INFECTIONS IN PREGNANCY

Question 1

What is the virus responsible for fetal varicella syndrome?

Answer 1

Varicella zoster virus (chickenpox)

Question 2

What are the features of fetal varicella syndrome?

Answer 2

Skin scarring - 78%

Microcephaly

Eye defects (microphthalmia) - 60%

Limb hypoplasia - 68%

Learning disabilities

Question 3

At what point in the pregnancy is the fetus at risk of developing fetal varicella syndrome?

Answer 3

1% risk before 20 weeks (often between 8-20 weeks)

Very rare after this

Does not occur after 28 weeks

Question 4

Apart from fetal varicella syndrome, what are the other risks (to the fetus) of the mother contracting chickenpox whilst pregnant?

Answer 4

Severe neonatal chickenpox

Shingles in infancy

Question 5

What is the risk of chickenpox to the pregnant mother?

Answer 5

There is a 5 fold increase in the risk of pneumonitis if pregnant with chickenpox vs non-pregnant women

Question 6

How do we manage a mother who is worried about her exposure to chickenpox?

Answer 6

if doubt about maternal status -> check varicella Ab

If the pregnant women is not immune to varicella + within 96 hours of exposure -> varicella zoster immunoglobulin (VZIG)

If > 96 hours of exposure -> PO valaciclovir (if late pregnancy, lung disease, immunocompromised, smokers or presenting within 24 hours of rash)

vaccine cannot be given

Question 7

How do you manage a foetus with known exposure to VZV?

Answer 7

1) detailed foetal US at least 5 weeks after infection - repeated until delivery
2) if abnormal US -> amniocentesis for VZV PCR

Question 8

How do you manage a neonate exposure to maternal chickenpox?

Answer 8

• exposed > 7 days before delivery -> nil intervention
• exposed < 7 days before delivery -> ZIG within 24 hours
• exposed 2-28 days after birth -> ZIG

Question 9

How do you manage a neonate exposure to chickepox (acquired on their own)?

Answer 9

• if maternal Hx of chickenpox/age appropriate vaccine -> no intervention required
• if uncertain –> check maternal serology –> if negative –> ZIG
• if Sx/preterm –> IV acyclovir

Question 10

At what point in the pregnancy is the fetus at risk of developing fetal varicella syndrome?

Answer 10

first 8-10 weeks -> 90% risk

rare after 16 weeks

Question 11

Sx of maternal rubella

Answer 11

ASx in up to 50%
mild fever
macpap rash
arthralgia
lymphadenopathy: post-auricular, suboccipital
self-limiting

Question 12

Dx of rubella in mother

Answer 12

paired sample (10-14 days apart)

• appearance of IgM Abs
• > 4x fold increase in IgG

(check parvovirus serology too)

Question 13

Congenital Rubella Syndrome Sx

Answer 13

sensorineural deafness
cardiac: VSD, PDA
cataracts
hepatosplenomegaly
purpuric skin lesions - blueberry muffin
microcephaly

Question 14

Dx of foetal infection

Answer 14

after 20 weeks amniocentesis/cordocentesis;

i. viral PCR/culture
ii. foetal IgM

Question 15

Px of maternal parvovirus B19

Answer 15

up to 40% is subclinical
rubella-like rash
arthralgia

Question 16

Foetal effects of parvovirus B19

Answer 16

foetal anaemia & hydrops - 5 weeks after maternal infection

US findings:
ascites, skin oedema, pleural & pericardial effusion, placental oedema

Question 17

Mx of foetal exposure to maternal infection of Parvovirus B19

Answer 17

nothing to prevent hydrops

monitor w serial US every 1-2 weeks for 12 weeks

Question 18

Mx of maternal influenza infection

Answer 18

Sx Tx with paracetamol
anti-influenza medication to reduce severity of disease

if infected after birth:
considered non-infectious after 72 hours of Tx w anti-influenza medication - continue breastfeeding but sleep 1m apart

Question 19

Sx of primary maternal CMV

Answer 19

mononucleosis like syndrome (flu-like)
abnormal LFTs/
rash

Question 20

What % of neonates develop symptomatic congenital CMV syndrome?

Answer 20

10%

Question 21

Features of congenital CMV

Answer 21

liver shit - late pregnancy:

• petechiae
• jaundice
• hepatosplenomegaly
• thrombocytopenia

early pregnancy:

• SGA
• microcephaly
• intracranial calcifications

sensorineural hearing loss
chorioretinitis
seizures

Question 22

Management of Maternal HCV

Answer 22

• maternal HCV serology (note that seroconversion takes 21 days)
• avoid foetal scalp electrodes, scalp blood sampling, vigorous aspiration or oral suction
• encourage breastfeeding
• HBV vaccine within 12 hours of birth
• test baby’s HCV Abs at > 18 months
• test maternal follow up in 6-12 months

Question 23

What is the risk of Toxoplasmosis transmission to baby?

Answer 23

< 13 weeks: 5-15% -> 60-80% risk of abnormalities
13-24 weeks: 25-40% -> 15-25% risk of abnormalities
24-36 weeks: 30-75%
36 weeks: 72% risk -> 2-10% risk of abnormalities

Question 24

Px of congenital toxoplasmosis syndrome?

Answer 24

majority are ASx
fever
macpap rash
hepatomegaly
microcephaly
chorioretinitis
seizures
jaudnice 
thrombocytopenia

Question 25

What are the long term sequelae of untreated congenital toxoplasmosis?

Answer 25

intellectual disability
deafness
chorioretinitis
seizures
spasticity

Question 26

Tx of toxoplasmosis

Answer 26

spiramycin PO syrup for 12 months -> repeat IgG at 6 months