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Prefrontal space ratio in second- and third-trimester screening for trisomy 21
1Department of Obstetrics and Gynaecology, University of Tuebingen, Tuebingen, Germany.
Summary
The prefrontal space ratio (PFSR) is a novel ultrasound marker for detecting trisomy 21 in fetuses. This simple measurement effectively identifies fetuses with Down syndrome during the second and third trimesters.
Area of Science:
- Prenatal Medicine
- Fetal Ultrasound
- Genetics
Background:
- Trisomy 21, or Down syndrome, is a common chromosomal disorder.
- Accurate prenatal screening is crucial for timely diagnosis and management.
- Novel imaging markers are needed to improve screening accuracy.
Purpose of the Study:
- To evaluate the utility of the prefrontal space ratio (PFSR) as a screening tool.
- To compare PFSR in euploid fetuses versus fetuses with trisomy 21.
- To assess PFSR in the second and third trimesters of pregnancy.
Main Methods:
- Retrospective analysis of fetal facial ultrasound images.
- Measurement of PFSR in 279 euploid and 91 trisomy 21 second- and third-trimester fetuses.
- Statistical comparison of PFSR values between groups, controlling for gestational and maternal age.
Main Results:
- PFSR was significantly lower in fetuses with trisomy 21 (0.2 ± 0.38) compared to euploid fetuses (0.97 ± 0.29).
- PFSR was below the 5th centile in 79.1% of trisomy 21 fetuses versus 5.0% of euploid fetuses.
- PFSR demonstrated independence from maternal and gestational age.
Conclusions:
- The PFSR is a simple and effective sonographic marker for trisomy 21 screening.
- This ratio can aid in identifying fetuses at higher risk for Down syndrome.
- PFSR offers a valuable addition to second- and third-trimester prenatal screening protocols.
