EMQ — Extended Matching Question · Review
Question 32
Feto-maternal medicine → Multiple pregnancy
Classification
Question
EEMQAnswer Bank
Correct Answer
Explanation
Accurate fetal mapping is essential when invasive prenatal diagnosis is performed in a multiple pregnancy. RCOG recommends documenting fetal positions using a fixed maternal anatomical orientation, for example maternal left and right or upper and lower, rather than relying only on numerical labels. Numerical designations may become ambiguous as fetal positions change. When there are no distinguishing fetal features, two operators should confirm the labelling of samples. Reliable mapping is particularly important because any subsequent selective intervention must be directed to the correct fetus. Sampling order, fetal weight or arbitrary alphabetical labels are less robust than a reproducible maternal anatomical reference.
Option Validity
A) Numerical labels alone may become ambiguous as fetal positions change.
B) Estimated fetal weight is not a sufficiently reliable identifier.
C) Fetal sex may not distinguish the fetuses and is not the recommended mapping system.
E) Sampling order alone does not provide reliable continuing fetal identification.
F) Placental size is not the recommended fetal mapping method.
G) Arbitrary alphabetical labels without anatomical orientation may be ambiguous.
H) Formal fetal mapping is important during invasive diagnosis in multiple pregnancy.
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. doi:10.1111/1471-0528.16821.