Efficacy of antenatal zidovudine in reducing perinatal transmission of human immunodeficiency virus type 1. The New York City Perinatal HIV Transmission Collaborative Study Group

Adverse perinatal outcomes associated with antiretroviral therapy in women living with HIV: A systematic review and meta-analysis

Background

Maternal HIV infection is associated with an increased risk of adverse perinatal outcomes. The World Health Organization (WHO) recommends immediate initiation of lifelong antiretroviral therapy (ART) for all people living with HIV, including pregnant women living with HIV (WLHIV). We aimed to assess the risk of adverse perinatal outcomes in WLHIV receiving ART compared to ART-naïve WLHIV and HIV-negative women.

Materials and methods

We conducted a systematic literature review by searching PubMed, CINAHL, Global Health, and EMBASE for studies published between Jan 1, 1980, and April 20, 2020. Two investigators independently selected relevant studies and extracted data from studies reporting on the association of pregnant WLHIV receiving ART with adverse perinatal outcomes. Perinatal outcomes examined were preterm birth (PTB), very PTB, spontaneous PTB (sPTB), low birth weight (LBW), very LBW (VLBW), term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Random-effects meta-analyses examined the risk of adverse perinatal outcomes in WLHIV receiving ART compared to ART-naïve WLHIV and HIV-negative women. Subgroup and sensitivity analyses were performed based on country income status and study quality, and adjustment for confounding factors assessed.

Results

Of 94,594 studies identified, 73 cohort studies, including 424,277 pregnant women, met the inclusion criteria. We found that WLHIV receiving ART are associated with a significantly decreased risk of PTB (relative risk 0.79, 95% CI 0.67-0.93), sPTB (0.46, 0.32-0.66), LBW (0.86, 0.79-0.93), and VLBW (0.62, 0.39-0.97) compared to ART-naïve WLHIV. However, WLHIV receiving ART are associated with a significantly increased risk of PTB (1.42, 1.28-1.57), sPTB (2.20, 1.32-3.67), LBW (1.58, 1.36-1.84), term LBW (1.88, 1.23-2.85), SGA (1.69, 1.32-2.17), and VSGA (1.22, 1.10-1.34) compared to HIV-negative women.

Conclusion

ART reduces the risk of adverse perinatal outcomes in pregnant WLHIV, but the risk remains higher than in HIV-negative women. Our findings support the WHO recommendation of immediate initiation of lifelong ART for all people living with HIV, including pregnant WLHIV.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42021248987.

Adverse perinatal outcomes associated with HAART and monotherapy: systematic review and meta-analysis

OBJECTIVES

Assess adverse perinatal outcomes in women living with HIV (WLHIV) receiving HAART or zidovudine (ZDV) monotherapy, compared with antiretroviral therapy (ART)-naive WLHIV and HIV-negative women.

DESIGN

Systematic review and meta-analysis.

METHODS

We conducted a systematic literature review by searching PubMed, CINAHL, Global Health, and EMBASE for studies published during 1 January 1980 to 20 April 2020. We included studies reporting on the association of pregnant WLHIV receiving HAART or ZDV monotherapy with 11 perinatal outcomes: preterm birth (PTB), very PTB, spontaneous PTB (sPTB), low birth weight (LBW), very LBW, term LBW, preterm LBW, small for gestational age (SGA), very SGA (VSGA), stillbirth, and neonatal death. Random-effects meta-analyses were conducted.

RESULTS

Sixty-one cohort studies assessing 409 781 women were included. WLHIV receiving ZDV monotherapy were associated with a decreased risk of PTB [relative risk 0.70, 95% confidence interval (CI) 0.62-0.79] and LBW (0.77, 0.67-0.88), and comparable risk of SGA, compared with ART-naive WLHIV. WLHIV receiving ZDV monotherapy had a comparable risk of PTB and LBW, and an increased risk of SGA (1.16, 1.04-1.30) compared with HIV-negative women. In contrast, WLHIV receiving HAART were associated with a comparable risk of PTB and LBW, and increased risk of SGA (1.38, 1.09-1.75), compared with ART-naive WLHIV. WLHIV receiving HAART were associated with an increased risk of PTB (1.55, 1.38-1.74), sPTB (2.09, 1.48-2.96), LBW (1.79, 1.51-2.13), term LBW (1.88, 1.23-2.85), SGA (1.80,1.34-2.40), and VSGA (1.22, 1.10-1.34) compared with HIV-negative women.

CONCLUSION

Pregnant WLHIV receiving HAART have an increased risk of a wide range of perinatal outcomes compared with HIV-negative women.

Evolución de la transmisión vertical del VIH y posibles factores involucrados

INTRODUCTION

Since the introduction of zidovudine, perinatal transmission (PT) of HIV-1 has markedly decreased, although a transmission rate of zero has still not been achieved. The present study describes the trend in PT over 13 years, as well as changes in medical-surgical management and their influence on PT.

PATIENTS AND METHODS

We performed a prospective cohort study of all HIV-1-infected mother-infant pairs born between January 1987 and December 1999 in Hospital 12 Octubre in Madrid. Univariate analysis was performed to determine the relationship between possible risk factors and PT.

RESULTS

A total of 290 mothers and 291 children were included. Thirty-eight children were infected, 28 of these before 1994 (PT rate: 13 %). There were no cases of infection when the full ACTG 076 protocol was implemented. Factors significantly associated with a higher transmission rate were prolonged rupture of membranes and nonelective caesarean section. The main protective factor was antiretroviral therapy.

CONCLUSIONS

PT markedly decreased after the introduction of the ACTG 076 protocol. In the last 13 years, maternal age and maternal infection due to heterosexual transmission have increased. Other changes observed were modifications in obstetric interventions and the generalized use of zidovudine and antiretroviral therapy during pregnancy.

Single-dose perinatal nevirapine plus standard zidovudine to prevent mother-to-child transmission of HIV-1 in Thailand

BACKGROUND

Although zidovudine prophylaxis decreases the rate of transmission of the human immunodeficiency virus (HIV) type 1 substantially, a large number of infants still become infected. We hypothesized that the administration, in addition to zidovudine, of a single dose of oral nevirapine to mothers during labor and to neonates would further reduce transmission of HIV.

METHODS

We conducted a randomized, double-blind trial of three treatment regimens in Thai women who were receiving zidovudine therapy during the third trimester of pregnancy. In one group, mothers and infants received a single dose of nevirapine (nevirapine-nevirapine regimen); in another, mothers and infants received nevirapine and placebo, respectively (nevirapine-placebo regimen); and in the last, mothers and infants received placebo (placebo-placebo regimen). The infants also received one week of zidovudine therapy and were formula-fed. The end point of the study was infection with HIV in the infants, established by virologic testing.

