The association between maternal HIV infection and perinatal outcome: a systematic review of the literature and meta-analysis

Determinants of low birth weight among HIV-infected pregnant women in Tanzania

BACKGROUND

Low birth weight (LBW) increases the risk of infant death, but little is known about its causes among HIV-infected populations in sub-Saharan Africa.

OBJECTIVE

We assessed sociodemographic, nutritional, immunologic, parasitic, and infant risk factors for birth weight, LBW, and small-for-gestational-age (SGA) status in a cohort of 822 HIV-positive women enrolled in a clinical trial of vitamin supplementation and pregnancy outcomes in Dar es Salaam, Tanzania.

DESIGN

Women were enrolled at prenatal care clinics during their second trimester, at which time blood, stool, urine, and genital specimens were collected, and anthropometric measurements and sociodemographic data were recorded. Birth weight was measured at hospital delivery.

RESULTS

The mean (+/-SD) birth weight was 3015 +/- 508 g, 11.1% of newborns weighed <2500 g (LBW), and 11.5% were SGA. In multivariate analyses, maternal weight at enrollment and a low CD8 cell count were inversely associated with LBW. Advanced-stage HIV disease, previous history of preterm birth, Plasmodium falciparum malaria, and any helmintic infection were associated with higher risk of LBW. The intestinal parasites Entamoeba histolytica and Strongyloides stercoralis were predictors of LBW despite their low prevalence in the cohort. In a multivariate-adjusted linear regression model, BMI, midupper arm circumference, a CD4 cell count <200 x 10(6) cells/L (200 cells/mm(3)), primiparity, maternal literacy, and infant HIV infection at birth were significantly associated with birth weight in addition to risk factors included in the LBW model. Determinants of SGA included maternal weight, low serum vitamin E concentration, candidiasis, malaria, and infant HIV infection at birth.

CONCLUSION

Prevention of HIV disease progression and vertical transmission, improved nutritional status, and better management of malaria and intestinal parasitic infections are likely to reduce the incidence of LBW in Tanzania.

The association between maternal HIV-1 infection and pregnancy outcomes in Dar es Salaam, Tanzania

OBJECTIVE

To examine the association between maternal HIV infection and pregnancy outcomes controlling for potential confounding factors among a cohort of HIV-uninfected and HIV-infected pregnant women in Dar es Salaam, Tanzania.

DESIGN

Prospective cohort study.

METHODS

A cohort of 1,078 HIV-infected and 502 HIV-uninfected pregnant women between 12 and 27 weeks of gestation were enrolled and followed up until delivery. Multiple regression models were used to compare the risk of adverse pregnancy outcomes among HIV-uninfected women with those among HIV-infected women overall, and separately among asymptomatic or symptomatic HIV-infected women.

RESULTS

No significant differences between HIV-uninfected women and HIV-infected women were observed in risks of fetal loss or low birthweight or in the weight, head circumference and gestational age of infants at birth. HIV-infected women were more likely to have severe immature infants (<34 weeks) than HIV-uninfected women (multivariate RR 1.54 [95% CI 0.90-2.48]; P= 0.05). There was a significantly higher risk of low birthweight (RR 2.29, 95% CI 1.34-3.92; P = 0.03) and prematurity (<37 weeks) (RR 1.93, 95% CI 1.35-2.77; P = 0.0003) among symptomatic HIV-infected women when compared with HIV-uninfected women.

CONCLUSION

HIV-infected women, particularly those whoare symptomatic, are at a higher risk of adverse pregnancy outcomes.

The relationship of maternal and child HIV infection to security of attachment among Ugandan infants

This study was designed to examine the relationship of maternal and child human immunodeficiency virus (HIV) infection to the security of attachment of Ugandan infants. The attachment patterns of two groups of Ugandan mother-infant pairs: 35 HIV-positive mothers and their infants and 25 HIV-negative mothers and their infants were compared. We tested the hypothesis that infants of HIV-positive mothers would demonstrate less secure attachment as measured by the Waters Attachment Q-set than infants of HIV-negative mothers. No differences were found in the security of attachment of infants of HIV-positive versus HIV-negative mothers. Infants of HIV-positive mothers with Acquired Immunodeficiency Syndrome (AIDS) were less securely attached than infants of mothers without AIDS. These findings underscore the relationship of infant security of attachment to maternal HIV infection in the presence of AIDS-related symptoms but not to asymptomatic maternal HIV infection.

