Twin pregnancy as a risk factor for mother-to-child transmission of HIV-1: trends over 20 years

Frequency of differential placental transfer to twins of maternal antiretroviral medications

BACKGROUND

Placental passage of drugs in twins is poorly understood, and is unknown regarding antiretrovirals (ARVs). In the event of large differences in the exposure of 2 twins to the same maternal therapy, this could have a clinical impact in terms of prevention of perinatal HIV transmission or adverse effects.

OBJECTIVE

To describe the frequency of differential transplacental passage of antiretrovirals between twins.

STUDY DESIGN

The study was performed retrospectively, on data from women included in a multicenter perinatal HIV cohort study. All twin pairs for which the mother received antiretroviral therapy and for which drug concentrations in both of the umbilical cords after cord clamping at delivery were studied. We considered that a difference in concentrations of more than 50 % between twins was a substantial difference (ratios below 0.67 or above 1.50).

RESULTS

We analyzed 29 twin pairs, 27 dichorionic and 2 monochorionic diamniotic. Cord blood concentrations differed between the 2 twins by more than 50 % for at least one ARV in 9 twin pairs, 8 dichorionic and 1 monochorionic. Discordant concentrations were observed in one or more cases for several nucleoside reverse transcriptase inhibitors (tenofovir, emtricitabine, lamivudine, zidovudine) and protease inhibitors (atazanavir, lopinavir, saquinavir et ritonavir); within individual twin pairs placental transfer was discordant for one or more ARVs, but identical for others.

CONCLUSION

Concentrations differed in nearly one third of twin pairs. This may be due to interindividual genetic variability of placental transporters between dizygotic twins as well as physiological differences between twins.

Retrospective analysis of risk factors and gaps in prevention strategies for mother-to-child HIV transmission in Rio de Janeiro, Brazil

Background

Despite great progress made in methods to prevent mother-to-child transmission of HIV (MTCT), delivery and uptake of these measures remains a challenge in many countries. Although the Brazilian Ministry of Health aimed to eliminate MTCT by 2015, infection still occured in 15–24% of infants born to HIV-infected mothers. We sought to identify remaining factors that constrain MTCT elimination.

Methods

We conducted a retrospective, matched case-control study by reviewing hospital charts of infants born to HIV-infected mothers between 1997 and 2014 at three MTCT reference hospitals in the Rio de Janeiro metropolitan area. Cases were defined as HIV-exposed children with two positive HIV tests before 18 months of age; controls were defined as HIV-exposed children with two negative HIV tests before 18 months of age. We performed bivariate and MTCT cascade analyses to identify risk factors for MTCT and gaps in prevention services.

Results

We included 435 infants and their mothers (145 cases, 290 controls). Bivariate analyses of MTCT preventative care (PMTCT) indicated that cases were less likely to complete all individual measures in the antenatal, delivery, and postnatal period (p < 0.05). Assessing completion of the PMTCT cascade, the sequential steps of PMTCT interventions, we found inadequate retention in care among both cases and controls, and cases were significantly less likely than controls to continue receiving care throughout the cascade (p < 0.05). Motives for incompletion of PMTCT measures included infrastructural issues, such as HIV test results not being returned, but were most often due to lack of care-seeking. Over the course of the study period, PMTCT completion improved, although it remained below the 95% target for antenatal care, HIV testing, and antenatal ART set by the WHO. Adding concern, evaluation of co-infections indicated that case infants were also more likely to have congenital syphilis (OR: 4.29; 95% CI: 1.66 to 11.11).

Conclusions

While PMTCT coverage has improved over the years, completion of services remains insufficient. Along with interventions to promote care-seeking behaviour, increased infrastructural support for PMTCT services is needed to meet the HIV MTCT elimination goal in Brazil as well as address rising national rates of congenital syphilis.

Socio-economic, clinical and biological risk factors for mother - to - child transmission of HIV-1 in Muhima health centre (Rwanda): a prospective cohort study

BACKGROUND

Three decades since the first HIV-1 infected patients in Rwanda were identified in 1983; the Acquired Immunodeficiency Syndrome epidemic has had a devastating history and is still a major public health challenge in the country. This study was aimed at assessing socioeconomic, clinical and biological risk factors for mother - to - child transmission of HIV- in Muhima health centre (Kigali/Rwanda).

METHODS

The prospective cohort study was conducted at Muhima Health centre (Kigali/Rwanda).During the study period (May 2007 - April 2010), of 8,669 pregnant women who attended antenatal visits and screened for HIV-1, 736 tested HIV-1 positive and among them 700 were eligible study participants. Hemoglobin, CD4 count and viral load tests were performed for participant mothers and HIV-1 testing using DNA PCR technique for infants.Follow up data for eligible mother-infant pairs were obtained from women themselves and log books in Muhima health centre and maternity, using a structured questionnaire.Predictors of mother-to-child transmission of HIV-1 were assessed by multivariable logistic regression analysis.

