Comparing first trimester screening performance: routine care gynaecologists' practices vs. prenatal centre

Ultraschall Med. 2007 Jun;28(3):291-5. doi: 10.1055/s-2006-926714. Epub 2007 Feb 21.


Objective: To evaluate and compare the screening performance for fetal trisomy 21 in the first trimester of pregnancy in general gynaecologists' practices and specialised centres for prenatal care in Germany.

Methods: This study included 15,026 serum samples analysed in our laboratory for free beta-human chorionic gonadotropin (hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11-14 weeks of gestation between 1.1.2000 and 31.12.2003. Fetal risk for trisomy 21 was calculated using nuchal translucency (NT) values and crown-rump-lengths (CRL), measured either in general gynaecologists' practices or in a tertiary level prenatal centre. The detection rate for a fixed risk cut-off (1:300) and a fixed false-positive rate (5 %) was calculated for NT, serum biochemistry, maternal age and the combination of these components.

Results: The estimated risk for trisomy 21 based on maternal age, fetal NT and maternal serum free beta-hCG and PAPP-A was 1 in 300 or greater in 5.1 % (362 of 6897) and 8 % (329 of 3840) of normal pregnancies, and in 78.9 % (15 of 19) and 88.5 % (23 of 26) of those with trisomy 21. For a fixed false-positive rate of 5 %, the respective detection rates of screening for fetal Down's syndrome by maternal age and serum free beta-hCG and PAAP-A, maternal age and fetal NT and by maternal age, fetal NT and maternal serum biochemistry were (general gynaecologists' practices/prenatal centre) 68.4/69.2 %, 42.1/65.4 % and 78.9/88.5 %, respectively.

Conclusion: The screening results are satisfactory in both general gynaecologists' practices and a prenatal centre.

Publication types

  • Comparative Study

MeSH terms

  • Blood Chemical Analysis
  • Diagnostic Tests, Routine
  • Down Syndrome / diagnosis
  • Down Syndrome / embryology*
  • Down Syndrome / epidemiology
  • Female
  • Gynecology
  • Humans
  • Karyotyping
  • Mass Screening / methods*
  • Mass Screening / standards
  • Pregnancy
  • Pregnancy Trimester, First*
  • Prenatal Care / methods
  • Prenatal Care / standards
  • Risk Factors
  • Sensitivity and Specificity