Noninvasive first-trimester screening for fetal aneuploidy

Area of Science:

• Maternal-Fetal Medicine
• Prenatal Diagnostics
• Genetics

Background:

• Fetal aneuploidy screening in the first trimester is crucial for early detection and management.
• Noninvasive methods offer a safer alternative to invasive diagnostic procedures.
• Existing literature was reviewed to assess current noninvasive screening modalities.

Purpose of the Study:

• To review and evaluate noninvasive methods for first-trimester fetal aneuploidy screening.
• To assess the feasibility and potential of ultrasound and biochemical markers.
• To identify gaps in current knowledge regarding diagnostic accuracy and clinical application.

Main Methods:

• Comprehensive MEDLINE search and cross-referencing of studies up to June 1996.
• Review of three potential noninvasive modalities: ultrasound, maternal biochemical markers, and fetal cell analysis.
• Analysis of reported sensitivities and limitations of each method.

Main Results:

• Ultrasound (nuchal translucency thickness) combined with maternal age shows up to 86% sensitivity for trisomy 21.
• Maternal biochemical markers independently achieve up to 60% sensitivity.
• Established sensitivity, specificity, and predictive values in large, low-risk populations are not yet determined.

Conclusions:

• Noninvasive first-trimester screening for fetal aneuploidy using ultrasound and biochemical markers is feasible.
• Analysis of fetal cells from maternal sources may offer definitive diagnosis but is not clinically available.
• Further research is needed to establish clinical feasibility and comprehensive management paradigms for these early screening methods.