RESULTS

Between January 15, 2001, and February 28, 2003, a total of 1844 Thai women were enrolled. At the first interim analysis, the independent data monitoring committee stopped enrollment in the placebo-placebo group. Among women who delivered before the interim analysis, the as-randomized Kaplan-Meier estimates of the transmission rates were 1.1 percent (95 percent confidence interval, 0.3 to 2.2) in the nevirapine-nevirapine group and 6.3 percent (95 percent confidence interval, 3.8 to 8.9) in the placebo-placebo group (P<0.001). The final per-protocol transmission rate in the nevirapine-nevirapine group, 1.9 percent (95 percent confidence interval, 0.9 to 3.0), was not significantly inferior to the rate in the nevirapine-placebo group (2.8 percent; 95 percent confidence interval, 1.5 to 4.1). Nevirapine had an effect within subgroups defined by known risk factors such as viral load and CD4 count. No serious adverse effects were associated with nevirapine therapy.

CONCLUSIONS

A single dose of nevirapine to the mother, with or without a dose of nevirapine to the infant, added to oral zidovudine prophylaxis starting at 28 weeks' gestation, is highly effective in reducing mother-to-child transmission of HIV.

Prevention of perinatal HIV transmission: a review of novel strategies

Significant progress has been made in preventing transmission of HIV-1 from mother to infant. With combination antiretroviral therapies, transmission rates lower than 2% have been achieved in clinical studies. Abbreviated regimens covering labour and the first few days of neonatal life have shown considerable promise in the developing world. Several questions and challenges remain, however. These include choice of the optimal antiretroviral agent(s) and duration of the regimens, availability of antiretroviral agents in developing countries, long-term safety of antiretrovirals during pregnancy and early neonatal life and the problem of breastfeeding transmission in countries where alternatives to breastfeeding are not available. A wider array of strategies for prevention of mother-to-child transmission of HIV-1 during breastfeeding, including passive and active immunisation, may offer much needed answers to the problem of continued HIV transmission from mother to infant.

Prevention of perinatal HIV transmission: current status and future developments in anti-retroviral therapy

Significant progress has been made in the battle against transmission of HIV-1 from mother to infant. Antiretroviral regimens covering the later part of gestation, labour and the first few weeks of neonatal life have shown great efficacy in reducing such transmission. With the advent of combination antiretroviral therapies, transmission rates lower than 2% have been achieved in clinical studies. Elective caesarean delivery has been shown to enhance the benefit of antiretroviral regimens; however, the risks associated with this approach in many resource-poor settings in developing countries limit its role worldwide. Abbreviated antiretroviral regimens covering labour and the first few days of neonatal life have shown considerable promise in the developing world, resulting in 50% reduction in transmission. Several questions and challenges remain, however. Amongst them, choice of the optimal antiretroviral agent(s), evaluation of purely post-exposure neonatal prophylaxis, availability of antiretroviral agents in developing countries, long-term safety of antiretroviral therapy during pregnancy and early neonatal life, and the problem of breastfeeding transmission in the developing world are some issues that need urgent attention.

Human immunodeficiency virus and pregnancy

The recent spread of HIV infection into the heterosexual population in the United States, Europe, and Australia, as well as its earlier heterosexual presence in the developing world, has led to increased scientific and clinical attention to the role of HIV infection in pregnancy. In managing a pregnant HIV-positive woman, it is most important to treat the patient as someone who is HIV-positive rather than someone who is pregnant. Withholding antiviral or prophylactic therapies from the mother for fear of harming the child is not justified, because failure to treat the mother increases the fetal risk. The most important parameter to follow is the maternal plasma HIV-RNA level, and the most important treatment issue is to reduce this level because it is directly related to the risk of vertical transmission.

Prenatal HIV counseling, testing, and antiretroviral prophylaxis by obstetric and family medicine providers in Alabama

BACKGROUND

The study reported here assessed the implementation of recommendations for routine universal prenatal counseling and voluntary HIV testing among Alabama physicians who provide prenatal care and determined factors associated with noncompliance.

METHODS

Voluntary, confidential mailed survey of obstetrics and family medicine practitioners.

RESULTS

Of the 138 physicians who responded to a mailed survey in Alabama, 17 (12.3%) indicated that they did not offer universal HIV counseling and testing to pregnant women. Factors associated with failure to offer universal HIV counseling and testing included having more than 50% of patients refuse HIV counseling and testing when offered and never knowingly having given prenatal/perinatal care to women with HIV. Low/medium familiarity with the US Public Health Service recommendations for perinatal zidovudine use to reduce HIV transmission and physician specialty are also suggested as predictors of not offering universal testing.

CONCLUSIONS

Despite the well-established benefits of antiretroviral prophylaxis to prevent vertical transmission of HIV, some physicians in Alabama have been slow to adopt universal testing of their pregnant patients for HIV in the prenatal period. Practitioner education is as important as patient education in eliminating pediatric HIV in the Deep South.

Options for prevention of HIV transmission from mother to child, with a focus on developing countries

Use of antiretroviral drugs among HIV-infected pregnant women in many developed countries has significantly reduced rates of mother-to-child HIV transmission, demonstrating that this route of transmission is amenable to intervention. Prevention of transmission in developing countries has proved to be more difficult, although recent advances in short-course antiretroviral drug interventions have made it an immediate possibility, rather than a distant hope as it was seen to be in the recent past. Non-antiretroviral drug interventions, including washing of the birth canal with antiseptic solution and micronutrient supplementation, have not been found to be effective at interrupting mother-to-child HIV transmission, but may have other benefits for maternal and child health. An important issue for developing countries is prevention of postnatal HIV transmission through breast feeding. In most developing countries, formula feeding is not a reasonable option, given the higher rates of mortality from diarrheal and respiratory disease associated with avoidance of all breast feeding. A promising new line of research has recently been broached with the findings from a study in South Africa, which demonstrated that exclusive breast feeding is associated with a significant reduction in postnatal transmission of HIV.

Zidovudine and perinatal human immunodeficiency virus type 1 transmission: a population-based approach

OBJECTIVE

This study examined the impact of the full 3-arm zidovudine regimen on the perinatal transmission of human immunodeficiency virus type 1 (HIV-1) using population-based data.

METHODS

We retrospectively ascertained information on zidovudine prescription and other characteristics of HIV-infected pregnant women and children for birth cohort years 1993, 1995, 1996, and 1997 using HIV/acquired immunodeficiency syndrome registry data from a state health department supplemented by medical record reviews.

RESULTS

The transmission rate decreased from 12.5% in 1993 to 4.6% in 1997. The proportions of HIV-1-infected mothers and children who were prescribed all 3 arms of zidovudine increased from 68% in 1995 to 93% in 1997. Unadjusted and adjusted odds ratios for the relationship between the prescription of 3 arms of zidovudine and the infants' HIV status were 0.19 (95% confidence interval: 0.05-0.84) and 0.15 (95% confidence interval: 0.02-0.96), respectively.

CONCLUSION

Perinatal HIV-1 transmission rates have decreased over time. This study demonstrates the effectiveness of the rapid implementation of the United States Public Health Service recommendations for the comprehensive use of zidovudine among HIV-1-infected pregnant women in a predominantly rural state.

[Prevention of vertical transmission of HIV-1 in Mallorca, Spain. Impact of antiretroviral therapy from 1995 to 2000]

BACKGROUND

Our objective was to evaluate the impact of antiretroviral therapy (ART) in the prevention of maternal-fetal HIV transmission in a population of HIV-infected pregnant women.

