Question:medium
Which of the following statements about multiple pregnancies is true?
Which of the following statements about multiple pregnancies is true?
Show Hint
Lambda or twin peak sign means a wedge of placenta, which means two chorions.
Updated On: Jun 24, 2026
- Fetuses of the same gender exclude dichorionicity
- Twin peak sign is seen in dichorionicity
- Thick separating membrane is a feature of monochorionic twins
- Chorionicity can be reliably detected only after 16 weeks of gestation
Show Solution
The Correct Option is B
Solution and Explanation
Tackle this by going to the dividing membrane on ultrasound, since that is where chorionicity is decided. Look at the spot where the membrane attaches to the placenta. If placental tissue pushes up into the membrane and forms a triangular tongue, that is the twin peak or lambda sign, and it tells you the pregnancy is dichorionic. A flat, right angle junction with no wedge is the T sign of a monochorionic pregnancy. So the statement that the twin peak sign indicates dichorionicity is correct.
Now test the rest. Same gender fetuses do not rule out dichorionicity, because dizygotic twins of the same sex are common and even monozygotic twins can be dichorionic if splitting happened early, so that statement fails. A thick separating membrane signals dichorionicity, since it is made of two chorions plus two amnions, whereas a monochorionic membrane is thin, so calling it a monochorionic feature is wrong. And chorionicity is assessed most accurately in the first trimester around 10 to 14 weeks, not only after 16 weeks, so that statement is also false.
Only one statement survives, and it is the twin peak sign in dichorionicity.
\[\boxed{\text{Twin peak sign is seen in dichorionicity}}\]
Now test the rest. Same gender fetuses do not rule out dichorionicity, because dizygotic twins of the same sex are common and even monozygotic twins can be dichorionic if splitting happened early, so that statement fails. A thick separating membrane signals dichorionicity, since it is made of two chorions plus two amnions, whereas a monochorionic membrane is thin, so calling it a monochorionic feature is wrong. And chorionicity is assessed most accurately in the first trimester around 10 to 14 weeks, not only after 16 weeks, so that statement is also false.
Only one statement survives, and it is the twin peak sign in dichorionicity.
\[\boxed{\text{Twin peak sign is seen in dichorionicity}}\]
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