Background/Purpose: Systemic lupus erythematosus (SLE) is associated with increased risk of adverse perinatal outcomes (APOs), including preeclampsia, preterm birth, fetal growth restriction, and stillbirth. Placental findings of maternal vascular malperfusion (MVM), particularly intervillous fibrin deposition (IVFD), are more frequently observed in patients with SLE and antiphospholipid syndrome (APS). While IVFD has been linked to small-for-gestational-age (SGA) neonates in SLE pregnancies, its association with other severe APOs remains poorly characterized. The aim of our study is t compare the incidence of high-grade MVM between pregnant individuals with and without SLE and to evaluate the association between these placental lesions and APOs.

Methods: We included women aged ≥18 years with singleton pregnancies and a preexisting diagnosis of SLE (2012 SLICC criteria), managed at the National Institute of Perinatology between January 2016 and May 2024, with available placental histopathology. Placental lesions were assessed using the 2016 Amsterdam Working Group criteria and classified based on Freedman’s phenotypes incorporating lesion severity. Exclusion criteria included other autoimmune diseases (except APS), pregnancies in women ≤18 years, multiple gestations, assisted reproduction, absence of prenatal care, or SLE diagnosed during pregnancy. The control group comprised healthy pregnant women matched 1:1 by maternal and gestational age. The primary outcome was the frequency of high-grade MVM. Associations between high-grade MVM and APOs—fetal or neonatal death, preterm birth < 37 weeks due to placental insufficiency (i.e., preeclampsia, hypertension, fetal growth restriction), and SGA neonates (birthweight < 10th percentile)—were assessed using univariable logistic regression, with odds ratios (ORs) and 95% confidence intervals (CIs). P < 0.05 was considered statistically significant.

Results: Among 130 SLE patients (mean age 28.0 ± 5.5 years; gestational age 36.5 ± 3.4 weeks), 25.4% had APS and 23.8% experienced an SLE flare during pregnancy. APOs occurred in 31.5%, including SGA (19%), fetal/neonatal death (3.8%), and preterm birth (19.2%). Placental weight was significantly lower in SLE patients compared to controls (388.9 ± 102.7 g vs. 440.4 ± 81.1 g; P < 0.001), particularly in those with flares (P = 0.014). High-grade MVM was significantly more frequent in SLE patients (33.8% vs. 3.8%; P = 0.001) and was associated with increased odds of fetal/neonatal death (OR 6.81; 95% CI: 1.10–41.95), preterm birth < 37 weeks due to placental insufficiency (OR 4.07; 95% CI: 1.71–9.65), and SGA neonates (OR 5.81; 95% CI: 2.86–11.79).

Conclusion: High-grade MVM is significantly more prevalent in pregnancies complicated by SLE and is strongly associated with increased odds of fetal/neonatal death, preterm birth due to placental insufficiency, and SGA neonates.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/maternal-vascular-malperfusion-association-with-adverse-perinatal-outcomes-in-lupus-pregnancies/