Genitourinary tract infections in pregnancy and low birth weight: case-control study in Australian aboriginal women

Maternal Infection during Pregnancy and Attention-Deficit Hyperactivity Disorder in Children: A Systematic Review and Meta-Analysis

Background

We aimed to determine the association between maternal infections during pregnancy with risk of Attention-Deficit Hyperactivity Disorder (ADHD) in children.

Methods

A systematic literature search was performed utilizing the online databases PubMed, Scopus, and Web of Sciences up to July 2020. Random-effects meta-analyses were applied to estimate pooled relative risk (RR). Heterogeneity, study quality and publication bias were assessed through I² value, Newcastle-Ottawa scale (NOS) and Egger's test, respectively.

Results

Thirteen articles involving 1401904 mother-child pairs were included. The result of meta-analysis showed that the risk of ADHD increased by 30% among children whose mothers took any infections during pregnancy (pooled RR=1.30, 95% CI: 1.14-1.49; I²=85.5, P<0.001). Overall, the included studies were good in quality and no publication bias was found (P=0.23, Egger's test).

Conclusion

Maternal infections during pregnancy might be associated with an increased risk of ADHD in children.

Sexually transmitted infections and preterm birth among Indigenous women of the Northern Territory, Australia: A case-control study

BACKGROUND

The incidence of both sexually transmitted infection (STI) and preterm birth is high among Indigenous women in the Northern Territory, Australia. It was hypothesised that these factors are linked.

AIMS

To analyse whether antenatal STI is associated with preterm birth among Northern Territory Indigenous women.

MATERIALS AND METHODS

A retrospective case-control study was conducted at a tertiary maternity hospital in the Northern Territory. Rates of STI among pregnant Indigenous women were compared between cases (singleton births at <37 weeks gestation) and controls (singleton births at 37 or greater weeks gestation). The association between the composite of any STI (chlamydia, gonorrhoea, trichomonas or syphilis) and preterm birth was evaluated by logistic regression analysis, adjusting for confounders. Secondary endpoints were the associations between each of these infections and preterm birth.

RESULTS

There were 380 cases and 380 controls. Diagnosis of any sexually transmitted infection (composite) in pregnancy was not associated with preterm birth (adjusted odds ratio (aOR) 0.9, 95%CI 0.58-1.39). Women were at increased risk of preterm birth if they had gonorrhoea in pregnancy (aOR 2.92, 95%CI 1.07-7.97); there was no association with chlamydia (aOR 1.38, 95%CI 0.63-3.04) or trichomonas (aOR 0.66, 95%CI 0.39-1.12). There were three syphilis diagnoses among controls and none among cases.

CONCLUSIONS

Sexually transmitted infection (considered overall) in pregnancy did not affect preterm birth risk among Northern Territory Indigenous women. An association with preterm birth was observed for gonorrhoea in pregnancy but not with chlamydia, trichomonas or syphilis.

Asymptomatic urinary tract infection among pregnant women attending the antenatal clinic of Hawassa Referral Hospital, Southern Ethiopia

Background

Untreated asymptomatic bacteriuria (ASB) during pregnancy may cause serious complications including pyelonephritis and delivery of premature or low-birth-weight infants. However, little is known about asymptomatic bacteriuria in pregnancy in Ethiopia. This study aimed to assess the prevalence of asymptomatic bacteriuria, bacterial agents, and their antibiotic susceptibility pattern in pregnant women attending antenatal clinic of the Hawassa Teaching and Referral Hospital.

Methods

A cross-sectional study was conducted in a total of 244 pregnant women with no sign and symptom of urinary tract infection from March 2012 to September 2012. Clean catch mid-stream urine samples were collected from all study participants using sterile containers. Urine samples were cultured using standard bacteriological methods. Identification of suspected colonies and antibiotic sensitivity testing were done.

