The relationship of HIV prevalence in pregnant women to that in women of reproductive age: a validated method for adjustment

Sexual behavior and job stress in software professionals, Bengaluru - India

Background:

Sexually transmitted diseases are now gradually affecting the general population groups increasingly. Our earlier observations from qualitative research called for an effort to understand the sexual exposure, activity and behavior of the workers in these software professionals in Bengaluru, India.

Aim:

The current study is explored to understand the association of the sexual behaviors with Job.

Materials and Methods:

The study design employed was a cross-sectional study using a mixed sampling method. A total of 1071 subjects from software sector in Bengaluru, the capital city of Karnataka completed the self-administered questionnaire. The source population comprised all information technology/information technology enabled services (IT/ITES) professionals aged 20-59 years working in “technical functions” in 21 selected worksites (units) of the software industry. The exposure of interest was job stressors and the outcome measures were sexual behaviors in the form of having multiple sexual partners, paid sex in last 3 months and frequency of intercourse with irregular sexual partners and condom use with regular partners during last sexual act.

Results:

Among the study population, 74.3% reported not using a condom during their last vaginal intercourse with their regular partner. Regression estimates indicated that workers with high physical stressors had 6 times odds of having paid for sex in last 3 months and those with a moderate level of income related stress had 2.4 times likelihood of not using a condom during the last sexual intercourse with their regular partner.

Conclusion:

There is scope for starting prevention programs among young professionals in the IT/ITES sector to mitigate their possible risk behaviors.

Extrapolating respiratory tract infection incidences to a rural area of Ghana using a probability model for hospital attendance

OBJECTIVE

The aim of the current study was to extrapolate incidences for respiratory tract infections (RTI) using referral data from a local hospital in Ghana weighted by the individual likelihood of a hospital visit.

METHODS

Diagnoses from children visiting a rural hospital in Ghana during August 2007 to September 2008 were recorded. A logistic regression model, based on a population study conducted within the hospital catchment area, was used to calculate the individual probability of clinic attendance and to extrapolate the number of recorded cases. Cumulative incidences for children living in the hospital catchment area were estimated.

RESULTS

Upper RTI was the most common respiratory diagnosis, with an extrapolated incidence of 17481 cases per 100000 per year, followed by pneumonia with an incidence of 2496 per 100 000 per year. All diseases analyzed were most common in the first year of life.

CONCLUSIONS

In general the study results are in line with comparable studies. Several methodological issues biasing the results in different directions were identified. For example, opportunistic infections that are more often observed in hospital attendees are likely to be overestimated. However, the applied approach presents a tool for areas where disease monitoring systems are not established.

Impact of targeted interventions on heterosexual transmission of HIV in India

Background

Targeted interventions (TIs) have been a major strategy for HIV prevention in India. We evaluated the impact of TIs on HIV prevalence in high HIV prevalence southern states (Tamil Nadu, Karnataka, Andhra Pradesh and Maharashtra).

Methods

A quasi-experimental approach was used to retrospectively compare changes in HIV prevalence according to the intensity of targeted intervention implementation. Condom gap (number of condoms required minus condoms supplied by TIs) was used as an indicator of TI intensity. Annual average number of commercial sex acts per female sex worker (FSW) reported in Behavioral Surveillance Survey was multiplied by the estimated number of FSWs in each district to calculate annual requirement of condoms in the district. Data of condoms supplied by TIs from 1995 to 2008 was obtained from program records. Districts in each state were ranked into quartiles based on the TI intensity. Primary data of HIV Sentinel Surveillance was analyzed to calculate HIV prevalence reductions in each successive year taking 2001 as reference year according to the quartiles of TI intensity districts using generalized linear model with logit link and binomial distribution after adjusting for age, education, and place of residence (urban or rural).

Results

In the high HIV prevalence southern states, the number of TI projects for FSWs increased from 5 to 310 between 1995 and 2008. In high TI intensity quartile districts (n = 30), 186 condoms per FSW/year were distributed through TIs as compared to 45 condoms/FSW/year in the low TI intensity districts (n = 29). Behavioral surveillance indicated significant rise in condom use from 2001 to 2009. Among FSWs consistent condom use with last paying clients increased from 58.6% to 83.7% (p < 0.001), and among men of reproductive age, the condom use during sex with non-regular partner increased from 51.7% to 68.6% (p < 0.001). A significant decline in HIV and syphilis prevalence has occurred in high prevalence southern states among FSWs and young antenatal women. Among young (15-24 years) antenatal clinic attendees significant decline was observed in HIV prevalence from 2001 to 2008 (OR = 0.42, 95% CI 0.28-0.62) in high TI intensity districts whereas in low TI intensity districts the change was not significant (OR = 1.01, 95% CI 0.67-1.5).

