What is twin placentas?

➢ Twin pregnancies arise from fertilization of two ova (dizygotic) or from division of one fertilized ovum (monozygotic). ➢ There are three basic types of twin placentas: – diamnionic dichorionic (which may be fused), – diamnionic monochorionic, and – monoamnionic monochorionic. ➢ Monochorionic placentas imply monozygotic (identical) twins, and the time at which splitting of the developing embryo occurs determines whether one or two amnions are present. ➢ Dichorionic placentation may occur with either monozygotic or dizygotic twins and is not specific