Intrapartum use of zidovudine in a large cohort of pregnant women living with HIV in Italy

Background: Intravenous administration of zidovudine (ZDV) during labour is a key step for vertical HIV transmission (VT) prevention, but there is no evidence of benefit when maternal HIV-RNA at delivery is < 50 copies/mL. The aim of this study is evaluating the appropriateness of intrapartum ZDV use in Italy.Methods: Observational study including mother-infant pairs with perinatal HIV exposure during 2002-2019, enrolled in the Italian Register for HIV Infection in Children. Univariable and multivariable logistic regression were used to evaluate factors associated with VT.Results: A total of 3,861 infants, born from 3,791 pregnancies were included. The frequency of ZDV use was 79.9%, 92.1%, 93.7% and 92.8% when HIV-RNA was not available, >= 400 copies, between 50 and 399 copies, and < 50 copies/mL. Thirty-three out of 3861 (0.85%) infants were subsequently diagnosed with HIV, 25/3861 (0.6%) of them born to mothers receiving intrapartum ZDV, and 31 (93.9%) to mothers with HIV-RNA >= 50 copies/mL or not available. In women with HIV-RNA < 50 copies/mL, ART discontinuation during pregnancy was the strongest risk factor for VT (odds ratio, OR, 23.1, 95%CI 2.4-219.3), while a higher gestational age (OR 0.6, 95%CI 0.4-0.8) and PEP administration to the newborn (aOR 0.004, 95%CI < 0.0 0 01-0.4) were protective factors. Intrapartum ZDV administration did not influence the final outcome in this group.Conclusions: In ART era, more transmission events may occur in utero, limiting value of intrapartum ZDV, particularly for women with suppressed HIV-RNA load. More attention to the HIV-RNA testing of mothers before delivery may avoid unnecessary ZDV use. (c) 2022 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study evaluated the appropriateness of intrapartum ZDV use in Italy. The results showed that in women with HIV-RNA < 50 copies/ml, discontinuation of ART during pregnancy was the strongest risk factor for vertical transmission, while higher gestational age and newborn receiving PEP were protective factors. The use of intrapartum ZDV did not influence the final outcome in this group.