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Question 24
Feto-maternal medicine → Multiple pregnancy
Classification
Question
SSBAQuestion Header
Miscarriage risk in twin pregnancy
Question Stem
A woman with a twin pregnancy is counselled before invasive prenatal diagnosis. What approximate additional risk of pregnancy loss attributable to the procedure should be discussed?
Options
A
Around 1%
B
Below 0.1%
C
Around 5%
D
Around 10%
E
There is no additional procedure-related risk
Explanation
In twin pregnancies, RCOG advises counselling that the additional risk of miscarriage following invasive prenatal diagnosis is approximately 1%. This is higher than the likely additional risk of below 0.5% quoted for singleton pregnancies when amniocentesis or CVS is performed by an appropriately trained operator. Counselling in multiple pregnancy should also address procedure technique, pregnancy mapping and the possibility of selective termination if a discordant abnormality is diagnosed.
Option Validity
B) The additional loss risk quoted for twin invasive testing is substantially higher than 0.1%.
C) A 5% additional loss risk exceeds the approximate procedure-related figure.
D) A 10% additional loss risk is much higher than the expected procedure-related risk.
E) Invasive testing in twins carries an additional procedure-related pregnancy-loss risk.
Further Reading
Navaratnam K, Alfirevic Z; Royal College of Obstetricians and Gynaecologists. Amniocentesis and chorionic villus sampling: Green-top Guideline No. 8. BJOG. 2022;129:e1-e15.