All are causes of Antepartum hemorrhage (APH) except:
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.
Placenta previa
Abruptio placenta
Circumvallate placenta
Battledore placenta