Result

Out of 244 pregnant women, 46(18.8%) were positive for asymptomatic bacteriuria (Colony Forming Unit ≥ 10⁵/mL). There was no difference in prevalence of asymptomatic bacteriuria with respect to age (p = 0.07) and trimester (p = 0.27).The most frequently isolated bacteria were coagulase negative Staphylococcus (32.6%), followed by Escherichia coli (26.1%), and Staphylococcus auerus (13%). The susceptibility rate of bacterial isolate was highest for norfloxacin (64.7%) and lowest for ampicillin (17.6%).

Conclusion

The high prevalence of ASB in pregnant women warrant the need to screen all pregnant women and treat those infected with appropriate antimicrobial regimens in order to reduce its complications.

Microbiological characteristics and inflammatory cytokines associated with preterm labor

PURPOSE

To evaluate vaginal microflora and interleukin-1β (IL-β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) concentrations in the cervicovaginal fluid of a group of pregnant women in preterm labor when compared with a group of full-term pregnant women not yet in labor.

METHOD

Case-control study performed in a University tertiary referral maternity in Campinas, Brazil with 45 pregnant women in preterm labor and 45 full-term pregnant women not in labor. All patients underwent speculum examination for the collection of cervicovaginal fluid. Bacterial vaginosis (BV) was diagnosed according to the criteria of Amsel and Nugent. Culture was performed for group B streptococcus (GBS) and lactobacilli, and hybrid capture assay for screening for chlamydial and gonococcal infection. Cytokine concentrations were measured using ELISA technique. Statistical analysis was performed using χ(2), Fisher's exact, and crude and adjusted odds ratios. Significance level was defined at 5%. The main outcome measures were cervicovaginal cytokines in preterm labor.

RESULTS

IL-6 and IL-8 were significantly associated with preterm labor. The changes in vaginal microflora, as well as BV and GBS, were more frequent in women in preterm labor, although BV and GBS showed no statistical significance. The presence of Candida sp., absence of lactobacilli, positive screening for chlamydial and gonococcal infection and the presence of IL-1β and TNF-α were not associated with preterm labor.

CONCLUSIONS

IL-6 and IL-8 and the presence of any type of vaginal infection were the factors that were significantly associated with preterm labor.

Bibbulung Gnarneep ('solid kid'): causal pathways to poor birth outcomes in an urban Aboriginal birth cohort

AIM

To explore the causal pathways leading to poor birth outcomes among a cohort of Aboriginal infants.

METHODS

A cross-sectional study was conducted. Data were collected via face-to-face interviews conducted 6-12 weeks post partum and links to the WA Midwives' Notification System. Two hundred and seventy-three Aboriginal infants and their families from Perth, Western Australia were recruited in the mid to late 1990s.

RESULTS

Poor birth outcome was defined as low birth weight and/or preterm birth. Criteria for poor birth outcome were met by 12.3% of the cohort. A history of maternal hypertension, vaginal bleeding and consumption of excess spirits in pregnancy were independent predictors of poor birth outcome. Mother being raised on a mission, maternal education, smoking during pregnancy and being exposed to passive smoke during pregnancy were also important risk factors.

CONCLUSIONS

Results indicate that maternal social exposures, maternal ill-health before the index pregnancy and maternal ill-health during the index pregnancy are all important contributors to poor birth outcomes for urban Aboriginal infants. While the causes of poor birth outcomes are complex, the current study highlights several areas where preventive measures may be useful.

Risk factors for preterm, low birth weight and small for gestational age birth in urban Aboriginal and Torres Strait Islander women in Townsville

OBJECTIVES

To assess the characteristics of Indigenous births and to examine the risk factors for preterm (<37 weeks), low birth weight (<2,500 g) and small for gestational age (SGA) births in a remote urban setting.

DESIGN

Prospective cohort of singleton births to women attending Townsville Aboriginal and Islander Health Services (TAIHS) for shared antenatal care between 1 January 2000 and 31 December 2003.

