11 Virus infection in pregnancy Flashcards
why are viruses important in pregnancy
have to consider the potential effects the infection will have on the developing foetus and/or the new-born
what do all human herpesviruses have in common
all exhibit latency – remain infected for life, latent virus can reactivate and cause disease
how many herpesviruses are there
8
examples of herpesviruses
- Herpes simplex type 1
- Herpes simplex type 2
- Varicella-zoster virus
- Epstein-Barr virus
what is chickenpox called
varicella pneumonia
where does chickenpox infect
blood stream
what does chickenpox cause
rash over body
what does chickenpox infection do
During infection enters nerve terminals to nerve cell body – have the latent virus within the spinal cord and cranial nerves, can reactivate and cause rashes where only affects the area of skin that is supplied by the nerve the virus is reactivating
- causes shingles rash
what increases shingles likeliness
age
what is the effect on mother when pregnant with chickenpox
more likely to die
how can chickenpox in pregnancy be treated
aciclovir
what can chickenpox lead to
encephalitis = post infection, rare
what is Congenital varicella
- as virus in the blood stream in chickenpox, viremia = affects foetus
- can interfere with foetal development
what does Varicella embryopathy cause
- Skin loss, scarring, usually unilateral, segmented
- Impaired limb bud development
- Many other, less specific features e.g. microcephaly, cataracts, IUGR
what is the problem neonatal varicella
- baby is born before the mother has chance to make any antibodies that can cross placenta and infect baby
= risk – neonatal chicken pox - rationale – exposure to virus in absence of passively acquired maternal antibody
how are maternal chickenpox situations managed
Try to stop the baby being born
Delivery >7 days after onset maternal rash – not sure if have any antibodies so do passive immunisation
VZIg to neonates born within 7 days of onset of maternal rash – or if post-natal maternal c-pox up to 30 days
Acyclovir given for 2 weeks-worth
what does VZIg do
does not prevent infection, but attenuates severity
what is the risk of mother and child infected with chickenpox
Mother and baby are infection risk to staff, other patients
> infectious before you know it (have symptoms)
what does the anti-VZV medication do
= reduce the chances that she will die of varicella pneumonia
= reduce the chances the virus is going to cross the placenta
- need to give the VZV within 10 days of exposure
what are the problems with c-pox in pregnancy
- C-pox in mother – risk to mother
- C-pox in 1st 20 weeks – risk of fetal damage
- C-pox in late pregnancy – risk of neonatal c-pox
- Shingles in pregnancy – not common
how many people die from neonatal herpes
of the 50% disseminated and/or neurological disease - 70% of these die
what causes neonatal herpes
- Primary
- Recurrent
Non-maternal source e.g. cold sore
what is the difference for mothers that know they have genital herpes
risk of transmission very low (probably because of maternal antibody)
if recurrent genital herpes during pregnancy what happens
c-section
how can recurrence of genital herpes be reduced
aciclovir
how is CMV infection spread to foetus
Crosses the placenta - primary infection - recurring infection - was infected as a child Secondary infection are much more common
is there effect on the foetus when the infection occurs during pregnancy
defects are likely to be greater the earlier in pregnancy
what % of maternal infections are transmitted to foetus
40%
where is CMV present
oral and genital tract secretions, and urine
how is CMV transmitted
sexual and via contact with contaminated objects – will survive on inaminate object
how is CMV transmission reduced
Avoidance of contact with young kids implies very substantial behavioural modification
why is CMV screening not advertised
(i) there is no sensible advice to give to seronegative women
(ii) recurrent CMV infection may also cause symptomatic congenital infection
how is maternal CMV infection diagnosed
- CMV IgM positive
- CMV genome detection in blood, urine
- Comparison with booking sample
what are Hepatitis B virus: modes of transmission
- Mother-to-baby (ie vertical)
- Sexual
- Blood exposure
how is mother to baby transmission of hep B prevented
screen all babies
vaccinate if don’t have the antibodies needed
what is the vertical transmission rate of hep C virus
3-5% (unless HIV co-infected)
is it ok to breast feed with Hep C
yes
what are the vertical HIV transmission routes
- Antenatal – transplacental (unusual)
- Perinatal – infected birth canal, exposure to maternal blood (most prevalent)
- Postnatal – breast milk (HIV infected breast milk)
is it ok to breast feed with HIV
no
what is the overall rate of transmission for HIV to foetus
15-25
how is HIV being prevented
Screen all antenates – anti-HIV If anti-HIV positive - Antiretroviral therapy during pregnancy - Elective Caesarian section - No breast-feeding
what is the effect of parvovirus on pregnancy
increased spontaneous miscarriage
Foetal heart failure = accumulation of fluid – hydrops fetalis
No congenital developmental abnormalities
