Clinical characteristics, pregnancy outcomes and placental description in patients with chronic deciduitis

Chronic deciduitis (CD) is a rare, poorly documented placental inflammatory lesion. This study describes maternal characteristics, pregnancy progression, neonatal outcomes, and associated placental findings in patients with histologically confirmed CD.

We conducted a retrospective descriptive study at a tertiary maternity center in Toulouse (January 2014 - June 2025), including singleton pregnancies with histopathological evidence of CD.

Among 63 patients, 10% had autoimmune diseases, 21% developed gestational diabetes, 16% fetal growth restriction (FGR), and 10% preeclampsia. The mean gestational age at delivery was 33 weeks, with a 57% preterm birth rate and 24% incidence of premature rupture of membranes. Neonatal outcomes included a mean birth weight of 2026 g, 27% confirmed FGR, and 46% NICU admissions. Adverse outcomes co-occurred in 20% of the CD cases (including late miscarriage, fetal or neonatal death). CD was isolated in 27% of cases, and in the remaining cases, it was associated with maternal vascular malperfusion (29%), chronic villitis (22%), or acute chorioamnionitis (22%). These findings may suggest immune stimulation possibly by microorganisms, autoantigens or fetal alloantigens.

CD co-occurred with significant obstetric and neonatal complications. However, potential selection bias regarding clinical indications for placental examination may limit generalizability.