Mode of delivery and gestational age influence perinatal HIV-1 transmission. Italian Register for HIV Infection in Children

Adverse Perinatal Outcomes among Adolescent Pregnant Women Living with HIV: A Propensity-Score-Matched Study

HIV infection and adolescent pregnancy are known to increase the risk of adverse perinatal outcomes. However, data are limited concerning the outcomes of pregnancies among adolescent girls living with HIV. This retrospective propensity-score matched study aimed to compare adverse perinatal outcomes in adolescent pregnant women living with HIV (APW-HIV-positive) with HIV-negative adolescent pregnant women (APW-HIV-negative) and adult pregnant women with HIV (PW-HIV). APW-HIV-positive were propensity-score matched with APW-HIV-negative and PW-HIV. The primary endpoint was a composite endpoint of adverse perinatal outcomes, comprising preterm birth and low birth weight. There were 15 APW-HIV-positive and 45 women in each control group. The APW-HIV-positive were aged 16 (13-17) years and had had HIV for 15.5 (4-17) years, with 86.7% having perinatally acquired HIV. The APW-HIV-positive had higher rates of perinatally acquired HIV infection (86.7 vs. 24.4%, p < 0.001), a longer HIV infection time (p = 0.021), and longer exposure to antiretroviral therapy (p = 0.034) compared with the PW-HIV controls. The APW-HIV-positive had an almost five-fold increased risk of adverse perinatal outcomes compared with healthy controls (42.9% vs. 13.3%, p = 0.026; OR 4.9, 95% CI 1.2-19.1). The APW-HIV-positive and APW-HIV-negative groups had similar perinatal outcomes.

National-level effectiveness of ART to prevent early mother to child transmission of HIV in Namibia

Background

Namibia introduced the prevention of mother to child HIV transmission (MTCT) program in 2002 and lifelong antiretroviral therapy (ART) for pregnant women (option B-plus) in 2013. We sought to quantify MTCT measured at 4–12 weeks post-delivery.

Methods

During Aug 2014-Feb 2015, we recruited a nationally representative sample of 1040 pairs of mother and infant aged 4–12 weeks at routine immunizations in 60 public health clinics using two stage sampling approach. Of these, 864 HIV exposed infants had DNA-PCR HIV test results available. We defined an HIV exposed infant if born to an HIV-positive mother with documented status or diagnosed at enrollment using rapid HIV tests. Dried Blood Spots samples from HIV exposed infants were tested for HIV. Interview data and laboratory results were collected on smartphones and uploaded to a central database. We measured MTCT prevalence at 4–12 weeks post-delivery and evaluated associations between infant HIV infection and maternal and infant characteristics including maternal treatment and infant prophylaxis. All statistical analyses accounted for the survey design.

Results

Based on the 864 HIV exposed infants with test results available, nationally weighted early MTCT measured at 4–12 weeks post-delivery was 1.74% (95% confidence interval (CI): 1.00%-3.01%). Overall, 62% of mothers started ART pre-conception, 33.6% during pregnancy, 1.2% post-delivery and 3.2% never received ART. Mothers who started ART before pregnancy and during pregnancy had low MTCT prevalence, 0.78% (95% CI: 0.31%-1.96%) and 0.98% (95% CI: 0.33%-2.91%), respectively. MTCT rose to 4.13% (95% CI: 0.54%-25.68%) when the mother started ART after delivery and to 11.62% (95% CI: 4.07%-28.96%) when she never received ART. The lowest MTCT of 0.76% (95% CI: 0.36% - 1.61%) was achieved when mother received ART and ARV prophylaxis within 72hrs for infant and highest 22.32% (95%CI: 2.78% -74.25%) when neither mother nor infant received ARVs. After adjusting for mother’s age, maternal ART (Prevalence Ratio (PR) = 0.10, 95% CI: 0.03–0.29) and infant ARV prophylaxis (PR = 0.32, 95% CI: 0.10–0.998) remained strong predictors of HIV transmission.

Conclusion

As of 2015, Namibia achieved MTCT of 1.74%, measured at 4–12 weeks post-delivery. Women already on ART pre-conception had the lowest prevalence of MTCT emphasizing the importance of early HIV diagnosis and treatment initiation before pregnancy. Studies are needed to measure MTCT and maternal HIV seroconversion during breastfeeding.

Perinatal HIV-1 Infection in an Extremely Low Birth Weight Infant

There is limited guidance on how to treat extremely premature infants with HIV infection. This can lead to delay of antiretroviral therapy initiation adversely affecting magnitude of HIV reservoir and disease progression. We report perinatal HIV-1 infection in an extremely low birth weight infant born at 24 5/7 weeks of gestation. Treatment challenges, viral dynamics and clinical outcomes are described.

HIV Transmission to Premature Very Low Birth Weight Infants

There is sparse literature about HIV transmission in preterm infants. Eighty-two HIV-exposed preterm infants received birth polymerase chain reactions (PCRs). Five (6.1%) were HIV positive with all 5 mothers receiving inadequate antiretrovirals. Of the PCR-negative infants, 9 died and 87% of the survivors received further PCR testing which remained negative. With correct care, intrapartum transmission of HIV can virtually be eliminated.

