Monochorionic/diamniotic placentation implies what?

Monochorionic/diamniotic placentation implies what?

• A. One placenta shared with two amniotic sacs
• B. Two placentas with one amniotic sac
• C. Two placentas with two amniotic sacs
• D. One placenta with one amniotic sac

Answer: (A)

Monochorionic/diamniotic describes a twin pregnancy where there is one placenta shared by both fetuses, but two separate amniotic sacs. In ultrasound, you’d expect to see a single placental mass with two distinct amniotic cavities separated by the intertwin membrane. This arrangement occurs when the fertilized egg splits after the chorion forms but before the amnion forms, so one chorion (one placenta) and two amnions (two sacs) are present. This is best described by one placenta shared with two amniotic sacs.

Monochorionic/diamniotic describes a twin pregnancy where there is one placenta shared by both fetuses, but two separate amniotic sacs. In ultrasound, you’d expect to see a single placental mass with two distinct amniotic cavities separated by the intertwin membrane. This arrangement occurs when the fertilized egg splits after the chorion forms but before the amnion forms, so one chorion (one placenta) and two amnions (two sacs) are present. This is best described by one placenta shared with two amniotic sacs.