HIV acquisition during pregnancy and postpartum is associated with genital infections and partnership characteristics

Abstract

Objective: The objective of this study is to determine the risk and cofactors for HIV acquisition during pregnancy and postpartum.

Design: A prospective cohort study

Methods: : Pregnant women in western Kenya were enrolled if HIV seronegative at that visit or within 3 months. Serial HIV nucleic acid amplification tests (NAATs) were conducted at 1 to 3-month intervals to 9 months postpartum. Genital swabs were collected for detection of chlamydia and gonorrhoea at baseline, and for trichomonas, bacterial vaginosis and yeast at baseline and follow-up.

Results: Among 1304 pregnant women, median age was 22 years, 78% were married for a median of 4 years, 66% reported knowing partner HIV status and 8% reported using condoms. Study retention was 98%. During 1235 person-years of follow-up, HIV incidence was 2.31/100 person-years [95% confidence interval (95% CI) 0.71-4.10]. Incident HIV was associated with syphilis (hazard ratio 9.18, 95% CI 2.15-39.3), chlamydia (hazard ratio 4.49, 95% CI 1.34-15.0), bacterial vaginosis (hazard ratio 2.91, 95% CI 1.25-6.76), yeast (hazard ratio 3.46, 95% CI 1.46-8.19), sexually transmitted infection (STI) history (hazard ratio 3.48, 95% CI 1.31-9.27), lifetime number of sex partners (hazard ratio 1.19, 95% CI 1.03-1.37), partner age discordance (hazard ratio 1.07 per year, 95% CI 1.02-1.13) and shorter marriage (hazard ratio 1.19 per year, 95% CI 1.03-1.38). No women with incident HIV reported an HIV-infected partner. In multivariate analyses, chlamydia, older partners and yeast infection remained significant; however, power was limited.

Conclusion: Pregnant and lactating women may not perceive HIV risk and rarely used condoms. Prevention and treatment of genital infections and risk stratification to identify women for pre-exposure prophylaxis (PrEP) could decrease HIV acquisition in pregnant/lactating women.

Figure 1

Study Recruitment, Eligibility, and Enrollment.¹ Included 429 women rebooked to come back at a later date, 176 women who consulted their male partner, and 39 women who wanted to think about it.² Includes women who completed the last study visit or acquired HIV at or prior to study exit; 20 women were lost to follow-up and 5 refused to continue study participation.

Figure 2

Timing of detection of HIV infection and incidence rates during pregnancy and postpartum

Figure 3

Cumulative risk of HIV acquisition during pregnancy and postpartum, by risk factor a) age, b) marriage duration, c) chlamydia d) syphilis, e) bacterial vaginosis, f) history of sexually transmitted infection (STI). Parentheses indicate number of HIV infections between each risk period.