CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

998

Prematurity and Low Birth Weight in Children Born to Mothers Living With HIV in Spain Blanca Bravo Queipo de Llano 1 , Talía Sainz 1 , Carlos Grasa 1 , Marta Illán 2 , Arantxa Berzosa 2 , Asuncion Diaz 3 , Inma Jarrin 3 , Luis Prieto Tato 4 , Rosa Polo 3 , Maria Luisa Navarro 5 , Jose Tomás Ramos Amador 4 , Luis Escosa 1 , for the Cohorte Nacional de Mujeres Embarazadas con VIH y sus hijos expuestos y Cohorte Nacional de VIH pediátrico (CoRISpe) 1 Hospital Universitario La Paz, Madrid, Spain, 2 Hospital Clinico San Carlos, Madrid, Spain, 3 Instituto de Salud Carlos III, Madrid, Spain, 4 Hospital Universitario 12 de Octubre, Madrid, Spain, 5 Hospital General Universitario Gregorio Marañón, Madrid, Spain Background: Children uninfected but exposed to HIV intra-utero (CHEU) are at higher risk of prematurity and low birth weight (LBW), factors associated with long-term growth impairment. Data is scarce regarding the effects of integrase inhibitor regimens during pregnancy in non-limited resource settings. Methods: Descriptive retrospective study of mother-child pairs from 62 Spanish hospitals in the National Cohort of Pregnant Women with HIV and their Children. All children born between January 2020 and December 2023 were included. Data on obstetric, virological, immunological, and antiretroviral treatment (ART) variables were analyzed for association with premature birth or LBWGA via univariate logistic regression models. Results: We included 502 pregnant women living with HIV and their 516 newborns. 32.6% were Caucasian and 44% had a first pregnancy. The median maternal age was 36 years [IQR 32-40]. At the last prenatal checkup, the median CD4 count was 631 cells/mm³ [IQR 435-835] and 88.4% of women were under viral suppression (<50 copies/mL). Regarding maternal ART, 59.7% were on integrase inhibitors (INSTIs), of which 17.9% (49/274) were on bictegravir. Prematurity incidence was 11.6%, with a median gestational age of 34.5 weeks [IQR 32-36]. An 8.7% of newborns were diagnosed with LBG, with a median weight of 2380 g [IQR 2250-2600]. Singleton pregnancies were associated with a 79% lower probability of prematurity (OR 0.21, 95%CI 0.06-0.66; p=0.007 ) and LBW (OR 0.21, 95% CI 0.06-0.71; p=0.012 ) than multiple pregnancies. Additionally, having at least one prenatal checkup each trimester was associated with a 69% lower likelihood of LBW (OR 0.31, 95% CI 0.14-0.68; p=0.003 ). We found no association between CD4 count or viral load at the last prenatal checkup and prematurity or LBWGA. Regarding ART, there were no significant differences in the clinical characteristics of mothers treated with INSTI-based regimens compared to those on protease inhibitors or non-nucleoside reverse transcriptase inhibitors. However, regimens including bictegravir were associated with a higher incidence of LBW (OR 2.5, 95%CI 1.08-5.84; p=0.03 ). Conclusions: Optimizing regimens during pregnancy is key for the prevention of poor outcomes, including impaired growth, in the expanding population of CHEU. Larger cohorts and long-term follow-ups are needed to identify optimal treatments, adjust for potential confounders, and inform future prevention and intervention strategies. Birth Outcomes and HIV-1 Transmission in a Contemporary HIV Pregnancy Cohort, Washington State Jane Hitti 1 , Ann Melvin 2 , Heather Jaspan 2 , Alison C. Roxby 1 , Jennifer E. Balkus 3 , Lilian Manahan 4 , Ronit Katz 1 1 University of Washington, Seattle, WA, USA, 2 Seattle Children's Hospital, Seattle, WA, USA, 3 Public Health–Seattle & King County, Seattle, WA, USA, 4 Washington State Department of Health, Olympia, WA, USA Background: People living with HIV (PLWH) receiving contemporary treatment may have increased risk for low birth weight (LBW) or preterm birth (PTB). We hypothesized that LBW and PTB rates among PLWH in an HIV Pregnancy cohort (HP) would not differ from Washington State (WA) birth registry data. We also evaluated perinatal HIV-1 transmission among births to PLWH in WA, comparing those who participated in HP with those who did not. Methods: This observational retrospective cohort study compared LBW and PTB rates for 292 HP and 1,173,408 WA live births, 2009-2022. The proportion of all PLWH births in WA that received care with HP was calculated from WA HIV surveillance data. HP participants received prenatal and HIV care and delivered at the University of Washington Medical Center (UW). HP birth outcomes were abstracted from the UW HP Cohort Registry, while WA outcomes were obtained from public birth registry data, subtracting HP births to avoid counting them twice. Rates of LBW(<2500g) and PTB(<37 weeks) among singleton HP and WA were assessed in 2-year blocks. Perinatal HIV-1 transmission among all live births for PLWH in HP was compared to WA HIV surveillance data for births to

