327 - Placental changes in pregnancies with anti-Ro/La antibodies.

Poster Number: 327
Publication Number: 327.439

Nikola Wilk, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Mayssa Moukarzel, McGill University Faculty of Medicine and Health Sciences, Montréal, PQ, Canada; Jessica simoneau, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Wadi Mawad, Muhc, Montréal, PQ, Canada; Gabriel Altit, McGill University Faculty of Medicine and Health Sciences, Montreal, PQ, Canada; Évelyne Vinet, McGill University Health Centre, Montreal, PQ, Canada

Background: Some maternal rheumatological conditions are known to be associated with placenta-mediated pregnancy complications, such as preeclampsia. Yet, placental changes in this population remain understudied.

Objective: Our objectives were to review placental pathological changes in anti-Ro/La-positive pregnancies and compare them to those observed in anti-Ro/La-negative pregnancies from mothers with and without rheumatic diseases.

Design/Methods: Using an electronic database, we identified all pregnancies referred for fetal echocardiogram between 2013 and 2021 at the McGill University Health Centre, with the following key words: “congenital heart block”, “anti-Ro”, “anti-La”, “lupus”, “SLE”, “Sjogren”, or “mixed connective tissue disease”. Pregnancies with a fetus exhibiting cardiac anatomical and/or genetic anomalies were excluded. Pregnancies were classified as follows: 1) those with positive anti-Ro/La antibodies, 2) those with a rheumatic disease with negative anti-Ro/La, and 3) control pregnancies identified from the fetal echocardiography database without maternal rheumatic disease nor anti-Ro/La.

Results: Out of 117 pregnancies screened, 62 were included, with a total of 75 fetuses studied. In total, 55 placenta pathology results were available, for a total of 38 placenta in the first group, 9 in the second group and 8 in controls. Placenta was described as normal in only 34.2% of anti-Ro/La-exposed pregnancies and 44.4% of anti-Ro/La-negative autoimmune disease pregnancies compared to 75.0% of controls (p=0.27). Different pathological changes were observed, including ischemic-hypoxic changes, chronic villitis, decreased placental weight, inappropriately advanced villous maturation and fetal vascular malperfusion, all more frequent in the anti-Ro/La-positive pregnancies, although not statistically significant. Interestingly, these changes occurred in the setting of having similar incidence of gestational hypertension (4 [8.5%] vs 2 [18.2%] vs 2 [11.8%], p=0.67), and preeclampsia/eclampsia (no cases).Conclusion(s): Though limited by a small sample size, we observed a potential trend for more placental pathological anomalies in anti-Ro/La-exposed pregnancies compared to those from mothers with and without rheumatic disease. It is possible that confounding by maternal disease severity contributed to our findings. However, prior evidence demonstrates that anti-Ro/La antibodies are transported across the placenta via Fcγ receptors on the trophoblast and bind apoptotic fetal cells. Further studies are needed to investigate placental changes in anti-Ro/La-exposed pregnancies.