1) Σε αυτή την μελέτη φαίνεται ότι οι γυναίκες  προτιμούν την αυχενική διαφάνεια ως κύρια μέθοδο screening

για να ελέγξουν το μωρό τους για τον κύριο λογά ότι αυτή εκτελείται εξ ολοκλήρου στο πρώτο τρίμηνο και σε περίπτωση προβλήματος μπορεί κάποιος να τερματίσει την κύηση χωρίς να αναγκαστεί να περιμένει έως το δεύτερο τρίμηνο.
U O G 2004 Dec;24(7):735-9.
Factors affecting women's preference for type of prenatal screening test for chromosomal anomalies.
Spencer K, Aitken D.
CONCLUSIONS: A first-trimester test is preferred by the majority of women over a test with marginally higher detection rate that delivers results later in pregnancy. Timing and rapid reporting of results appear to influence women's choice of test.

2) Αλλη ανεξαρτητη μελετη οπου συγκρινει τα screening σε πρωτο και δευτερο τριμηνο 
NEJM 2005 Nov 10;353(19):2001-11.
First-trimester or second-trimester screening, or both, for Down's syndrome.
Malone FD, Canick JA, Ball RH, Nyberg DA, Comstock CH, Bukowski R, Berkowitz RL, Gross SJ, Dugoff L, Craigo SD, Timor-Tritsch IE, Carr SR,
First-trimester combined screening at 11 weeks of gestation is better than second-trimester quadruple screening but at 13 weeks has results similar to second-trimester quadruple screening. Both stepwise sequential screening and fully integrated screening have high rates of detection of Down's syndrome, with low false positive rates.

3) Αλλη μελετη που τονιζει το οικονιμικο ωφελος της στρατηγικής ελέγχου στο πρώτο τρίμηνο
BMJ 2001 Aug 25;323(7310):423-5.
Screening for Down's syndrome: effects, safety, and cost effectiveness of first and second trimester strategies.
Gilbert RE, Augood C, Gupta R, Ades AE, Logan S, Sculpher M, van Der Meulen JH.

The choice of screening strategy should be between the integrated test, first trimester combined test, quadruple test, or nuchal translucency measurement depending on how much service providers are willing to pay, the total budget available, and values on safety. Screening based on maternal age, the second trimester double test, and the first trimester serum test was less effective, less safe, and more costly than these four options.