Conclusion

Targeted interventions are associated with HIV prevalence decline.

Comparison of HIV-1 prevalence and risk factors between pregnant, non-pregnant, all women and the general population in Tanzania: implications for second-generation surveillance

The aim of this study was to compare HIV-1 prevalence between pregnant, non-pregnant, all women and the general population (men and women) and investigate how well risk behaviours of pregnant women reflect those of all women in the general population in rural Kilimanjaro, Tanzania. A cross-sectional survey involving all individuals aged 15-44 years was conducted in Oria village between March and May of 2005. All consenting individuals were interviewed and offered HIV-1 and syphilis testing. The response proportion among women was found to be 73.7% (914/1241). Age-adjusted HIV-1 prevalence among pregnant women (n = 92) was 32.5% lower (5.4% versus 8.0%, P < 0.001) than that of all women but only 8.5% (5.4% versus 5.9%, P = 0.639) lower compared with that of the general population. HIV-1 risk factors among pregnant women were comparable to that of all women in the general population. In conclusion, pregnant women in the general population underestimate the HIV-1 magnitude among women but closely approximate that of the general population. HIV-1 risk factors are similar between pregnant and all women in the general population. Second-generation surveillance could utilize pregnant women risk behaviours to approximate that of all women in the general population.

Refusal bias in HIV prevalence estimates from nationally representative seroprevalence surveys

OBJECTIVES

To assess the relationship between prior knowledge of one's HIV status and the likelihood to refuse HIV testing in populations-based surveys and explore its potential for producing bias in HIV prevalence estimates.

METHODS

Using longitudinal survey data from Malawi, we estimate the relationship between prior knowledge of HIV-positive status and subsequent refusal of an HIV test. We use that parameter to develop a heuristic model of refusal bias that is applied to six Demographic and Health Surveys, in which refusal by HIV status is not observed. The model only adjusts for refusal bias conditional on a completed interview.

RESULTS

Ecologically, HIV prevalence, prior testing rates and refusal for HIV testing are highly correlated. Malawian data further suggest that amongst individuals who know their status, HIV-positive individuals are 4.62 (95% confidence interval, 2.60-8.21) times more likely to refuse testing than HIV-negative ones. On the basis of that parameter and other inputs from the Demographic and Health Surveys, our model predicts downward bias in national HIV prevalence estimates ranging from 1.5% (95% confidence interval, 0.7-2.9) for Senegal to 13.3% (95% confidence interval, 7.2-19.6) for Malawi. In absolute terms, bias in HIV prevalence estimates is negligible for Senegal but 1.6 (95% confidence interval, 0.8-2.3) percentage points for Malawi. Downward bias is more severe in urban populations. Because refusal rates are higher in men, seroprevalence surveys also tend to overestimate the female-to-male ratio of infections.

CONCLUSION

Prior knowledge of HIV status informs decisions to participate in seroprevalence surveys. Informed refusals may produce bias in estimates of HIV prevalence and the sex ratio of infections.

Association between fertility and HIV status: what implications for HIV estimates?

BACKGROUND

Most estimates of HIV prevalence have been based on sentinel surveillance of pregnant women which may either under-estimate or over-estimate the actual prevalence in adult female population. One situation which can lead to either an underestimate or an overestimate of the actual HIV prevalence is where there is a significant difference in fertility rates between HIV-positive and HIV-negative women. Our aim was to compare the fertility rates of HIV-infected and HIV-uninfected women in Cameroon in order to make recommendations on the appropriate adjustments when using antenatal sentinel data to estimate HIV prevalence.

METHODS

Cross-sectional, population-based study using data from 4493 sexually active women aged 15 to 49 years who participated in the 2004 Cameroon Demographic and Health Survey.

RESULTS

In the rural area, the age-specific fertility rates in both HIV positive and HIV negative women increased from 15-19 years age bracket to a maximum at 20-24 years and then decreased monotonically till 35-49 years. Similar trends were observed in the urban area. The overall fertility rate for HIV positive women was 118.7 births per 1000 woman-years (95% Confidence Interval [CI] 98.4 to 142.0) compared to 171.3 births per 1000 woman-years (95% CI 164.5 to 178.2) for HIV negative women. The ratio of the fertility rate in HIV positive women to the fertility rate of HIV negative women (called the relative inclusion ratio) was 0.69 (95% CI 0.62 to 0.75).

