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Maternal prenatal screening programs that predict trisomy 21, trisomy 18, and neural tube defects in offspring
Yiming Chen1,2, Wenwen Ning2, Yezhen Shi3
1Department of Prenatal Diagnosis and Screening Center, Hangzhou Women's Hospital (Hangzhou Maternity and Child Health Care Hospital), Hangzhou, Zhejiang.
Insights
The combined first- and second-trimester screening (FSTCS) program is superior for identifying high-risk pregnancies for trisomy 21 and 18. This approach significantly reduces false positives compared to other screening methods.
Area of Science:
- Perinatal Medicine
- Prenatal Diagnostics
- Genetics
Background:
- Maternal screening programs are crucial for identifying fetal aneuploidies.
- Different screening strategies exist, including first-trimester screening (FTS), individual second-trimester screening (ISTS), and combined first- and second-trimester screening (FSTCS).
- Comparative efficacy of these programs for trisomy 21, trisomy 18, and neural tube defects (NTDs) requires evaluation.
Purpose of the Study:
- To compare the efficacy of FTS, ISTS, and FSTCS in predicting trisomy 21, trisomy 18, and NTDs.
- To assess detection rates, positivity rates, positive predictive values (PPVs), and false positive rates (FPRs) for each screening program.
Main Methods:
- A retrospective cohort study of 108,118 pregnant women in Hangzhou, China (2019).
- Data collected from women undergoing FTS (n=72,096), ISTS (n=36,022), and FSTCS (n=67,631).
- Analysis of screening performance metrics for trisomy 21 and 18.
Main Results:
- FSTCS demonstrated lower high and intermediate risk positivity rates for trisomy 21 compared to ISTS and FTS (P < 0.05).
- Detection rates for trisomy 21 were 48.57% (FTS), 68.75% (ISTS), and 63.64% (FSTCS).
- Detection rates for trisomy 18 were 66.67% (FTS/FSTCS) and 60.00% (ISTS). PPVs were highest with FTS, while FPR was lowest with FSTCS.
Conclusions:
- FSTCS is superior to FTS and ISTS, significantly reducing high-risk pregnancies for trisomy 21 and 18.
- No significant difference was observed in the detection rates of fetal trisomy 21 and 18 among the three programs.
- FSTCS offers improved risk stratification with a lower false positive rate.
Objective:
To determine the efficacy of three different maternal screening programs (first-trimester screening [FTS], individual second-trimester screening [ISTS], and first- and second-trimester combined screening [FSTCS]) in predicting offspring with trisomy 21, trisomy 18, and neural tube defects (NTDs).
Methods:
A retrospective cohort involving 108,118 pregnant women who received prenatal screening tests during the first (9-13+6 weeks) and second trimester (15-20+6 weeks) in Hangzhou, China from January-December 2019, as follows: FTS, 72,096; ISTS, 36,022; and FSTCS, 67,631 gravidas.
Result:
The high and intermediate risk positivity rates for trisomy 21 screening with FSTCS (2.40% and 5.57%) were lower than ISTS (9.02% and 16.14%) and FTS (2.71% and 7.19%); there were statistically significant differences in the positivity rates among the screening programs (all P < 0.05). Detection of trisomy 21 was as follows: ISTS, 68.75%; FSTCS, 63.64%; and FTS, 48.57%. Detection of trisomy 18 was as follows; FTS and FSTCS, 66.67%; and ISTS, 60.00%. There were no statistical differences in the detection rates for trisomy 21 and 18 among the 3 screening programs (all P > 0.05). The positive predictive values (PPVs) for trisomy 21 and 18 were highest with FTS, while the false positive rate (FPR) was lowest with FSTCS.
Conclusion:
FSTCS was superior to FTS and ISTS screening and substantially reduced the number of high risk pregnancies for trisomy 21 and 18; however, FSTCS was not significantly different in detecting fetal trisomy 21 and 18 and other confirmed cases with chromosomal abnormalities.
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