PATIENTS AND METHOD

We studied prospectively all HIV-infected pregnant women attended in our hospital from January 1995 to December 2000. We offered treatment with zidovudine (ZDV) alone or in combination according to women's requirements.

RESULTS

There were 98 mother-infant pairs and we studied 93 of them. The rate of vertical transmission was 1.4% when ART was started in pregnancy. Risk of HIV transmission was greater in mothers not being treated with ART during pregnancy (relative risk [RR]: 18; 95% confidence interval [CI]: 2.2-145.4), in mothers who only received ZDV at delivery and child vs those who received ART during pregnancy (RR: 16.4; 95% CI: 1.8-145.6) and in mothers who were active intravenous drug users (RR: 9.3; 95% CI: 2.2-38.5), with significant differences between vaginal delivery and caesarean section.

CONCLUSIONS

We observed a substantial benefit from ART, especially in the group of HIV-infected pregnant women who started treatment during pregnancy. Preventive interventions are needed.

Clinical and epidemiologic aspects of human immunodeficiency virus-1-infected children in Buenos Aires, Argentina

BACKGROUND

Argentina has the sixth largest number of cumulative pediatric cases of acquired immunodeficiency syndrome (AIDS) in the Americas; therefore, this study was designed to characterize human immunodeficiency virus-1 (HIV-1) infection in children in Buenos Aires, Argentina.

MATERIALS AND METHODS

Medical records of 389 children at risk and infected with HIV-1, an urban population followed by the AIDS Reference Center at the Hospital de Niños "Dr. Ricardo Gutiérrez" of Buenos Aires, from February 1990 to June 1997, were retrospectively reviewed. Mother-infant pairs were analyzed according to clinical and epidemiologic patterns.

RESULTS

Perinatal transmission occurred in 94.9% of the 389 cases classified as seroreverter (n=104, 26.7%), exposed (n=64, 16.4%), asymptomatic (n=13, 3.4%), and symptomatic patients (n=208, 53.5%); 132 patients met the Centers for Disease Control and Prevention (CDC) criteria for AIDS. The main maternal risk factor was sexual transmission 58.9% (73.4% of their sexual partners were injection drug users [IDU]). Among the AIDS patients, the most common AIDS-defining condition and death-related disease were severe bacterial infection and Pneumocystis carinii pneumonia, respectively. Death occurred in 51 of 221 HIV-infected children. Low CD4 was related to death (P < 0.001). Mortality was estimated for two periods: January 1990 to December 1995 (G1) and January 1996 to May 1997 (G2). In G1, 37 of 127 (29.1%) died compared with 14 of 154 (9.1%) in G2 (P=0.001). The median age of death was 10 months for G1 and 29 months for G2 (P=0.01). The 3-year survival rate was 72% for G1 and 87% for G2 (log rank P=0.06).

CONCLUSIONS

Intravenous drug use is the leading risk factor among parents of children exposed to HIV. Infant mortality was related to age less than 12 months, low CD4 count, severe bacterial infection and P. carinii pneumonia. In this study, P. carinii pneumonia prophylaxis and combined antiretroviral therapy routinely implemented since 1996 has demonstrated a trend toward increased survival rates (P=0.06) and a lower mortality rate (P=0.001).

Maternal characteristics associated with antenatal, intrapartum, and neonatal zidovudine use in four US cities, 1994-1998

OBJECTIVES

To evaluate implementation of 1994 United States Public Health Service guidelines for zidovudine (ZDV) use in HIV-infected women and their newborns by describing the prevalence of use of perinatal ZDV and other antiretrovirals and by investigating determinants of not receiving perinatal ZDV.

DESIGN/METHODS

The Perinatal AIDS Collaborative Transmission Study is a prospective cohort study designed to collect information related to mother-to-child HIV transmission that was conducted in New York City (NY), Newark (NJ), Baltimore (MD), and Atlanta (GA), U.S.A. The current analysis was restricted to infants born between July 1994 and June 1998.

RESULTS

Utilization rates for antenatal, intrapartum, and neonatal ZDV increased from 41% to 70% during the 4-year period. Use of combination antiretrovirals increased from fewer than 2% of women in 1994 to 1995 to 35% in 1997 to 1998. Antenatal and neonatal ZDV use increased each year, but intrapartum ZDV use reached a plateau after 1996. Mother-infant pairs with the following characteristics were less likely to have received a complete 3-part ZDV regimen: older maternal age, CD4 count >500 cells/microl, preterm birth, cocaine or heroin use during pregnancy, positive newborn drug screen test result, and smoking or alcohol use during pregnancy. By multivariate logistic regression adjusted for hospital and year of birth, cocaine or heroin use during pregnancy (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.6-3.3), maternal CD4 count (OR, 0.4; 95% CI, 0.2-0.8; comparing <200 with >500 cells/microl), and preterm birth (OR, 1.6; 95% CI, 1.1-2.5) remained independently associated with not receiving the complete ZDV regimen.

CONCLUSIONS

ZDV use by pregnant HIV-infected women and their infants has increased dramatically since publication of the 1994 guidelines. Nevertheless, women who abuse substances, give birth preterm, or have less advanced immunosuppression, were at substantial risk of not receiving the complete ZDV regimen.

Effect of immediate neonatal zidovudine on prevention of vertical transmission of human immunodeficiency virus type 1

OBJECTIVE

To describe the effects of various short zidovudine (ZDV) prophylactic regimens on vertical transmission of human immunodeficiency virus type 1 (HIV-I) infection, especially the effect of immediate neonatal ZDV prophylaxis.

MATERIALS AND METHODS

The study included children of HIV-1-infected mothers who were born at a teaching hospital in Bangkok. The ZDV prophylaxis regimens varied by time periods that included: (1) no ZDV (1991-1996); (2) antenatal oral ZDV, 250 mg given twice a day starting at 34 to 36 weeks gestation and continued until labor (1995-1998); (3) antenatal oral ZDV plus immediate neonatal oral ZDV, 6 mg/0.6 mL/dose started within the first 2 hours after birth and continued at 6-hour intervals for 4 to 6 weeks (1997-1998); and (4) intrapartum intravenous ZDV given in addition to regimen 3 (1998-1999). Neonatal ZDV was administered within 2 hours after birth in 95% of the neonates.

RESULTS

In a cohort of 136 children born at least 9 months before the analysis date, the HIV-1 vertical infection rates were: (1) no ZDV, 11 of 48 (22.9%, 95% confidence interval [CI] = 12.0-37.3); (2) late antenatal ZDV, 10 of 47 (21.3%, 95% CI = 10.7-35.7); (3) late antenatal ZDV plus immediate neonatal ZDV, 0 of 28 (0%, 95% CI = 0-12.3); (4) late antenatal, intrapartum intravenous ZDV, plus immediate neonatal ZDV, 0 of 13 (0%, 95% CI = 0-24.7). An estimated 0% (95% CI = 0-8.6) of the infants who received immediate neonatal ZDV with or without intrapartum ZDV were infected, as compared with 22.1% (95% CI = 14.2-31.8 ) of those who received no ZDV or only late antenatal ZDV (P < 0.001).