MAIN OUTCOME MEASURES

Demographic, obstetric, and antenatal care characteristics are described. Risk factors for preterm birth, low birth weight and SGA births are assessed.

RESULTS

The mean age of the mothers was 25.0 years (95% CI 24.5-25.5), 15.8% reported hazardous or harmful alcohol use, 15.1% domestic violence, 30% had an inter-pregnancy interval of less than 12 months and 9.2% an unwanted pregnancy. The prevalence of infection was 50.2%. Predictors of preterm birth were a previous preterm birth, low body mass index (BMI) and inadequate antenatal care, with the subgroup at greatest risk of preterm birth being women with a previous preterm birth and infection in the current pregnancy. Predictors of a low birth weight birth were a previous stillbirth, low BMI and an interaction of urine infection and non-Townsville residence; predictors of an SGA birth were tobacco use, pregnancy-induced hypertension and interaction of urine infection and harmful alcohol use.

CONCLUSION

The prevalence of demographic and clinical risk factors is high in this group of urban Indigenous women. Strategies addressing potentially modifiable risk factors should be an important focus of antenatal care delivery to Indigenous women and may represent an opportunity to improve perinatal outcome in Indigenous communities in Australia.

Maternal urinary tract infection alters water maze performance in the offspring

The effects of maternal urinary tract infection (UTI) or endotoxin exposure on fetal outcome in rats were investigated. Prior to conception, dams of the UTI group were water-deprived and anesthetized. The urinary tract was then catheterized and injected with 0.2 of 1 x 10(9) Escherichia coli. The endotoxin group was injected with 0.03 mg/kg lipopolysaccharide on the fourth day of gestation and then every third day thereafter. The control groups were treated in the same manner, with the exception that the infection control was not catheterized or injected with E. coli, and the endotoxin control was not exposed to lipopolysaccharide. A nontreated control group was weighed daily. Beginning on postnatal day (PD) 19, offspring were tested daily in a water maze spatial navigation task. The retention latencies (Sessions 7--10) revealed deficits in the infection and endotoxin groups. In the rat model, these findings suggest that exposure during gestation to a maternal immune challenge may result in adverse fetal outcome.

Experimental gestational pyelonephritis induces preterm births and low birth weights in C3H/HeJ mice

Urinary tract infections (UTIs) are associated with approximately 27% of premature births. Escherichia coli is the most frequent causal agent of UTIs and expresses virulence factors, including surface adhesins that recognize specific host tissue receptors. We have reported that E. coli Dr adhesin recognizes decay-accelerating factor as the host tissue receptor and that these receptors are increased during pregnancy. Induction of pathogenesis is a cumulative effect of the host-pathogen relationship involving specific host factors and virulence characteristics of the invading organism. Recently, an experimental model of chronic pyelonephritis has been developed with E. coli bearing Dr adhesin (E. coli Dr(+)) in nonpregnant lipopolysaccharide hyporesponder C3H/HeJ mice. In this study, we investigated the role of E. coli Dr(+) on the outcome of pregnancy in C3H/HeJ mice. Groups of pregnant mice were infected with E. coli Dr(+) or its isogenic mutant which does not bear the Dr adhesin (E. coli Dr(-)) by urethral catheterization. Nearly 90% of pregnant mice infected with E. coli Dr(+) delivered preterm (before 90% gestation) compared to 10% of mice infected with E. coli Dr(-) and none of the mice treated with phosphate-buffered saline (PBS). Also, there was a significant reduction in fetal birth weight in the E. coli Dr(+)-infected group compared to the E. coli Dr(-)- and PBS-treated groups (P = 0.003). This experimental model of E. coli Dr(+)-induced preterm delivery in mice may help in understanding the molecular mechanisms involved in UTI-induced preterm labor involving bacterial adhesins.