Comparison of Tanner staging of HIV-infected and uninfected girls at the University of Nigeria Teaching Hospital, Ituku/Ozalla, Enugu, Nigeria

BACKGROUND

A number of factors influence sexual maturation in adolescents, including chronic illnesses like HIV. Marshall and Tanner devised a method of classifying the adolescent based on the level of sexual maturation into five stages. This study compared the Tanner staging of HIV-infected and uninfected girls.

METHODS

This was a cross-sectional study of 100 HIV-infected girls aged 8-18 years and 100 uninfected counterparts matched for age and social class. Using standard photographs as a guide, stages of sexual maturation were determined according to the method proposed by Marshall and Tanner. Data analysis was done with SPSS version 20. p-values <0.05 were regarded as significant.

RESULTS

The study participants were aged 8-17 years. Fifty-five subjects compared to 39 controls were still in pre-pubertal breast developmental stages while 45 subjects (45%) compared to 61 controls (61%) have commenced breast development (p=0.024). Similarly, 52 subjects compared to 31 controls were in the pre-pubertal pubic hair developmental stages, while 48 subjects (48%) compared to 69 controls (69%) had commenced pubic hair development (p=0.003).

CONCLUSIONS

Perinatal HIV infection affected the onset of pubic hair and breast development but did not significantly affect the attainment of sexual maturation.

HIV transmission to extremely low birth weight infants

BACKGROUND

Prematurity increases the perinatal HIV transmission rate compared with term infants. There is sparse literature documenting the risk of transmission of HIV to extremely low birth weight (ELBW) infants.

OBJECTIVE

To determine the risk of perinatal transmission of HIV to ELBW infants in a tertiary neonatal unit in South Africa.

METHODS

A prospective database was maintained on all inborn ELBW infants over a 1-year period from March 2010 to February 2011. Survival and DNA HIV polymerase chain reaction results at 6 weeks were recorded.

RESULTS

Of the 180 ELBW infants, 51 (28%) of these babies were HIV exposed. Of these 51 infants, 37 survived until 6 weeks of age. Polymerase chain reaction testing revealed 1 HIV-positive infant for a rate of 2.7% (95% confidence interval: 0.7-14.1%). Twenty-six (72%) of the 36 mothers received antiretroviral drugs, but only 16 (44%) had been treated for more than 1 month.

CONCLUSIONS

The rate of HIV transmission in this cohort of ELBW infants is very low despite only 44% of the mothers receiving adequate antiretroviral drugs. We postulate that this is due to our high (89%) cesarean section rate, universal (100%) infant prophylactic antiretroviral drugs and the use of pasteurized breast milk.

Materno-fetal transmission of human immune deficiency virus

Mother-to-child transmission of human immune deficiency virus (HIV) is a multifactorial event highly associated with advanced maternal HIV disease and obstetric incidents taking place during parturition. Thus, various approaches to prevention may be beneficial. Although the time and the route of materno-fetal HIV transmission are still not sufficiently clear, much speaks in favor of a late HIV transmission, most probably taking place during parturition or the phase before the delivery. The fetus is remarkably protected by the placenta and the intact fetal membranes against many viral infections during gestation. These conditions change at parturition and the chance for a transition of HIV-infected carrier cells or virus into the fetal compartment increases. Proinflammatory cytokines secreted at the materno-fetal interface accumulate in amniotic fluid and may chemoattract and stimulate potentially HIV-infected immunocytes. After rupture of membranes, maternal cells of the decidua are directly exposed to the amniotic fluid. Aside from the contamination of the fetal skin at vaginal delivery as a debatable route of infection, blood-to-blood contacts and the fetal swallowing of contaminated amniotic fluid may be the major path of fetal HIV infection. For the fetal prophylaxis of an intrauterine infection, the application of zidovudine is recommended. However, cesarian section before the onset of labor leads also to a diminution of the transmission rate. As the transmission seems to have both systemic and local causes, it makes sense to combine different intervention strategies. Whether a combination of zidovudine and elective cesarean section can lower the transmission risk further has to be evaluated.

Growth and puberty in children with HIV infection

Children with perinatal HIV infection may present with clinical features of endocrine dysfunction such as growth failure and pubertal delay. Pediatric care providers and pediatric endocrinologists should implement appropriate preventive, screening, and therapeutic strategies to maximize survival and quality of life in these children. Growth and pubertal delay can be exacerbated by a variety of treatable infectious, endocrine, nutritional, and immunological disorders. Timely diagnosis and appropriate treatment of these conditions may lead to improvement or even normalization of growth and puberty. HIV-infected children with advanced disease should undergo periodic growth evaluation, including GH levels, IGF-I, IGF binding protein 3 and androgens, in order to identify subclinical endocrine dysfunction. However, little is known about the association between HIV infection and endocrine dysfunction in children. Highly active antiretroviral therapy may also be associated with endocrine dysfunction with consequences on growth and puberty. Growth retardation and pubertal delay are always seen in children with advanced HIV infection and are often related to the proinflammatory milieu found in advanced AIDS. Growth and pubertal impairment are markers of advanced disease and require proper evaluation. A dysregulation of the hypothalamic-pituitary axis, toxic or allergic drug reactions may play a role in growth and pubertal delay of HIV-infected children. These dysfunctions require careful monitoring, in order to assess metabolic alterations that may be important in regulation of growth among HIV infected children. Better understanding of the mechanisms leading to impairment of growth and puberty in children with perinatal HIV-1 infection might lead to appropriate treatment when required.

