Analysis of Prenatal Serological Screening of 116 Pregnant Women with Trisomy 21 Syndrome Fetus.

Background: Prenatal serological screening is commonly used to screen for trisomy 21 syndrome (T21); however, it carries a risk of missed detection. In this study, we explored how to reduce missed diagnosis of T21 in serological screening.
Methods: A total of 116 pregnant women with T21 fetuses confirmed by prenatal diagnosis were evaluated. Serological screening and non-invasive prenatal test (NIPT) findings were analyzed.
Results: Twenty-nine T21 fetuses were missed in serological screening; the missed diagnosis rate was 25%, 67.65% of the missed cases were of moderate risk, and 79.31% of the missed pregnant women were under 35 years of age. Nuchal translucency (NT) and the free beta subunit of human chorionic gonadotropin (free-HCGβ) were higher in the detected T21 cases than in the missed T21 cases, while alpha-fetoprotein (AFP) levels were decreased. Forty-eight pregnant women who underwent NIPT in the second trimester were at high-risk for T21.
Conclusions: Prenatal screening should not be ignored in young pregnant women. For serological screening, moderate risk and abnormal single serum markers should also receive greater attention. NIPT can be extended to first-tier screening.