POS1125 HYDROXYCHLOROQUINE USE IN PREGNANT WOMEN WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND MAJOR CONGENITAL MALFORMATIONS IN THE OFFSPRING

Background Hydroxychloroquine (HCQ) is currently recommended for all pregnant women with systemic lupus erythematosus (SLE) if tolerated. Some studies have reported an increased risk of malformations associated HCQ, but others find no risk. Objectives To assess the major congenital (MCM) exposure to HCQ during 1st trimester in offspring SLE. Methods We conducted a population-based cohort study pregnancies singleton birth from 2006 2020 among prevalent SLE Sweden. Pregnancies were identified Medical Birth Register (MBR). Prevalent was defined as having at least two ICD-coded visits National Patient before pregnancy, one specialist. The filling prescription (Prescribed Drug Register). unexposed births required not any dispensations three months preconception end trimester. outcome ICD code MCM assessed listed MBR, according European Surveillance Congenital Anomalies classification. Inverse probability treatment weighting (IPTW) using propensity score applied adjust confounding. included maternal characteristics, comorbidities (e.g., diabetes, other autoimmune diseases), and medication use corticosteroids, disease-modifying anti-rheumatic drugs) model priori variables. Risk ratios 95% confidence intervals (RR 95%CI) estimated modified Poisson regression models weighted population robust variance estimation. Results comprised 407 exposed 520 births. mothers’ mean age delivery 32 (standard deviation ± 5). Overall, there 21 MCM, corresponding overall 2.3%. most common type ventricular septal defect (n = 6). unadjusted risks 2.7% 1.9%, respectively (unadjusted RR 1.42, 95%CI 0.60-3.28). IPTW-adjusted achieved good balance across patient characteristics. 1.59 (95%CI 0.67-3.75). adjusted difference 0.01 -0.01-0.03). In sensitivity analysis which dispensation trimester, 1.56 0.69-3.54). could examine different categories daily dose due very few events each category. Conclusion this cohort, our findings show increased, statistically significant, born compared those without exposure. Our should be interpreted considering lack data on early pregnancy termination or loss induced by MCM. Future are warranted investigate association further utilize longer follow-up ascertainment (i.e., within year birth). For managing benefits may still outweigh risks. References [1]Diav-Citrin O, Blyakhman S, Shechtman Ornoy A. Pregnancy following utero hydroxychloroquine: prospective comparative observational study. Reprod Toxicol Elmsford N. 2013 Aug;39:58–62. [2]Huybrechts KF, Bateman BT, Zhu Y, Straub L, Mogun H, Kim SC, et al. defects. Am J Obstet Gynecol. 2021 Mar;224(3):290.e1-290.e22. [3]Howley MM, Werler Fisher Van Zutphen AR, Carmichael SL, Broussard CS, Maternal hydroxychloroquine Defects Res. Oct 15;113(17):1245–56. Acknowledgements: NIL. Disclosure Interests Ngoc V. Nguyen: None declared, Elisabet Svenungsson Shareholder of: AstraZeneca Pfizer, Speakers bureau: Janssen, Grant/research support from: Grant Merck, Annica Dominicus AstraZeneca, Consultant Employee Karin Hellgren: Julia Simard: Elizabeth Arkema: declared.