Are nuchal translucency, pregnancy associated plasma protein-A or free-beta-human chorionic gonadotropin depending on maternal age? A multicenter study of 8,116 pregnancies.
BACKGROUND
First-trimester screening according to Nicolaides uses maternal age to obtain a common background risk for trisomy 21. The likelihood ratios by nuchal translucency, free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A are not with respect to maternal age. It was the aim of this study to investigate if likelihood ratios should better take care of it.


METHODS
Pearson's correlation and different models of regression analysis had been performed on the results of 8,116 first-trimester screenings. The total number of pregnancies was subdivided into three subgroups of healthy fetuses (n = 8,038); fetuses with Down's syndrome (n = 46) and fetuses with other genetic abnormalities (n = 32). Statistical testing was applied to each of the three groups.


RESULTS
Strong independence from maternal age could be found for each of the first-trimester screening measurement parameter, as well for healthy and as for affected fetuses. Neither Pearson's test nor nonlinear regression models could detect a correlation. Accordingly significance of Pearson's test is not given.


CONCLUSIONS
First-trimester screening would not be improved by considering the maternal age in the calculation of the likelihood ratios. Therefore the currently used algorithm is adequate. According, to the results, it seems to be proper as well to disregard the maternal age in newer test strategies advanced first-trimester screening (AFS) at all.
Schmidt
Peter
P
University Women's Hospital, Hannover, Germany. info@dr-schmidt.info
Pruggmayer
Michael
M
Steinborn
Andrea
A
Schippert
Cordula
C
Staboulidou
Ismini
I
Hillemanns
Peter
P
Scharf
Alexander
A
D000293:Adolescent; D000328:Adult; D000782:Aneuploidy; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000032:analysis*; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008423:Maternal Age; D008875:Middle Aged; D048208:Nuchal Translucency Measurement; D011247:Pregnancy; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D012044:Regression Analysis; D012189:Retrospective Studies
D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A