Is elective caesarian section really essential for prevention of mother to child transmission of HIV in the era of antiretroviral therapy and abstinence of breast feeding?

AIM

To determine whether vaginal delivery along with antiretroviral therapy and avoidance of breast feeding is safe in preventing mother to child transmission (MTCT) of HIV.

SETTING

Pediatric & Perinatal HIV clinic, B.J. Wadia Hospital for children, Mumbai.

STUDY DESIGN

Retrospective analysis.

METHODS AND MATERIALS

222 HIV-infected pregnant women were treated with zidovudine from 14 weeks of gestation onwards. 174 women underwent an elective caesarian section whereas 48 women delivered spontaneously vaginally. All infants were treated with zidovudine for 6 weeks and breast feeding was withheld. The HIV status of infants was determined at 18 months by ELISA test.

RESULTS

Of the 174 infants delivered through LSCS delivery, two were HIV infected whereas 172 (98.9%) were HIV uninfected. Of the 48 infants delivered vaginally, 47 (97.9%) were HIV negative and one child was HIV infected. Thus, elective caesarean section was not statistically better as compared to vaginal delivery (p = 0.8696) suggesting that vaginal delivery was as effective as caesarean section for prevention of MTCT of HIV when added with antiretroviral therapy and no breast feeding.

CONCLUSION

Vaginal delivery along with antiretroviral therapy in mother and baby and avoidance of breast feeding is equivalent to that of an elective LSCS delivery for prevention of mother-to-child transmission of HIV. Surgical intervention may thus not be required in these women.

Lower mother-to-child HIV-1 transmission in boys is independent of type of delivery and antiretroviral prophylaxis: the Italian Register for HIV Infection in Children

The relationship between infant's gender and rate of HIV-1 mother-to-child transmission (MTCT) was evaluated in a prospective cohort of 4151 children (2166 boys and 1985 girls) born to HIV-1-infected mothers enrolled in the Italian Register for HIV Infection in Children. Logistic regression models were performed to estimate crude odds ratios (ORs) and adjusted odds ratios (AORs) and 95% CIs for factors potentially influencing MTCT separately for the period 1985-1995 and the period 1996-2001. To evaluate rates of MTCT by gender in specific subgroups, separate logistic regression models by mode of delivery and antiretroviral prophylaxis were performed. Among children born in 1985-1995, 15.5% boys (95% CI: 13.6-17.7) and 17.9% girls (95% CI: 15.7-20.3) were infected (P = 0.1181). After 1995, a lower proportion of boys (3.1% [95% CI: 2.0-4.4]; AOR: 0.43 [95% CI: 0.26-0.71], P = 0.0008) than girls (AOR: 6.3%, 95% CI: 4.8-8.1) was infected. Lower AORs for boys persisted independently of elective cesarean delivery (AOR: 0.31, 95% CI: 0.14-0.71); other than elective cesarean (AOR: 0.38, 95% CI: 0.19-0.78) and antiretroviral prophylaxis (zidovudine monotherapy (AOR: 0.11, 95% CI: 0.03-0.38); none (AOR: 0.43, 95% CI: 0.21-0.90). No difference was observed when combined therapy in the mother was administered (AOR: 1.14, 95% CI: 0.30-4.32), but results were likely to be biased by the very low rate of infected children in this group. A lower proportion of HIV-1-infected boys in children born after 1995 was found. Factor(s) intrinsic to gender (rather than type of delivery or maternal antiretroviral prophylaxis) may be involved, because the risk of infection in boys was lower independent of interventions. A possible explanation is that, among infected fetuses, more girls survive up to the end of pregnancy and may take advantage of the benefits of preventive strategies.

Risk factors for in utero and intrapartum transmission of HIV

OBJECTIVE

To identify predictors of in utero and intrapartum HIV-1 transmission in infants born in the Women and Infants Transmission Study between 1990 and 2000.

METHODS

In utero HIV-1 infection was defined as an infant with the first positive HIV-1 peripheral blood mononuclear cell culture and/or DNA polymerase chain reaction assay at 7 days of age or younger; intrapartum infection was defined as having a negative HIV-1 culture and/or DNA polymerase chain reaction assay at 7 days of age or younger and the first positive assay after 7 days of age.

RESULTS

Of 1709 first-born singleton children with defined HIV-1 infection status, 166 (9.7%) were found to be HIV-1 infected; transmission decreased from 18.1% in 1990-1992 to 1.6% in 1999-2000. Presumed in utero infection was observed in 34% of infected children, and presumed intrapartum infection, in 66%. Among infected children, the proportion with in utero infection increased over time from 27% in 1990-1992 to 80% (4 of 5) in 1999-2000 (P = 0.072). Maternal antenatal viral load and antiretroviral therapy were associated with risk of both in utero and intrapartum transmission. Controlling for maternal antenatal viral load and antiretroviral therapy, low birth weight was significantly associated with in utero transmission, while age, antenatal CD4 cell percentage, year, birth weight, and duration of membrane rupture were associated with intrapartum transmission.

CONCLUSION

Although there have been significant declines in perinatal HIV-1 infection over time, there has been an increase in the proportion of infections transmitted in utero.

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.