Predictors of intrauterine and intrapartum transmission of HIV-1 among Tanzanian women

OBJECTIVE

To examine predictors of vertical transmission of HIV-1 in Dar-es-Salaam, Tanzania.

DESIGN

Observational design.

METHODS

Consenting HIV-1-infected pregnant women (n = 1078) were enrolled in a trial to examine the role of vitamin supplements. Intrauterine HIV-1 infection (HIV-positive at birth); intrapartum and early breastfeeding transmission (HIV-positive at 6 weeks among those uninfected at birth) were defined using the PCR.

RESULTS

Of 734 infants who had a specimen taken at birth, 62 were HIV positive [8.4%; 95% confidence interval (CI),6.4--10.5%], whereas 59 infants were positive among 367 infants who were uninfected at birth and were retested at 6 weeks (16.1%; 95%CI, 12.3--19.8%). In multivariate analyses, maternal CD4 cell count, viral load, and clinical stage were significant predictors of both definitions of transmission. Viral load of 50 000 copies/ml or more at delivery was associated with a 4.21-fold increase in risk of intrapartum and early breastfeeding transmission (95%CI, 1.59--11.13;P = 0.004). Babies who were HIV negative at birth and born before 34 weeks of gestation were 2.19 times more likely to become infected during intrapartum and early breastfeeding periods compared with those born after 37 weeks (95%CI, 1.19--4.04; P = 0.01). Gonorrhea at baseline was related to intrauterine transmission [multivariate risk ratio (RR), 5.50; 95%CI, 2.04--14.81; P < 0.001] but not intrapartum and early breastfeeding transmission. Signs of lower genital infections at or after enrollment were also associated with transmission.

CONCLUSIONS

Reducing prematurity, rate of HIV disease progression, and maternal viral load at or after delivery could help to reduce vertical transmission. Treatment of sexually transmitted infections at onset of prenatal care, about 20 weeks on average, was inadequate for prevention of transmission. Whether sustained clearance of lower genital tract infections result in reduced transmission remains to be determined.

Pregnancy and infection with human immunodeficiency virus

During the past decade, there has been a dramatic increase in the number of women infected with HIV and the number of women with clinical AIDS. One of the most prominent features of HIV infection is that it is usually diagnosed during the peak reproductive years, and in 1998, HIV/AIDS was the fourth leading cause of death among women between the ages of 25 and 44 years. For this reason, there has been long-standing concern regarding the obstetric implications of HIV infection: both the impact of pregnancy on possibly accelerating the course of HIV disease and the impact of HIV infection on the course of pregnancy. There appears to be some immunologic changes associated with pregnancy, but they are not dramatic, and immune markers generally resume their prepregnancy values after delivery. With regard to long-term effects of pregnancy on HIV disease progression, no study to date has shown significant increases in mortality or in AIDS incidence associated with pregnancy. Studies have generally been small, however, and none have accounted for antiretroviral therapy usage. Many studies have shown that certain adverse outcomes are more common in HIV-positive pregnant women as compared with HIV-negative pregnant women, and concerns have been raised that spontaneous abortions may be more common among HIV-infected women and that this may impact fertility rates. Although important understanding has been acquired regarding the associations between pregnancy and the course of HIV infection, much remains to be understood. Additional, well-designed studies are clearly needed to rigorously address the many remaining questions that exist. We can anticipate that the resolution of these questions will continue to be of broad public health interest as the epidemic impacts increasing numbers of women, a large fraction of whom will be adolescents.

Human immunodeficiency virus and assisted reproduction: reconsidering evidence, reframing ethics

OBJECTIVE

To review the advances in the treatment of human immunodeficiency virus (HIV) infection and revisit the medical, ethical, and legal issues surrounding infertility management in HIV-infected couples.

DESIGN

Analytic review.

RESULTS(S)

HIV infection continues to be a serious public health and reproductive issue. However, present policies which allow for the categorical exclusion of HIV-infected individuals from infertility services should be reconsidered in light of improvements in the prognosis of infected individuals and a dramatic decrease in the risk of vertical transmission. An analysis of the ethical cogency of the arguments against the provision of services does not substantiate the exclusion of HIV-infected individuals; rather, the principle of justice requires that HIV-infected women be treated the same way as a woman who might have an increased risk of conceiving a child with a disability or a may have a decreased life expectancy due to a chronic illness such as diabetes. Ethical disagreement notwithstanding, with the precedents recently established by the Americans with Disabilities Act (ADA), discrimination based on HIV status would also likely be unlawful under most circumstances.

