Cesarean delivery for HIV-infected women: recommendations and controversies

Clinical Trials That Have Changed Clinical Practice and Care of Pregnant People With HIV

Over the last 4 decades, significant advances in the care of HIV during pregnancy have successfully reduced, and nearly eliminated, the risk of perinatal HIV transmission. The baseline risk of transmission without intervention (25% to 30%) is now <1% to 2% in the United States with contemporary antepartum, intrapartum, and postnatal interventions. In this review, we discuss 3 landmark clinical trials that substantially altered obstetric practice for pregnant individuals with HIV and contributed to this extraordinary achievement: 1) the Pediatric AIDS Clinical Trials Group 076 Trial determined that antepartum and intrapartum administration of antiretroviral drug zidovudine to the pregnant individual, and postnatally to the newborn, could reduce the risk of perinatal transmission by approximately two-thirds; 2) the European Mode of Delivery Collaboration Trial demonstrated performance of a prelabor cesarean birth before rupture of membranes among pregnant people with viremia reduced the risk of perinatal transmission compared with vaginal birth; and 3) the International Maternal Pediatric Adolescent AIDS Clinical Trials Network 2010 Trial identified that dolutegravir-containing, compared with efavirenz-containing, antiretroviral regimens during pregnancy achieved a significantly higher rate of viral suppression at delivery with shorter time to viral suppression, with fewer adverse pregnancy outcomes. Collectively, these trials not only advanced obstetric practice but also advanced scientific understanding of the timing, mechanisms, and determinants of perinatal HIV transmission. For each trial, we will describe key aspects of the study protocol and outcomes, insights gleaned about the dynamics of perinatal transmission, how each study changed clinical practice, and relevant updates to current practice since the trial's publication.

Antiretroviral Options and Treatment Decisions During Pregnancy

The majority of pediatric human immunodeficiency virus (HIV) infections are the result of vertical transmissions that occur during pregnancy, childbirth, and breastfeeding. The treatment of all pregnant persons living with HIV remains a global health initiative. Early and consistent use of antiretroviral therapy throughout pregnancy and childbirth drastically reduces the risk of perinatal transmission of HIV, resulting in fewer children living with the disease worldwide. Given that the maternal HIV viral load is the strongest predictor of perinatal transmission, suppressive antiretroviral treatment during pregnancy is the principal means to eliminate transmission of HIV from mother to child. With the use of combined antiretroviral therapy, typically with dual-nucleoside reverse transcriptase inhibitors plus an integrase strand transfer inhibitor or a ritonavir-boosted protease inhibitor, HIV-infected mothers can now achieve virologic suppression to undetectable levels and yield a perinatal transmission rate of less than 2%. Important considerations of HIV treatment in pregnancy include the safety and efficacy of antiretroviral drugs, altered pregnancy-related pharmacokinetics, potential for birth defects or adverse neonatal outcomes, and individualized delivery planning based on maternal viral load. This practical review article summarizes the options, considerations, and recommendations for antiretroviral treatment in pregnancy to reduce perinatal HIV transmission and optimize health outcomes for mothers and infants worldwide.

Prevention of Mother-to-Child Human Immunodeficiency Virus Transmission in Resource-Limited Countries

The first pediatric AIDS cases were reported in 1982. A decade later, the World Health Organization estimated there were more than 500,000 pediatric AIDS cases resulting from mother-to-child transmission, 90% of which were in sub-Saharan Africa. Although the rate of new infections globally has been cut in half since the peak of the pandemic, human immunodeficiency virus (HIV) remains a public health threat, and rates of new infections continue to increase in some regions. Mother-to-child transmission of HIV has now been virtually eliminated in many parts of the world but remains an issue in resource-limited countries.