Preventing perinatal transmission of HIV: an evidence-based update for midwives

This article presents an update on human immunodeficiency virus care in the United States, with an emphasis on care during pregnancy and strategies to prevent perinatal transmission. Common drug regimens are reviewed. Obstetric factors related to transmission, such as mode of delivery, also are discussed. Guidelines for collaboration between midwives and human immunodeficiency virus specialists are outlined.

Puberty in perinatal HIV-1 infection: a multicentre longitudinal study of 212 children

OBJECTIVE

To define age at entry into Tanner stages in children with perinatal HIV-1 infection.

DESIGN

Multicentre longitudinal study including 212 perinatally HIV-1-infected children (107 girls and 105 boys) followed-up during puberty (from 8 and 9 years onwards in girls and boys, respectively). Healthy children (843 girls and 821 boys) provided reference percentiles. P2 or B2 stages in girls and P2 or G2 stages in boys defined onset of puberty.

METHODS

The cumulative probability [95% confidence limit (CI)] of entry into each stage at different ages was estimated by the Kaplan-Meier product-limit method; differences were evaluated by log rank test. Relationships were tested using the Spearman's rank correlation coefficient.

RESULTS

Ages of girls [years (95%CI)] at P2 [12.9 (12.6-13.2)], P3 [13.4 (13.0-13.8)], P4 [14.6 (14.0-15.2)], B2 [12.7 (12.2-13.2)], B3 [13.3 (12.8-14.0)] and B4 [14.6 (14.0-15.2)] stages were > 97th percentile (> or = 21 month delay) of controls. Ages of boys [years (95%CI)] at P2 [12.6 (12.1-13.1)], P3 [13.9 (13.4-14.4)], P4 [14.9 (14.2-15.6)], G2 [12.1 (11.5-12.7)], G3 [13.6 (13.1-14.1)] and G4 [14.9 (14.1-15.7)] stages were at the 75-97th percentiles (< or = 15 month delay). Age at onset of puberty was not related to clinical and immunological condition, antiretroviral treatment, weigh for height and age at onset of severe disease or immune suppression.

CONCLUSION

Perinatal HIV-1 infection interferes with sexual maturation. The mechanisms by which this occurs should be elucidated and intervention strategies designed. Intervention could save much psychological distress, since associated linear growth failure can exacerbate adolescents' feelings of being different and unwell.

An effective and safe protocol involving zidovudine and caesarean section to reduce vertical transmission of HIV-1 infection

OBJECTIVE

To investigate zidovudine prophylaxis with caesarean section to reduce mother-to-infant HIV transmission.

INTERVENTIONS

Elective caesarean section before labour, usually at 36-38 weeks of gestation, plus a short oral course of zidovudine, normally starting at week 32, intravenous zidovudine before caesarean section and for 10 days for the neonate (the reduced Berlin regimen).

RESULTS

Of 179 mother-infant pairs 104 received no antiretroviral prophylaxis or therapy (control group), 48 received the reduced Berlin prophylaxis regimen, 18 received combination therapy and nine received only part of the prophylaxis regimen. Of the antiretroviral group, 68 were delivered by elective caesarean section. The HIV transmission rate was zero in the antiretroviral group [95% confidence interval (CI) 0-4.7] and 12.6% (6.4-19.0) in the control group. The reduction in vertical transmission was 90% for the Berlin regimen, with an 80 and 70% reduction in risk associated with antiretroviral treatment and caesarean section, respectively. Maternal CD4 cell count but not viral load had some confounding effect on the reduction in risk attributed to caesarean section and the prophylactic regimen. Neonatal haematological abnormalities associated with antiretroviral intervention lasted for up to 7 weeks. Weight and length, although significantly lower at birth, were normal by 6-8 weeks.

CONCLUSION

A much reduced three-arm regimen of zidovudine prophylaxis in combination with caesarean section before labour is highly effective in reducing the risk of vertical HIV transmission and is safe for the infant.

Nonoccupational HIV postexposure prophylaxis: a new role for the emergency department

Despite numerous primary prevention campaigns, new cases of HIV infection are occurring at high rates. Postexposure prophylaxis (PEP) after possible HIV exposures from sexual encounters or injection drug use may prove to be a worthwhile means of reducing HIV infection. Although there are no studies that directly demonstrate its efficacy, indirect support comes from animal and human studies. Multiple animal studies have shown that antiretroviral medications can reduce simian immunodeficiency virus infections if given early and for a prolonged period. A study of health care workers suggests that zidovudine taken after needlestick injuries can dramatically reduce HIV seroconversion. Zidovudine and nevirapine use recently showed great reductions in perinatal HIV transmission. Studies of dendritic and T-cell processing of simian immunodeficiency virus and HIV indicate that antiretroviral medications taken soon after a viral exposure may terminate viral replication. Regimens of 2 or 3 antiretroviral medications have been suggested as prophylactic measures after certain exposures. Even though limited experience exists with these populations, HIV PEP is most likely safe in pregnancy and for children. Emergency departments are encouraged to anticipate the probable demands for nonoccupational HIV PEP by establishing protocols for its rapid provision and ensuring proper follow-up care.

The changing HIV epidemic in Italian pregnant women

OBJECTIVE

To describe changes in the characteristics of HIV-pregnant women in Italy and the impact of strategies for prevention of HIV vertical transmission.

STUDY DESIGN

Since 1985, HIV-infected women and their children are followed in 23 European centres in the European Collaborative Study (ECS), according to a standard protocol. Eight Italian Obstetric units participating in the ECS enrolled 815 patients.

