Maternal Infections in Pregnancy Flashcards
Why is it important to know about maternal infections during pregnancy?
Some infections have the propensity for vertical transmission to the foetus despite mother being asymptomatic.
There is a potential for suboptimal management unless discussed with relevant expert colleagues.
Which viruses have the propensity to cause deleterious effects on the foetus?
Parvovirus
Cytomegalovirus
Varicella zoster virus
How can likelihood of infection be minimised?
Educate mothers/partners/doctors on infection transfer
Antenatal screening / preconception (rubella immunity, HBV sAg, HCV, HIV, syphilis, be especially rigorous with non-Australian born patients.
Active immunisation pre-conception against HBV, VZV, measles, mumps, rubella, HPV,
Passive immunisation (post exposure prohylaxis) involving IgG antibodies or normal human IgG if the former is not available.
When can pregnant women be vaccinated?
It is always fine provided the vaccine is not a live virus.
When is it best to administered a vaccine against whooping cough?
Last trimester of pregnancy i.e >16 weeks in
When is contact with rash illness during pregnancy a concern?
Only with direct contact. Otherwise, majority of cases are of no concern
What are the differential diagnoses for an infective rash?
Varicella-zoster virus
Parvovirus B19
Enteroviruses (coxsachie, echovirus, etc)
etc
When is rubella an issue during pregnancy?
Before 16 weeks it can be problematic, after 16 weeks it is harmless to the foetus.
How is diagnosis of viral infection conducted?
Serology for pre-existing immunity (IgG)
Serology for IgM, or IgG seroconversion (need 1 - 2 weeks to demonstrate)
Compare with booking antenatal sera (held for 12 months min)
IF of rash material: for VZV, herpes simplex but not perfect
PCR and/or culture
What percentage of pregnancies are estimated to be complicated by varicella? What should be considered?
10 - 60/year. Consider utero foetal or neonatal infection
What complications can arise from maternal varicella infection?
Causes morbidity in later pregnancy
Increase risk of viral pneumonitis
Risk factors for pneumonitis include smoking and >100 lesions.
What must be done if maternal varicella is diagnosed?
Antiviral therapy must be utilised early to maximise the benefit
What investigations should be done with mothers that have been exposed to chickenpox?
Attempt to confirm the index case (Check whether they’ve had VZV vaccination)
Determine mothers serostatus (95 to 99% of people who had chicken pox have detectable anti VZV IgG and are thus immune)
What percentage of people who do not report a history of chicken pox have anti VZV IgG?
60 to 93%
How many chickenpox vaccine shots need to be given to be considered immune to VZV?
2 doses.
If 1 dose immunity should be tested for via serology.
How is the maternal risk of VZV infection different to other adults (<20 weeks)?
Maternal risk for serious disease not increased over that of other non-pregnant adults.
How is congenital varicella zoster treated (if <20 weeks)?
Small risk of congenital varicella syndrome is ~1% and this should be treated with VZIG antibodies asap.
Consider acyclovir if chickenpox is developed.
No evidence that these methods work but it may do so
What are the risks associated with VZV exposure at >20 weeks?
Increased maternal risk of pneumonitis particularly if smoker.
Increased risk of shingles in infant (from birth to adolescence)
Scattered case reports of congenital abnormalities.
