Trends in post-partum viral load among women living with perinatal HIV infection in the USA: a prospective cohort study.

BACKGROUND:Small studies reported poor post-partum outcomes among young women living with perinatal HIV infection who are now ageing into adulthood and becoming pregnant. For targeted clinical intervention, we sought to identify women in this population at risk of poor post-partum virological control. METHODS:We abstracted data on pregnancy history for women living with perinatal HIV infection in the Pediatric HIV/AIDS Cohort Study-AMP Up protocol, a prospective study of young adults living with perinatal HIV from 14 sites in the USA. Linear models with generalised estimating equations described trends in HIV viral load through 1 year post-pregnancy by pregnancy outcome. We used group-based trajectory modelling to identify viral load trajectory groups in the first post-partum year after livebirths. We then compared sociodemographic and clinical factors across identified groups. We defined viraemia as 400 copies per mL or more. FINDINGS:Between April 15, 2014, and Oct 1, 2017, we enrolled 323 women, of whom 234 had perinatal HIV infection, and reported age at sexual debut and history of heterosexual vaginal intercourse. Of the 172 pregnancies recorded in these women, 147 (85%, 104 livebirths and 43 spontaneous or elective abortions) were eligible for post-pregnancy viral load trajectory analyses (ie, had at least two viral loads in the year after end of pregnancy). Viral load increased by 0·7 log10 copies per mL (95% CI 0·5 to 1·0) in the first 12 weeks post partum after 104 livebirths, and subsequently stabilised from 13 weeks to 1 year post partum (slope -0·01 log10 copies per mL, 95% CI -0·3 to 0·3). By comparison, the average viral load trajectory after 43 spontaneous or elective abortions remained at less than 400 copies per mL. We identified three distinct groups of viral load trajectories after 104 livebirths, classified as reflecting sustained suppression (31 [30%]), rebound viraemia (55 [53%]), and persistent viraemia (18 [17%]). Women with sustained post-partum suppression were older at conception (22·9 years, IQR 19·4-25·9) than those with rebound viraemia (20·4 years, 18·8-22·2), or persistent post-partum viraemia (19·0 years, 17·7-20·5). Pre-conception viraemia and immune suppression were also strong risk factors for post-partum viraemia. INTERPRETATION:Despite success achieving viral load suppression during pregnancy, women living with perinatal HIV infection have a high risk of post-partum viraemia. Younger age at conception, pre-conception viraemia, and pre-conception immune suppression could identify women in this population most likely to benefit from post-partum adherence interventions. FUNDING:National Institutes of Health.