RESULTS

Overall use of zidovudine to reduce HIV vertical transmission has increased significantly since 1994 and between 1995 and 1997, 57% of Italian women were treated. However, 27% of babies received the infant component of the 076 regimen. Over the years, age at delivery has increased and their CD4 count at delivery decreased, most likely reflecting heterosexually infected women with a longer duration of infection. The increasing rate of elective caesarean section (42%) is not related to maternal, foetal or obstetrical indications, but its use as an intervention to reduce HIV vertical transmission.

CONCLUSIONS

The identification of HIV-infected women during pregnancy or before delivery ensures the appropriate management of the woman and her child, and clinicians should be aware of the increasing number of women with heterosexual acquisition of HIV-infection who may be less easily identified.

Risk factors for preterm birth, low birth weight, and intrauterine growth retardation in infants born to HIV-infected pregnant women receiving zidovudine. Pediatric AIDS Clinical Trials Group 185 Team

OBJECTIVE

To evaluate independent contributions of maternal factors to adverse pregnancy outcomes (APO) in HIV-infected women receiving antiretroviral therapy (ART).

DESIGN

Risk factors for preterm birth (< 37 weeks gestation), low birth weight (LBW) (< 2500 g), and intrauterine growth retardation (IUGR) (birth weight < 10th percentile for gestational age) examined in 497 HIV-infected pregnant women enrolled in PACTG 185, a perinatal clinical trial.

METHODS

HIV RNA copy number, culture titer, and CD4 lymphocyte counts were measured during pregnancy. Information collected included antenatal use of cigarettes, alcohol, illicit drugs; ART; obstetric history and complications.

RESULTS

Eighty-six percent were minority race/ethnicity; 86% received antenatal monotherapy, predominantly zidovudine (ZDV), and 14% received combination antiretrovirals. Preterm birth occurred in 17%, LBW in 13%, IUGR in 6%. Risk of preterm birth was independently associated with prior preterm birth [odds ratio (OR) 3.34; P < 0.001], multiple gestation (OR, 6.02; P = 0.011), antenatal alcohol use (OR, 1.91; P = 0.038), and antenatal diagnosis of genital herpes (OR, 0.24; P = 0.022) or pre-eclampsia (OR, 6.36; P = 0.025). LBW was associated with antenatal diagnosis of genital herpes (OR, 0.08; P = 0.014) and pre-eclampsia (OR, 5.25; P = 0.049), and baseline HIV culture titer (OR, 1.41; P = 0.037). IUGR was associated with multiple gestation (OR, 8.20; P = 0.010), antenatal cigarette use (OR, 3.60; P = 0.008), and pre-eclampsia (OR, 12.90; P = 0.007). Maternal immune status and HIV RNA copy number were not associated with APO.

CONCLUSIONS

Risk factors for APO in antiretroviral treated HIV-infected women are similar to those reported for uninfected women. These data suggest that provision of prenatal care and ART may reduce APO.

Epidemiology of HIV infection in the newborn

Vertical transmission of HIV infection can take place in utero, during delivery and postnatally through breastfeeding, with about three-quarters of infections occurring around the time of delivery in non-breastfeeding populations. In Europe, in the absence of specific interventions, the vertical transmission rate was 15-20%. High maternal load is the major risk factor for both intra-uterine and intra-partum mother-to-child transmission. Prematurity is the most common adverse neonatal outcome associated with maternal HIV infection. Earlier diagnosis of paediatric HIV infection than previously available is now possible with virological tests, particularly HIV DNA polymerase chain reaction. An estimated one fifth of infected children will have been diagnosed with AIDS or have died by 12 months of age, rising to a third by 6 years of age. Surgical and therapeutic interventions are effective in reducing vertical transmission risk, in addition to the avoidance of breastfeeding. Caesarean section delivery before labour and before rupture of membranes approximately halves the risk of transmission, while prophylactic zidovudine therapy according to the ACTG076 regimen reduces transmission by up to two-thirds, transmission is reduced even further with both interventions. Trials of short-course zidovudine regimens show their effectiveness in reducing vertical transmission, in breastfeeding and non-breastfeeding populations. Nevirapine has been shown to be significantly more effective than short course zidovudine regimens in breastfeeding populations, but is still under evaluation in non-breastfeeding populations additionally receiving routine anti-retroviral prophylaxis. Reports of a small number of serious adverse events in uninfected children exposed in utero or neonatally to antiretroviral therapy need further investigation. Trials of vitamin A supplementation to reduce vertical transmission have had negative results, while the effectiveness of vaginal lavage and passive immune therapy in reducing vertical transmission remains uncertain.

Lack of mother-to-child HIV-1 transmission is associated with elevated serum levels of 90 K immune modulatory protein

BACKGROUND

90 K is a secreted human serum glycoprotein with immune modulatory activity.

METHODS

Serum 90 K levels were determined by an enzyme-linked immunosorbent assay in 19 HIV-1-infected mothers at the time of delivery, in their new-borns (11 HIV-1 infected and eight uninfected), in 26 HIV-1-uninfected mothers and in 86 new-borns of HIV-1-uninfected mothers.

