To say twin discordance the differences in the two twins should be:
Correct Answer: 25% with the larger twin as index
Description: Unequal sizes of twin fetuses with a difference of 25% (larger twin being used as the index), is called as Discordant growth.
It is a sign of pathological growth restriction in the smaller fetus.
As the weight difference within a twin pair increases and the earlier the growth discordance is evident, perinatal mortality increases.
Most common cause of discordance:
In dichorionic twins – unequal placental mass.
In monochorionic twins – Twin-twin transfusion syndrome/genetic syndrome.
Hazards of discordant growth.
The smaller fetus is at increased risk of perinatal mortality due to:
Respiratory distress
Intra ventricular hemorrhage
Seizure
Sepsis
Periventricular leukomalacia
Necrotising enterocolitis.
At a difference of more than 30%—Risk of fetal death increases.
Extra Edge
Besides weight—other ultrasonographic parameters indicating discordance:
Difference in biparietal diameter is 6 mm or more.
Difference in head circumference is 5% or more.
Difference in abdominal circumference is 20 mm or more.
On colour Doppler ultrasound in umbilical arteries systolic to diastolic (S/D) ratio difference is 15% or more.
But amongst all criterias best is fetal weight difference i.e. more than equal to 25%.
Route of delivery: In case of discordant growth vaginal delivery is indicated if:
Cervix is ripe
Presentation is vertex/vertex
Weight of smaller twin is > 1500 gm.
Category:
Gynaecology & Obstetrics
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now