CONCLUSIONS

The results of this study suggests high protective effect of immediate administration of neonatal ZDV. Perinatal components of antiretroviral prophylaxis provided the best results for protecting against vertical HIV-1 transmission.

Effect of prenatal zidovudine on disease progression in perinatally HIV-1-infected infants

OBJECTIVE

To determine the influence of prenatal zidovudine (ZDV) prophylaxis on the course of HIV- 1 infection in children by comparing the clinical outcome of infants born to HIV- 1-seropositive mothers who did versus those who did not receive ZDV during pregnancy.

METHODS

Medical records of HIV-1-seropositive mothers and their infants were reviewed retrospectively. Participants were divided according to maternal ZDV use: no ZDV (n = 152); ZDV (n = 139). The main outcome measure was rapid disease progression (RPD) in the infant, defined as occurrence of a category C disease or AIDS-related death before 18 months of age.

RESULTS

HIV vertical transmission rates were significantly different (no ZDV versus ZDV: 22.3% versus 12.2%; p = .034). Among infected infants, the RPD rate was 29.4% in the no ZDV group compared with 70.6% in the ZDV group (p = .012), and prematurity was significantly associated with a higher risk of RPD (p = .027).

CONCLUSIONS

The rate of RPD was significantly higher among perinatally infected infants born to HIV-infected mothers treated with ZDV than among infected infants born to untreated mothers. The decreased proportion of infected infants with nonrapid disease progression in the former group might be related to the ability of ZDV to block intrapartum transmission preferentially and also to nonrapid disease progression resulting from intrapartum transmission.

[Estimate of HIV-1 infection prevalence in pregnant women and effectiveness of zidovudine administered during pregnancy in the prevention of vertical transmission]

BACKGROUND

Despite the proven efficacy of zidovudine (ZDV) for reducing perinatal transmission of HIV-1, questions remain about its implementation and effectiveness in routine practice. The aims of this study were to assess the impact of ZDV administered during pregnancy in preventing perinatal HIV-1 transmission, and to determine the proportion of early identification of maternal HIV-1 infection over time.

PATIENTS AND METHODS

We prospectively followed from birth a cohort of children born between 1/1/1987 and 31/10/1997 to HIV-1-infected mothers. Infant infection status was assessed by follow-up beyond 18 months or HIV-PCR up to 3 months of age.

RESULTS

229 mothers and 248 infants were identified in the cohort. ZDV was administered during pregnancy as monotherapy to 34 mothers for a mean of 4.7 (3.1) months prior to delivery. There were no differences in baseline characteristics between the treated and untreated groups. Mean (SD) CD4 cell count was 465 (261) cells x 10(6)/l. Factors associated with transmission were a more prolonged time of rupture of obstetric membranes (median 6 vs 1.04 hours; p = 0.023) and ZDV treatment. Among the ZDV-treated mothers only one child was infected (2.9%), whereas 37 children born to 212 untreated women became infected. (OR: 0.14; 95% CI: 0.07-0.92). The estimated prevalence of HIV-1 in pregnant women in our area is about 0.39% (95% CI: 0.34-0.45). From 1987 to 1991, 9.7% of infected women were nor identified at the perinatal period, as compared to 2.5% in the last 5 years of the study period (p = 0.034).

CONCLUSIONS

In this study, the estimated prevalence of HIV-1 infection is high. ZDV during pregnancy is significantly associated with a decrease in perinatal transmission in our setting. The awareness of an effective treatment might have contributed to the increased identification of HIV-infected mothers prior to delivery observed over time in our cohort of children born to HIV-infected mothers.

Epidemiology of HIV/AIDS in children

HIV infection has been a major cause of morbidity and mortality since the first cases of AIDS among children were reported in 1982 in the United States. Considerable advances, especially in the past 5 years, in the understanding of the pathogenesis, diagnosis, treatment, monitoring, and prevention of HIV infection in children have changed the rate of pediatric HIV infection in the United States. Efforts to maximally decrease perinatal HIV transmission in the United States are ongoing. Physicians must try to prevent HIV infection among women, especially adolescents.

Prevention of HIV infection in children

The threshold of a new century is an opportune time to review advances in the prevention of HIV infection in children. In the United States, progress in the ability to virtually eliminate perinatal HIV transmission that was unthinkable just a few years ago has been achieved. Clinicians providing care to pregnant women should educate and counsel women about HIV and strongly recommend that they be tested. They should also counsel HIV-infected women about the means available to substantially decrease the risk for HIV transmission to their infants (e.g., antiretroviral drug use, avoidance of breast-feeding, elective C-section, encouraging pregnant women to use barrier methods during sexual intercourse, and to discontinue injection drug use). This article has highlighted some of the remaining challenges that constitute barriers to achieving maximal decrease of HIV infection in children. Studies conducted in resource-poor countries have added greatly to the understanding of vertical transmission of HIV, and they are now leading to practical and affordable approaches to reduce vertical HIV transmission world-wide. The results of this research must lead to coordinated public health action and a global political commitment to extend the benefits of antiretroviral drug prophylaxis that now exist widely in the United States to more resource-poor countries.

Frequency and predictors of medically attended injuries in HIV-infected children

The extent to which medically attended injuries complicate the clinical course of HIV-infected (HIV+) children is unknown. In a cohort of HIV+ children delivered from 1985 to 1990 and aged less than 60 months, we determined medically attended injuries per 100 child-years, Injury Severity Scores (ISS), and predictors of medically attended injuries by using New York State Medicaid claims from 1986 to 1992 linked to birth certificates. Injury rates and ISS were compared to those of a population of black, inner city children aged less than 60 months from emergency room records. HIV+ children had slightly more injuries (19.3 vs. 16.8/100 child-years) but similar ISS (2.4 vs. 2.3). Predictors of injuries in HIV+ children included younger maternal age (24/100 child-years, p = 0.008) and delivery outside of New York City (29/100 child-years, p = 0.02). Illicit drug use and alcohol use were associated with greater ISS while cocaine use was associated with a higher rate of possibly intentional injuries. Medically attended injuries affected one in five HIV+ children in our cohort annually, slightly more than the comparison population. Specific maternal and birth characteristics such as substance abuse and younger age at delivery may help target at-risk children.

Reproductive choice in individuals HIV-1 infected in south eastern Italy

OBJECTIVE

To evaluate the impact of counseling on reproductive choices in seropositive women in South-Eastern Italy.

SETTING

University Hospital, Apulia region, South-Eastern Italy, tertiary referral center for high risk obstetrics and infectious diseases.

METHODS

Between March 1985 and December 1996, two hundred and twenty-five HIV-infected women, receiving treatment at our clinic for infectious diseases were enrolled. They were all regularly given treatment and counseling and their sexual partners, if negative, tested for HIV-1 antibodies. Their reproductive choices and their attitude toward pregnancy were recorded and analyzed.

RESULTS

Seventy-six pregnancies were observed during this period in 76 women. Twenty-one of these women (27.7%) decided to terminate the pregnancy. Women that were intravenous drug users or with a longer history of known seropositivity were more likely to have a termination. A decreasing trend in the request of abortion was observed with time.

