Elective cesarean delivery plus short-course lamivudine and zidovudine for the prevention of mother-to-child transmission of human immunodeficiency virus type 1

Impact of human immunodeficiency virus, malaria, and tuberculosis on adverse pregnancy outcomes in the United States

OBJECTIVE

To compare rates of adverse pregnancy outcomes for HIV, tuberculosis, and malaria-infected patients in the United States with those of uninfected patients.

STUDY DESIGN

A nationally representative sample of 24,149,664 singleton live births were identified using pregnancy hospitalizations that resulted in delivery between 1998-2000 and 2009-2011 in this retrospective cohort study. Maternal and fetal outcomes were evaluated.

RESULTS

There were 7204 HIV cases, 1450 TB cases, and 296 malaria cases over the two time periods, and the average age of infected subjects was 28.3. The HIV group was more likely to have almost all adverse pregnancy outcomes than the control group in both time periods. The 2009-2011 HIV group was more likely to undergo cesarean delivery than the 1998-2000 HIV group [1959 versus 1649, p < 0.0001].

CONCLUSION

Out of pregnant women infected with HIV, malaria, or tuberculosis, those infected with HIV are more likely to experience several adverse pregnancy outcomes than uninfected women.

Mitochondrial disorders among infants exposed to HIV and antiretroviral therapy

Although antiretroviral therapy (ART) is critical for preventing mother-to-child transmission of HIV, concern has been raised about the possibility that it may cause mitochondrial dysfunction in infants. There is adequate evidence for a mechanism by which exposure to nucleoside reverse transcriptase inhibitors (NRTIs) could lead to mitochondrial dysfunction; animal studies have shown evidence of mitochondrial dysfunction in the offspring of animals treated with NRTIs and mitochondrial disorders occur in adults treated with NRTIs. This systematic review synthesises the published research on mitochondrial dysfunction and disorders in infants exposed to HIV and antiretrovirals. We found conflicting evidence regarding the possible association of in utero ART exposure with mortality and morbidity due to mitochondrial dysfunction. ART exposure in utero or postpartum was associated with persistent decreases in lymphocytes, neutrophils and platelets as well as an increased risk of transient lactic acidaemia, anaemia and mitochondrial DNA depletion, although these laboratory findings were generally not associated with clinical symptoms. We conclude that large, prospective studies of HIV-exposed infants are needed to resolve the discrepant results regarding morbidity and mortality related to mitochondrial disorders, to ascertain the clinical significance of effects on laboratory values, to determine whether or not the incidence of mitochondrial disorders differs by regimen and to develop predictive models that might identify which infants are at the greatest risk. The challenges that remain to be addressed include the development of a sensitive but affordable screening algorithm in combination with specific diagnostic criteria; consistent collection of data on ART exposure and other risk factors, long-term follow-up of HIV-exposed but uninfected children and implementation in resource-limited settings.

Mechanisms of genotoxicity of nucleoside reverse transcriptase inhibitors

Nucleoside analogs were first approved by the U.S. Food and Drug Administration for use against HIV-AIDS in 1987. Since then, these agents, now commonly referred to as nucleoside reverse transcriptase inhibitors (NRTIs), have become essential components of the Highly Active Antiretroviral Therapy (HAART) drug combinations used for treatment of Human Immunodeficiency Virus-1 (HIV-1) infections. Their antiretroviral activity is likely two-fold: incorporation of the drug into viral DNA and inhibition of the viral reverse transcriptase. However, incorporation of the drug into host nuclear and mitochondrial DNA may be largely responsible for dose-limiting toxicities. Azidothymidine (AZT, 3'-azido-3'-deoxythymidine, zidovudine), the first NRTI approved for the therapy of HIV-1, is incorporated into DNA, causes mutations in the hypoxanthine-guanine phosphoribosyl-transferase (HPRT) and thymidine kinase (TK) genes, and induces micronuclei, chromosomal aberrations, sister chromatid exchange, shortened telomeres, and other genotoxic effects in cultured cells. Genomic instability would be predicted as a consequence of these events. Metabolic pathways that result in the phosphorylation of AZT play a crucial role in AZT-DNA incorporation, and may be altered after prolonged treatment. For example, thymidine kinase 1, the enzyme responsible for AZT mono-phosphorylation, is down-regulated during long-term exposure and appears to be associated with AZT-induced replication inhibition and the accumulation of cells in S-phase. Detailed information on the mechanisms underlying NRTI-associated antiretroviral efficacy, toxicity, and metabolic resistance were not available when AZT was first approved for use as an antiretroviral agent. Current insights, based on 15 years of research, may lead to intervention strategies to attenuate toxicity without altering drug efficacy.

Mode of delivery and postpartum morbidity in Latin American and Caribbean countries among women who are infected with human immunodeficiency virus-1: the NICHD International Site Development Initiative (NISDI) Perinatal Study

OBJECTIVE

The purpose of this study was to test whether cesarean delivery before labor and before ruptured membranes is associated with a higher risk of postpartum morbidity than vaginal delivery among women who are infected with human immunodeficiency virus-1 in Latin America and the Caribbean.

STUDY DESIGN

Data from a prospective cohort study (National Institute of Child Health and Human Development International Site Development Initiative Perinatal Study) were analyzed. The study population consisted of women who were followed for > or = 6 to 12 weeks after delivery, who had singleton infants, and with a known mode of delivery.