RESULTS

Among the 679 exposed and followed-up infants, HIV-1 status was significantly associated with disclosure of HIV status to partner both at 6 weeks of age (non-disclosure of HIV status, adjusted odds ratio [AOR] 4.68, CI 1.39 to 15.77, p < 0.05; compared to disclosure) and at 6 months of age (non-disclosure of HIV status, AOR, 3.41, CI 1.09 to 10.65, p < 0.05, compared to disclosure).A significant association between mother's viral load (HIV-1 RNA) and infant HIV-1 status was found both at 6 weeks of age (> = 1000 copies/ml, AOR 7.30, CI 2.65 to 20.08, p < 0.01, compared to <1000 copies/ml) and at 6 months of age (> = 1000 copies/ml, AOR 4.60, CI 1.84 to 11.49, p < 0.01, compared to <1000 copies/ml).

CONCLUSION

In this study, the most relevant factors independently associated with increased risk of mother - to - child transmission of HIV-1 included non-disclosure of HIV status to partner and high HIV-1 RNA. Members of this cohort also showed socioeconomic inequalities, with unmarried status carrying higher risk of undisclosed HIV status. The monitoring of maternal HIV-1 RNA level might be considered as a routinely used test to assess the risk of transmission with the goal of achieving viral suppression as critical for elimination of pediatric HIV, particularly in breastfeeding populations.

Mother-to-child transmission of human immunodeficiency virus in aten years period

Objectives

to evaluate mother-to-child transmission (MTCT) rates and related factors in HIV-infected pregnant women from a tertiary hospital between 2000 and 2009.

Subjects and method

cohort of 452 HIV-infected pregnant women and their newborns. Data was collected from recorded files and undiagnosed children were enrolled for investigation. Statistical analysis: qui-square test, Fisher exact test, Student t test, Mann-Whitney test, ANOVA, risk ratio and confidence intervals.

Results

MTCT occurred in 3.74%. The study population displayed a mean age of 27 years; 86.5% were found to have acquired HIV through sexual contact; 55% were aware of the diagnosis prior to the pregnancy; 62% were not using HAART. Mean CD4 cell-count was 474 cells/ml and 70.3% had undetectable viral loads in the third trimester. HAART included nevirapine in 35% of cases and protease inhibitors in 55%; Zidovudine monotherapy was used in 7.3%. Mean gestational age at delivery was 37.2 weeks and in 92% by caesarian section; 97.2% received intravenous zidovudine. Use of AZT to newborn occurred in 100% of them. Factors identified as associated to MTCT were: low CD4 cell counts, elevated viral loads, maternal AIDS, shorter periods receiving HAART, other conditions (anemia, IUGR (intra uterine growth restriction), oligohydramnium), coinfecctions (CMV and toxoplasmosis) and the occurrence of labor. Use of HAART for longer periods, caesarian and oral zidovudine for the newborns were associated with a decreased risk. Poor adhesion to treatment was present in 13 of the 15 cases of transmission; in 7, coinfecctions were diagnosed (CMV and toxoplasmosis).

Conclusion

Use of HAART and caesarian delivery are protective factors for mother-to-child transmission of HIV. Maternal coinfecctions and other conditions were risk factors for MTCT.

Prevention of mother-to-child transmission of HIV-1: the role of cesarean delivery

The risk of mother-to-child transmission (MTCT) of HIV can be reduced through cesarean delivery prior to the onset of labor and prior to rupture of the membranes (elective cesarean delivery [ECD]). As a result of this evidence, the American College of Obstetricians and Gynecologists and the Department of Health and Human Services Panel on Treatment of HIV-Infected Pregnant Women and Prevention of Perinatal Transmission developed guidelines recommending ECD for HIV-infected women with plasma viral loads of more than 1000 copies/mL. Since the release of the recommendations, an increase in ECD has been seen among HIV-infected women in the United States. This article discusses the evidence on efficacy of ECD, current recommendations in the United States, and risks and morbidity related to ECD. Although the benefit of ECD in preventing MTCT of HIV is substantial, some questions remain. Specifically, the benefit of ECD for women with very low viral loads or for women using combination antiretroviral regimens is unclear, as is the timeframe after onset of labor or rupture of membranes within which ECD will still confer preventive benefits.

Identical twin parents; research reviews: twin pregnancy risk factors, a new twin type and a school legislation update; twin parents and twin researchers in the news

Some legal and social complications that arise when identical twins have children are examined. The specific case presented concerns assignment of paternity. This section is followed by a review of recent studies of multiple birth pregnancy risk factors, namely mother to infant HIV transmission and congenital hypothyroidism. Honors given to recently recognized twin researchers are noted, as is the birth of twins to an older mother in the United States.