CONCLUSIONS

The data show that the scenario of HIV-infected women is changing in our setting. As a consequence, many seropositive women deliberately choose to have a pregnancy and factors different from those we expect to be modified by the counseling influence their reproductive choice. They should be taken into account in the management of these women before and during pregnancy.

Management of HIV-infected pregnant patients in malaria-endemic areas: therapeutic and safety considerations in concomitant use of antiretroviral and antimalarial agents

Chemotherapy in pregnancy is an intricate process requiring prudent use of pharmacologic agents. Malarial infection during pregnancy is often fatal, and prophylaxis against the causative parasite necessitates rational therapeutic intervention. Various agents have been used for prophylaxis against malaria during pregnancy, including chloroquine, mefloquine, proguanil, pyrimethamine, and pyrimethamine-sulfadoxine. Use of these agents has been based on a risk-benefit criterion, without appropriate toxicologic or teratologic evaluation. Some of the aforementioned prophylactic agents have been shown to alter glutathione levels and may exacerbate the oxidation-reduction imbalance attendant on HIV infection. HIV-infected patients traveling to or residing in malaria-endemic areas require protection from malarial infection to avoid placing themselves in double jeopardy. Zidovudine (AZT) is recommended for the prevention of vertical transmission of HIV-1 from mother to child. Other agents, such as lamivudine alone or in combination with AZT, nevirapine, or the HIV-1 protease inhibitors, are either being considered or are currently undergoing trials for use in preventing vertical transmission of HIV-1 or managing HIV infection in infants and children. Although the potential for antimalarial agents to cause congenital malformations is low when they are used alone, their ability to cause problems when combined with antiretroviral drugs needs to be evaluated. In developing countries that have high birth rates, a high endemicity of malaria, and alarming rates of new cases of HIV, prophylaxis against both diseases with combination agents during pregnancy is a challenge.

Adequacy of prenatal care and prescription of zidovudine to prevent perinatal HIV transmission

In 1994, data were published on the effectiveness of zidovudine in preventing perinatal transmission of HIV infection. Using data from surveillance projects in San Antonio, Dallas, and Houston, Texas, U.S.A., we linked records of children born from 1987 through 1996 with records of their HIV-infected mothers. Prenatal care was measured by Kotelchuck's Adequacy of Prenatal Care Utilization (APNCU) Index. We examined the association between adequacy of prenatal care and four measures of zidovudine prescription: prenatal, intrapartum, neonatal, and the complete regimen. Inclusion criteria was that the mother's HIV infection was diagnosed before a live birth; 221 mother-infant pairs were included in the analysis. Overall, 68% received inadequate or no prenatal care. Over time, the proportion of mother-infant pairs with adequate prenatal care doubled (24%-48%; relative risk [RR], 2.0; 95% confidence interval [CI], 1.3-3.0), and the proportion prescribed prenatal zidovudine tripled (20%-67%; RR, 3.4; 95% CI, 2.4-4.9). In logistic regression, APNCU (adjusted odds ratio [aOR], 2.6; 95% CI, 1.1-6.2) and time period (aOR, 19.9; 95% CI, 8.1-48.7) were associated with prenatal prescription of zidovudine. The benefits of prenatal care, including HIV testing and zidovudine treatment, underscore the urgent need to improve access to and use of prenatal care services.

Is zidovudine therapy in pregnant HIV-infected women associated with gestational age and birthweight?

OBJECTIVE

Prophylactic zidovudine during pregnancy and labour reduces maternal viral load and, with neonatal therapy, has been shown to reduce vertical transmission. However, zidovudine may have additional effects. Advanced HIV disease is associated with premature delivery, which in turn results in increased vertical transmission. Data from the European Collaborative Study (ECS) were analysed to investigate whether zidovudine could be associated with decreased prematurity risk and/or with a reduced frequency of low birthweight.

METHODS

HIV-infected pregnant women enrolled in the ECS were followed prospectively according to a standard protocol. Gestational age was assessed by ultrasound, prematurity was defined as delivery before 37 weeks and the cut-off for low birthweight was 2500 g. We calculated odds ratios (OR) to estimate the effect of zidovudine on the risk of premature of low birthweight delivery.

RESULTS

In 2299 mothers, zidovudine taken to reduce the risk of vertical transmission decreased the odds of premature delivery by a quarter (OR = 0.76, 95% confidence interval (CI) 0.53-1.09), and the odds of low birthweight by nearly half (OR = 0.55, 95% CI 0.39-0.79). Allowing for CD4 count and mode of delivery did not greatly alter these OR values. A multivariate analysis suggested that prophylactic zidovudine and prematurity were independently associated with risk of transmission.

CONCLUSION

Our findings suggest an additional health benefit of zidovudine. Even if most vertical transmission occurs around the time of delivery, therapy earlier in pregnancy could have an indirect effect on transmission rates through delaying delivery. This hypothesis needs to be confirmed or refuted by more appropriate studies.

Comparison of human immunodeficiency virus 1 DNA polymerase chain reaction and qualitative and quantitative RNA polymerase chain reaction in human immunodeficiency virus 1-exposed infants

BACKGROUND

HIV-1 RNA PCR is a widely available and sensitive assay but has not been studied for use in early diagnosis of HIV-1 infection in infants.

METHODS

Research HIV-1 DNA PCR and HIV-1 RNA PCR were performed on peripheral blood mononuclear cells and plasma, respectively, from 284 blood samples from 204 infants. A commercially available HIV-1 quantitative RNA PCR was also performed on plasma from the 132 samples from HIV-1-infected infants and 22 of the samples from HIV-1-uninfected infants.

RESULTS

Sensitivities of all assays varied with infant age. HIV-1 DNA PCR had a sensitivity of 27% in the < or = 3-week age group (n = 11) whereas qualitative and quantitative RNA PCR had sensitivities of 64 and 55%, respectively (P not significant). Each assay had a sensitivity of 96.2% at 4 to 6 weeks (n = 26) and 100% at > or = 7 weeks of age (n = 95). Specificity of HIV-1 DNA PCR for all age groups was 100%, whereas specificities of qualitative and quantitative RNA PCR assay were 96.1 and 95.5%, respectively.

CONCLUSIONS

HIV-1 RNA PCR may offer a slight advantage in sensitivity over DNA PCR in the diagnosis of HIV infection in young infants. Positive RNA results can be found in a small number of infants who are not HIV-1-infected. HIV-1 RNA detection should not be routinely used alone for the diagnosis of HIV infection in young infants.

Use of combination antiretroviral therapy in pregnant women with HIV disease

Important advances in human immunodeficiency virus (HIV) medicine have brought about numerous changes in the clinical care of HIV-infected individuals. The availability of protease inhibitors to treat HIV infection, the introduction of HIV-RNA polymerase chain reaction viral load tests to monitor responses to therapy, and the greater clinical benefit offered by combination highly active antiretroviral therapy (HAART) over monotherapy have dramatically decreased morbidity and mortality rates. The safety and efficacy of HAART has not been proved in pregnant women with HIV, although withholding HAART in HIV-infected women because of pregnancy is not recommended. This article presents an overview of important clinical issues relevant to the use of combination antiretroviral therapy in pregnancy.