CONCLUSION

Fertility rates are lower in HIV-positive than HIV-negative women in Cameroon. The findings of this study support the use of summary RIR for the adjustment of HIV prevalence (among adult female population) obtained from sentinel surveillance in antenatal clinics.

Estimating adult HIV prevalence in the UK in 2003: the direct method of estimation

BACKGROUND

Estimates of the total number of prevalent HIV infections attributable to the major routes of infection make an important contribution to public health policy, as they are used for planning services.

METHODS

In the UK, estimates were derived through the "direct method" which estimated the total number of diagnosed and undiagnosed HIV infections in the population. The direct method has been improved over a number of years since first used in 1994, as further data became available such as the inclusion of newly available behavioural survey data both from the National Survey of Sexual Attitudes and Lifestyles (Natsal 2000) and community surveys of men who have sex with men (MSM). These data were used to re-estimate numbers of people unaware of their infection and provided ethnic breakdowns within behavioural categories. The total population was divided into 10 mutually exclusive behavioural categories relevant to HIV risk in the UK-for example, MSM and injecting drug users. Estimates of the population size within each group were derived from Natsal 2000 and National Statistics mid-year population estimates. The total number of undiagnosed HIV infections was calculated by multiplying the undiagnosed HIV prevalence for each group, derived from the Unlinked Anonymous HIV Prevalence Monitoring Programme surveys (UAPMP), by the population size. These estimates were then added to the prevalent diagnosed HIV infections within each group derived from the national census of diagnosed HIV infections, the Survey of Prevalent HIV Infections Diagnosed (SOPHID). The estimates were then adjusted to include all adults in the UK. Because undiagnosed HIV prevalence estimates were not available for each of the behavioural categories, the UAPMP prevalence estimates were adjusted using available data to provide the best estimates for each group.

RESULTS

It is estimated that 53,000 individuals are infected with HIV in the UK in 2003, of whom 27% were unaware of their infection. Of the total of 53,000, an estimated 26,000 were among heterosexually infected and 24,500 among MSM.

CONCLUSION

The direct method uses an explicit framework and data from different components of the HIV surveillance system to estimate HIV prevalence in the UK, allowing for a comprehensive picture of the epidemic.

A high prevalence of HIV-1 infection among pregnant women living in a rural district of north Uganda severely affected by civil strife

This study aims at estimating the recent trends in HIV-1 prevalence and the factors associated with infection among pregnant women in the Gulu District of north Uganda, a rural area severely affected by civil strife. In 2000-2003, a total of 4459 antenatal clinic attendees of Lacor Hospital were anonymously tested for HIV-1 infection. The overall and age-specific prevalence did not show any significant trend over time. The age-standardized prevalence slightly declined, from 12.1% in 2000 to 11.3% in 2003. Increased age [20-24 years: adjusted odds ratio (AOR) 1.63; 95% CI 1.18-2.25; >or=25 years: AOR 2.56; 95% CI 1.91-3.44], residence in urban areas (AOR 1.76; 95% CI 1.41-2.18), being unmarried (AOR 1.60; 95% CI 1.27-2.01), increased age of partner (25-34 years: AOR 1.87; 95% CI 1.29-2.73; >or=35 years: AOR 2.68; 95% CI 1.72-4.16), modern occupation of partner (AOR 1.98; 95% CI 1.53-2.58), and short time of residence at the current address (AOR 1.36; 95% CI 1.05-1.76) were associated with infection. The HIV-1 prevalence in this rural district is high and similar to that observed in urban antenatal clinics, probably reflecting the effect of the last 18 years of civil strife.

Trends in HIV-1 in young adults in south India from 2000 to 2004: a prevalence study

BACKGROUND

Major increases in HIV-1 prevalence in India have been predicted. Incident infections need to be tracked to understand the epidemic's course, especially in some southern states of India where the epidemic is more advanced. To estimate incidence, we investigated the prevalence of HIV-1 in young people attending antenatal and sexually transmitted infection (STI) clinics in India.

METHODS

We analysed unlinked, anonymous HIV-1 prevalence data from 294 050 women attending 216 antenatal clinics and 58 790 men attending 132 STI clinics in 2000-04. Southern and northern states were analysed separately.

