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