<unk>  occurs in between 0.1%-1.8% of all pregnancies, and is eight to ten times more frequent in multiple pregnancies. This risk is doubled in the case of monochorionic twins, and tripled in the case of fetal growth restriction. It is thought that sex may be a determinant of abnormal<unk><unk> s, however there is conflicting evidence as to whether male or female fetuses are linked to greater risk of<unk> .
Velamentous cord insertion
Neural clique
Vaginal septum
Uterine septum
Fetal movement
Placental expulsion
Peritomy
Circumvallate placenta