Fetus or newborn affected by placental oedema or large placenta

**Definition:** A large placenta, also known as placentomegaly, is one that weighs > 750 g. Placentomegaly can be seen in the following conditions: fetal hydrops, maternal diabetes mellitus, Rh incompatibility, chronic infections (e.g. syphilis, cytomegalovirus), maternal anaemia, or acute placental oedema with acute chorioamnionitis.