chorionicity
Pronunciation: /kɔːriːəˈnɪsɪti/
The determination of placental arrangement in multiple pregnancies, crucial for risk stratification and management planning.
Full Definition
Chorionicity refers to the number of placentas (chorions) in a multiple pregnancy and represents one of the most important factors in determining pregnancy risks and management strategies. Monochorionic pregnancies (sharing one placenta) carry significantly higher risks including twin-to-twin transfusion syndrome, selective growth restriction, and increased perinatal mortality compared to dichorionic pregnancies (separate placentas). Accurate determination of chorionicity should be performed in the first trimester using ultrasound markers such as the lambda sign (dichorionic) or T-sign (monochorionic). This assessment guides the frequency of monitoring, specialized care requirements, and delivery planning throughout the pregnancy.
Usage
Usage note: Often paired with 'amnionicity' when describing twin pregnancies; note the 'icity' suffix.
In Context
- "First trimester assessment confirmed dichorionic diamniotic twin pregnancy based on lambda sign visualization." — Ultrasound report
- "Monochorionic twins require serial growth assessments due to increased risk of selective IUGR." — High-risk obstetric note