1. NPW Microbiology Antenatal Presentation

3. The Royal College of Pathologists
The Royal College which deals with:
Clinical Chemistry
Microbiology
Histopathology
Haematology
Immunology

4. NPW Microbiology Antenatal Presentation
The patient’s antenatal visit

5. The patient Ms Ivy User 22 years old No previous pregnancies
16 weeks pregnant
Current intravenous drug user
Multiple sexual partners
Unprotected sex
Says she is always tired but no other symptoms

6. What infections could she have acquired as a result of her lifestyle?
Hepatitis B
Hepatitis C
HIV
Syphilis
All of these

7. What infections could she have acquired as a result of her lifestyle?
Hepatitis B
Hepatitis C
HIV
Syphilis
All of these - CORRECT

8. Microbiology Tests Performed on blood taken at the first antenatal visit
Hepatitis B surface antigen
HIV antibody and antigen
Treponema pallidum (syphilis) antibody
Rubella virus antibody

9. Results of microbiology blood tests taken at the first antenatal visit
Hepatitis B surface antigen POSITIVE
HIV antibody/antigen POSITIVE
Treponema pallidum antibody POSITIVE
Rubella IgG antibody POSITIVE

10. Hepatitis B

11. What do these HBV results mean?
Hepatitis B surface antigen POSITIVE
This is a screening result which needs to be confirmed by other tests before we know her true HBV status
She could be currently infected with hepatitis B virus
This could transmit to her baby at birth
Need to test for other hepatitis B markers:
Confirmation second hepatitis B surface antigen test
Hepatitis B e antigen and antibody
Hepatitis B core IgM antibody

12. What do these HBV confirmatory results mean?
(Hepatitis B surface antigen POSITIVE)
Confirmation second hepatitis B surface antigen test
– strongly positive – She IS infected with HBV
Hepatitis B e antigen and antibody
Hepatitis B e antigen positive – She is very infectious
Hepatitis B core IgM antibody
Negative – she has not been infected in the last few months and so is likely to be a persistently infected carrier of HBV

13. How is Hepatitis B spread?
By having unprotected sex?
By kissing?
By using a public toilet?
By standing next to an infected person on a bus?
By sharing mobile phones?

14. How is Hepatitis B spread?
By having unprotected sex? YES
By kissing? NO
By using a public toilet? NO
By standing next to an infected person on a bus? NO
By sharing mobile phones? NO

15. HIV

16. What do these HIV results mean?
HIV antibody/antigen POSITIVE
This is a screening result which needs to be confirmed in at least two other sensitive HIV antibody/antigen tests

17. What do these HIV results mean?
(HIV antibody/antigen POSITIVE)
Second sensitive HIV antibody/antigen test – POSITIVE
Third sensitive HIV test – POSITIVE
Conclusion – she has confirmed HIV infection and her baby could acquire infection
Need a repeat blood to confirm that these results do relate to this patient

18. How can you catch HIV? By sharing towels with blood on them?
By having unprotected sex?
By sharing intravenous drug needles?
By breastfeeding?
By all of these?

19. How can you catch HIV? By all of these? YES
By sharing towels with blood on them?
By having unprotected sex?
By sharing intravenous drug needles?
By breastfeeding?
By all of these? YES

20. Syphilis

21. What do these syphilis results mean?
(Treponema pallidum antibody POSITIVE)
A screening test using an enzyme immunoassay (EIA) is used to indicate the possibility of treponemal infection.
The EIA is highly sensitivity and can give non-specific reactions in pregnant women.
The EIA positive result requires confirmation before we know whether she has syphilis currently or has had syphilis in the past.
If infection is current or inadequately treated in the past this can be transmitted to the baby with serious outcomes.

22. What do these syphilis results mean?
Treponema pallidum antibody POSITIVE
Confirmation tests
TPPA – Treponema pallidum Particle Agglutination test
RPR – Rapid Plasma Reagin test
Sera that are EIA positive and
Are positive with a second test (TPPA) - this indicates presence of treponemal antibody
Are reactive in the RPR test – this can indicate current infection (above a titre of =>32)
Are negative with TPPA and RPR indicates a non-specific reaction – No evidence of syphilis infection.

23. How does congenital syphilis occur?
By vertical transmission from an infected mother at any stage of pregnancy?
Directly from the father, via semen?
Direct from a syphilitic ulcer on the mother?
By transfer of antibody from the mother?
Trans-vaginally during delivery?

24. How does congenital syphilis occur?
By vertical transmission from an infected mother at any stage of pregnancy? YES
Directly from the father, via semen? NO
Direct from a syphilitic ulcer on the mother? NO
By transfer of antibody from the mother? NO
Trans-vaginally during delivery? NO

25. Rubella

26. What do these Rubella results mean?
Rubella IgG antibody POSITIVE
This result means this lady has immunity to rubella virus
If she had been negative, any rubella-like illness would have been carefully investigated and she would have been recommended to have rubella vaccine after she delivered
If a pregnant woman has rubella infection in the first 16 weeks of pregnancy, the baby could be born with brain, ear, heart and eye damage and could even die

27. Management of Hepatitis B Infection in Pregnancy

28. Management of Hepatitis B in Pregnancy
Confirm Hepatitis B surface antigen (HBsAg) status of the mother
Confirm Hepatitis B e status
She is HBe Antigen positive – HIGHLY INFECTIOUS
Confirm if this is an acute case of HBV in pregnancy
She is anti-HBc IgM negative so she has not acquired HBV infection in the last few months and during this pregnancy

