MCDA
Also written as: MCDA — Monochorionic Diamniotic
Monochorionic Diamniotic - twin pregnancy sharing one placenta but with separate amniotic sacs.
Full Definition
Monochorionic Diamniotic (MCDA) refers to identical twin pregnancies that share a single placenta (monochorionic) but have separate amniotic sacs (diamniotic). This occurs in approximately 70% of identical twin pregnancies when splitting occurs between days 4-8 after conception. MCDA twins are at increased risk for complications including twin-to-twin transfusion syndrome, selective intrauterine growth restriction, and twin anemia-polycythemia sequence. These pregnancies require specialized monitoring with serial ultrasounds every 2-3 weeks from 16 weeks gestation.
Usage
Usage note: Always specify chorionicity and amnionicity separately when first mentioned; high-risk pregnancy category.
In Context
- "The ultrasound confirmed MCDA twin pregnancy with evidence of the T-sign at the membrane insertion." — First trimester twin assessment
- "MCDA twins require intensive monitoring for twin-to-twin transfusion syndrome development." — High-risk obstetric consultation