Antenatal screening - the first and second trimester

Area of Science:

• Medical screening
• Prenatal diagnostics
• Genetics

Background:

• Antenatal screening detects chromosomal abnormalities like Down syndrome and Edward syndrome, and open neural tube defects.
• Screening occurs in the first or second trimester of pregnancy.
• Prevalence rates are 1 in 500 for Down syndrome, 1 in 3000 for Edward syndrome, and 1 in 750 for neural tube defects.

Purpose of the Study:

• To outline antenatal screening protocols for common fetal abnormalities.
• To describe the methodologies employed in first and second-trimester screening.
• To detail the specific screening approach implemented in Victoria, Australia.

Main Methods:

• First-trimester screening involves a blood test combined with nuchal translucency and nasal bone ultrasound.
• Second-trimester screening utilizes a blood test.
• The study focuses on the protocol used in Victoria, Australia.

Main Results:

• First-trimester screening integrates biochemical markers and ultrasound measurements.
• Second-trimester screening relies solely on maternal serum markers.
• The Victorian protocol standardizes screening procedures.

Conclusions:

• Antenatal screening is crucial for identifying pregnancies at increased risk of major fetal abnormalities.
• Different screening modalities are available depending on the gestational trimester.
• Standardized protocols, like Victoria's, ensure consistent and effective prenatal care.