RESULTS

90 K levels in HIV-1-infected transmissive mothers (22.4 +/- 13.9 microg/ml) were similar to those of HIV-1-uninfected mothers (21.1 +/- 7.6 microg/ml; P = 0.715), but lower than those of HIV-1-infected non-transmissive mothers (45.5 +/- 24.8 microg/ml; P = 0.019). The levels were higher in HIV-1-uninfected (47.6 +/- 22.4 mg/ml) than HIV-1-infected (23.7 +/- 15.6 microg/ml; P = 0.014) new-borns of HIV-1-infected mothers. The new-borns of HIV-1-uninfected mothers had lower levels (11.7 +/- 5.3 microg/ml) than both HIV-1-infected and HIV-1-uninfected new-borns of HIV-1-infected mothers (all differences, P < 0.001).

CONCLUSION

These results suggest that high 90 K protein serum levels in HIV-1-infected mothers and their new-borns are associated with lack of mother-to-child HIV-1 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.

Update on perinatal HIV transmission

Over the past decade, much progress has been made in understanding the risk factors and timing of perinatal HIV transmission. Even more impressive have been the successful clinical trials with antiretrovirals, such as ZDV, ZDV-3TC, and nevirapine, that demonstrated significant reductions in the risk for infant infection. Within the United States and Europe, these trial results have led to rapid implementation and dramatic decreases in new perinatal HIV cases since 1994. An immediate challenge is to rapidly translate the short-course antiretroviral trial results with ZDV and nevirapine into public health policy and practice in resource-poor settings, where almost 600,000 neonates continue to become infected by mother-infant HIV transmission each year. Physicians must also test strategies to further decrease the risk for infant HIV infection during the breast-feeding period.

Pertussis immunization in HIV-1-infected infants: a model to assess the effects of repeated T cell-dependent antigen administrations on HIV-1 progression. Italian Register for HIV infection in children

Several data evidence that HIV-1 replication may increase in temporal association with immunizations, raising concerns on potential negative effects of vaccinations on HIV-1 progression. Among patients prospectively followed by the "Italian Register for HIV infection in children", we evaluated, using the Cox-Mantel method, conditional probabilities of progressing to CDC clinical categories 'B' or 'C', and immunological categories '2' or '3' in 88 children immunized against pertussis and 244 non-immunized. No selection criteria were followed in vaccinating children. No significant differences were observed between the two groups. The lack of a significant impact on clinical and immunological deterioration by the repeated administrations of a T cell-dependent vaccine endorses the current recommendations for routine immunizations in HIV-1-infected children.

Role of maternal humoral immunity in vertical transmission of HIV-1 subtype E in Thailand

The significance of the maternal humoral immune response in relation to vertical transmission of HIV-1 was investigated in 123 mothers infected with subtype E from Thailand. Antibody binding titers to HIV-1 env domains (monomeric gp120, the CD4/gp120 binding site [BS], V3 loop, and gp41) and antibody-mediated neutralization of primary and T-cell line-adapted (TCLA) subtypes B and E HIV-1 isolates were investigated. No correlation between maternal anti HIV-1 antibodies at delivery and vertical transmission of HIV-1 subtype E was found. However, a trend to higher titer antibody-mediated cross-neutralization of a heterologous subtype B TCLA isolate, HIV-1MN, was observed in nontransmitting mothers postpartum. The HIV-1-specific antibody titers in these infected mothers increased significantly from delivery to 6 months postpartum (p < .05), but this was only partially attributable to hemodilution and an additional factor or factors appear to affect humoral immunity to HIV-1 during late pregnancy.

Timing of human immunodeficiency virus type 1 (HIV-1) transmission from mother to child: bayesian estimation using a mixture

The timing of mother-to-child HIV transmission is not directly observable but influences the infected child's viral and immune status in the neonatal period. A hierarchical model was developed in a Bayesian framework to 'back-calculate' the timing of HIV-1 transmission from mother to child from the virological and immunological kinetics in the infected infant. Joint evolution of viral markers and immune response was modelled as a continuous time Markov process. The modelling of the period from infection to birth was based on a mixture of three distributions taking into account the various mother-to-child transmission pathways: In utero (early or late in gestation) and intrapartum (during the delivery process), integrating the fact that transmission is a continuum during the pregnancy. Gibbs sampling was used to estimate the marginal posterior distributions of the transition intensities between stages of HIV infection and those of the individual times from infection to birth. We applied our model to data on 135 perinatally HIV-1-infected children included in the French Prospective Study on Pediatric HIV infection. The model suggested that transmission occurred late in utero during the last month of pregnancy and that the day of delivery was a particularly critical time in HIV-1 transmission from mother to child. The paper ends with a discussion of model assumptions and a comparison with results obtained using a non-parametric method.

The mode of delivery and the risk of vertical transmission of human immunodeficiency virus type 1--a meta-analysis of 15 prospective cohort studies

BACKGROUND

To evaluate the relation between elective cesarean section and vertical transmission of human immunodeficiency virus type 1 (HIV-1), we performed a meta-analysis using data on individual patients from 15 prospective cohort studies.

METHODS

North American and European studies of at least 100 mother-child pairs were included in the meta-analysis. Uniform definitions of modes of delivery were used. Elective cesarean sections were defined as those performed before onset of labor and rupture of membranes. Multivariate logistic-regression analysis was used to adjust for other factors known to be associated with vertical transmission.

