Infections in pregnancy

Question 1

What is CMV?

Answer 1

herpesvirus and transmitted by personal contact
10% of infected neonates are symptomatic at birth – with IUGR, pneumonia and thrombocytopenia
most develop severe neurological sequelae, such as hearing, visual and mental impairment- asymptomatic neonates are at risk of deafness (15%)

Question 2

How is CMV diagnosed and managed?

Answer 2

USS abnormalities are evident in 20% (intracranial or hepatic calcification)
CMV IgM remains +ve for a long time after infection and could predate the pregnancy
amniocentesis at least 6 weeks after maternal infection will confirm or refute vertical transmission
USS can help determine those most at risk- no prenatal treatment and termination may be offered, no vaccine

Question 3

What is HSV?

Answer 3

type 2 DNA virus causes genital herpes- <5% of pregnant women have history of prior infection, but many have antibodies
HSV is not teratogenic and neonatal infection is rare, but has a high mortality- vertical transmission occurs at vaginal delivery, particularly in vesicles are present
usually clear clinically and swabs are of little use in pregnancy

Question 4

What is the management for HSV?

Answer 4

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 the time of labour, so C-section is not recommended, daily aciclovir in late pregnancy may reduce the frequency of recurrences at term, exposed neonates are given aciclovir

Question 5

What is herpes zoster?

Answer 5

primary infection with DNA herpesvirus causes chickenpox and reactivation causes shingles
teratogenicity is rare (1-2%) in early pregnancy infection and is treated immediately with oral acyclovir
maternal infection in 4 weeks preceding delivery can cause severe neonatal infection- most common if delivery occurs within 5 days after or 2 days before maternal symptoms

Question 6

What is the management for herpes zoster?

Answer 6

immunoglobulin is used to prevent and aciclovir to treat
regnant women exposed to zoster are tested for immunity and immunoglobulin given within 10 days if non-immune or aciclovir given if infection occurs
in late pregnancy is delivery is 5 days after or 2 days before maternal symptoms then neonate are given immunoglobulins and aciclovir if infection occurs- vaccination is possible

Question 7

What is rubella?

Answer 7

rubella virus usually affects children and causes mild febrile illness with macular rash
maternal infection in early pregnancy causes multiple foetal abnormalities – including deafness, cardiac disease, eye problems and mental retardation, probability and severity decreases with gestation

Question 8

What is the management for rubella?

Answer 8

if non-immune women develops rubella <16 weeks then termination is offered
screening remains routine at booking, vaccine is live and contraindicated in pregnancy

Question 9

What is parvovirus?

Answer 9

B19 infects 0.25% of pregnant women, but 50% are immune-‘slapped cheek’ appearance is
classical, but may have arthralgia or be asymptomatic
viruses suppresses foetal erythropoiesis causing anaemia- variable degrees of thrombocytopenia can also occur- foetal death in 10% of pregnancy, usually with infection <20 weeks

Question 10

How is parvovirus diagnosed and managed?

Answer 10

if maternal exposure or symptoms have occurred, +ve maternal IgM testing will prompt foetal surveillance
anaemia is detectable on USS as increased blood flow velocity in foetal MCA and subsequent oedema (hydrops) from cardiac failure
mothers infected are scanned regularly to look for anaemia
if hydrops is detected in utero
transfusion can be given if this is severe- excellent prognosis in survivors

Question 11

What is hepatitis B?

Answer 11

caused by small DNA virus and transmitted by blood products or sexual activity
vertical transmission occurs in delivery- 90% of infected neonates become chronic carriers, compared to 10% of adults

Question 12

What is the management for hepatitis B?

Answer 12

maternal screening is routine in UK
neonatal immunisation reduces the risk of infection by
>90% and given to all +ve women
women with high viral loads are treated with antiviral agents from 32 weeks and passive immunisation given postnatally to neonate

Question 13

What is hepatitis C?

Answer 13

• Main risk factors: drug abuse and sexual transmission
• Hep C leads to chronic hepatitis in 80%- but most pregnant women are asymptomatic
• Vertical transmission of HCV occurs in 3-5%, but higher if large viral load or co-existing HIV
• Elective C-section, avoidance of breast feeding and administration of immunoglobulin do not reduce vertical transmission to neonate
• Screening is restricted to high risk groups

Question 14

What is HIV?

Answer 14

pregnancy does not hasten progression to AIDS
incidence of pre-eclampsia is greater and may be increased by anti-retroviral therapy, as well as gestational diabetes
stillbirth, pre-eclampsia, growth restriction and prematurity are more common
vertical transmission is mostly beyond 36 weeks ( ruptured membranes >4hrs), intrapartum or during breastfeeding
25% of HIV infected neonates will develop AIDS in 1yr and 40% in 5 yrs

Question 15

What is the management for HIV?