Risk factors for aboriginal low birthweight, intrauterine growth retardation and preterm birth in the Darwin Health Region

Risk factors for Aboriginal low birthweight (< 2500 g), preterm birth (< 37 weeks' gestation) and intrauterine growth retardation (under the tenth percentile of Australian birthweights for gestational age) were examined in 503 live-born singletons recorded as born to an Aboriginal mother and routinely delivered at the Royal Darwin Hospital between January 1987 and March 1990. Infants born to mothers with body mass index less than 18.5 kg/m2 had five times the risk of having low birthweight and 2.5 times the risk of intrauterine growth retardation. Population-attributable risk percentages suggest that 28 per cent of low birthweight and 15 per cent of growth retardation could be attributed to maternal malnutrition. Risk percentages for maternal smoking of more than half a packet of cigarettes a day were 18 per cent for low birthweight and 10 per cent for growth retardation. For growth retardation, 18 per cent could be attributed to a maternal age under 20 years. Risk factors for preterm birth were predominantly obstetric: the population-attributable risk percentage for pregnancy-induced hypertension was 26 per cent and for other obstetric conditions was 16 per cent. For Aboriginal births in the Darwin Health Region, maternal malnutrition and smoking are key elements in the prevention of low birthweight and intrauterine growth retardation. Teenage pregnancy is an important risk for intrauterine growth retardation, and pregnancy-induced hypertension is a risk for preterm birth.

Bacteriuria in pregnancy: a comparison of Bangladeshi and Caucasian women

During a 5-year period all urine culture results from pregnant Caucasian and Bangladeshi women booked for confinement at the Royal London Hospital, London, UK, were reviewed to determine race-specific rates of bacteriuria. The results showed that the overall prevalence of bacteriuria in the Caucasian group was 6.3% compared to 2.0% for the Bangladeshi women. Caucasian women were found to be at significantly greater risk across all pregnancy outcome and history categories, with the greatest risk observed in grand multiparous women (RR: 4.7, 95% CI: 2.8-8.3). Pregnancies that resulted in preterm delivery showed a strong association of bacteriuria in Caucasian women which was not seen in the Bangladeshi women (RR: 4.4, 95% CI: 2.0-8.7). The data suggest that Caucasian women have a significantly higher prevalence of bacteriuria in pregnancy than their Bangladeshi neighbors. Differences in hygiene practices and clothing may explain the observed differences in the bacteriuria rates.

Gestational pyelonephritis--associated Escherichia coli isolates represent a nonrandom, closely related population

OBJECTIVE

A select group of Escherichia coli strains known as uropathogenic cause pyelonephritis in nonpregnant individuals. We investigated whether Escherichia coli from gestational pyelonephritis represent a random population or possess common uropathogenic characteristics.

STUDY DESIGN

Repetitive element sequence-based polymerase chain reaction, plasmid profiles, hemolysin, and O serotypes were assayed from Escherichia coli isolates of 57 pregnant patients with acute pyelonephritis at different gestational ages.

RESULTS

The majority of the first trimester isolates fell primarily into repetitive element sequence-based patterns 1 and 3 and O6, O15, and O75 serotypes. Second-trimester isolates had multiple patterns with high-frequency repetitive element sequence-based polymerase chain reaction 1 and 5 and an unknown (OX) serotype. Pattern 3, predominantly O75 serotype, was found primarily among third-trimester isolates.

CONCLUSION

It is likely that Escherichia coli associated with acute pyelonephritis during different trimesters of pregnancy represents nonrandom closely related isolates, and some of these strains may be characteristic in pregnant patients only.

Perinatal mortality trends among South Australian aboriginal births 1981-92

OBJECTIVE

To assess changes in perinatal mortality and risk factors for births to Aboriginal mothers in South Australia in 1981-92.

METHODOLOGY

All 4013 singleton Aboriginal births in the South Australian perinatal data collection were included. Trends in proportions with specific maternal and infant characteristics, and perinatal mortality by year of birth, were investigated by logistic regression analysis.

