A major HIV risk factor facing many Thai women is the sexual behavior of their husband or partner

International Family Planning Perspectives, Dec 1998 by O'Connor, M L

HIV infection among women attending prenatal clinics in two Bangkok hospitals increased from 1.0% in 1991 to 2.3% in 1996, according to a study addressing HIV risk and prevalence among pregnant Thai women.1 The risk of infection was greatest among women who had had more than one sexual partner, those with a history of sexually transmitted disease (STD) and those whose partner had engaged in highrisk behavior, such as injectable drug use and contact with commercial sex workers. The partners of more than a quarter of the HIV-positive women were seronegative; women who reported no high-risk behaviors were less likely than other women to have an uninfected partner.

Most studies of the HIV epidemic in Thailand have concentrated on female sex workers and their clients, although large increases in rates of HIV infection are now occurring among women of childbearing age in monogamous relationships. To determine which demographic and behavioral factors put these women at risk of HIV infection, a study was conducted among women attending prenatal clinics at two Bangkok hospitals that have the largest maternity units in Thailand (each with about 18,000 deliveries annually). Since 1991, women registering for prenatal care at these hospitals have routinely been tested for HIV infection and offered counseling if the test results are positive. A review of hospital records showed that HIV prevalence among pregnant women had increased from 1.0% in 1991 to 2.3% in 1996.

From November 1992 through March 1994, women who tested positive were asked to participate in the study if they registered for prenatal care prior to their third trimester of pregnancy, lived in the Bangkok area, had a national ID card and planned to deliver and obtain follow-up care for themselves and their children at the hospital. Women were invited to participate as controls if they were seronegative and in the same trimester of pregnancy as the HIV-positive participant who registered at the clinic immediately before them. The final sample consisted of 342 seropositive women and 344 seronegative women.

Women in both groups were given a questionnaire that covered their demographic, behavioral and obstetric characteristics, as well as their perceptions of their partner's risk behaviors. Partners of HIV-positive women were also tested for HIV and STD infection.

Results

Compared with women who were seronegative, those infected with HIV were younger (22 vs. 24 years) and had been with their partner for a shorter time (1.5 vs. 3.0 years). Seropositive women were also more likely to be from a rural area, to be nulliparous and primigravid and to be separated from a prior partner. HIV-positive and HIV-negative women were similar in terms of literacy, time spent in Bangkok, marital status and family income.

When the investigators looked at behavioral factors, they found that HIV-positive women were significantly more likely than seronegative women to have first had intercourse before age 18 (odds ratio of 1.5), to have been pregnant by more than one partner (3.1), to have a history of STD infection (5.4), to have had a partner who used injectable drugs (4.9) and to have had more than one sex partner (3.3). Compared with women who had had only one partner, women who had had two lifetime sex partners were almost three times as likely to be HIV-infected (odds ratio of 2.7) and women with more than two partners were almost seven times as likely to be infected (6.9). Among women who were not commercial sex workers, the risk of HIV infection was almost three times as high among those with two partners as among those with one (odds ratio of 2.6), and the risk among women with more than two partners was almost five times as high (4.5). Women's injectable drug use and contraceptive use did not significantly affect their risk of HIV infection.

Certain partner behaviors were also associated with women's HIV status. Compared with partners of seronegative women, partners of HIV-infected women were significantly more likely to have had contact with female sex workers (odds ratio of 6.3), to have had contact with sex workers since marriage (2.5-10.0, depending on frequency of contact) and to have a history of STD infection (7.2).

A multivariate analysis of women's behaviors and characteristics associated with HIV infection indicated that the risk of infection was almost six times as high among women who had had more than two lifetime partners as among those who had had only one (odds ratio of 5.6), and almost three times as high among those who had had two partners (2.9). Women with a history of STD infection were about four times as likely to be HIV-positive as were those without such a history (3.9). The odds of being HIV-infected were elevated among women who were injectable drug users or whose partner was a user (3.6). Other significant risk factors included having had no live births (odds ratio of 2.2), having a rural background (1.6) and having been with the current partner for less than a year and a half (1.5).