Placentitis

Placentitis is an inflammation of the placenta. The main forms of placentitis are:

Villitis, inflammation of chorionic villi.
Intervillositis, inflammation of the intervillous space.

It may be caused by vertically transmitted infections.
Because of the close proximity, placentitis often occurs simultaneously as funisitis and chorioamnionitis.
Chronic lymphocytic placental inflammation occurs in 5% to 15% of pregnancies, and are generally not associated with documented infection.

Villitis of unknown etiology

Villitis of unknown etiology, also known as chronic villitis, is a placental injury. VUE is an inflammatory condition involving the chorionic villi. VUE is a recurrent condition and can be associated with intrauterine growth restriction. IUGR involves the poor growth of the foetus, stillbirth, miscarriage, and premature delivery.placenta.2013.07.002"> VUE recurs in about 1/3 of subsequent pregnancies.
VUE is a common lesion characterised by inflammation in the placental chorionic villi. VUE is also characterised by the transfer of maternal lymphocytes across the placenta.
VUE is diagnosed in 7–10% placentas in pregnancies. Roughly 80% of the VUE cases are in term placentas. A case of VUE in a placenta less than 32 weeks old should be screened for infectious villitis.

Chronic histiocytic intervillositis

Chronic Histiocytic Intervillositis also known as Chronic Intervillositis of Unknown etiology and Massive Chronic Intervillositis is defined as a diffuse infiltration of mononuclear cells of maternal origin into the intervillous space within the placenta. It often results in severe intrauterine growth restriction which can lead to miscarriage or stillbirth. Overall perinatal mortality rate is high: 41% to 77%. Recurrence rate is also high: 67% to 100%.