RESULTS

Changes found included an increase in the proportion of mothers aged 35 years and over, preterm births and births of very low birthweight (< 1500 g), but a decrease in the proportions of births to women under 20 years of age, and of births with a birth defect. There was no statistically significant change in the crude perinatal mortality rate nor in the risk of perinatal death after adjusting for risk factors.

CONCLUSIONS

The perinatal mortality rate among Aboriginal births, which is three times higher than the rate for all South Australian births, is not declining, in contrast to the State rate overall. This highlights the need for a concerted approach to Aboriginal perinatal health.

Early-onset group B streptococcal infections in Aboriginal and non-Aboriginal infants. Australasian Study Group for Neonatal Infections

OBJECTIVES

To survey early-onset neonatal infections in Australian and New Zealand neonatal units and to compare the incidence of group B streptococcal (GBS) sepsis among Aboriginal and non-Aboriginal babies.

DESIGN

Second year of an ongoing longitudinal, prospective study.

SETTING

Nine Australian units and one New Zealand unit with level 3 neonatal care and one Australian unit with level 2 care, between October 1992 and September 1993 inclusive.

OUTCOME MEASURES

Episodes of early-onset sepsis (within 48 hours of birth), causative organisms, mortality, birthweight and gestational age.

SUBJECTS

Babies in the neonatal units with early-onset systemic sepsis, either born in attached maternity hospitals or referred.

RESULTS

In the Australian units there were 100 episodes of early-onset sepsis (incidence among babies born in attached maternity hospitals of 2.9 per 1000 live births). GBS was the commonest infecting agent (70% of cases) and caused all 12 cases of early-onset meningitis. The mortality from early-onset sepsis was 10%. The incidence of GBS sepsis was 1.7 per 1000 live births in non-Aboriginal babies and 5.2 per 1000 in Aboriginal babies (odds ratio, 3.1; 95% confidence interval, 1.4-6.6).

CONCLUSIONS

Early-onset GBS sepsis is more than three times as common in Aboriginal babies delivered in hospital than in non-Aboriginal babies. Four of seven Australian maternity hospitals surveyed had no firm policy for reducing the incidence of early-onset GBS sepsis. All should urgently consider such a policy.

Obstetric outcome of Bangladeshi women in east London

OBJECTIVE

To study the obstetric outcome of women of Bangladeshi origin in comparison with the white caucasian population in East London.

DESIGN

A retrospective study of 16718 pregnancies over a five year period (1987-1991).

SETTING

An East London teaching hospital district.

SUBJECTS

Six thousand four hundred and sixty Bangladeshi women compared with 7592 white caucasian women.

MAIN OUTCOME MEASURES

Maternal: antenatal complications; induction and augmentation rates; analgesia and anaesthesia; instrumental delivery and caesarean section rates; third stage complications. Fetal: gestation and weight at birth; perinatal mortality rates.

RESULTS

The following statistically significant findings were noted: Bangladeshi women had a longer reproductive age span and were of greater parity including grand multiparity. They suffered fewer antenatal complications except for gestational diabetes. They had lower induction rates and, among the parous group, lower augmentation rates. During labour they required less analgesia but more commonly had general anaesthesia for caesarean section deliveries. They required instrumental delivery less often but there was no difference in overall caesarean section rate for the two groups. However, overall Bangladeshi women had a lower elective caesarean section rate, although parous Bangladeshi women had a higher emergency section rate. In the third stage there were no differences in the complication rates for the nulliparous women, however the parous Bangladeshi women had a higher postpartum haemorrhage rate and a lower perineal repair rate consistent with their higher parity. Whilst preterm births were more common in Bangladeshi women, significant prematurity (less than 28 weeks gestation) was less common. Similarly, although Bangladeshi babies weighed less at birth, they had fewer babies weighing less than 1500 grammes. There was no statistically significant difference in the perinatal mortality rate between the two groups, being 8.1 per thousand births overall. Whilst there was a statistically insignificant decline in death rates over the five-year period, between the groups there was no consistent difference.