FINDINGS

The age-standardised HIV-1 prevalence in women aged 15-24 years in southern states fell from 1.7% to 1.1% in 2000-04 (relative reduction 35%; p(trend)<0.0001, yearly reduction 11%), but did not fall significantly in women aged 25-34 years. Reductions in women aged 15-24 years were seen in key demographic groups and were similar in sites tested continuously or in all sites. Prevalence in the north was about a fifth of that in the south, with no significant decreases (or increases) in 2000-04. Prevalence fell in men aged 20-29 years attending STI clinics in the south (p(trend)<0.0001), including those with ulcerative STIs (p(trend)=0.0008), but reductions were more modest in their northern counterparts.

INTERPRETATION

A reduction of more than a third in HIV-1 prevalence in 2000-04 in young women in south India seems realistic, and is not easily attributable to bias or to mortality. This fall is probably due to rising condom use by men and female sex workers in south India, and thus reduced transmission to wives. Expansion of peer-based condom and education programmes for sex workers remains a top priority to control HIV-1 in India.

HIV epidemic in Central African Republic: high prevalence rates in both rural and urban areas

A sentinel serosurveillance study was conducted in Central African Republic to estimate the prevalence of HIV seropositivity in the general adult population in each province so that the public health authorities can target HIV prevention programmes to the priority areas. Blood samples were collected from women attending 48 antenatal clinics in urban and rural areas of the Central African Republic. These samples were tested for HIV antibodies in an anonymous and unlinked manner using strategy II recommended by WHO. The data were extrapolated to all women of reproductive age in Central African Republic by use of a parity-based adjustment involving the application of correction factors to the observed prevalence rates. A total of 9,305 pregnant women were recruited from November 2001 to October 2002. HIV seroprevalence was high in all age groups (12% in the less than 20 year age group to 17% in the 25-29 year age group). The median prevalence of HIV in antenatal clinics was similar for rural areas, for Bangui and for other urban areas (16.5, 15.0, and 12.5% respectively). Adjustment for parity and fertility pattern increased the prevalence of HIV in all antenatal clinics except in Bangui. This first national study of HIV prevalence in Central African Republic revealed that the HIV epidemic is continuing to spread in both urban and rural areas. Thus, efforts to reduce transmission should be made in every part of the country.

HIV and population dynamics: a general model and maximum-likelihood standards for east Africa

In high-prevalence populations, the HIV epidemic undermines the validity of past empirical models and related demographic techniques. A parsimonious model of HIV and population dynamics is presented here and fit to 46,000 observations, gathered from 11 East African populations. The fitted model simulates HIV and population dynamics with standard demographic inputs and only two additional parameters for the onset and scale of the epidemic. The underestimation of the general prevalence of HIV in samples of pregnant women and the fertility impact of HIV are examples of the dynamic interactions that demographic models must reproduce and are shown here to increase over time even with constant prevalence levels. As a result, the impact of HIV on population growth appears to have been underestimated by current population projections that ignore this dynamic.

Evaluating two adjustment methods to extrapolate HIV prevalence from pregnant women to the general female population in sub-Saharan Africa

OBJECTIVE

To evaluate two methods for estimating HIV prevalence among the general female population of reproductive age by adjusting data observed among antenatal clinic (ANC) attendees.

METHODS

We adjusted the HIV prevalence among ANC attendees in Fort Portal (Uganda; 1994-1995), Mwanza municipality (Tanzania; 1990-1991), rural Mwanza (Tanzania; 1991-1993), Mposhi district (Zambia; 1994), Chelston (Lusaka, Zambia; 1994, 1996 and 1998) and Ndola (Zambia; 1998), using firstly a method that accounts for differences in age-specific fertility by HIV serostatus and secondly a method that accounts for differences in HIV prevalence by fertility risk category and parity.

RESULTS

The non-adjusted HIV prevalence among ANC attendees underestimates the prevalence among the general female population by 8.0% in Chelston in 1998 and by between 20.7% and 31.9% in all other cases. The adjusted prevalence obtained using the first method underestimates the prevalence among the general female population by about 0.5% in Fort Portal and Mposhi; it overestimates that observed in Chelston in 1994 and 1996 by about 3.5%, and that observed in Ndola, urban Mwanza and rural Mwanza, by 6.5%, 10.6% and 12.8%, respectively. The second method (applied for only four sites) provides an overestimate of 7.0% in Chelston in 1994 and an underestimate of 3.8% and 2.1% in Ndola and rural Mwanza, respectively. Both adjustment methods overestimate the 1998 prevalence in Chelston, producing less accurate estimates than the non-adjusted data.