Preconceptual Priming Overrides Susceptibility to Escherichia coli Systemic Infection during Pregnancy

Maternal sepsis is a leading cause of morbidity and mortality during pregnancy. Escherichia coli is a primary cause of bacteremia in women and occurs more frequently during pregnancy. Several key outstanding questions remain regarding how to identify women at highest infection risk and how to boost immunity against E. coli infection during pregnancy. Here, we show that pregnancy-induced susceptibility to E. coli systemic infection extends to rodents as a model of human infection. Mice infected during pregnancy contain >100-fold-more recoverable bacteria in target tissues than nonpregnant controls. Infection leads to near complete fetal wastage that parallels placental plus congenital fetal invasion. Susceptibility in maternal tissues positively correlates with the number of concepti, suggesting important contributions by expanded placental-fetal target tissue. Remarkably, these pregnancy-induced susceptibility phenotypes are also efficiently overturned in mice with resolved sublethal infection prior to pregnancy. Preconceptual infection primes the accumulation of E. coli-specific IgG and IgM antibodies, and adoptive transfer of serum containing these antibodies to naive recipient mice protects against fetal wastage. Together, these results suggest that the lack of E. coli immunity may help discriminate individuals at risk during pregnancy, and that overriding susceptibility to E. coli prenatal infection by preconceptual priming is a potential strategy for boosting immunity in this physiological window of vulnerability.IMPORTANCE Pregnancy makes women especially vulnerable to infection. The most common cause of bloodstream infection during pregnancy is by a bacterium called Escherichia coli This bacterium is a very common cause of bloodstream infection, not just during pregnancy but in all individuals, from newborn babies to the elderly, probably because it is always present in our intestine and can intermittently invade through this mucosal barrier. We first show that pregnancy in animals also makes them more susceptible to E. coli bloodstream infection. This is important because many of the dominant factors likely to control differences in human infection susceptibility can be property controlled for only in animals. Despite this vulnerability induced by pregnancy, we also show that animals with resolved E. coli infection are protected against reinfection during pregnancy, including having resistance to most infection-induced pregnancy complications. Protection against reinfection is mediated by antibodies that can be measured in the blood. This information may help to explain why most women do not develop E. coli infection during pregnancy, enabling new approaches for identifying those at especially high risk of infection and strategies for preventing infection during pregnancy.

The Value of Twins for Health and Medical Research: A Third of a Century of Progress

In 1984, Hrubec and Robinette published what was arguably the first review of the role of twins in medical research. The authors acknowledged a growing distinction between two categories of twin studies: those aimed at assessing genetic contributions to disease and those aimed at assessing environmental contributions while controlling for genetic variation. They concluded with a brief section on recently founded twin registries that had begun to provide unprecedented access to twins for medical research. Here we offer an overview of the twin research that, in our estimation, best represents the field has progress since 1984. We start by summarizing what we know about twinning. We then focus on the value of twin study designs to differentiate between genetic and environmental influences on health and on emerging applications of twins in multiple areas of medical research. We finish by describing how twin registries and networks are accelerating twin research worldwide.

ACOG Committee Opinion No. 751: Labor and Delivery Management of Women With Human Immunodeficiency Virus Infection

This Committee Opinion is being revised to provide updated guidance on the management of pregnant women during pregnancy and delivery to prevent mother-to-child transmission of the human immunodeficiency virus (HIV). Prevention of transmission of HIV from the woman to her fetus or newborn is a major goal in the care of pregnant women infected with HIV. Continuing research into mother-to-child transmission of HIV has suggested that a substantial number of cases of perinatal HIV transmission occur as the result of fetal exposure to the virus during labor and delivery. The precise mechanisms are not known. Established and ongoing research has shown that treatment of HIV-infected pregnant women with combined antiretroviral therapy can achieve a 1-2% or lower risk of mother-to-child transmission if maternal viral loads of 1,000 copies/mL or less can be sustained, independent of the route of delivery or duration of ruptured membranes before delivery. Vaginal delivery is appropriate for HIV-infected pregnant women who have been maintained on combined antiretroviral therapy and who have viral loads of 1,000 copies/mL or less at or near delivery. The risk of mother-to-child transmission in HIV-infected women with high viral loads can be reduced by performing cesarean deliveries before the onset of labor and before rupture of membranes (termed scheduled cesarean delivery in this document), in conjunction with the use of peripartum maternal antiretroviral therapy. Discussion of the option of scheduled cesarean delivery and its advantages in the situation of suboptimal viral suppression should begin as early as possible in pregnancy with every pregnant woman with HIV infection to give her an adequate opportunity to ask questions and consider her decision-making concerning the delivery plan. The patient's decision regarding her route of delivery should be respected after maternal and neonatal risks have been discussed.