CONCLUSION

Pregnant Bangladeshi women in East London constitute a relatively high parity, low risk population who have less obstetric intervention and yet manage an equivalent (or better) perinatal outcome compared to their white caucasian neighbours.

A multicentre study of perinatal mortality in Nepal

A prospective survey was carried out in two Kathmandu hospitals and two rural districts to establish urban and rural perinatal mortality rates (PNMRs) for these four centres in Nepal and to ascertain the causes of perinatal mortality. All perinatal deaths occurring over a 1-year period in the four centres were included (during which time there was a total of 14,967 births). Cause of death was established by contemporary review of hospital case records or by structured questionnaire ('verbal autopsy') in the rural areas. The PNMRs in the hospitals were 48.0 and 23.7 per thousand total births respectively, whilst those of the rural settings were 96.2 and 42.5 per thousand births. Perinatal asphyxia, low birthweight and infection were the most common causes but many of the deaths were unexplained. The high mortality rates were felt to reflect the difficult circumstances of childbirth in Nepal. It was concluded that a number of interventions would appear appropriate, but that these should be introduced in a scientific manner.

A population database for maternal and child health research in Western Australia using record linkage

This paper describes a linked total population database established in Western Australia for monitoring and evaluating maternal and child health and for conducting epidemiological studies. Good vital statistics data including all Western Australian hospitalisations and excellent birth defects and cerebral palsy registers have ensured that complete data are available. Examples of studies which have been conducted using the database are given.

Reagent strip testing of antenatal urine specimens for infection

OBJECTIVE

To compare reagent strip testing (RST) with microscopy and culture in identifying significant bacteriuria, and secondly, to consider potential cost savings if RST screening proved to be reliable.

DESIGN

Prospective descriptive study.

SETTING

Antenatal Clinic, Bristol Maternity Hospital.

SUBJECTS

Eight hundred and ninety-eight women having urine testing in pregnancy for microscopy and culture either routinely or because of a clinical infection.

INTERVENTIONS

The midstream specimens of urine had RST examination using Ames Multistix 8SG prior to being sent to the laboratory.

MAIN OUTCOME MEASURE

Significant culture (> 10(5) colonies/ml) of a single organism in culture.

RESULTS

The highest predictive value for a negative result of the urine culture (99.7%) was obtained when using four RSTs in combination. The RST for nitrite had a high predictive value for a positive urine culture (90%). The samples which gave a false negative result with RST screening were mainly infected with low grade urinary pathogens or genital tract contaminants.

CONCLUSION

RST screening for bacteriuria provides a reliable and cheap alternative to culture of all urine specimens.

Health gains from screening for infection of the lower genital tract in women attending for termination of pregnancy

Infection of the upper genital tract after abortion is well recognised, but routine screening for infection before termination is rare, and few centres are aware of the prevalence of post-abortion complications in their population. We undertook a study to assess the prevalence and sequelae of genital-tract infection in patients undergoing termination of pregnancy and to estimate the costs and potential benefits of introducing screening and prophylaxis for the most commonly found organisms. The study in Swansea, UK, was of 401 consecutive patients attending for termination of pregnancy; only 1 patient refused to take part. Immediately before the termination procedure vaginal and cervical swabs were taken for microscopic examination and culture of Trichomonas vaginalis, Neisseria gonorrhoeae, and candida species. We sought Chlamydia trachomatis by enzyme-linked immunosorbent assay. 112 (28%) women had the typical bacterial flora of anaerobic (bacterial) vaginosis, 95 (24%) had candidal infection, 32 (8%) chlamydial infection, 3 (0.75%) trichomonas infection, and 1 (0.25%) gonorrhoea. Postoperative follow-up of 30 of the women with chlamydial infection showed that pelvic infection developed in 19 (63%), of whom 7 were readmitted to hospital. 9 male partners of women with chlamydial (plus gonococcal in 1 case) infection were examined; 8 were symptom-free, 3 had C trachomatis infection, and 1 N gonorrhoeae. Estimated costs of hospital admissions for complications of chlamydial infection were more than double the costs of providing a routine chlamydia screening programme and prophylactic treatment. Screening for chlamydial infection before termination of pregnancy is essential. Prophylactic treatment for both chlamydial infection and anaerobic vaginosis should also be considered. Male partners of women infected with chlamydia are often symptom-free, but they must be traced to avoid reinfections.

