Over 2 million children are thought to be living with HIV/AIDS worldwide, of whom over 80% live in sub-Saharan Africa. Without anti-retroviral treatment, the risk of HIV transmission from infected mothers to their children is 15-30% during gestation or labour, and 15-20% during breast feeding. HIV-1 infection accounts for most infections; HIV-2 is rarely transmitted from mother to child. Transmission is more likely in mothers with high viral loads and/or advanced disease, in the presence of other sexually transmitted diseases, and with increased exposure to maternal blood.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of measures to reduce mother to child transmission of HIV? We searched: Medline, Embase, The Cochrane Library and other important databases up to January 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions.
We found 18 systematic reviews, RCTs, or observational studies that met our inclusion criteria.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiretroviral drugs, different methods of infant feeding, elective caesarean section, immunotherapy, vaginal microbicides, and vitamin supplements.
Without active intervention, the risk of mother-to-child transmission (MTCT) of HIV-1 is high, especially in populations where prolonged breast feeding is the norm.
Without antiviral treatment, the risk of transmission of HIV from infected mothers to their children is approximately 15-30% during pregnancy and labour, with an additional 10-20% transmission risk attributed to prolonged breast feeding.HIV-2 is rarely transmitted from mother to child.Transmission is more likely in mothers with high viral loads and/or advanced HIV disease.Without antiretroviral treatment (ART), 15-30% of vertically infected infants die within the first year of life.The long-term treatment of children with ART is complicated by multiple concerns regarding the development of resistance, and adverse effects.From a paediatric perspective, successful prevention of MTCT remains the most important focus.
Antiretroviral drugs given to the mother during pregnancy or labour, and/or to the baby immediately after birth, reduce the risk of MTCT of HIV-1.
Reductions in MTCT are possible using simple ART regimens.
Longer courses of ART are more effective, but the greatest benefit is derived from treatment during late pregnancy, labour, and early infancy.Suppression of the maternal viral load to undetectable levels (below 50 copies/mL) using highly active antiretroviral therapy (HAART) offers the greatest risk reduction, and is currently the standard of care offered in most resource-rich countries, where MTCT rates have been reduced to 1-2%. Alternative short-course regimens have been tested in resource-limited settings where HAART is not yet widely available. RCTs demonstrate that short courses of antiretroviral drugs have proven efficacy for reducing MTCT. Identifying optimal short-course regimens (drug combination, timing, and cost effectiveness) for various settings remains a focus for ongoing research.
Avoidance of breast feeding prevents postpartum transmission of HIV, but formula feeding requires access to clean water and health education.
The risk of breast feeding-related HIV transmission needs to be balanced against the multiple benefits that breast feeding offers. In resource-poor countries, breast feeding is strongly associated with reduced infant morbidity and improved child survival.
Modified breastfeeding practices may reduce the risk of HIV transmission while retaining some of its associated benefits.In settings where formula feeding is not feasible (no clean water, insufficient health education, significant cultural barriers) modified breastfeeding practices may offer the best compromise.Early breast feeding with weaning around age 4-6 months may offer an HIV-free survival benefit compared with either formula, mixed feeding, or prolonged breast feeding.Heat- or microbicidal-treated expressed breast milk may offer value in particular settings.
Elective caesarean section at 38 weeks may reduce vertical transmission rates (apart from breast-milk transmission).
The potential benefits of this intervention need to be balanced against the increased risk of surgery-associated complications, high cost, and feasibility issues. These reservations are particularly relevant in resource-limited settings.
Immunotherapy with HIV hyperimmune globulin or immunoglobulin without HIV antibody does not reduce HIV-1 MTCT risk.
Vaginal microbiocides have not been demonstrated to reduce HIV-1 MTCT risk.
There is no evidence that vitamin A or multivitamin supplementation reduces the risk of HIV-1 MTCT or infant mortality.