Incident HIV during pregnancy and early postpartum period: a population-based cohort study in a rural area in KwaZulu-Natal, South Africa

• Published in: BMC pregnancy and childbirth Vol. 17; no. 1; p. 248
• Main Authors: Chetty, Terusha, Vandormael, Alain, Thorne, Claire, Coutsoudis, Anna
• Format: Journal Article
• Language: English
• Published: England BioMed Central 26-07-2017; BMC
• Subjects: Acquired immune deficiency syndrome; Adolescent; Adolescents; Adult; Age Factors; AIDS; Antiretroviral drugs; Cohort analysis; Cohort Studies; Female; HIV; HIV incidence; HIV Infections - epidemiology; HIV Infections - prevention & control; Households; Human immunodeficiency virus; Humans; Middle Aged; Population-based studies; Postpartum; Postpartum Period; Pregnancy; Pregnancy Complications, Infectious - epidemiology; Pregnancy Complications, Infectious - prevention & control; Prenatal Care - statistics & numerical data; Prevalence; Retrospective Studies; Risk Factors; Rural Population - statistics & numerical data; Seroconversion; Sexual behavior; Sexual Behavior - statistics & numerical data; South Africa; Teenagers; Womens health; Young Adult; South Africa; Uganda; Africa; Pregnancy; HIV incidence; Adolescents; Seroconversion; Postpartum
• ISSN: 1471-2393; 1471-2393
• DOI: 10.1186/s12884-017-1421-6

The evidence on the effect of pregnancy on acquiring HIV is conflicting, with studies reporting both higher and lower HIV acquisition risk during pregnancy when prolonged antiretroviral therapy was accessible. The aim of this study was to assess the pregnancy effect on HIV acquisition where antiretroviral therapy was widely available in a high HIV prevalence setting.
This is a retrospective cohort study nested within a population-based surveillance to determine HIV incidence in HIV-uninfected women from 15 to 49 years from 2010 through 2015 in rural KwaZulu-Natal. HIV incidence per 100 person-years according to pregnancy status (not pregnant, pregnant, to eight weeks postpartum) were measured in 5260 HIV-uninfected women. Hazard ratios (HR) were estimated by Cox proportional hazards regression with pregnancy included as a time varying variable.
Overall, pregnancy HIV incidence was 4.5 per 100 person-years (95% CI 3.4-5.8), higher than non-pregnancy (4.0; 95% CI 3.7-4.3) and postpartum incidences (4.2 per 100 person-years; 95% CI 2.3-7.6). However, adjusting for age, and demographic factors, pregnant women had a lower risk of acquiring HIV (HR 0.4; 95% CI 0.2-0.9, P = 0.032) than non-pregnant women; there were no differences between postpartum and non-pregnant women (HR 1.2; 95% CI 0.4-3.2; P = 0.744). In models adjusting for the interaction of age and gravidity, pregnant women under 25 years with two or more pregnancies had a 2.3 times greater risk of acquiring HIV than their older counterparts (95% CI 1.3-4.3; P = 0.008).
Pregnancy had a protective effect on HIV acquisition. Elevated HIV incidence in younger women appeared to be driven by those with higher gravidity. The sexual and biological factors in younger women should be explored further in order to design appropriate HIV prevention interventions.