29. Management of Hepatitis B in Pregnancy
Hepatitis B e status
HBe Antigen positive means the woman is highly infectious and has a high risk of transmitting HBV to the baby at birth
HBe Antigen positive people also have a high risk of transmitting infection to others via unprotected sex or through blood contact
Anti-HBe positivity status implies people are much less infectious

30. Management of Hepatitis B in Pregnancy
If a pregnant woman has confirmed HBV infection in pregnancy there is a risk of transmission to her baby
If she has anti HBe antibody, the baby is given HBV vaccine soon after birth and then at months 1,2 and 12
If she has no anti-HBe antibody or the mother acquired HBV infection during pregnancy, the baby should receive HBV vaccine as above PLUS hepatitis B immunoglobulin as soon after birth as possible

31. Scale of the problem England – about 600,000 pregnancies a year
Region
% of all HBV mothers
East Midlands
2.4%
East of England
5.8%
London
55.0%
North East
1.3%
North West
8.8%
South East
8.6%
South West
West Midlands
8.1%
Yorks and Humber
7.6%
England – about 600,000 pregnancies a year
About 3,000 (0.5%) women infected with hepatitis
3,000 babies – up to 600 – at the highest risk of persistent infection

32. Management of Hepatitis B in Pregnancy
Mother to be referred to a ‘liver doctor’ or infectious disease physician for clinical review – she may benefit from antiviral treatment
Mother to be informed that baby will need immunisation at birth and at 1, 2 and 12 months old – the addition of hepatitis B immune globulin (ready made antibody) might also be required at birth based on the following criteria:
Mother HBeAg positive
Mother negative for both HBeAg and Anti-HBe
Mother positive for anti-HBc IgM (indicating an acute infection in pregnancy)
Mother had high level of virus DNA (>1,000,000IU/ml)
Baby will need a blood test at 12months to ensure that he/she has not become infected

33. Effect of hepatitis B vaccination on perinatal transmission
Without intervention 70% - 90% of the babies born to HBeAg mothers would become persistently infected
With vaccination started just after birth 30% may become infected (70% are protected)
With vaccination after birth with immune globulin less than 10% become infected (over 90% protection)

34. Perinatal transmission of hepatitis B - Birmingham studies
Perinatal transmission associated with HBeAg positive mothers

35. Prevention of perinatal transmission of hepatitis B by immunization - Studies - % infected children
Vaccine alone - works well - some improvement if HBIG added actual %
Improvement varies from 0% to 12%: average 7.5% in this comparison

36. Systematic review of HBV vaccination of neonates at high risk
Vaccine reduced HBV infections in babies
Addition of HBIG improved outcome for babies of HBeAg+ mothers, but no evidence of improved outcome for babies of HBeAg - mothers
No evidence that HBIG timing within the first 48 hours is crucial
Vaccine alone almost as good as with HBIG

37. Neonatal Hepatitis B vaccination – outcome – blood test at 12 months for evidence of infection
Why is outcome important?
Measure of success of programme
Identification of infected babies to ensure referral to specialist services
Recognition of reasons for ‘failures’

38. Neonatal Hepatitis B vaccination
Recognition of reasons for ‘failures’
Vaccine delivery failures –
patients move away
compliance
failure of healthcare systems
true vaccine failures – variant viruses
“vaccine escape mutants”
HBeAg negative variants
mothers with very high maternal viraemia

39. HIV Management

40. Management of HIV in pregnancy
This lady is confirmed HIV positive
Any person who is HIV positive benefits from early diagnosis so that anti- HIV treatment can be given as soon as possible to slow down the advance of the disease
In pregnancy, the primary concern is to prevent transmission to the baby in late pregnancy, at delivery and early in life
If untreated, the risk of transmission to the baby could be as high as 30%

41. How to reduce the risk of HIV transmission from mother to baby
The risk can be reduced by giving HIV antiviral treatment in late pregnancy
In rich countries combination HIV treatment has reduced the risk of infecting the baby to 1-2%
In poor countries even giving one dose of anti-HIV drug at delivery and to the newborn baby can reduce the risk

42. Syphilis Management

43. How to reduce the risk of syphilis infection in the baby
All pregnant women should be screened for treponemal antibody.
Any women with confirmed positive tests for treponemal antibody should be urgently referred to a GUM clinician for specialist care.
Women with infectious syphilis should be treated with benzathine penicillin or procaine penicillin.
Retreatment of previous cases where treatment history is unknown should be considered.
Management of the mother should be in close liaison with obstetric, midwifery, GUM and paediatric departments.

44. The Outcome in the Baby

45. How do you think the baby did?
Infected with HBV?
Infected with HIV?
Infected with Syphilis?
Infected with two of these three ?
Not infected?

46. The outcome for the baby
The baby is now 18 months old
It is good news
The hepatitis B vaccine and immunoglobulin prevented HBV infection in the baby
The baby has not been infected with HIV but precautions need to be taken to prevent infection from the mother in the future
The maternal treponemal antibody has disappeared and the baby does not have congenital syphilis.

47. Microbiology Antenatal Screening
The Pathologists’ Roles

48. The Pathologists’ Roles
Virologist
Perform virology tests – HBV, HIV, Rubella
Interpret the findings of those tests
Give advice on treatment and management
Microbiologist
Perform microbiology tests - Syphilis