Before revision: Diagnosis thumbnail|λ Sign in 8 week pregnancy By performing an obstetric ultrasound at a gestational age of 10–14 weeks, monochorionic-diamniotic twins are discerned from dichorionic twins.
After revision: ASE21Diagnosis thumbnail|λ Sign in 8 week pregnancy By performing an obstetric ultrasound at a gestational age of 10–14 weeks, monochorionic-diamniotic twins are discerned from dichorionic twins.