You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is All are causes of Antepartum hemorrhage (APH) except: and explain in detail?
Causes of Antepartum Hemorrhage

Placenta previa
Abruptio placenta
Vasa previa
Circumvallate placenta
Local causes like:


Polyp
Carcinoma cervix
Varicose veins
Trauma


Unclassified or indeterminate

Circumvallate placenta

It is an uncommon cause of antepartum hemorrhage.
In this condition, the chorionic plate which is on the fetal side of the placenta is smaller than the basal plate on the maternal side.
The fetal surface of the placenta presents a central depression surrounded by a thickened grayish white ring.
These pregnancies may be complicated by IUGR and an increased chance of fetal malformations.
Bleeding is usually painless.
Antenatal diagnosis is unlikely and the diagnosis is usually made after examination of the placenta post delivery.