Cesarean delivery and risk of HIV vertical transmission in Southern Brazil, 2008-2018

BACKGROUND: Childbirth via cesarean delivery can prevent intrapartum vertical transmission for women who are not virally suppressed at the time of delivery. Few studies have compared cesarean delivery trends between women living with HIV and women without HIV and have examined the role of cesarean delivery in the prevention of vertical transmission in the era of potent combination antiretroviral therapy. OBJECTIVE: We hypothesized that the cesarean delivery rate is high in women living with HIV compared with women without HIV and that cesarean delivery usage decreases over time among women living with HIV with advances in combined antiretroviral therapy in a country with a high national cesarean delivery rate. This study aimed (1) to evaluate cesarean delivery trends in women with and without HIV and (2) to examine its role in preventing vertical transmission among women living with HIV in a setting of free, universal combined antiretroviral therapy coverage in a retrospective cohort of nearly 56,000 deliveries at a major referral institution in a city with the highest prevalence of maternal HIV in Brazil. STUDY DESIGN: Data from maternal-infant pairs from January 1, 2008, to December 31, 2018, were extracted. Cesarean delivery rates were compared using the Pearson chi-square test. Cesarean delivery predictors were evaluated by multivariate log-linear Poisson regression using a generalized estimating equations approach. HIV viral suppression was defined as a viral load of <1000 copies/ml at delivery. HIV vertical transmission was determined following national guidelines. RESULTS: Over 11 years, 48,688 pregnancies occurred in 40,375 women; HIV seroprevalence was 2.7%; 18,886 cesarean deliveries (38.8%) were performed; 47.7% of women living with HIV and 38.6% of women without HIV underwent cesarean delivery (P<.001). Although HIV was associated with cesarean delivery (adjusted relative risk, 1.17 [95% confidence interval, 1.05–1.29]), women living with HIV with vertical transmission achieved similar cesarean delivery rates (36.7%) as women without HIV (39.8%) in 2018. Cesarean delivery in women living with HIV with an unknown viral load at delivery (42.6%) did not increase over time. HIV vertical transmission rate was 2.2%, the highest in women living with HIV with an unknown viral load (8.4%) vs women living with HIV without vertical transmission (4.1%) and women living with HIV with vertical transmission (0.5%) (P<.001). CONCLUSION: In the HIV epicenter of Brazil, women living with HIV with vertical transmission had fewer surgical deliveries, likely because of the use of potent combination antiretroviral therapy. Nearly half of the women living with HIV with an unknown viral load did not undergo cesarean delivery, a potential missed opportunity for the prevention of HIV vertical transmission.