Pharmacoeconomics of antibacterial treatment

Antibacterial drugs account for between 3 and 25% of all prescriptions, between 6 and 21% of the total market value of drugs in a single country, and up to 50% of the drug budget in hospitals. Bacterial infection is widely perceived as disease caused by harmful outside agents which can be isolated and tested to select the best drug for treatment. In fact, the need for any treatment and the pros and cons of different drugs are just as debatable as in any other therapeutic area. Moreover, the bacteria which make up the normal flora of the body fulfil important roles, so that the ecological implications of treatment for the individual and for society should be considered in assessing the costs and consequences of antibacterial treatment. In this review we outline the most important issues relating to the treatment of bacterial infection in the community and in the hospital, contrasting information from developed and developing countries where appropriate. We review the existing literature on economic evaluation, but in general most of the literature deals with containing the costs of antibacterial drugs in hospitals, and there are many gaps in the literature on cost-effectiveness of treatment. Consequently there are still extreme variations in medical practice which present a challenge for future evaluation. As the outcomes of antibacterial treatment are apparent in a few weeks or months, this is an ideal field for testing pharmacoeconomic methodology. The desire to overcome medical practice variation through consensus statements should be avoided. Instead we recommend wider application of decision analysis to acknowledge that choices exist for the diagnosis and treatment of bacterial infection and to gather information about the implications of these choices. Much of the existing literature would be improved by a more explicit definition of costs. Direct costs to the health services should be distinguished from non medical costs. Moreover, the analysis should consider whether savings from one budget result in costs to another health service budget, or to the patient (transfer costs). These deficiencies in cost analysis will be relatively easy to correct. Of more concern is the fact that the efficacy of much antibacterial treatment is either totally debatable, or variable, depending on factors such as the type of patient treated or the quality of delivery of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk factors for mother-to-child transmission of HIV-1

Children born to women known to be infected with human immunodeficiency virus type 1 (HIV-1) before delivery were followed prospectively from birth in nineteen European centres. This analysis, encompassing the period end-December, 1984, to beginning-August, 1991, focuses on risk factors for mother-to-child transmission of HIV-1 infection. Rate of vertical transmission, based on 721 children born to 701 mothers more than 18 months before the time of analysis, was 14.4% (95% Cl 12.0-17.1%). Transmission was associated with maternal p24-antigenaemia and a CD4 count of less than 700/microliters. In a multivariate analysis, odds ratios of transmission were: 2.25 (95% Cl 0.97-5.23) in breastfed children vs never-breastfed children; 3.80 (1.62-8.91) in children born before 34 weeks' gestation; and 0.56 (0.30-1.04) in children delivered by caesarean section. Transmission was higher with vaginal deliveries in which episiotomy, scalp electrodes, forceps, or vacuum extractors were used, but only in centres where these procedures were not routine. On the basis of these results, HIV-infected women contemplating pregnancy should be counselled according to their immunological findings and, if they have p24-antigenaemia or a low CD4 count, warned of an increased risk of viral transmission. Caesarean deliveries may have a protective effect, although it is premature to recommend routine operative delivery. The mechanism for the higher infection rate in children born before 34 weeks' gestation is unclear, but could reflect inadequate passive or active immunity at that age, combined with substantial transmission during labour or delivery. The balance of evidence suggests that mothers with established infection can transmit HIV infection through breastmilk, although the relative importance of this route remains to be defined.