy 8%
7-📌 epilepsy + learning disability
8-📌 IUGR

Question 9

What is the percentage of
deafness / cerebral palsy
caused by congenital CMV ?

Answer 9

12 % deafness
8 % cerebral palsy

Question 10

How many of Congenital CMV are asymptomatic at birth?

Answer 10

Asymptomatic 75 - 90 %
Symptomatic at birth 10%

Question 11

What is the percentage of infected infants identified by US ?

Answer 11

1 / 3

Question 12

What are the US markers suggestive of CMV infection?

Answer 12

1- echogenic fetal bowel
2- periventicular calcification
3- hydrops / ascites/ pleural efusion
4- cerebral ventriculomegaly / microcephaly
5- hepatospleenomegaly
6- periventricular cysts
7- FGR

Question 13

What is the clinical significance of fetal echogenic bowel by ultrasound?

Answer 13

90 % normal findings
Fetal aneuploidy especially trisomy21
Viral infections especially CMV

Question 14

What is the serological tests in maternal infection with CMV ?

Answer 14

CMV IgM :
within 2 w & persist 3-4 months
may persist at low levels for years
False positive 2%
Not diagnostic
CMV IgG :
2-3 w of primary infection
ℹ seroconversion from IgG negative to positive : is diagnostic of acute infection
ℹ reinfection: ⬆️ IgG 4 folds

Question 15

For most viral infections, such as rubella , IgM is diagnostic of recent primary infection, why this isn’t the case for CMV ?

Answer 15

1- IgM may persist for many months after the primary infection
2- IgM may be detected in a secondary infection
3- there may be cross reactivity with IgM due to another viral infection ( Epstein barr virus)
4- IgM may be detected as a result of nonspecific stimulation of immune system

Question 16

What is the AVIDITY INDEX ? What does it suggestive of in CMV infection?

Answer 16

AVIDITY INDEX: Expresses the percentage of IgG bound to the antigen
> 60 - 65 % 👉 past or secondary infection
< 30 % highly suggestive recent primary infection

Question 17

What are the cases where AVIDITY index help to distinguish between primary and reinfection with CMV ?

Answer 17

Low or equivocal IgM response and positive IgG and no previous sample to look at for seroconversion
ℹ this test has high sensitivity & specificity

Question 18

What is the serological diagnosis of primary CMV infection during pregnancy?

Answer 18

1- seroconversion ( IgG)
2- IgM + IgG with low AVIDITY index

Question 19

What is the diagnostic test for fetal CMV infection ?

Answer 19

AMNIOCENTESIS: should be done:
1- 7 weeks after maternal infection
2- after 21 weeks of pregnancy
*This interval allows excretion the virus in the urine into the amniotic fluid
* PCR

Question 20

What is the maternal management in maternal CMV infection ?

Answer 20

1- no acceptable treatment
2- serial US : 3-4w to monitor growth & HC
3- MRI : to assess any obvious lesions

Question 21

What is the next step if fetal infection with CMV is confirmed by amniocentesis?

Answer 21

1- detailed US every 2 - 4 weeks
2- fetal brain MRI 28- 32 weeks
3- fetal blood sample