Maternal and umbilical cord serum zidovudine levels in human immunodeficiency virus infection

The aim of this study was to determine the maternal and umbilical cord serum ZDV levels at delivery in HIV-1 infected parturients treated with a short-course ZDV regimens in late pregnancy and labour. Serum ZDV and its metabolite were measured by high-performance liquid chromatography. Concentrations of ZDV and its metabolite in umbilical cord blood appeared similar to maternal concentrations. There was a significant positive correlation between serum ZDV and its metabolite in maternal and umbilical cord concentrations. At delivery, maintenance of optimal virustatic ZDV concentration with oral antenatal and oral intermittent intrapartum ZDV dosage regimen can be achieved in only 53% of cases. The regimens used in this study were useful but not as effective as the ACTG 076 regimen with an intravenous dose intrapartum plus the oral administration to the infants for 6 weeks.

Trends in zidovudine prescription for pregnant women infected with HIV

OBJECTIVE

The purpose of this analysis was to describe trends in zidovudine prescription during pregnancy among women infected with HIV.

METHODS

We used data from the Adult and Adolescent Spectrum of Disease Surveillance Project, which collects information on HIV-related conditions through medical record review. Women who were reported pregnant from 1990 through 1996 were included in the analysis.

RESULTS

From 1990 through 1996, of 7047 women in the project, 714 (10%) were pregnant for a total of 782 pregnancies. We found a high proportion (82%) of pregnancies during which zidovudine was prescribed for women with CD4+ T-lymphocyte count of 0 to 199 cells/microl (n = 125), but no trend over time. In contrast, from 1990 through 1996 zidovudine was prescribed for an increasing proportion of pregnancies in which the woman's CD4+ count was 200 to 499 cells/microl (62%-78%; p = .01; n = 337) and > or = 500 cells/microl (22%-55%; p = .001; n = 250).

CONCLUSIONS

Our study demonstrated differences in zidovudine prescription over time by CD4+ count; these differences may be based on the woman's health and guidelines for perinatal prevention.

Therapeutic and other interventions to reduce the risk of mother-to-child transmission of HIV-1 in Europe. The European Collaborative Study

OBJECTIVES

To document policies regarding the use of interventions to reduce risk of vertical transmission of human immunodeficiency virus (HIV) and assess the extent of changes since 1994.

DESIGN

A postal questionnaire survey and data from the European Collaborative Study (ECS), a prospective multi-centre cohort study.

SETTING

Fifty-four obstetric centres in 16 European countries.

SAMPLE

A questionnaire response from 54 obstetricians; 669 deliveries to HIV-infected women enrolled in the ECS from 1994 to 1997.

MAIN OUTCOME MEASURES

Use of zidovudine during pregnancy, at delivery and to the neonate; caesarean section delivery rates; vaginal lavage; avoidance of breastfeeding; vertical transmission rate.

RESULTS

Zidovudine therapy to reduce vertical transmission is now widespread in Europe and routine in all but one centre surveyed, although regimens vary. In 11 (26%) centres elective caesarean section is offered to all HIV-infected women and a further nine (21%) have a policy of routine vaginal lavage. In all centres HIV-infected women are advised to avoid breastfeeding. In the ECS there has been a significant temporal decline in the vertical transmission rate with an increase in zidovudine use. More than 90% of women in the ECS who were delivered in 1997 received one or more components of zidovudine therapy; the rate of vertical transmission is 9% where zidovudine has been used, compared with 15% without use of zidovudine.

CONCLUSIONS

Although the use of zidovudine to reduce vertical transmission is increasing in Europe and, with the avoidance of breastfeeding, is associated with a decline in vertical transmission, the success of these interventions will be limited by the uptake of antenatal screening.

HIV in pregnancy

Pregnancy in individuals infected with HIV has become an important problem because of a fourfold rise of infection in women of childbearing age in the developed world. The incidence of vertical transmission varies in different continents and is highest in Africa. Transmission may occur in utero (antepartum), during delivery (intrapartum), or after birth (postpartum), occurring during the latter period, in many cases, through breastfeeding. Maternal viral burden around the time of delivery is the strongest determinant of the risk of disease transmission. While breastfeeding may account for up to one-third of cases of vertical transmission in Africa, the benefits of breastfeeding outweigh its risks, even in HIV infection, and breastfeeding is recommended in those areas. Treatment of the mother with antiretroviral agents significantly decreases the risk of vertical transmission.

Impact of zidovudine use on risk and risk factors for perinatal transmission of HIV. Perinatal AIDS Collaborative Transmission Studies

OBJECTIVES

To evaluate the impact of perinatal zidovudine use on the risk of perinatal transmission of HIV and to determine risk factors for transmission among women using perinatal zidovudine.

DESIGN

Prospective cohort study of 1533 children born to HIV-infected women between 1985 and 1995 in four US cities.

METHODS

The association of potential risk factors with perinatal HIV transmission was assessed with univariate and multivariate statistics.

RESULTS

The overall transmission risk was 18% [95% confidence interval (CI), 16-21]. Factors associated with transmission included membrane rupture > 4 h before delivery [relative risk (RR), 2.1; 95% CI, 1.6-2.7], gestational age < 37 weeks (RR, 1.8; 95% CI, 1.4-2.2), maternal CD4+ lymphocyte count < 500 x 10(6) cells/l (RR, 1.7; 95% CI, 1.3-2.2), birthweight < 2500 g (RR, 1.7; 95% CI, 1.3-2.1), and antenatal and neonatal zidovudine use (RR, 0.6; 95% CI, 0.4-0.9). For infants exposed to zidovudine antenatally and neonatally, the transmission risk was 13% overall but was significantly lower following shorter duration of membrane rupture (7%) and term delivery (9%). The transmission risk declined from 22% before 1992 to 11% in 1995 (P < 0.001) in association with increasing zidovudine use and changes in other risk factors.

CONCLUSIONS

Perinatal HIV transmission risk has declined with increasing perinatal zidovudine use and changes in other factors. Further reduction in transmission for women taking zidovudine may be possible by reducing the incidence of other potentially modifiable risk factors, such as long duration of membrane rupture and prematurity.

Medical management of the pregnant woman infected with human immunodeficiency virus type 1 and her child

Heterosexual contact and intravenous drug use continue to result in new cases of human immunodeficiency virus type 1 (HIV-1) infection among adolescents and women of childbearing age. In North American and European surveys, 0.1% to 0.3% of childbearing women are infected with HIV; rates are 10 to 20 times higher in some inner-city areas. Timely, comprehensive, and well-coordinated care of the pregnant HIV-infected mother offers a unique opportunity to significantly influence two lives simultaneously. The mother can be offered therapeutic and prophylactic agents to treat her own infection, including antiretroviral therapy, which has been shown to markedly reduce the risk of vertical HIV-1 transmission. Recent advances in diagnostic virology now make it possible to definitively identify by 3 to 4 months of age those infants who are infected with HIV. Infants infected with HIV can be offered effective prophylaxis against Pneumocystis carinii pneumonia, which has dramatically reduced the incidence of this once common infection. Infected infants also should be monitored closely to institute antiretroviral therapy, and to diagnose and treat opportunistic and intercurrent infections and other acquired immunodeficiency syndrome-defining illnesses in a timely way.

