What does the lambda sign indicate in twin pregnancies?

What does the lambda sign indicate in twin pregnancies?

• A. Dichorionic placentation
• B. Monochorionic placentation
• C. Increased risk of IUGR
• D. Conjoined twins

Answer: (A)

The lambda sign, also known as the "twin peak sign," is used in ultrasound imaging to indicate a dichorionic twin pregnancy. It appears as a triangular or V-shaped projection of placental tissue extending between the two amniotic sacs and is a key feature for distinguishing between dichorionic and monochorionic placentation. In twin pregnancies, the type of chorionicity can significantly impact the management and monitoring of the pregnancy. In a dichorionic pregnancy, each twin has its own separate placenta and amniotic sac, which reduces the risk of complications associated with shared placentation, such as twin-to-twin transfusion syndrome. The presence of the lambda sign confirms that each twin is developing independently with its own chorion and placenta, providing valuable information for the clinician regarding expected outcomes and prenatal care. In contrast, the absence of the lambda sign, especially if a single placenta is observed, would suggest monochorionic placentation, which requires further surveillance due to the associated risks. The lambda sign does not imply an increased risk of intrauterine growth restriction (IUGR) or conjoined twins, as these conditions are not directly related to the type of placentation indicated by the sign. Recognizing the lambda sign is

The lambda sign, also known as the "twin peak sign," is used in ultrasound imaging to indicate a dichorionic twin pregnancy. It appears as a triangular or V-shaped projection of placental tissue extending between the two amniotic sacs and is a key feature for distinguishing between dichorionic and monochorionic placentation.

In twin pregnancies, the type of chorionicity can significantly impact the management and monitoring of the pregnancy. In a dichorionic pregnancy, each twin has its own separate placenta and amniotic sac, which reduces the risk of complications associated with shared placentation, such as twin-to-twin transfusion syndrome. The presence of the lambda sign confirms that each twin is developing independently with its own chorion and placenta, providing valuable information for the clinician regarding expected outcomes and prenatal care.

In contrast, the absence of the lambda sign, especially if a single placenta is observed, would suggest monochorionic placentation, which requires further surveillance due to the associated risks. The lambda sign does not imply an increased risk of intrauterine growth restriction (IUGR) or conjoined twins, as these conditions are not directly related to the type of placentation indicated by the sign.

Recognizing the lambda sign is