Changing Patterns and Factors Associated With Mode of Delivery Among Pregnant Women With Human Immunodeficiency Virus Infection in the United States

OBJECTIVE

To describe patterns and factors associated with mode of delivery among pregnant women with human immunodeficiency virus (HIV) infection in the United States in relation to evolving HIV-in-pregnancy guidelines.

METHODS

We conducted an analysis of two observational studies, Pediatric AIDS Clinical Trials Group and International Maternal Pediatric Adolescent AIDS Clinical Trials Network Protocol P1025, which enrolled pregnant women with HIV infection from 1998 to 2013 at more than 60 U.S. acquired immunodeficiency syndrome clinical research sites. Multivariable analyses of factors associated with an HIV-indicated cesarean delivery (ie, for prevention of mother-to-child transmission) compared with other indications were conducted and compared according to prespecified time periods of evolving HIV-in-pregnancy guidelines: 1998-1999, 2000-2008, and 2009-2013.

RESULTS

Among 6,444 pregnant women with HIV infection, 21% delivered in 1998-1999, 58% in 2000-2008, and 21% in 2009-2013; 3,025 (47%) delivered by cesarean. Cesarean delivery increased from 30% in 1998 to 48% in 2013. Of all cesarean deliveries, repeat cesarean deliveries increased from 16% in 1998 to 42% in 2013; HIV-indicated cesarean deliveries peaked at 48% in 2004 and then dropped to 12% by 2013. In multivariable analyses, an HIV diagnosis during pregnancy, initiation of antiretroviral therapy in the third trimester, a plasma viral load 500 copies/mL or greater, and delivery between 37 and 40 weeks of gestation increased the likelihood of an HIV-indicated cesarean delivery. In analyses by time period, an HIV diagnosis during pregnancy, initiation of antiretroviral therapy in the third trimester, and a plasma viral load of 500 copies/mL or greater were progressively more likely to be associated with an HIV-indicated cesarean delivery over time.

CONCLUSION

Almost 50% of pregnant women with HIV infection underwent cesarean delivery. Over time, the rate of repeat cesarean deliveries increased, whereas the rate of HIV-indicated cesarean deliveries decreased; cesarean deliveries were more likely to be performed in women at high risk of mother-to-child transmission. These findings reinforce the need for both early diagnosis and treatment of HIV infection in pregnancy and the option of vaginal delivery after cesarean among pregnant women with HIV infection.

Role of HIV exposure and infection in relation to neonatal GBS disease and rectovaginal GBS carriage: a systematic review and meta-analysis

Streptococcus agalactiae (GBS) is the leading cause worldwide of neonatal sepsis. We sought to assess to which extent HIV exposure of neonates is associated with GBS neonatal disease. Furthermore, we assessed to which extent HIV infection in women is associated with maternal rectovaginal GBS carriage, the single most important risk factor for GBS neonatal disease. We searched Pubmed, Embase, and Web of Science for studies assessing the association between neonatal GBS disease and HIV-status of the mother and studies that assessed the association between rectovaginal GBS colonization and HIV status in women. HIV-exposed uninfected neonates were more than twice as likely to have neonatal GBS disease compared to unexposed neonates. HIV-exposed neonates were not at increased risk for early-onset neonatal disease, but were 4.43 times more likely to have late-onset neonatal GBS disease. There was no significant association between HIV infection status and rectovaginal GBS carriage. Public health interventions preventing neonatal GBS disease are urgently needed for the increasing group of HIV-exposed neonates. A framework integrating and explaining our findings highlights opportunities for the clinical practice and global health policy to prevent disease. Well-designed studies should clarify the relation between HIV-status and GBS carriage.

Evaluation of factors associated with vertical HIV-1 transmission

OBJECTIVE

To compare the prevalence and factors associated with vertical transmission of human immunodeficiency virus 1 (HIV-1) among pregnant women treated in the periods of 1998-2004 and 2005-2011 in a reference service for the care of HIV-infected patients in southern Brazil.

