[Combined test in the first trimester of pregnancy in 3,316 unselected pregnant patients for diagnosing Down syndrome].
The high detection rate (DR) for Down syndrome pregnancies which can be achieved by measuring fetal nuchal translucency (NT) early in pregnancy can be improved by combining it with placental hormones (PAPP-A, f beta hCG) and maternal age ("combined test"). In this study we wanted to assess the DR using the "combined test" in an unselected population of self-referred pregnant women at a false positive rate (FPR) of about 5%.


METHODS
NT, PAPP-A, f beta hCG and maternal age were measured in all women with singleton pregnancies who booked for delivery in our hospital from 1.12.97 to 31.12.99 and who were between 10 and 13 completed weeks of gestation (crown-rump-length 35-70 mm). Calculation of the specific Down risk was done with the computer program Alpha, Version 5aa (Logical medical systems, London).


RESULTS
A total of 3316 women were tested. Out of 10 Down pregnancies, which occurred in this period of time 9 could be detected with the test. 137 women had a positive test result but a non-Down pregnancy (FPR 4.1%).


CONCLUSIONS
The combined test is an excellent test for the detection of Down syndrome pregnancies in a low-risk population.


CONCLUSIONS
The constant increase in maternal age at the time of delivery can also lead to an improved DR if a simple age dependant protocol for Down-detection is used, but only at the price of a much higher number of amniocenteses and subsequent abortions. The DR for Down syndrome can be increased much more markedly using the "combined test" at a much lower FPR (approximately 5%).
Hafner
E
E
Ludwig Boltzmann Institut für klinische Gynäkologie und Geburtshilfe, Donauspital am SMZO, Wien, Osterreich. erich.hafner@smz.magwien.gv.at
Schuchter
K
K
Metzenbauer
M
M
Höfinger
D
D
Stangl
G
G
Philipp
K
K
D000025:Abortion, Eugenic; D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D009333:Neck / Q000000981:diagnostic imaging; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D018566:Pregnancy, High-Risk; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D016216:Ultrasonography, Prenatal
D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A