RESULTS

The primary analysis included data on 8533 mother-child pairs. After adjustment for receipt of antiretroviral therapy, maternal stage of disease, and infant birth weight, the likelihood of vertical transmission of HIV-1 was decreased by approximately 50 percent with elective cesarean section, as compared with other modes of delivery (adjusted odds ratio, 0.43; 95 percent confidence interval, 0.33 to 0.56). The results were similar when the study population was limited to those with rupture of membranes shortly before delivery. The likelihood of transmission was reduced by approximately 87 percent with both elective cesarean section and receipt of antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, as compared with other modes of delivery and the absence of therapy (adjusted odds ratio, 0.13; 95 percent confidence interval, 0.09 to 0.19). Among mother-child pairs receiving antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, rates of vertical transmission were 2.0 percent among the 196 mothers who underwent elective cesarean section and 7.3 percent among the 1255 mothers with other modes of delivery.

CONCLUSIONS

The results of this meta-analysis suggest that elective cesarean section reduces the risk of transmission of HIV-1 from mother to child independently of the effects of treatment with zidovudine.

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.

Breastfeeding, genetic, obstetric and other risk factors associated with mother-to-child transmission of HIV-1 in Sao Paulo State, Brazil. Sao Paulo Collaborative Study for Vertical Transmission of HIV-1

OBJECTIVES

To evaluate the effect of maternal, obstetric, neonatal and post-natal factors on the risk of vertical transmission of HIV-1.

DESIGN

Multicentre retrospective cohort study.

SETTING

Obstetric and paediatric clinics in four cities in Sao Paulo State, Brazil.

MAIN OUTCOME

Child's HIV-1 infection status.

METHODS

Data were collected by standardized record abstraction and interview on 553 children born to women identified as HIV-1-infected before or at delivery. Paediatric infection was determined by immunoglobulin G anti-HIV-1 tests at age 18 months or by AIDS diagnosis at any age. Multivariate logistic regression was used to assess the effect of potential risk factors on vertical transmission of HIV-1.

RESULTS

HIV-1 infection status was determined for 434 children (follow-up rate of 78%); 69 were classified as HIV-1-infected [transmission risk, 16%; 95% confidence interval (CI), 13-20%]. In multivariate analysis, advanced maternal HIV-1 disease [odds ratio (OR), 4.5; 95% CI, 2.1-9.5], ever breastfed (OR, 2.2; 95% CI, 1.2-4.2), child's negative Rhesus blood group (OR, 2.5; 95% CI, 1.2-5.5), third trimester amniocentesis (OR, 4.1; 95% CI, 1.2-13.5) and black racial group (OR, 0.3; 95% CI, 0.1-0.9) were independently and significantly associated with mother-to-child transmission of HIV-1. Transmission was increased marginally with prematurity, more than 10 lifetime sexual partners and prolonged duration of membrane rupture. No association was found between child's HIV-1 infection and mode of delivery or serological evidence of syphilis during pregnancy.

CONCLUSION

These findings support the importance of severity of maternal HIV-1 disease in the risk of vertical transmission of HIV-1, indicate measures to reduce transmission by avoiding amniocentesis and breastfeeding and suggest that race and Rhesus blood type may be markers for genetic susceptibility to infection.

Mother-child HIV-1 transmission: Timing and determinants

Prevention of mother-to-child transmission of HIV is a significant public health priority. A regimen of zidovudine administered during pregnancy, intrapartum, and to the newborn significantly reduces transmission, and incorporation of this regimen into clinical practice has been associated with significant decreases in perinatal transmission in industrialized countries. This regimen, however, is not applicable in the developing world (where most perinatal transmission occurs), and simpler, shorter, less costly regimens are urgently needed. An understanding of the pathogenesis of perinatal transmission is crucial for the design of new preventive and therapeutic regimens, and current knowledge is reviewed in this article, with an emphasis on relevance to prevention.

Mother-to-child transmission of HIV-1

After reviewing the evidence on the relation of vertical transmission of HIV to stage of infection in the mother, I developed a stochastic model of transmission in which the probability of transmission per week is proportional to the virus load in the mother. The virus load in different stages of the infection is measured by viral RNA levels or tissue culture infectious virus levels in plasma. The constant of proportionality is assumed to be different for transmission during pregnancy, during parturition, and during breast-feeding. Using data on transmission from mothers who are in the primary stage of infection, I estimated the constant of proportionality and calculated the probability of transmission during pregnancy as a function of the time pregnancy starts in relation to the stage of the infection. For breast-feeding, I calculated the conditional probability of transmission by breast-feeding for 20 weeks, dependent on the infant escaping infection during pregnancy and parturition. As might be expected, the probabilities of transmission are highest if the mother is in the primary stage of infection or in late stages of the disease and is quite low when the mother is in the asymptomatic stage of the infection.

Incidence of premature birth and neonatal respiratory disease in infants of HIV-positive mothers. The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted Human Immunodeficiency Virus Infection Study Group

OBJECTIVE

We sought to determine the prematurity rate in infants of HIV-positive mothers and to characterize the incidence and severity of neonatal respiratory disease in this population.

STUDY DESIGN

From 1990 to 1994, 600 live-born infants of HIV-infected mothers were enrolled prenatally (73%) or postnatally (27%) from five U.S. centers. Logistic regression was used to determine the association of HIV status in the infant with prematurity (< or = 37 weeks), low birth weight (< or = 2.5 kg), and very low birth weight (< or = 1.5 kg) rates. The incidence of respiratory distress syndrome (RDS), bronchopulmonary dysplasia, meconium aspiration syndrome, and neonatal pneumonia was compared with anticipated rates for gestational age and birth weight.

