Which of the following is true regarding chorionicity in multifetal pregnancy
Monochorionic pregnancies have dividing membrane that is 2 layer thick. Monozygous twins can be dichorionic as well.
Monochorionic membranes should have four layers
Dichorionic pregnancies are always dizygotic
Monochorionic pregnancies are always dizygotic
Chorionicity is accurately determined by first trimester ultrasound scan