CONCLUSIONS(S)

With advances in the treatment of HIV infection, contextualized counseling and a respect for patients' decisions regarding infertility treatment should be adopted as public policy. It is neither ethically nor legally justifiable to categorically exclude individuals from infertility services on the basis of HIV infection.

Experience of nevirapine use in a London cohort of HIV-infected pregnant women

OBJECTIVE

To describe the experience of four London HIV centres prescribing nevirapine (NVP) to HIV-1 infected pregnant women with respect to immunological and virological response, tolerability and pregnancy outcome.

METHODS

We identified all HIV-1-infected women who received NVP as part of a triple antiretroviral regimen during pregnancy between January 1997 and September 1999. Laboratory results, clinical events, side-effects and pregnancy outcome were abstracted using a standardized proforma from the medical records.

RESULTS

Forty-six women were identified, 85% of whom were black African. At initiation of NVP, the median age was 29 years and the median baseline CD4 cell count and viral load were 242 cells/microL and 4.15 log10 copies/mL, respectively. Thirty-two out of 36 women who had a plasma sample obtained at, or just prior to, delivery had an undetectable viral load (< 50 to < 400 copies/mL). Adverse events that were definitely attributed to NVP included a generalized rash (n = 2) and hepatitis (n = 2). Obstetric complications occurred in nine women (19.5%), which was not statistically different (P = 0.36) from that found in a historical (1990-96) control group 7/51 (14%). The rate of preterm delivery (13%) was similar to that previously reported in HIV-1 infected pregnant women (18%).

CONCLUSIONS

NVP (as part of highly active antiretroviral therapy) reduced plasma viraemia to below the limit of detection in 89% of women. It was generally well tolerated and clinical and laboratory adverse events were infrequent. There was no evidence of an increase in obstetric complications including preterm delivery during the second and third trimesters of pregnancy.

Decreased fertility among HIV-1-infected women attending antenatal clinics in three African cities

Population HIV prevalence estimates rely heavily on sentinel surveillance in antenatal clinics (ANCs), but because HIV reduces fertility, these estimates are biased. To aid interpretation of such data, we estimated HIV-associated fertility reduction among pregnant women in ANCs in Yaoundé (Cameroon), Kisumu (Kenya), and Ndola (Zambia). Data collection followed existing HIV sentinel surveillance procedures as far as possible. HIV prevalence among the women was 5.5% in Yaoundé, 30.6% in Kisumu, and 27.3% in Ndola. The birth interval was prolonged in HIV-positive multiparous women compared with HIV-negative multiparous women in all three sites: adjusted hazard ratios of pregnancy were 0.84 (95% confidence interval [CI]: 0.62-1.1) in Yaoundé, 0.82 (95% CI: 0.70-0.96) in Kisumu, and 0.74 (95% CI: 0.61-0.90) in Ndola, implying estimated reductions in the risk of pregnancy in HIV-positive women of between 16% and 26%. For primiparous women, the interval between sexual debut and birth was longer in HIV-positive women than in HIV-negative women in all sites, although the association was lost in Ndola after adjusting for age and other factors. Consistent results in different study sites help in the development of standard methods for improving ANC-based surveillance estimates of HIV prevalence. These may be easier to devise for multiparous women than for primiparous women.

Adjusting ante-natal clinic data for improved estimates of HIV prevalence among women in sub-Saharan Africa

OBJECTIVES

To find a simple and robust method for adjusting ante-natal clinic data on HIV prevalence to represent prevalence in the general female population in the same age range, allowing for fertility differences by HIV status.

BACKGROUND

HIV prevalence comparisons for pregnant women and women in the general community show that prevalence in the latter is significantly higher than in the former. An adjustment procedure is needed that is specific for the demographic and epidemiological circumstances of a particular population, making maximum use of data that can easily be collected in ante-natal clinics or are widely available from secondary sources.

METHODS

Birth interval length data are used to allow for subfertility among HIV-positive women. To allow for infertility, relative HIV prevalence ratios for fertile and infertile women obtained in community surveys in populations with similar levels of contraception use are applied to demographic survey data that describe the structure of the population not at risk of child-bearing.

