Prevention of Mother-to-child HIV transmission Flashcards Preview

Module 2 > Prevention of Mother-to-child HIV transmission > Flashcards

Flashcards in Prevention of Mother-to-child HIV transmission Deck (49):
1

When does HIV transmission from mother-to-child mainly take place?

in the 2 months preceding birth; highest at birth

2

Wihtout intervention, how high can mother-to-child transmission be?

upto 45% by the end of breastfeeding

3

What is the route by which transmission takes place pre-partum?

transplacentally and transmiamniotically

4

What are the routes of transmission intra-partum?

transplacental; birth canal

5

What is the most important factor determining risk of HIV transmission?

viral load

6

Why do pre-term labour and low birth wt increase the risk of transmission?

they are signs of hte materno-fetal unit not functioning correctly

7

What was the effect of giving AZT to mothers and babies to reduce transmission?

reduced transmission rate by 2/3rds

8

How does elective C/S change the risk of transmission compared with SVD when using AZT?

80% reduction in transmission with ECS both with and without ZDV

9

What did the women, infant transmission study look at?

the difference in transmission rates between no ART; ZDV; combo and HAART

10

What were the results of the women; infant transmission study?

HAART was most effective at reducing tranmission; then combo; then ZDV then no ART

11

What is the overall rate of MTCT in UK between 200-2006?

1.1% overall

12

What is the impact of ECS vs SVD if the patient is on HAART and VL is undetectable?

no difference in transmission rate

13

When should cART be started during pregnnacy according to a retrospective London study?

before 24 weeks GA

14

what is the overall risk of transmission when duration of ART is 9 weeks?

1%

15

When does MTCT plateau in terms of ART duration?

aroudn 13 weeks

16

What is the asbolute risk of MTCT with breastfeeding?

15-20%

17

What was the overall HIV-free survival bewteen breast and formula
in a RCT in 2000?

58% with breast and 70% with formula

18

What are the benefits of using ARt whilst breastfeeding?

MTCT rates <1%; improved maternal health; benefits of breastfeeding

19

What are hte risks of using ART whilst breastfeeding?

infant exposure to drug; risk of HIV resistance if infant ebcomes HIV+; possible ongoing transmission risk

20

What are the WHO guidelines for breastfeeding for HIV+ mothers?

in settings where lifelong ARt is provided and supported, a mother should breastfeed for at least 12 months and may continue upto 24 hours

21

What is the BHIVA recommendation for breastfeeding?

not recommended

22

How is HIV related to preterm birth?

HIV associated immune deficiency is assoacited with PTB, but also HIV is a risk even with immune restoration

23

What is the impact of mixed breastfeeding compared with exclusive?

mixed breastfeeding is a much higher risk

24

Which type of ART is the worst for increasing the risk of PTB?

protease inhibitors

25

What is the effect of ART on PTB in mothers with CD4>200?

50% increase in risk compared with no ART or AZT monotherapy in a Swiss study

26

What is the impact on PTB depending on when ART is started?

risk of PTB is higher if started during pregnancy- especially with PI

27

What happens to the Th1/Th2 cytokine balance in pregnancy?

shifts towards Th2

28

What happens to the Th1/Th2 cytokine balance in untreated HIV?

shifts twards Th2

29

What happens to the Th1/Th2 cytokine balance with treated HIV?

shifts back to Th1

30

What type of cytokine balance is PTB assocaited with?

Th1

31

What is a proposed mechanism for the increased risk of PTD with PIs?

PIs may reduce progesterone levels in pregnancy leading ot fetal growth restriction

32

What did the NSHPC study find when looking at ART and PTD?

increased rate of PTD with cART (14%) vs mono/dual therapy (10%)

33

What was the risk of PTD with women who conceived on PI based regimens vs NNRTI?

higher with PI

34

What is the risk of PTD if on ART at conception vs starting in pregnancy?

higher if on for conception

35

What is the effect of CD4 count on PTD?

PTD risk is higher in those with lower CD4 coutns

36

Which studies support the hypothesis that ZDV-based therapies are associated with a lower risk of PTD?

PROMISE; Mma Bana and NSHPC

37

What is a possible reason for a resurgance in the risk of pre-eclampsia in the cART era?

restoration of immune function- a form of IRIS?

38

What might influence the data on the timing of ART initiation- pre-conception vs in pregnancy?

ART was only prescribed outside of pregnancy until recently to women with immune deficiency and/or low CD4 so pre-conception ART risk may be a reflection of the causes of the HIV disease

39

What finding in the HIV PTB study supports the cytokine shift as a mechnism for ART increasing risk of PTD?

women with PTD had much lower IL10 and IL4 concentrations compared with those who delivered to term, and PIs decreased IL10 and IL4 concs

40

What is the effect of HIV infection upon vaginal flora?

HIV infection is assocaited with a reduction in lactobacillus species; increased anaerobes- Gardnerella and Prevotella--- much lower levels of protective vaginal flora in HIV infected mothers

41

What was the relationship bewteen vaginal flora and PTB?

women with PTB had much higher levels of anaerobes

42

What is the impact of tenofovir on vaginal flora?

women exposed have a higher % of gardnerella

43

Where do 85% of HIV-infected pregnant women live?

Africa

44

When should ART be started in pregnancy if viral load >100,000 or CD4 <200 according to BHIVA?

first trimester

45

When should ART be started in pregnancy if VL <100000?

second trimester

46

When should planed vaginal delivery be supported in women with HIV?

when have a VL <50 at 36 weeks

47

When should CS be carried out to prevent vertical transmission?

between 38 and 39 weeks

48

How often should a HIV positive women who chooses to breasfeed be monitored in clinic?

her and baby should be reviewd monthly for HIV RNA during and for 2 months after breasfeeding

49

Why should ART be started as soon as possible?

in both UK and a French cohort, vertical transmission was significantly assocaited with starting treatment later in pregnancy