Differential tropism and chemokine receptor expression of human immunodeficiency virus type 1 in neonatal monocytes, monocyte-derived macrophages, and placental macrophages

Laboratory-adapted (LA) macrophage-tropic (M-tropic) human immunodeficiency virus type 1 (HIV-1) isolates (e.g., HIV-1(Ba-L)) and low-passage primary (PR) isolates differed markedly in tropism for syngeneic neonatal monocytes, monocyte-derived macrophages (MDMs), and placental macrophages (PMs). Newly adherent neonatal monocytes and cultured PMs were highly refractory to infection with PR HIV-1 isolates yet were permissive for LA M-tropic isolates. Day 4 MDMs were also permissive for LA M-tropic isolates and additionally, were permissive for over half the PR isolates tested. Qualitative differences in PR HIV-1 infection of monocytes/MDMs could not be correlated with CD4 levels alone, and in all three cell types the block to PR HIV-1 strain replication preceded reverse transcription. Neonatal monocyte susceptibility to PR HIV-1 strains correlated with increasing CCR-5 expression during maturation. CCR-5 could not be detected on newly adherent (day 1) neonatal monocytes, in contrast to adult monocytes (H. Naif et al., J. Virol. 72:830-836, 1998), but was readily detectable after 4 to 7 days of culture. However, moderate CCR-5 mRNA levels were present in day 1 neonatal monocytes and remained constant during monocyte maturation. CCR-5 was not detectable on the surface of PMs, yet the receptor was present within permeabilized cells. Notably, two brain-derived PR HIV-1 isolates from a single patient, differing in their V3 loops, were discordant in their abilities to infect neonatal monocytes/MDMs and PMs, yet both isolates could infect newly adherent adult monocytes. Together these data strongly suggest that LA HIV-1 isolates are able to infect neonatal monocytes at earlier stages of maturation and lower-level expression of CCR-5 than PR isolates. The differences between neonatal and adult monocytes in susceptibility to PR isolates may also be related to the level of CCR-5 expression.

Initial multicenter experience with double nucleoside therapy for human immunodeficiency virus infection during pregnancy

OBJECTIVE

To study maternal and neonatal effects of combination nucleoside analog therapy administered to human immunodeficiency virus (HIV)-infected pregnant women for maternal indications.

METHODS

A multicenter, prospective observational study was undertaken at six perinatal centers in the United States and Canada that supported regional referral programs for the treatment of HIV-infected pregnant women. Demographic, laboratory, and pregnancy outcome data were collected for 39 women whose antiretroviral treatment regimens were expanded to include more than one nucleoside analog for maternal indications. The 40 newborns were monitored at pediatric referral centers through at least three months of age to ascertain their HIV infection status.

RESULTS

For all 39 women, zidovudine (ZDV) therapy was instituted at 13.4 +/- 8.2 weeks, with a second agent (lamivudine [3TC] in 85% of cases) being added at a mean gestational age of 17.6 weeks. Duration of therapy with two agents was 20.6 +/- 10.4 weeks overall, with no women stopping medications because of side effects or toxicity. No significant changes in maternal laboratory values were seen, except for an increase in mean corpuscular volume, over the course of pregnancy. No clinically significant adverse neonatal outcomes were noted, with all but the three preterm newborns leaving hospital with their mothers. Neonatal anemia (hematocrit < 50%) was seen in 62% of newborns, with no children needing transfusion; mild elevations of liver function tests, primarily aspartate aminotransferase, were noted in 58% of newborns tested, though none were clinically jaundiced. Overall rate of neonatal HIV infection was 2.5% (95% confidence interval: 0.1-13.2%).

CONCLUSION

Combination antiretroviral therapy during pregnancy with two nucleoside analogs was well-tolerated by mothers and newborns, with no significant short-term toxicities or side effects noted. Surveillance of exposed newborns' hematologic and liver function appears warranted.

Zidovudine

Zidovudine was the first agent approved for treatment of HIV disease, and since its widespread availability in 1987, the pharmacokinetic disposition and clinical effects of ZDV have been extensively evaluated. In addition to its utility as a component of a multidrug combination regimen for the treatment of adult and pediatric HIV-1 infection, it is the only agent approved by the FDA for the prevention of mother-to-child HIV-1 transmission. The effectiveness of ZDV for the prevention of mother-to-child HIV-1 transmission has been demonstrated in several studies. The optimal time during gestation to initiate ZDV therapy and the relative importance of the intrapartum and newborn components is the focus of both current interventional and observational studies. Until more information is available from these trials, the combined maternal/newborn ZDV regimen studied in ACTG 076 remains the recommended treatment regimen of choice in the United States.

Prevention of transmission. Pharmaceutical and obstetric approaches

An increasing body of information regarding risk factors for perinatal HIV transmission suggests the use of logical management strategies during the prenatal period and parturition directed at maximizing maternal health and minimizing perinatal transmission. This article reviews the recommendations for pharmacologic therapy and rational obstetric management strategies to decrease perinatal HIV transmission based on published clinical trials and a review of data relevant to transmission.

Acceptability and impact of zidovudine for prevention of mother-to-child human immunodeficiency virus-1 transmission in France

We studied the propagation and the impact of zidovudine prevention on the human immunodeficiency virus-1 transmission rate from infected mothers to their infants in the French nationwide prospective cohort. Infection was diagnosed in the children on the basis of at least two positive human immunodeficiency virus-1 polymerase chain reaction tests, culture, or both. The transmission rate among treated women was compared with that among untreated women during the same period and with that among women enrolled in the cohort since 1986. The impact of zidovudine was analyzed according to the women's clinical and biologic characteristics, the mode of delivery, and use of zidovudine therapy before the pregnancy. Nearly 90% of women were treated as soon as the second half of 1994. In 1994 and 1995, 80% of mother-child pairs received at least one of the three phases of preventive treatment. Among the 663 mothers enrolled during these 2 years, only six refused the treatment. Zidovudine treatment was associated with a reduction in the transmission rate of nearly two-thirds, from 14% +/- 6% to 5% +/- 2% (p < 0.01). The degree of reduction was not influenced by the maternal CD4+ cell count or p24 antigenemia at delivery. Zidovudine treatment of the mother before the pregnancy considerably reduced the impact of preventive therapy; the transmission rate was significantly higher among pretreated mothers (20% versus 5%, p < 0.01) even after adjusting for maternal CD4+ cell count. Zidovudine prevention is now widely used in France and has had a major impact on the epidemiology of mother-child human immunodeficiency virus transmission. This justifies a policy of offering human immunodeficiency virus screening to all women before or shortly after the diagnosis of pregnancy.