CONCLUSIONS

The HIV prevalence among women in the general population could be estimated fairly accurately by these methods in settings with mature epidemics.

Comparison of HIV prevalences in community-based and antenatal clinic surveys in rural Mwanza, Tanzania

OBJECTIVES

First, to compare the prevalence of HIV infection among women in the general population and antenatal clinic (ANC) attenders in rural Mwanza, Tanzania, and second, to validate a method for adjusting HIV prevalence in ANC attenders to estimate the prevalence in the general female population aged 15-44 years.

METHODS

A cross-sectional population survey was conducted in 12 rural communities of Mwanza Region between 1991 and 1992. From the same communities sequential ANC attenders were recruited on two occasions between 1991 and 1993. Consenting subjects were interviewed, examined, treated and a serum sample was tested for HIV. The HIV prevalence in women in the general population was compared with unadjusted and adjusted prevalences in ANC attenders. Parity-adjusted prevalences were obtained by applying correction factors to the observed prevalences in parous and nulliparous ANC attenders.

RESULTS

A total of 5675 women aged 15-44 years from the general population and 2265 ANC attenders had complete socio-demographic and laboratory data. Unadjusted HIV prevalence was significantly lower in ANC attenders (3.6%) than women from the general population (4.7%, P = 0.025), but after adjustment there was no significant difference between the two groups (4.6 versus 4.7%, P = 0.95).

CONCLUSION

In this rural population, the HIV prevalence in ANC attenders underestimated the prevalence among women in the general population, but this difference was eliminated by applying parity-based correction factors. Information on parity should be routinely collected in ANC-based HIV sentinel surveillance.

Pregnancy and birth rates among HIV-infected women in the United States: the confounding effects of illicit drug use

OBJECTIVE

To determine the effect of HIV infection on pregnancy and birth rates and assess the potentially confounding effect of illicit drug use.

DESIGN

A retrospective record review of matched cohorts examining pregnancy outcomes for HIV-positive women and two HIV-negative comparison groups (one matched by drug use).

METHODS

Ninety HIV-positive women who gave birth in a US city between 1989 and 1993 were matched to HIV-negative women by race, age, parity and date of index birth (group 1, N = 180) and also by the type of illicit drug used (group 2, N = 90). Data were abstracted on tubal ligations and pregnancies occurring before April 1996.

RESULTS

A total of 63% of HIV-positive women used cocaine during the index pregnancy and 26% also used opiates. HIV-positive women had fewer tubal ligations than group 1 (38.9% versus 51.1%, P = 0.058), but there was no difference when matching included drug use (38.9% in group 2). HIV infection was associated with a decrease in the number of pregnancies; this decrease was most marked when matching included drug use (18.0 versus 32.1 pregnancies per 100 woman-years,P < 0.01). There were no significant differences in spontaneous or therapeutic terminations. Poisson regression analysis demonstrated that HIV infection and older age were associated with fewer pregnancies, and cocaine use with an increased pregnancy rate.

CONCLUSION

This study confirms that HIV infection is associated with a decrease in the number of pregnancies, but also illustrates the confounding effects of illicit drug use among women in the United States.

Reproductive behaviour of HIV-infected women living in France, according to geographical origin

Pregnancy rates were compared before and after HIV diagnosis according to geographical origin (sub-Saharan Africa versus Europe) among 533 HIV-infected women followed in the French SEROCO/SEROGEST cohorts between 1988 and 1996. Among European women, the incidence of deliveries and terminations decreased, respectively, by nearly twofold and fourfold after HIV diagnosis. Conversely, the pregnancy incidence increased among African women with fewer than two children. This study should help refine the reproductive counselling and management of HIV-infected women in France.

Trend in HIV-1 prevalence in an antenatal clinic in North Uganda and adjusted rates for the general female population

OBJECTIVES

To estimate HIV-1 prevalence among women attending an antenatal clinic in the Gulu District (North Uganda) and, based on these data, among the district's female population.

METHODS

Anonymous HIV-1 screening was performed for 8555 antenatal clinic attendees aged 15-39 years in the period 1993-1997. The results were used to estimate the prevalence among the district's female population, accounting for differences in fertility rates by HIV-1 serostatus.

