Trends of HIV-1 and sexually transmitted diseases among pregnant and postpartum women in urban Malawi

Abstract

Objectives: To examine rates of HIV-1 and sexually transmitted disease (STD) among pregnant and postpartum women in urban Malawi, Africa.

Design: Serial cross-sectional surveys and a prospective study.

Methods: Three major surveys were conducted in 1990, 1993 and 1994/1995. Consecutive first-visit antenatal women and women giving birth at the Queen Elizabeth Central Hospital were tested for HIV and STD after counseling and obtaining informed consent. Unlinked, anonymous HIV testing was also conducted on smaller samples of antenatal women in the same hospital to provide annual prevalence data. HIV-seronegative postpartum women from the 1990 and 1993 surveys were enrolled in a prospective study to determine HIV incidence.

Results: HIV seroprevalence rose from 2.0% in 1985 to 32.8% in 1996, a 16-fold increase. The highest age-specific HIV prevalence was in the following age-groups: 20-24 years during 1990, 25-29 years during 1993, and 30-34 years during 1996. Among 1173 women followed for a median of 30.9 months, HIV incidence was 5.98 per 100 person-years in women aged < 20 years and declined steadily in older women. The prevalence of STD significantly declined among both HIV-positive and negative women. This decline in STD prevalence, however, was not accompanied by increased condom use over time.

Conclusions: Among urban childbearing women in Malawi, incidence of HIV is highest among young women while, currently, prevalence is highest among older women. Recent declines in STD prevalence suggest that HIV prevention programs are having an impact either through improved STD diagnosis and treatment or reduced risk behaviors. Sequential cross-sectional STD prevalence measures may be useful in monitoring effectiveness of STD and HIV prevention activities.

PIP: Prevalence rates of HIV-1 and other sexually transmitted diseases (STDs) among pregnant and postpartum women were investigated in sequential, cross-sectional studies (1990, 1993, and 1994-95) conducted at Queen Elizabeth Central Hospital in Blantyre, Malawi. Annual anonymous, unlinked testing revealed a linear increase in HIV-1 prevalence among antenatal patients from 2.0% in 1985 to 32.8% in 1996. Analysis of demographic attributes of women enrolled in the 1990 and 1993 surveys of consecutive, first-visit antenatal women (n = 6603 and 2161, respectively) and the 1994-95 study of all women giving birth at the hospital during a 6-month period (n = 6964) indicated that HIV-infected women were most likely to be young, with fewer pregnancies, and be more educated. The highest age-specific HIV prevalence shifted from 20-24 years in 1990 to 30-34 years in 1996, indicating an aging cohort of women who became infected at a younger age. Reported lifetime use of condoms increased from 5.6% in 1990 to 17.5% in 1993, then declined to 4.9% in 1995; condom use was consistently higher among HIV-positive than HIV-negative women. The prevalence of all STDs (syphilis, trichomoniasis, gonorrhea, and genital warts and ulcers) declined significantly during 1990-96, with the most consistent decreases recorded among HIV-positive women. In a follow-up study of 1173 HIV-seronegative, postpartum women evaluated for 2302 person-years (average duration, 30.9 months), 97 seroconverted (4.21/100 person-years). The seroconversion rate declined steadily from 21.26/100 person-years in 1990 to 1.11/100 person-years in 1994-95. These findings are consistent with those from other sub-Saharan African countries, indicating a rapid increase in HIV prevalence followed by stabilization within about 10 years of the onset of the epidemic. The large decline in STD prevalence in the antenatal population suggests that Malawi's national AIDS prevention program is having an impact, either through improved STD diagnosis and treatment or reduced risk behaviors.