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Infection in Haematology
Prevention of Mother-to-child Transmission of HIV
a report by
Jennifer S Read
Medical Officer, Paediatric, Adolescent and Maternal AIDS Branch,
Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health
Mother-to-child transmission (MTCT) of HIV causes significant to the infant while breastfeeding.
21–23
In addition to these interventions,
morbidity and mortality among children. Our understanding of the observational data strongly suggest that maternal use of combination ARV
epidemiology, pathogenesis, diagnosis and prevention of MTCT of HIV regimens including highly active ARV therapy (HAART) during pregnancy is
infection has improved dramatically in recent years, and the objectives associated with very low rates of transmission.
24
of this review are to summarise current understanding of the
prevention of MTCT of HIV. Antiretroviral Prophylaxis
Maternal use of ARVs during pregnancy (whether for treatment of the
Most children acquire HIV infection through MTCT.
1
Although major woman’s HIV disease itself or, for women who do not meet criteria for
successes have been achieved in prevention of MTCT, these successes treatment, for prevention of MTCT) and ARV prophylaxis during the
have occurred primarily in those countries with the greatest resources intrapartum and post-natal periods are associated with significantly lower
and the lowest burden of HIV infection among women and children. rates of MTCT. In the first efficacy trial of ARV prophylaxis, zidovudine alone
Significant challenges remain, particularly in those countries with more was given to the mother during pregnancy and the intrapartum period and
limited resources and a greater population burden of HIV infection. to the infant.
17
Subsequently, the US Public Health Service (USPHS) issued
guidelines regarding the use of zidovudine prophylaxis,
25
and such
Rates of MTCT of HIV were calculated in studies conducted in various prophylaxis has played a central role in the prevention of MTCT in the US
26
countries prior to the development and implementation of and other resource-rich settings. More recently, an increasing number of
interventions to decrease transmission.
2
Usually a transmission rate in HIV-infected women are receiving combination ARV regimens, including
the range of 25–30% was reported, and higher transmission rates HAART, during pregnancy.
24
Guidelines for initiation of ARV therapy in
were observed in resource-poor settings (13–42%) than in resource- adults and adolescents have been developed by the USPHS
27
and other
rich settings (14–25%). groups. In addition, guidelines addressing the use of ARVs, including
combination ARV regimens, in pregnant women have been developed by
MTCT of HIV can occur during pregnancy, around the time of labour the USPHS
28
and other groups.
and delivery, and post-natally (through breastfeeding).
3
Most
transmission is estimated to occur during the intrapartum period (both Caesarean Delivery Before Labour and Before
in breastfeeding and non-breastfeeding populations).
4
Ruptured Membranes
Among women receiving no ARVs or zidovudine alone, Caesarean section
Various risk factors for MTCT of HIV have been identified or are under before labour and before ruptured membranes is associated with a lower
investigation,
1
and can be categorised as follows: risk of MTCT of HIV
29
and is efficacious in preventing MTCT.
18
Based on
these studies, the American College of Obstetricians and Gynecologists
• the amount of virus to which the child is exposed (i.e. maternal (ACOG)
30
and the USPHS
28
recommend Caesarean section for prevention of
viral load);
5–9
MTCT be considered for HIV-infected women with peripheral blood viral
• the duration of such exposure (i.e. the duration of ruptured loads greater than 1,000 copies/ml, irrespective of receipt of ARVs.
membranes
10
or of breastfeeding
11
); and Caesarean delivery for HIV-infected women has been performed with
• factors facilitating the transfer of virus from mother to child (e.g., increasing frequency in clinical centres in the US over the past several years.
31
mixed breastfeeding,
12,13
maternal breast pathology
7,8,14,16
and However, Caesarean section for prevention of MTCT of HIV is generally not
infant oral candidiasis).
15,16
Jennifer S Read is a Medical Officer in the Paediatric,
In addition to these risk factors, characteristics of the virus and the
Adolescent and Maternal AIDS Branch at Eunice Kennedy
child’s susceptibility to infection are important. Shriver National Institute of Child Health and Human
Development, National Institutes of Health (NIH). Her primary
research interest is prevention of mother-to-child transmission
Prevention of Mother-to-child Transmission of HIV
of HIV in the US and globally. Among other awards, Dr Read
Although different interventions to prevent MTCT of HIV have been and are
has received the NIH Director’s Award and the Pediatric
Infectious Diseases Society’s Young Investigator Award. She
being investigated, efficacy has been demonstrated to date only for the
trained in pediatrics and pediatric infectious diseases at the
following (see Table 1): antiretroviral (ARV) prophylaxis,
17
Caesarean section University of Michigan, Johns Hopkins University, in tropical medicine at the London School of
before labour and before ruptured membranes,
18
complete avoidance of
Hygiene and Tropical Medicine and in epidemiology at Harvard University and the NIH.
breastfeeding
19
and (in settings where complete avoidance of breastfeeding E: jennifer_read@nih.gov
is not feasible) exclusive breastfeeding
20
and ARV prophylaxis administered
© TOUCH BRIEFINGS 2008 67
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