METHODS

This was a descriptive and analytical study that used the databases of laboratories from the CD4 and STDs/AIDS Viral Load National Laboratory Network of the Brazilian Ministry of Health. HIV-1-infected pregnant women were selected after an active search for clinical information and obstetric and neonatal data from their medical records between the years of 1998 and 2011.

RESULTS

102 pregnant women were analyzed between 1998 and 2004 and 251 in the period between 2005 and 2011, totaling 353 children born to pregnant women with HIV-1. It was observed that the vertical transmission rate was 11.8% between 1998 and 2004 and 3.2% between 2005 and 2011 (p<0.001). The increased use of antiretroviral drugs (p=0.02), the decrease in viral load (p<0.001), and time of membrane rupture lower than 4h (p<0.001) were associated with the decrease of vertical transmission factors when comparing the two periods.

CONCLUSION

It was observed a decrease in the rate of vertical transmission in recent years. According to the studied variables, is suggested that the risk factors for vertical transmission of HIV-1 were absence of antiretroviral therapy, high viral load in the pregnant women, and membrane rupture time >4h.

Time to viral load suppression in antiretroviral-naive and -experienced HIV-infected pregnant women on highly active antiretroviral therapy: implications for pregnant women presenting late in gestation

OBJECTIVE

To compare time to achieve viral load <400 copies/ml and <1000 copies/ml in HIV-infected antiretroviral (ARV) -naive versus ARV-experienced pregnant women on highly active antiretroviral therapy (HAART).

DESIGN

Retrospective cohort study.

SETTING

Three university medical centers, USA.

POPULATION

HIV-infected pregnant women initiated or restarted on HAART during pregnancy.

METHODS

We calculated time to viral load <400 copies/ml and <1000 copies/ml in HIV-infected pregnant women on HAART who reported at least 50% adherence, stratifying based on previous ARV exposure history.

MAIN OUTCOME MEASURES

Time to HIV viral load <400 copies/ml and <1000 copies/ml.

RESULTS

We evaluated 138 HIV-infected pregnant women, comprising 76 ARV-naive and 62 ARV-experienced. Ninety-three percent of ARV-naive women achieved a viral load < 400 copies/ml during pregnancy compared with 92% of ARV-experienced women (P = 0.82). The median number of days to achieve a viral load < 400 copies/ml in the ARV-naive cohort was 25.0 (range 3.5-133; interquartile range 16-34) days compared with 27.0 (range 8-162.5; interquartile range 18.5-54.3) days in the ARV-experienced cohort (P = 0.02). In a multiple predictor analysis, women with higher adherence (adjusted relative hazard [aRH] per 10% increase in adherence 1.29, 95% confidence interval [CI] 1.08-1.54, P = 0.01) and receiving a non-nucleotide reverse transcriptase inhibitor (NNRTI) -based regimen (aRH 2.48, 95% CI 1.33-4.63, P = 0.01) were more likely to achieve viral load <400 copies/ml earlier. Increased baseline HIV log10 viral load was associated with a later time of achieving viral load <400 copies/ml (aRH 0.60, 95% CI 0.39-0.92, P = 0.02). In a corresponding model of time to achieve viral load <1000 copies/ml, adherence (aRH per 10% increase in adherence 1.79, 95% CI 1.34-2.39, P < 0.001), receipt of NNRTI (aRH 2.95, 95% CI 1.23-7.06, P = 0.02), and CD4 cell count (aRH per 50 count increase in CD4 1.12, 95% CI 1.03-1.22, P = 0.01) were associated with an earlier time to achieve viral load below this threshold. Increasing baseline HIV log10 viral load was associated with a longer time of achieving viral load <1000 copies/ml (aRH 0.54, 95% CI 0.34-0.86, P = 0.01). In multiple predictor models, previous ARV exposure was not significantly associated with time to achieve viral load below thresholds of <400 copies/ml and <1000 copies/ml.

CONCLUSIONS

Pregnant women with ≥50% adherence, whether ARV-naive or ARV-experienced, on average achieve a viral load <400 copies/ml within a median of 26 days and a viral load of <1000 copies/ml within a median of 14 days of HAART initiation. Increased adherence, receipt of NNRTI-based regimen and lower baseline HIV log10 viral load were all statistically significant predictors of earlier time to achieve viral load <400 copies/ml and <1000 copies/ml. Increased CD4 count was statistically significant as a predictor of earlier time to achieve viral load <1000 copies/ml.

