MULTISCAN--a Scandinavian multicenter second trimester obstetric ultrasound and serum screening study

Area of Science:

• Prenatal diagnostics
• Maternal-fetal medicine
• Medical imaging

Background:

• Second trimester screening is crucial for detecting fetal anomalies in low-risk populations.
• Evaluating the efficacy of ultrasound versus biochemical markers is essential for optimizing prenatal care.

Purpose of the Study:

• To assess the detection rates of ultrasound screening for neural tube defects (NTD), abdominal wall defects (AWD), and Down's syndrome (DS) in low-risk pregnancies.
• To compare ultrasound screening performance against biochemical serum screening (double test).

Main Methods:

• A prospective multicenter study included 27,844 low-risk women undergoing second trimester ultrasound.
• Serum screening (double test) was performed on 10,264 women.
• Ultrasound and serum tests were conducted at 17-19 weeks gestation.

Main Results:

• Ultrasound detected 79.4% of NTDs, 85.7% of AWDs, and 6.3% of DS cases.
• In women with both tests, serum screening showed higher detection rates for DS (46.2%) compared to ultrasound (7.7%).
• False positive rates for ultrasound were 0.01% for NTD/AWD and 0.1% for DS, while for serum screening they were 3.3% and 4.0%, respectively.

Conclusions:

• Second trimester ultrasound offers acceptable detection for NTD and AWD in low-risk populations.
• Ultrasound screening demonstrated a low detection rate for fetal DS.
• Biochemical serum screening proved more effective than the applied ultrasound method for DS detection in this study.