Clinical outcomes in chronic intervillositis of unknown etiology

Chronic intervillositis of unknown etiology (CIUE) is a histopathological lesion of the placenta that is frequently accompanied by unfavourable pregnancy outcomes, e.g. miscarriage, fetal growth restriction (FGR) and intrauterine fetal death. Earlier described case series and cohorts have been based on diverse diagnostic criteria of CIUE. To improve our understanding of clinical outcomes associated with CIUE, we report the obstetric and perinatal outcomes in a cohort based on the recently described diagnostic criteria. CIUE is defined as an infiltrate occupying 5% or more of the intervillous space with approximately 80% of mononuclear cells positive for CD68 in the absence of an infection. Thirty-eight cases were included. Also previous and subsequent pregnancies were described. Pregnancies accompanied by CIUE frequently resulted in FGR (51.6%) and pre-term birth (55.3%). Twenty-nine out of 38 pregnancies (76.3%) with CIUE resulted in a living baby. Women with CIUE frequently have had a miscarriage (16/38; 42%). Four-teen subsequent pregnancies in 8 women resulted in 2 miscarriages, 2 terminations of pregnancy for FGR, 1 early neonatal death and 9 living babies (9/14; 64.3%). Histopathologically confirmed CIUE recurred in 5 out of 10 subsequent pregnancies. Two pregnancies with recurrent CIUE were terminated, one pregnancy ended in a late miscarriage and another resulted in term birth complicated by FGR. Recurrent CIUE can also be accompanied by an uncomplicated pregnancy (1/5; 20%). This study provides additional insight into the clinical phenotype of CIUE and emphasises the need for further research to understand the pathophysiology behind different pregnancy outcomes in CIUE. •Pregnancies with CIUE frequently resulted in FGR (51.6%) and pre-term birth (55.3%).•Women with a pregnancy with CIUE frequently have had a miscarriage (16/38; 42.1%).•Histopathological CIUE recurred in 5 out of 10 subsequent pregnancies (5/10; 50%).•Recurrent CIUE can be accompanied by an uncomplicated pregnancy.