Correlates of mother-to-child transmission of HIV in the United States and Puerto Rico

OBJECTIVE

The goal of this study was to examine associations between demographic, behavioral, and clinical variables and mother-to-child HIV transmission in 15 US jurisdictions for birth years 2005 through 2008.

METHODS

The study used Enhanced Perinatal Surveillance system data for HIV-infected women who gave birth to live infants. Multivariable logistic regression was used to assess variables associated with mother-to-child transmission.

RESULTS

Among 8054 births, 179 infants (2.2%) were diagnosed with HIV infection. Half of the births had at least 1 missed prevention opportunity: 74.3% of infected infants, 52.1% of uninfected infants. Among 7757 mother-infant pairs with sufficient data for analysis, the odds of having an HIV-infected infant were higher for women who received late testing or no prenatal antiretroviral medications (odds ratio: 2.5 [95% confidence interval (CI): 1.5-4.0] and 3.5 [95% CI: 2.0-6.4], respectively). The odds for mothers who breastfed were 4.6 times (95% CI: 2.2-9.8) the odds for those who did not breastfeed. The adjusted odds for women with CD4 counts <200 cells per microliter were 2.4 times (95% CI: 1.4-4.2) those for women with CD4 counts ≥500 cells per microliter. The odds for women who abused substances were twice (95% CI: 1.4-2.9) those for women who did not.

CONCLUSIONS

The odds of having an HIV-infected infant were higher among HIV-infected women who were tested late, had no antiretroviral medications, abused substances, breastfed, or had lower CD4 cell counts. Increases in earlier HIV diagnosis, substance abuse treatment, avoidance of breastfeeding, and use of prenatal antiretroviral medications are critical in eliminating perinatal HIV infections in the United States.

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.

Factors associated with HIV-positive women carrying pregnancies to term

OBJECTIVES

To determine predictors of HIV-positive women who choose to carry a pregnancy to term.

METHODS

We collected pregnancy data up to December 2008 on women who had attended the University Health Network Immunodeficiency Clinic in Toronto since 2000 and were < 50 years of age at the time of their first HIV-positive test. Data were included on all pregnancies, including those that occurred before the woman was known to be HIV positive or first attended the clinic.

RESULTS

Data were collected from a total of 341 women who were < 50 years of age at their first HIV-positive test. Of these women, 179 (52%) had a total of 484 pregnancies, and 110 of these pregnancies (23%) in 74 women were known to occur after the woman tested HIV positive. An additional 52 women (11%) were found to be HIV positive during the pregnancy. Predictors of a woman's carrying a pregnancy to term when HIV positive were age, region of maternal birth, number of previous live births, and pregnancy during the highly active antiretroviral therapy (HAART) era.

CONCLUSION

HIV-positive women are more likely to carry a pregnancy to term during the new HAART era than they were before this era. Younger African-born HIV-positive women who already have children are more likely than other HIV-positive women to choose to carry a pregnancy to term.

Mode of delivery and infant respiratory morbidity among infants born to HIV-1-infected women

OBJECTIVE

To estimate risk of infant respiratory morbidity associated with cesarean delivery before labor and ruptured membranes among HIV-1-infected women.

METHODS

In a prospective cohort study of HIV-1-infected women and their infants, mode of delivery was determined by clinicians at the participating sites. For this analysis, "elective cesarean delivery" was defined as any cesarean delivery, regardless of gestational age, without labor and with duration of ruptured membranes of less than 5 minutes. Nonelective cesarean deliveries were those performed after the onset of labor, rupture of membranes, or both. Vaginal delivery included normal spontaneous and instrument deliveries. Associations between mode of delivery and infant respiratory morbidity were assessed using chi or Fisher's exact test. Adjusted odds of respiratory distress syndrome by delivery mode were assessed using multivariable logistic regression.

