Background/Purpose: Systemic lupus erythematosus (SLE) is more frequent in women of reproductive age and pregnancy in these patients is considered as high risk. The inflammatory environment, with exacerbated activation of the complement system, formation, and tissue deposition of immune complexes promote placental histopathological changes that predispose to pregnancy complications. The objective of this study was to describe histopathological findings in the placentas of pregnant women with SLE and correlate them with adverse outcomes.

Methods: Patients with SLE (ACR criteria 1997) and singleton pregnancies, who received prenatal care at a tertiary hospital and delivered at the same institution, were included. They were divided in four groups: Group 1 – Preeclampsia (PE)/intrauterine growth restriction (IUGR); Group 2 – Active SLE (SLEPDAI > 4); Group 3 – Systemic infection during pregnancy; Group 4 – patients without PE/IUGR, active SLE or infection. Histopathological analysis of the placentas was performed according to Amsterdan Placental Workshop Group Consensus Statement.

Results: Ninety-seven patients were included and histopathological study of the placenta was performed in all cases by blinded pathologists for pregnancy outcome. Adverse outcomes were observed in 49 (50.5%) pregnancies. PE/IUGR was the most frequent, being found in 28 (28.8%) patients. Disease activity during pregnancy was diagnosed in 23 (23.7%) cases and an episode of systemic infection was identified in 13 (13.4%) pregnant women. Fifteen women were analyzed in more than one group due to multiple events (e.g., PE/CIUR and SLE activity). Considering all patients, maternal vascular hypoperfusion abnormalities (MVHA) were the most frequent histopathological findings: 19 (19.6%) had moderate to severe major MVHA; 59 (60.8%) had mild major MVHA; and 83 (85.6%) presented minor MVHA. Patients in Group 2 (PE/IUGR) had more frequently moderate to severe major MVHA compared to the other groups (32.1% x 14.5%, p=0.047), while patients in Group 4 (no studied outcomes) had significantly less acute fetal vascular hypoperfusion abnormalities (FVHA) (14.3% x 33.3%, p=0.027). In both Groups 2 (active SLE) and 3 (systemic infection), the most common finding was minor MVHA (82.6% and 84.6%, respectively), but there was no statistical difference compared to the other groups. Significant risk predictors for the outcome PE/IUGR were absence of acute (FVHA) (p=0.025), presence of hematogenous infection (p=0.005), presence of small for gestational age (SGA) newborn (p < 0.0001), need for neonatal intensive care unit (p=0.002), lower gestational age at delivery (p=0.0003) and lower birth weight (p < 0.0001). No variable was a significant predictor for the outcome disease activity and systemic infection. Based on multivariate analysis, it was observed that SGA newborn (p < 0.0001) and hematogenous infection (p=0.015) were significant independent variables to predict the PE/IUGR outcome.

Conclusion: This study demonstrates that MVHA are commonly found in placentas of patients with SLE. Moderate to severe MVHA are more frequent in patients who develop PE/IUGR, which may be linked to the pathophysiology of these obstetric adverse outcomes.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/analysis-of-histopathological-changes-in-the-placenta-of-patients-with-systemic-lupus-erythematosus/