Pregnancy & Childhood Infections Flashcards
What are the problems with infections during pregnancy?
Pregnancy does not alter resistance to infection
some infections during pregnancy are more severe and can affect the foetus
What may infections in pregnancy cause?
- Miscarriage
- congenital abnormalities
- fetal hydrops
- fetal death
- preterm delivery
- preterm rupture of the membranes
What is meant by “fetal hydrops”?
A serious fetal condition defined as an abnormal accumulation of fluid in two or more fetal compartments
this includes Ascites, pleural effusion, pericardial effusion and skin oedema
How can the foetus receive immunity?
Maternal antibodies cross the placenta and give passive immunity to the foetus
What is a key message during antenatal counselling?
Avoid exposure to infections during pregnancy
i.e. vaccination (pertussis vaccine b/w 16 - 32 weeks)
What screening is offered during pregnancy?
- Screening for HIV and syphilis and hepatitis B occurs early in pregnancy (by 10 weeks)
- it is reoffered before 20 weeks
- Hepatitis B, HIV and syphilis can all be passed from mother to baby during pregnancy and birth
- early detection aids specialist appointment and interventions/treatment to reduce the risk of transmission
Why is screening for rubella in pregnancy no longer offered?
Screening for rubella in pregnancy is no longer offered
rubella is now very rare in the UK because of the high uptake of the MMR vaccine
What is meant by the TORCH acronym for infections that can be transmitted from mother to baby during pregnancy (in utero)?
- Toxoplasmosis
- Others (syphilis, HIV, Coxsackie virus, Hepatitis B, Varicella zoster)
- Rubella
- Cytomegalovirus
- Herpes simplex virus
How are the following pathogens acquired?
How are they transmitted to the baby?
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- Cytomegalovirus - respiratory droplets / secretions
- Parvovirus B19 - respiratory droplets / secretions
- toxoplasmosis - ingestion of oocytes
- syphilis - sexually transmitted
- varicella zoster virus - respiratory droplets / secretions
- rubella - nasopharyngeal secretions
- zika virus - mosquito bite
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What do most of the TORCH infections cause?
They cause mild maternal morbidity, but have serious fetal consequences:
- abortion
- stillbirth
- prematurity
- IUGR
- congenital malformations - microcephaly, intracranial calcifications
What is IUGR?
Intrauterine growth restriction
this is a condition in which an unborn baby is smaller than it should be because it is not growing at a normal rate inside the womb
What are other perinatal infections?
- Group B streptococcus
- listeriosis
- gonorrhoea
- chlamydia
- influenza
- human immunodeficiency virus
- hepatits b virus
HIV and HBV virus can be passed in utero and postnatal via breast milk
What are the risks associated with transplacental passage of the influenza virus?
Teratogenesis has not been confirmed
premature delivery may occur (as in any febrile maternal illness), increasing the perinatal morbidity and mortality
the clinical syndrome in the mother is self-limited unless pneumonia occurs and the newborn manifests as any form of sepsis
What is meant by the “perinatal period”?
The period immediately before and after birth
usually starts at the 20th - 28th week of gestation and ends 1 - 4 weeks after birth
Why is screening for Group B Streptococci not recommended in the UK?
Until it is clear that antenatal screening for GBS carriage does more good than harm and that the benefits are cost-effective, routine screening is not recommended
What is the likelihood of maternal GBS carriage in current pregnancy if a mother has had previous GBS carriage?
What 3 options does the mother have in this situation?
If there is history of previous GBS carriage, likelihood of maternal GBS carriage in current pregnancy is 50%
3 choices are:
- To NOT have intra-partum antibiotics
- To have intra-partum antibiotics
- Screening at 35-37 weeks and offer antibiotics to those who have GBS colonisation
When are intrapartum antibiotics administered?
Intra-partum refers to the time period between onset of labour and the delivery of the placenta
What is chorioamnionitis?
How many pregnancies are affected by this?
Inflammation of the umbilical cord, amniotic membranes / fluid and placenta
it is a major cause of perinatal morbidity and mortality
affects 1-2% of term pregnancies and 20-25% of pregnancies with pre-term labour
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What are the symptoms of chorioamnionitis?
- Maternal fever
- uterine tenderness
- tachycardia
- purulent / foul amniotic fluid
obstetric complications + adverse outcomes for the neonate:
- sepsis
- pneumonia
- long term neurodevelopment disability
what usually causes chorioamnionitis?
What is it associated with?
It is inflammation of the fetal membranes (amnion / chorion) due to a bacterial infection
it typically results from bacteria ascending from the vagina into the uterus
it is most often associated with prolonged labour
What are the risk factors for intra-amniotic infections?
- Most common after prolonged rupture of membranes
- amniocentesis / cordocentesis
- cervical cerclage
- multiple vaginal examinations
- bacterial vaginosis
What is the pathogenesis of intra-amniotic infections like?
Bacteria present in the vagina cause infection by ascending through the cervix
Haematogenous (via blood) infection is rare e.g. Listeria monocytogenes
What organisms can cause intra-amniotic infections?
- Group B Streptococcus
- Escherichia coli
- Genital Mycoplasma (Mycoplasma hominis & Ureaplasma urealyticum)
it is caused by polymicrobial infections
What is involved in the management of intra-amniotic infections?
Intrapartum antimicrobials and delivery of the foetus
antimicrobials should be administered at the time of diagnosis (not after delivery)