Gestational pemphigoid: placental morphology and function

Gestational pemphigoid (PG), a very rare pregnancy-associated bullous dermatosis, is associated with adverse pregnancy outcome (miscarriage, preterm delivery, foetal growth restriction). The major antigen in PG is collagen XVII (BP180). PG autoantibodies cross-react with collagen XVII in the skin and have been suggested to cause placental failure. On this basis, we evaluated clinical outcome and morphological and functional placental data of 12 PG pregnancies in Finland during 2002 to 2011. The placental-to-birth weight ratio was abnormal in half of the pregnancies. Ultrastructural analysis of PG placentas showed detachment of basement membranes and undeveloped hemidesmosomes. Ultrasound evaluations of placental function prior to delivery were normal in all but one pregnancy. Three (25%) neonates were delivered preterm after 35 gestational weeks and one pregnancy was complicated by preeclampsia and severe foetal growth restriction. Neonatal outcome was uneventful in every case. In conclusion, in pregnancies complicated by PG, slight alteration in ultrastructural morphology of the placental basement membrane was detected, but umbilical artery Doppler evaluation indicated no functional placental changes.