Vitamin A supplementation for reducing the risk of mother-to-child transmission of HIV infection

Vitamin A supplements for reducing mother-to-child HIV transmission

BACKGROUND

Strategies to reduce the risk of mother-to-child transmission of the human immunodeficiency virus (HIV) include lifelong antiretroviral therapy (ART) for HIV-positive women, exclusive breastfeeding from birth for six weeks plus nevirapine or replacement feeding plus nevirapine from birth for four to six weeks, elective Caesarean section delivery, and avoiding giving children chewed food. In some settings, these interventions may not be practical, feasible, or affordable. Simple, inexpensive, and effective interventions (that could potentially be implemented even in the absence of prenatal HIV testing programmes) would be valuable. Vitamin A, which plays a role in immune function, is one low-cost intervention that has been suggested in such settings.

OBJECTIVES

To summarize the effects of giving vitamin A supplements to HIV-positive women during pregnancy and after delivery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) up to 25 August 2017, and checked the reference lists of relevant articles for eligible studies.

SELECTION CRITERIA

We included randomized controlled trials conducted in any setting that compared vitamin A supplements to placebo or no intervention among HIV-positive women during pregnancy or after delivery, or both.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed study eligibility and extracted data. We expressed study results as risk ratios (RR) or mean differences (MD) as appropriate, with their 95% confidence intervals (CI), and conducted random-effects meta-analyses. This is an update of a review last published in 2011.

MAIN RESULTS

Five trials met the inclusion criteria. These were conducted in Malawi, South Africa, Tanzania, and Zimbabwe between 1995 and 2005 and none of the participants received ART. Women allocated to intervention arms received vitamin A supplements at a variety of doses (daily during pregnancy; a single dose immediately after delivery, or daily doses during pregnancy plus a single dose after delivery). Women allocated to comparison arms received identical placebo (6601 women, 4 trials) or no intervention (697 women, 1 trial). Four trials (with 6995 women) had low risk of bias and one trial (with 303 women) had high risk of attrition bias.The trials show that giving vitamin A supplements to HIV-positive women during pregnancy, the immediate postpartum period, or both, probably has little or no effect on mother-to-child transmission of HIV (RR 1.07, 95% CI 0.91 to 1.26; 4428 women, 5 trials, moderate certainty evidence) and may have little or no effect on child death by two years of age (RR 1.06, 95% CI 0.92 to 1.22; 3883 women, 3 trials, low certainty evidence). However, giving vitamin A supplements during pregnancy may increase the mean birthweight (MD 34.12 g, 95% CI -12.79 to 81.02; 2181 women, 3 trials, low certainty evidence) and probably reduces the incidence of low birthweight (RR 0.78, 95% CI 0.63 to 0.97; 1819 women, 3 trials, moderate certainty evidence); but we do not know whether vitamin A supplements affect the risk of preterm delivery (1577 women, 2 trials), stillbirth (2335 women, 3 trials), or maternal death (1267 women, 2 trials).

AUTHORS' CONCLUSIONS

Antepartum or postpartum vitamin A supplementation, or both, probably has little or no effect on mother-to-child transmission of HIV in women living with HIV infection and not on antiretroviral drugs. The intervention has largely been superseded by ART which is widely available and effective in preventing vertical transmission.

Treatment of HIV infection in pregnant women: antiretroviral management options

Increasing rates of HIV infection in women worldwide, especially among those of childbearing age, reinforce the importance of understanding the management of HIV in pregnancy. Over the past decade, significant advances have been made in the prevention of vertical HIV transmission, including the use of single and combination antiretroviral therapy, elective caesarean section as the preferred mode of delivery and the elimination of breast feeding. Multiple clinical trials assessing antiretroviral therapy in pregnancy have been carried out worldwide. The first pivotal clinical trial, the AIDS Clinical Trials Group (ACTG) 076 study, was conducted in 1994 using a three-part zidovudine regimen. Despite the success of this regimen at decreasing rates of vertical transmission, it is not affordable in many developing countries. Consequently, many international clinical trials have concentrated on short-course antiretroviral regimens including zidovudine alone, zidovudine and lamivudine, and nevirapine alone. In the developed world, the management of nonpregnant HIV-infected individuals has also undergone significant advances and has implications for the management of HIV in pregnancy. A number of countries have participated in the development of guidelines for the management of HIV in pregnancy, which recommend that HIV-infected pregnant women should be offered combination antiretroviral therapy based on viral load and CD4+ cell count cut-offs used for individuals who are not pregnant, preferably with the inclusion of zidovudine. However, to maximise the benefits to their offspring, therapy is recommended at lower viral load thresholds than for nonpregnant adults. For antiretroviral-naive women, therapy is deferred until the second trimester because of the potential and uncertain risk of teratogenesis and the low risk of transmission during this period. Research has also found that maternal factors including viral load, immune status, chorioamnionitis, prematurely ruptured membranes and, to a lesser extent, intravenous drug use and smoking are associated with increased vertical transmission. These represent potentially modifiable risk factors that should be addressed before and throughout pregnancy. Despite the benefits of antiretroviral therapy to reduce HIV vertical transmission, its use can be complicated by known and unknown risks of toxicity to the mother, fetus or both as well as carrying the risk of developing drug-resistant virus. The latter can potentially compromise future treatment options for both the mother and child. Other important challenges include the use of antiretroviral drugs during pregnancy when the mother does not meet criteria for them for her own health, and balancing the relative risks and benefits of elective caesarean section at various degrees of viral load suppression. Clinicians managing HIV in pregnancy need to keep up to date with all the literature to provide optimal care, including counselling to allow mothers to balance the risks and benefits while deciding on treatment for both themselves and their children.