RESULTS

For populations with low contraception use, the procedure yields estimates of general female HIV prevalence of 35-65% higher than the observed ante-natal prevalence, depending on population structure. Results were verified using general population prevalence data collected in Kisesa (Tanzania) and Masaka (Uganda). For high contraception use populations, adjusted values range from 15% higher to 5% lower, but only limited verification has been possible so far.

CONCLUSIONS

The procedure is suitable for estimating general female HIV prevalence in low contraception use populations, but the high contraception variant needs further testing before it can be applied widely.

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.

Malnutrition, morbidity and mortality in children and their mothers

While being underweight or stunted is recognized as an important risk factor for increased prevalence and severity of infection and high mortality rates, there is increasing evidence for an independent role for micronutrient deficiency. Improving vitamin A status reduces mortality among older infants and young children and reduces pregnancy-related mortality; it also reduces the prevalence of severe illness and clinic attendance among children. Improving Zn status reduces morbidity from diarrhoeal and respiratory infection. Treatment of established infection with vitamin A is effective in measles-associated complications, but is not as useful in the majority of diarrhoeal or respiratory syndromes. Zn supplements, however, have significant benefit on the clinical outcome of diarrhoeal and respiratory infections. Concerns that Fe supplements might increase morbidity if given in malarious populations appear to be decreasing, in the light of new studies on Fe supplements showing improved haemoglobin without an increase in morbidity. Breast-feeding, well known to protect against diarrhoea, is also important in protecting against respiratory infection, especially in the young infant. Transmission of human immunodeficiency virus (HIV) in breast milk is recognized, but new data showing reduced transmission in infants who receive exclusive breast-feeding rather than mixed feeding reinforces the importance of promoting this practice in areas where environmental contamination precludes the safe use of other infant feeding regimens. The presence of subclinical mastitis, now recognized to occur in approximately 20 % of mothers in several developing countries, has been shown to increase the concentration of HIV in breast milk. Preliminary findings suggest that the prevalence of subclinical mastitis is reduced by dietary supplements containing antioxidants. Governments and international agencies now have a strong scientific basis to be much more active and innovative in the introduction of focused nutrition interventions especially micronutrients, for the control of infection.

Reduced fertility associated with HIV: the contribution of pre-existing subfertility

BACKGROUND

HIV-1 infection is associated with lower fertility among women in sub-Saharan Africa and this association is not explained by the frequency of sexual intercourse, illness, knowledge of HIV status or infection with other sexually transmitted diseases. Women with fertility problems are at increased risk of marital instability and, therefore, HIV infection; consequently, pre-existing subfertility among HIV-infected women may contribute to the association.

OBJECTIVE

This study examines the relationship between HIV-1 infection and the incidence of recognised pregnancy and the role of low gravidity prior to seroconversion in rural Uganda.

METHODS

A group of 176 women (80 HIV infected and 96 uninfected) were enrolled into an HIV-1 natural history cohort and invited to attend 3-monthly clinic appointments. Data from clinic visits were analysed to assess the independent effects of HIV infection and age, lactation, illness, reported frequency of sexual intercourse and sexually transmitted diseases (STD) on the risk of pregnancy in the following 3 months. The number of previous pregnancies was recorded at enrolment, and the effect of gravidity was examined for the subgroup of women who were uninfected at enrolment or who enrolled within 2 years of their estimated seroconversion date.

RESULTS

During follow-up, 124 pregnancies were observed in 83 women beginning in the 3 months following 47 (7.0%) of 669 visits made by HIV-infected women and 77 (9.5%) of 812 visits by HIV-negative women (P = 0.12). Adjusting for age, lactation, illness, STD and the reported frequency of sexual intercourse, the estimated reduction in the risk of pregnancy associated with HIV infection was 47% [95% confidence interval (CI) 18-66]. Pre-existing low gravidity was strongly associated with a reduced incidence of pregnancy (odds ratio 0.39; CI 0.19-0.81). Additionally, adjusting for low gravidity reduced the estimate of the effect of HIV infection by almost a half, to 25% (95% CI-57-29).

CONCLUSION

Low gravidity prior to seroconversion accounts for almost 50% of the observed association between HIV infection and lowered incidence of pregnancy, after adjusting for age, lactation, illness, STD and the frequency of sexual intercourse.