RESULTS

Of 819 enrollees, 697 women met inclusion criteria (299 vaginal deliveries, 260 cesarean deliveries before labor and before ruptured membranes, 138 cesarean deliveries after labor and/or after ruptured membranes); 36 women (5%) had postpartum morbidity (18 major, 18 minor). Mode of delivery was associated with postpartum morbidity (P = .02). Unadjusted odds ratios (95% CIs) for postpartum morbidity according to mode of delivery were cesarean delivery before labor and before ruptured membranes (odds ratio, 1.16 [95% CI, 0.5, 2.7]), cesarean delivery after labor and/or after ruptured membranes (odds ratio, 2.96 [95% CI, 1.3, 6.7]), and vaginal delivery (reference). These results did not differ appreciably with covariate adjustment.

CONCLUSION

The rate of postpartum morbidity was low. Mode of delivery was associated with postpartum morbidity, possibly reflecting the larger proportion of minor postpartum morbidity events among those with cesarean delivery after labor and/or after ruptured membranes.

HIV in pregnancy

PURPOSE OF REVIEW

This review discusses recent articles on various aspects of the prevention of mother-to-child transmission during pregnancy and delivery.

RECENT FINDINGS

Rapid human immunodeficiency virus (HIV) testing of women in labour whose status is not known allows the prompt treatment of mother and baby to reduce transmission risk. The feared clinical resistance in the mother after treatment with a single dose of nevirapine has been confirmed. Strategies are required to minimize this resistance and allow the use of nevirapine for treatment of the mother. There are new findings of mitochondrial toxicity in babies who have been exposed to anti-retroviral medicines during pregnancy or delivery, but the clinical implications are not clear. Long-term follow-up of exposed children is required. Resource-poor countries are starting to use multiple drugs to further reduce transmission to the infant. These efforts are reducing the rates of transmission to the level found in affluent countries.

SUMMARY

Improvements in treatment continue to reduce the risk of HIV transmission from mother to child in resource-poor countries, but subsequent maternal resistance continues to be a problem since treatment for the mother's health is now possible. The long-term effects on the infant are still not understood.

Efficacy and safety of cesarean delivery for prevention of mother-to-child transmission of HIV-1

BACKGROUND

Cesarean section before labor and before ruptured membranes ("elective cesarean section", or ECS) has been introduced as an intervention for the prevention of mother-to-child transmission (MTCT) of HIV-1. The role of mode of delivery in the management of HIV-1-infected women should be assessed in light of risks as well as benefits, since HIV-1-infected pregnant women must be provided with available information with which to make informed decisions regarding cesarean section and other options to prevent transmission of infection to their children.

OBJECTIVES

Our objectives were to assess the efficacy (for prevention of MTCT of HIV-1) and the safety of ECS among HIV-1-infected women.

SEARCH STRATEGY

Electronic searches were undertaken using MEDLINE and other databases. Hand searches of reference lists of pertinent reviews and studies, as well as abstracts from relevant conferences, were also conducted. Experts in the field were contacted to locate any other studies. The search strategy was iterative.

SELECTION CRITERIA

Randomized clinical trials assessing the efficacy and safety of ECS for prevention of MTCT of HIV-1 were included in the analysis, as were observational studies with relevant data.

DATA COLLECTION AND ANALYSIS

Data regarding HIV-1 infection status of infants born to HIV-1-infected women according to mode of delivery were extracted from the reports of the studies. Similarly, data regarding postpartum morbidity (PPM) (including minor (e.g., febrile morbidity, urinary tract infection) and major (e.g., endometritis, thromboembolism) morbidity) of the HIV-1-infected women, and infant morbidity, according to mode of delivery were extracted.

MAIN RESULTS

One randomized clinical trial of the efficacy of ECS for prevention of MTCT of HIV-1 was identified. No data regarding infant morbidity according to the HIV-1-infected mother's mode of delivery were available. Data regarding PPM according to mode of delivery were available from this clinical trial as well as from five observational studies. Among HIV-1-infected women not taking antiretrovirals (ARVs) during pregnancy or taking only zidovudine, ECS was found to be efficacious for prevention of MTCT of HIV-1. PPM is generally higher among HIV-1-infected women who undergo cesarean as compared to vaginal delivery, with the risk with ECS being intermediate between that of vaginal delivery and NECS (including emergency procedures). Other factors associated with the risk of PPM among HIV-1-infected women include HIV-1 disease stage (more advanced disease, as manifested by lower CD4 counts and higher viral loads, being associated with a greater risk of PPM) and co-morbid conditions (e.g., diabetes).

AUTHORS' CONCLUSIONS

ECS is an efficacious intervention for the prevention of MTCT among HIV-1-infected women not taking ARVs or taking only zidovudine. The risk of PPM with ECS is higher than that associated with vaginal delivery, yet lower than with NECS. Among HIV-1-infected women, more advanced maternal HIV-1 disease stage and concomitant medical conditions (e.g., diabetes) are independent risk factors for PPM. The risk of MTCT of HIV-1 according to mode of delivery among HIV-1-infected women with low viral loads (low either because the woman's HIV-1 disease is not advanced, or because her HIV-1 disease is well-controlled with ARVs) is unclear. Therefore, an important issue to be addressed in one or more large studies (individual studies or an individual patient data meta-analysis combining data from more than one study) is assessment of the effectiveness of ECS for prevention of MTCT of HIV-1 among HIV-1-infected women with undetectable viral loads (with or without receipt of highly active ARV therapy (HAART)).