Answer 15

+ve women should have regular Cd4 and viral load tests
drug toxicity is monitored with liver and renal function, haemoglobin and blood glucose testing
highly active anti-retroviral therapy (HAART) reduces viraemia and maternal disease progression and should be continued throughout pregnancy and delivery, with the neonate treated for first 6 weeks
if woman is not receiving pre-pregnancy treatment then it is started at 28 weeks
C-section is recommended if viral load is above 50 copies/ml and there is coexistent hepatitis C infection
Breast feeding is avoided

Question 16

What is influenza?

Answer 16

the pandemic influenza A H1N1 (swine flu) particularly affects pregnancy women (esp obese)
No known adverse effects on neonates
if symptoms are present then oseltamivir should be prescribed and admission considered if there is respiratory symptoms
seasonal, yearly vaccination with an inactivated vaccine is strongly recommended for pregnant women at any gestation

Question 17

What is the Zika virus?

Answer 17

• There is a likely link with foetal CNS abnormalities in maternal infection during 1st & 2nd trimester
o Intracranial calcification
o Ventriculomegaly
o Microcephaly
• Transmitted by the Aedes mosquito- maternal symptoms are mild and include rash and fever, but also Guillian-Barre syndrome
• Virus can be detected by PCR, but antibody testing is currently unreliable due to cross-reactivity
• Pregnant women should be advised not to travel to countries affected by outbreaks

Question 18

What is group A strep?

Answer 18

• Bacterium traditionally responsible for puerperal sepsis- most common bacterium associated with maternal death
Carried by 5-30% of people- sore throat
• Chorioamnionitis with abdominal pain, diarrhoea and severe sepsis may occur- infected foetus often dies in utero and labour will then usually ensue
• Early recognition, cultures and high dose antibiotics ± ICU is required

Question 19

What is group B strep?

Answer 19

bacterium Streptococcus agalactiae is carried without symptoms by 25% of pregnant women
foetus can be infected during labour after the membrane ruptures
causes severe illness and has mortality rate of 6% in term infants and 18% in preterm infants

Question 20

What is the management for group B strep?

Answer 20

vertical transmission can be mostly prevented by high-dose IV penicillin throughout labour
in UK treatment is only used if risk factors for GBS vertical transmission are present or if found incidentally:
o Previous affected neonate
o Positive urinary culture for GBS
o Preterm labour
o Ruptured membrane for >18hrs
o Maternal fever in labour

Question 21

What is syphilis?

Answer 21

• STI due to Treponema pallidum
• Active disease in pregnancy causes miscarriage, severe congenital disease or stillbirth
• Prompt treatment with benzylpenicillin is safe and will prevent, but not reverse, foetal damage
• Screening tests (VDRL) are still in routine use

Question 22

What is toxoplasmosis?

Answer 22

due to the protozoan parasite Toxoplasma gondii- follows contact with cat faeces or soil or eating infected meat 
Neonate:
o	Mental handicap
o	Convulsions
o	Spasticities
o	Visual impairment

Question 23

How is toxoplasmosis diagnosed and managed?

Answer 23

USS may show hydrocephalus, but maternal infection is usually diagnosed due to exposure or anxiety
vertical transmission is diagnosed or excluded via amniocentesis after 20 weeks
health education reduces maternal risk
Spiramycin is started as soon as women are diagnosed
additional combination therapy of pyrimethamine and sulfadiazine with folic acid is given if vertical transmission confirmed

Question 24

What is listeriosis?

Answer 24

• Caused by Listeria monocytogenes
Gram +ve bacillus- infection can follow consumption of pate, soft chesses and prepacked meals
• Causes non-specific febrile illness- bacteraemia occurs in pregnancy, potentially fatal infection of the foetus may follow
• Diagnosis is established from blood cultures- prevention is key

Question 25

What are chlamydia and gonorrhoea?

Answer 25

• Chlamydia is caused by Chlamydia trachomatis- occurs in 5% of pregnant women
• Gonorrhoea is caused by Neisseria gonorrhoeae- occurs in 0.1% of pregnant women
both have association with preterm labour and neonatal conjunctivitis
Causes PID and sub fertility
• Chlamydia is treated with azithromycin or erythromycin: tetracyclines cause foetal tooth discolouration
• Gonorrhoea is treated with cephalosporins

Question 26

What is bacterial vaginosis?

Answer 26

• Common overgrowth of normal vaginal lactobacilli by anaerobes- such as Gardnerella vaginalis and
Mycoplasma hominis
• Can be asymptomatic or cause offensive vaginal discharge- preterm labour and late miscarriage is common
• Treatment with oral clindamycin- reduces the risk of preterm birth if used <20 weeks