Infections in Pregnancy Flashcards
Why are infections particularly important in pregnancy?
Maternal illness - may be wore as with varicella
Maternal complications - as with pre-eclampsia in HIV +ve women, may be more common
Preterm labour - associated with infections
Vertical transmissions - innocuous infections can cause miscarriage, be teratogenic or damage developing organs
Neurological damage - more common in the presence of bacterial infection in both preterm and term babies
Abx - usage in pregnancy is occasionally limited by adverse effects to the foetus
Describe the pathology of CMV?
CMV is a herpesvirus - transmitted by personal contact
What is the impact of CMV in pregnancy?
common cause of childhood handicap or deafness
Fetal growth restriction Microcephaly Hearing loss Vision loss Learning disability Seizures
How is CMV diagnosed?
USS abnormalities are evident in 20% (intracranial or hepatic calcification)
CMV IgM remains +ve fora long time after infection and could predate the pregnancy, so can do IgM titters
IgG avidity will be low with recent infection
if maternal infection is confirmed, amniocentesis at least 6 weeks after maternal infection will confirm or refute vertical transmission
What is the management of maternal CMV?
USS
no prenatal treatment
termination may be offered
Routine screening is not advised and no vaccine available
What is the pathology of herpes simplex infection?
Type 2 DNA virus causes genital herpes
<5% women have history of prior infection, but many have antibodies
What is the foetal/neonatal effect of herpes simplex
HSV is not teratogenic and neonatal infection is rare, but has a high mortality
Vertical transmission occurs at vaginal delivery, particularly if vesicles are present. Most likely to follow recent primary maternal infection as the foetus will not have passive immunity from maternal antibodies
How is herpes simplex diagnosed?
clinically
swabs are of little use in pregnancy
What is the management of maternal herpes simplex?
referral to GUM - C-section is recommended for those delivering within 6 weeks of primary attack and those with genital lesions - risk is very low in recurrent herpes who have vesicles at time of labour, so C-section not recommended
Daily acyclovir in late pregnancy may reduce the frequency of recurrences at term - exposed neonates are given aciclovir
What are the risks of VZV in pregnancy?
More severe cases in the mother, such as varicella pneumonitis, hepatitis or encephalitis
Fetal varicella syndrome
Severe neonatal varicella infection (if infected around delivery)
What are the foetal/neonatal effects of herpes zoster?
Fetal growth restriction
Microcephaly, hydrocephalus and learning disability
Scars and significant skin changes located in specific dermatomes
Limb hypoplasia (underdeveloped limbs)
Cataracts and inflammation in the eye (chorioretinitis)
What is the management of maternal herpes zoster?
If exposed to chickenpox:
women are tested for immunity and immunoglobulin given within 10 days if non-immune or acivlovir given if infection occurs
in late pregnancy, if delivery is 5 days after or 2 days before maternal symptoms then neonate are given immunoglobulins and acivloir if infection occurs, vaccination is possible
describe the pathology of rubella
congenital rubella syndrome is caused by maternal infection with the rubella virus during the first 20 weeks of pregnancy. The risk is highest before ten weeks gestation.
What are the foetal/neonatal effects of rubella?
Congenital deafness
Congenital cataracts
Congenital heart disease (PDA and pulmonary stenosis)
Learning disability
What is the management of rubella?
Women planning to become pregnant should ensure they have had the MMR vaccine. When in doubt, they can be tested for rubella immunity. If they do not have antibodies to rubella, they can be vaccinated with two doses of the MMR, three months apart.
Pregnant women should not receive the MMR vaccination, as this is a live vaccine. Non-immune women should be offered the vaccine after giving birth.
if non-immune women develops rubella <16 weeks then termination is offered
What is the pathology of parvovirus?
Parvovirus B19 infects 0.25% of pregnant women, but 50% are immune
What is the appearance of parvovirus?
‘slapped cheek appearance’
A few days later a reticular mildly erythematous rash affecting the trunk and limbs appears, which can be raised and itchy.
may have arthralgia or be asymptomatic - infection usually from children
What are the foetal/neonatal effects of parvovirus?
Miscarriage or fetal death
Severe fetal anaemia
Hydrops fetalis (fetal heart failure)
Maternal pre-eclampsia-like syndrome
How is diagnosis of parvovirus done?
IgM to parvovirus, which tests for acute infection within the past four weeks IgG to parvovirus, which tests for long term immunity to the virus after a previous infection Rubella antibodies (as a differential diagnosis)
What is the management of of parvovirus?
Treatment is supportive. Women with parvovirus B19 infection need a referral to fetal medicine to monitor for complications and malformations
What is the pathology of Hepatitis B?
Caused by small DNA virus and transmitted by blood products or sexual activity - infection resolves in 90% adults, but persists in 10%
What are the fetal/neonatal effects of hepatitis B?
Vertical transmission occurs in delivery - 90% of infected neonates become chronic carriers, compared to 10% of adults
What is the management of hepatitis B?
Screening at booking
To reduce the risk of the baby contracting hepatitis B, at birth (within 24 hours) neonates with hepatitis B positive mothers should be given both:
Hepatitis B vaccine
Hepatitis B immunoglobulin infusion
Infants are given an additional hepatitis B vaccine at 1 and 12 months of age. They will also receive the hepatitis B vaccine as part of the normal 6 in 1 vaccine given to all infants aged 8, 12 and 16 weeks. They are tested for the HBsAg at 1 year to see if they have contracted hepatitis B.
What % of pregnant women in the UK are infected with Hepatitis C?
0.5%
Worldwide incidence of 3% and 30% in HIV +ve
What are the main risk factors of Hepatitis C?
Drug abuse and sexual transmission