receiving a DTG-based regimen had a high-level resistance mutation, G118R, which is associated with a 5-10-fold reduced susceptibility to DTG. Conclusions: The prevalence of INSTI mutations was low in the early phases of DTG scale-up. Nonetheless, a mutation against DTG was detected in an INSTI-naïve pregnant woman from Mozambique. This finding calls for continued surveillance of HIV drug resistance in vulnerable and high-risk populations from SSA. Perinatal and Infant Outcomes After Bictegravir Exposure in Pregnancy: A Canadian Surveillance Study Jeffrey Man Hay Wong 1 , Rosa Balleny 1 , Terry Lee 2 , Ari Bitnun 3 , Isabelle Boucoiran 4 , Jason Brophy 5 , Jeannette Cormeau 6 , Fatima Kakkar 4 , Athena McConnell 7 , Laura Sauvé 1 , Joel Singer 8 , Alena Tse-Cheng 9 , Deborah Money 1 , for the Canadian Perinatal HIV Surveillance Program 1 University of British Columbia, Vancouver, Canada, 2 Centre for Advancing Health Outcomes, Vancouver, BC, Canada, 3 University of Toronto, Toronto, Canada, 4 University of Montreal, Montreal, Canada, 5 University of Ottawa, Ottawa, Canada, 6 Dalhousie University, Halifax, Canada, 7 University of Saskatchewan, Saskatchewan, Canada, 8 CIHR Canadian HIV Trials Network, Vancouver, Canada, 9 University of Alberta, Edmonton, Canada Background: In January 2024, bictegravir (BIC) was upgraded to an alternative antiretroviral therapy in pregnancy in the United States despite limited data. Our study aimed to examine the perinatal and early infant outcomes following BIC exposure in pregnancy in Canada. Methods: Data was obtained from the Canadian Perinatal HIV Surveillance Program, which is a prospective cohort of infants born to women living with HIV across 23 Canadian centers. Liveborn infants from July 28, 2018 to December 31, 2023 were included in the analysis. Using univariate analyses, BIC-exposed infants were compared to infants born within the same timeframe with exposure to other integrase strand transfer inhibitors (INSTIs). To identify whether preterm births were independently associated with BIC exposure, a logistic regression analysis adjusting for relevant preterm birth risk factors. Results: In our included cohort, 161 infants were exposed to BIC in pregnancy, and 723 infants were exposed to non-BIC INSTIs. In the BIC-exposed group, 81 (52%) had pre-conception BIC with continued use in pregnancy, 34 (22%) had pre-conception BIC with discontinuation in pregnancy, and 41 (26%) were started on BIC in pregnancy. Infants exposed to BIC were more likely to be born to mothers identified as Indigenous (38% vs. 21%; p < 0.001) and with a mode of transmission associated with intravenous drug use (28% vs. 14%; p<0.001). Infants exposed to BIC in pregnancy were more likely to be born preterm (19.4% vs 11.7%; p=0.008), and their mothers were more likely to discontinue antiretroviral therapy until delivery (1.9% vs. 0.1%; p=0.021) and in the postpartum period (5.0% vs. 2.0%; p=0.037). After adjusting for ethnicity, maternal mode of HIV transmission, and viral load at delivery, preterm birth was not associated with BIC exposure (OR: 1.47; 95% CI: 0.80-2.71; p=0.214). There were no differences in maternal HIV viral load at delivery, mode of delivery, rate of small for gestational age, rate of perinatal transmission, or rate of congenital anomalies. Conclusions: BIC was not independently associated with adverse perinatal and early infant outcomes compared to other INSTIs in the Canadian cohort. Indigenous populations and people who use injection drugs were disproportionately exposed to off-label BIC use in pregnancy prior to guideline updates, highlighting a gap in preconception counselling in these populations.

997

Poster Abstracts

999

CROI 2025 317