RESULTS

Among 1,194 mother-infant pairs, there were significant differences according to mode of delivery in median gestational age (weeks) at delivery (vaginal, n=566, median=38.8; nonelective cesarean, n=216, median=38.0; and elective cesarean, n=412, median 38.1; P<.001) and incidence of respiratory distress syndrome (vaginal, n=9, 1.6%, reference; nonelective cesarean, n=16, 7.4%; elective cesarean, n=18; 4.4%; (P<.001). In analyses adjusted for gestational age and birth weight, mode of delivery was not statistically significantly associated with infant respiratory distress syndrome (P=.10), although a trend toward an increased risk of respiratory distress syndrome among infants delivered by cesarean was suggested (nonelective cesarean adjusted odds ratio [OR] 2.32, 95% confidence interval [CI] 0.95-5.67; elective cesarean OR 2.56, 95% CI 1.01-6.48).

CONCLUSION

Respiratory distress syndrome rates associated with elective cesarean delivery among HIV-1-infected women are low, comparable with published rates among uninfected women. There is minimal neonatal respiratory morbidity risk in near-term infants born by elective cesarean delivery to HIV-1-infected women.

LEVEL OF EVIDENCE

II.

HIV-1 vertical transmission in Rio Grande, Southern Brazil

The aim of this study was to determine the rate and risk factors of HIV-1 mother-to-child transmission (MTCT), the timing of transmission and the transmitted subtype in a population where subtypes B and C co-circulate. One hundred and forty-four babies born to HIV-1-infected mothers were studied. Subtype and timing of transmission were determined by a nested polymerase chain reaction of the gp41 gene. Seven children were infected (4.9%): four were infected intrautero and one intrapartum. The higher frequency of intrautero transmission was statistically significant ( P = 0.001). Use of antiretrovirals (ARVs) in the three stages of gestation was a protective risk factor for MTCT (PR = 0.42; CI: 0.21–0.83; P = 0.013). A higher HIV viral load at delivery was the only independent risk factor for MTCT. Early and universal access to ARVs during pregnancy are the most important measures to decrease vertical HIV-1 transmission even in areas where HIV clade distribution differs.

Infections related to pregnancy

Infections in pregnancy and in the postpartum period represent an important knowledge base that emergency physicians should have. Being able to understand the risk that pregnancy-related infections have on maternal and fetal health in addition to the initiation of appropriate treatment for these infections is crucial. In the postpartum period, most infections (94%) are likely to manifest after hospital discharge; therefore, patients frequently present to the emergency department.

Low rates of mother-to-child transmission of HIV following effective pregnancy interventions in the United Kingdom and Ireland, 2000-2006

AIM

In the United Kingdom (UK) and Ireland, avoidance of breastfeeding and alternative combinations of antiretroviral therapy regimen and mode of delivery are recommended according to maternal clinical status. The aim of this analysis was to explore the impact of different strategies to prevent mother-to-child transmission at a population level.

DESIGN

Comprehensive national surveillance study.

METHODS

Pregnancies in diagnosed HIV-infected women in the UK and Ireland are notified to the National Study of HIV in Pregnancy and Childhood; infant infection status is subsequently reported. Factors associated with transmission in this observational study were explored for singleton births between 2000 and 2006.

RESULTS

The overall mother-to-child transmission rate was 1.2% (61/5151, 95% confidence interval: 0.9-1.5%), and 0.8% (40/4864) for women who received at least 14 days of antiretroviral therapy. Transmission rates following combinations recommended in British guidelines were 0.7% (17/2286) for highly active antiretroviral therapy with planned Caesarean section, 0.7% (4/559) for highly active antiretroviral therapy with planned vaginal delivery, and 0% (0/464) for zidovudine monotherapy with planned Caesarean section (P = 0.150). Longer duration of highly active antiretroviral therapy was associated with reduced transmission after adjusting for viral load, mode of delivery and sex (adjusted odds ratio = 0.90 per week of highly active antiretroviral therapy, P = 0.007). Among 2117 infants born to women on highly active antiretroviral therapy with viral load less than 50 copies/ml, only three (0.1%) were infected, two with evidence of in-utero transmission.

CONCLUSION

Sustained low HIV transmission rates following different combinations of interventions in this large unselected population are encouraging. Current options for treatment and delivery offered to pregnant women according to British guidelines appear to be effective.