Failure of Neutralizing gp120 Monoclonal Antibodies to Prevent HIV Infection of Choriocarcinoma-Derived Trophoblasts

Although placental trophoblasts, the only fetal cells in direct contact with infectious maternal blood, can be infected with HIV, the precise cause for the low transmission rate of virus across the placental barrier is unknown. One of the most common conjectures is that maternal anti-HIV antibodies (Abs) contribute to the protection of the fetus. This hypothesis has been tested in vitro by infecting the CD4-negative placental trophoblast line, BeWo, with HIV-1(IIIB) in the presence of serial dilutions of neutralizing monoclonal Abs against the V3 loop (No. 694) or CD4-binding conformational domain (No. 588). The results, based on measurement of p24 production from virus-exposed cells, reveal that the titers of Abs, adequate in preventing the infection of control MT-4 T lymphocytes, were less effective in protecting trophoblasts. Furthermore, PCR analysis of HIV DNA formed after a single round of infection has shown no significant decrease in the number of viral copies in Ab-protected BeWo cells. An anti-HIV serum from a pregnant woman did also have no effect. Although our in vitro observations do not necessarily apply to the in vivo situation, the results suggest that the humoral immune response sustained by neutralizing Abs may be able to protect T lymphocytes, but not placental trophoblasts. The findings are consistent with recent clinical studies demonstrating a lack of correlation between the presence of neutralizing anti-HIV Abs in pregnant women and HIV transmission in utero. Copyright 1997 S. Karger AG, Basel

Prevention of mother-to-infant transmission of HIV-1

The number of children with AIDS continues to increase worldwide. Children who become infected with HIV-1 acquire the infection almost exclusively from their mothers during pregnancy or delivery, or via breast feeding. Mother-to-infant transmission has been, and continues to be, an area of active research with the goal being complete prevention. Treatment with zidovudine, an antiviral agent, has been found to decrease transmission from 25% to 8%. However, multiple obstacles impede the worldwide application of this advance.

Reducing the risk of perinatal HIV-1 transmission with zidovudine: results and implications of AIDS Clinical Trials Group protocol 076

This paper reviews the rationale for the AIDS Clinical Trials Group (ACTG) protocol 076 design, the study results and the implications of these results, including discussion of the US Public Health Service Task Force recommendations on the use of zidovudine to reduce perinatal transmission and for prenatal human immunodeficiency virus (HIV) counseling and testing.

Cigarette smoking and maternal-child HIV transmission

We investigated the association of cigarette smoking with maternal-child HIV transmission, adjusting for illicit drug use, maternal clinical status, and delivery factors. Vital statistics birth data were linked to the New York State Medicaid HIV/AIDS Research Database for HIV-infected women delivering a liveborn singleton from 1988 through 1990. Follow-up of these children was accomplished by Medicaid data > or = 2 years after birth, and their HIV status was ascertained by a clinically based classification. The adjusted relative risk or hazard (RH) of transmission for maternal factors was determined from Cox models. The overall transmission was 24.5% for the 901 maternal-child pairs. Smokers comprised 40% of women with data on smoking (n = 768); their transmission rate was 31% versus 22% for nonsmokers (p = 0.02). In the entire cohort, the adjusted RH of transmission for smokers was 1.45 (95% confidence interval [CI] 1.07-1.96); among women with advanced HIV, the adjusted RH was even higher (RH = 1.71; 95% CI 1.14-2.58). Users of cocaine (15% of the cohort) or of mixed or unspecified illicit drugs (28%) had higher transmission rates in unadjusted analysis (33%, p = 0.06 and 31%, p = 0.06 respectively); after adjustment for smoking and other maternal factors, neither cocaine (RH = 1.04 (95% CI 0.66-1.63)) nor mixed nor unspecified drug use (RH = 1.13 (95% CI = 0.75-1.70)) was significantly associated with transmission. Our data document an association of cigarette smoking during pregnancy with an increased risk of maternal-child HIV transmission that can be added to the growing list of complications caused by cigarette smoking.

Timing of maternal-infant HIV transmission: associations between intrapartum factors and early polymerase chain reaction results. New York City Perinatal HIV Transmission Collaborative Study Group

OBJECTIVE

To investigate the hypothesis that labour and delivery events, perinatal characteristics, and maternal factors are only associated with intrapartum HIV transmission, and not with intrauterine HIV transmission.

METHODS

In the New York City Perinatal HIV Transmission Collaborative Study 276 infants of HIV-infected women were followed prospectively and had results of early polymerase chain reaction (PCR) tests available. Among infected children, intrauterine infection was presumed if HIV DNA was detected by PCR in samples collected from children aged < or = 3 days, and intrapartum infection was presumed if HIV DNA was not detected in these early samples. The proportion of infants with presumed intrauterine and intrapartum infections were compared by selected intrapartum, perinatal and maternal characteristics.

RESULTS

Presumed intrapartum infection was found in 7% of infants delivered by Cesarean section and, among infants delivered vaginally, those with longer duration of membrane rupture (> 4 h) were significantly more likely to have presumed intrapartum HIV infection (22%) than those with shorter duration (9%; P = 0.02). There were no differences in presumed intrauterine HIV infection by mode of delivery or longer duration of membrane rupture. Infants born preterm and small for gestational age had significantly higher risks of presumed intrapartum infection, but only those who were small for gestational age had higher risks of intrauterine infection.

CONCLUSION

Our results support the notion that selected intrapartum conditions, long duration of membrane rupture prior to delivery in particular, are independent risk factors for maternal-infant transmission, and suggest that preterm infants may be especially vulnerable to intrapartum HIV exposure.

Reduction in the risk of vertical transmission of HIV-1 associated with treatment of pregnant women with orally administered zidovudine alone

In a prospective cohort study of 267 children born to mothers infected with HIV-1 in New Haven, Connecticut, an abrupt decline in the risk of mother-to-child transmission occurred in 1990 and persisted at least through December, 1993. A retrospective, observational study was undertaken to identify factors that might be responsible for this decline. Three variables were assessed: the use of orally administered zidovudine during pregnancy, the CD4+ T-lymphocyte count of the mother, and the mode of delivery. The risk of transmission was 18.6% (36/194; 95% CI: 14.1-24.8%) in infants of all women not treated with zidovudine compared with 5.5% (3/55; 95% CI: 1.1-15.1%) in infants of all women who were treated (odds ratio: 0.25; p = 0.02). In a subgroup of women with known CD4+ cell counts, the risk of transmission was 21.1% (20/95; 95% CI: 13.4-30.6%) in untreated women compared with 5.5% (3/55) in those who received zidovudine (odds ratio: 0.22; p = 0.01). In women with CD4+ T-cell counts < 200/microl, the differences remained significant (39.1% in those not treated vs. 4.2% in those treated; p < 0.004). There was an inverse relationship between CD4+ cell count and risk of transmission: among untreated mothers whose T-lymphocyte counts were > or = 500, 200-499, or < 200/microl, HIV-1 was transmitted to the offspring of 8.2, 30.4, and 39.1% of offspring, respectively (p < 0.002 by the exact trend test). There was no significant association between mode of delivery and vertical transmission of HIV. We conclude that treatment with orally administered zidovudine alone (500 mg/day) in the course of routine prenatal care is associated with a significant reduction in the risk of vertical transmission.