RESULTS

Among antenatal clinic attendees, HIV-1 prevalence showed a significant linear decrease (P < 0.001), from 26.0% in 1993 [95% confidence Interval (CI), 23.2-29.0%] to 16.1% in 1997 (95% CI, 14.8-17.5%). This decrease was mostly due to a marked decrease until 1995 (14.3%; 95% Cl, 12.7-16.0%) and was more pronounced among women aged under 30 years (P < 0.001), from both urban and rural areas (P < 0.001). The risk of being infected was higher among women from urban areas (Gulu Municipality), both over the entire period (adjusted prevalence proportion ratio = 1.54; 95% CI, 1.40-1.68) and by individual year. The estimated prevalence for the 15-39-year-old female population, standardized by age and area of residence, decreased from 25.4% in 1993-1994 to 17.8% in 1996-1997; these rates were 1.22 and 1.28 times higher, respectively, than those among antenatal clinic attendees.

CONCLUSIONS

The trend of decrease among young women, for whom changes in HIV-1 prevalence more closely reflect incidence, could be partially due to a reduction in risk behaviour and a consequent decreasing incidence. Differences in fertility rates by HIV-1 serostatus should be addressed when using antenatal clinic data to estimate prevalence among the general female population.

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.

Monitoring of HIV-1 infection prevalence and trends in the general population using pregnant women as a sentinel population: 9 years experience from the Kagera region of Tanzania

In the Kagera region of Tanzania, a population-based study was initiated in 1987 followed by the establishment of antenatal-clinic-based sentinel surveillance system in the town of Bukoba in 1990. Repeat studies in both populations in Bukoba in 1993 and 1996 made it possible to study the dynamics of HIV infection prevalence and incidence in the area. This study aims at comparing the findings from this sentinel surveillance system with those of cross-sectional studies in the general population to assess its validity in estimating HIV prevalence and their trends in the general population. A multistage cluster sampling technique was used in the population-based studies whereas the antenatal-clinic-based population was obtained by consecutively recruiting antenatal care attenders coming for the first time during a given pregnancy. Antibodies against HIV infection were tested using two independent enzyme-linked immunosorbent assay (ELISA) antibody detection tests. Unlinked anonymous testing strategy was adopted for the sentinel population. Age-adjusted prevalence among antenatal care attenders decreased from 22.4% (95% confidence interval [CI], 20.6-25.2) in 1990 to 16.1% (95% CI, 15.9-18.8) in 1993 and further to 13.7% (95% CI, 11.8-14.3) in 1996. These results closely resemble those of the general population of adult women in the clinic's catchment area (the town of Bukoba) where the age-adjusted prevalence of 29.1% (95% CI, 24.4-34.6) in 1987 showed a decrease in the studies in 1993 18.7% (95% CI, 15.1-23.0) and in 1996 14.9% (95% CI, 12.0-17.1). The study indicates that general population trend estimates can be generated using sentinel surveillance data based on pregnant women visiting an antenatal clinic for the first time during a given pregnancy. The benefits of using this group outweigh its limitations that are brought about by possible selection bias. Continued surveillance of the epidemic based on antenatal care patients as a sentinel population is therefore recommended.

Impaired fertility in HIV-1-infected pregnant women: a clinic-based survey in Abidjan, Côte d'Ivoire, 1997

OBJECTIVE

Differences in fertility among HIV-1-positive and HIV-negative women tested in prenatal clinics were suspected by routine data collection in Abidjan, Côte d'Ivoire. This study was conducted on detailed fertility patterns among women at the same antenatal care centres, in order to assess these differences.

METHOD

The survey was carried out on 1201 consecutive women who agreed to be tested for HIV. Data collected included a detailed account of pregnancies, the time interval between the last two pregnancies, and the health status at the time of the survey. Blood samples were tested for HIV and syphilis with informed consent.

RESULTS

Despite an earlier exposure to pregnancy risk, HIV-1-infected women aged 25 years and above, had, on the average, fewer pregnancies than uninfected women. An analysis of the interval between the last two pregnancies among multigravidae showed that, all things being equal, being HIV-1 positive decreased the risk of being pregnant by 17% (Cox regression, hazard ratio = 0.83, 95% confidence interval (CI): 0.69-0.99). This shift in the occurrence of the last pregnancy was more profound among HIV-1-positive women already at the symptomatic or AIDS stage, than among asymptomatic women.

CONCLUSION

These data confirm that women infected by HIV-1 would become pregnant less often than uninfected women, for an equal exposure to the risk of pregnancy. Therefore HIV-1-positive women could be under-represented at antenatal centres. Programmes involving such settings both for epidemiological surveillance and the reduction of mother-to-child transmission should take this observation into account.