RESULTS

Very high rates of prematurity (19%), low birth weight (18.3%), and very low birth weight (3.3%) were found in the infants of HIV-positive mothers; and HIV infection in the infant was associated with younger gestational age. The overall incidence of RDS was 3% (17/600), which coincided with the anticipated rate, after adjusting for prematurity and birth weight. Only five infants (all < or = 1.5 kg) had bronchopulmonary dysplasia, and none required assisted ventilation beyond 14 days. Three term infants had mild meconium aspiration syndrome, and there were no cases of documented neonatal pneumonia.

CONCLUSION

Infants born to HIV-positive mothers exhibited high prematurity and low birth weight rates, and the odds of prematurity were higher in infants who were infected with HIV. Despite the high incidence of prematurity and perinatal risk of this population, incidence and severity of neonatal respiratory disease were not higher than would be expected from available neonatal data in populations not exposed to HIV.

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.

Potential risk factors for vertical HIV-1 transmission in Catalonia, Spain: the protective role of cesarean section. The Working Group on HIV-1 Vertical Transmission in Catalonia

OBJECTIVE

To evaluate the roles of certain potential risk factors on the vertical transmission of HIV-1.

DESIGN

Prospective registry of infants born to HIV-1-infected women in Catalonia (north-east Spain) from 1987 to 1992.

METHODS

A total of 599 infants, born in Catalan hospitals to 520 women who were identified as being HIV-1-infected during gestation or at delivery, were included. Data on mode of delivery, birth weight, gestational age and breast-feeding as well as the mother's age, her route of HIV-1 infection, clinical stage and p24 antigenaemia, were recorded. HIV-1 infection status of 489 (82%) of the infants was determined according to the criteria of the US Centers for Disease Control and Prevention. Risk estimates and odds ratio (OR) were calculated and logistic regression was performed.

RESULTS

The overall rate of vertical transmission was 18.6% (95% confidence interval, 15.2-22.0%). Multivariate analyses revealed that Cesarean section was associated with a lower rate of vertical transmission (OR = 0.3; P = 0.001), as was maternal HIV-1 infection via injecting drug use (OR = 0.44; P = 0.02). Breast-feeding (OR = 6.9; P = 0.001), very low birth weight (< 1500 g; OR = 6.3; P = 0.001) and p24 antigenaemia (OR = 4.6; P = 0.04) were all related to increased risk. The crude rate of HIV-1 transmission was 6% among Cesarean births compared with 21% for infants born via vaginal deliveries. The population-attributable risk for vaginal deliveries was 61.7%.

CONCLUSIONS

The results show a protective effect of Cesarean section in the absence of zidovudine prophylaxis. However, current research should be directed towards the individual and combined effects that antiretroviral agents and Cesarean section may have on mother-to-child HIV-1 infection.

HIV in the neonate

Mother-to-infant transmission of human immunodeficiency virus (HIV) is a worldwide problem. Between 7 and 40% of infants born to HIV-positive mothers become infected. The prognosis of these infants is poor, with most developing early and rapidly progressive disease. A number of advances in diagnosis and therapy offer opportunities to reduce the rate of vertical transmission and to improve the outlook of infected infants. Antiretroviral therapy during pregnancy and the neonatal period can markedly reduce the risk of mother-to-infant transmission. Recognition that 50% or more of infections are transmitted peripartum offers scope to further reduce the rate of transmission. However there is currently no consensus on the optimal management of pregnancy in HIV-infected women, and there is an urgent need for large randomized controlled trials. The development of polymerase chain reaction and p24 antigen assays has greatly facilitated the diagnosis of neonatal HIV infection, thereby enabling earlier supportive and anti-retroviral therapy. The place of zidovudine in paediatric HIV infection is now well-established, but the future will undoubtedly bring combination anti-retroviral therapy. Optimism about the prospects for developments in the prevention and treatment of paediatric acquired immunodeficiency syndrome must be tempered by the fact that the majority of cases occur in countries where patients have little or no access to medical care.

Maternal clinical factors influencing HIV-1 transmission

The complex puzzle of maternal factors involved in mother-to-child human immunodeficiency virus type 1 (HIV-1) transmission is being put together. The risk of perinatal infection increases with mother's disease progression, but it remains stable in women seroconverting to HIV-1 during pregnancy and in consecutive pregnancies. Thus, transmission correlates with the HIV-1 progression rather than the duration of infection in the mother. Nutritional alterations such as vitamin A deficiency may also have a significant impact, whereas geographic origin and mode of maternal infection are of no influence. Placenta membrane inflammation and concurrent sexually transmitted diseases are other significant covariates. The rate of transmission appears directly correlated with maternal age and inversely with length of gestation. A protective effect of caesarean section has been reported in some observational studies but, being controversial, these results need to be corroborated by randomized trials.

Human immunodeficiency virus infection in women

This article describes current epidemiologic trends in HIV infection in women worldwide and in the United States, the natural history of HIV infection in women as currently understood, clinical management of HIV-infected women in those areas in which it differs from men, and multiple issues relating to pregnancy and childbearing in HIV-infected women.

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.