CELL FREE DNA TESTING AFTER COMBINED TEST: FACTORS AFFECTING THE UPTAKE.

Maiz N1,2, Alzola I1, Murua EJ1, Rodríguez Santos J1.

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Abstract

OBJECTIVE:

Firstly, to assess what was the uptake of cell free DNA (cfDNA) testing after a combined test and the maternal and fetal factors that influenced this decision, and secondly, to assess the uptake and factors that influence the choice of invasive testing.

METHODS:

This observational retrospective study included 1,083 singleton pregnancies who had a combined test for screening for Down syndrome between 11+0 and 13+6 weeks. Multivariate logistic regression analysis was used to determine which factors affected the uptake of cfDNA test and invasive testing among risk for trisomies 21, 18 and 13, maternal characteristics and fetal nuchal translucency (NT) thickness.

RESULTS:

257 (23.7%) women had a cfDNA test, 89 (8.2%) had an invasive test and 737 (68.1%) had no further test. The uptake of cfDNA increased with the risk for trisomies (p < 0.001), maternal age (p=0.013) and was higher in nulliparous women (p=0.004). The uptake of invasive test increased with the risk for trisomies (p < 0.001) and NT thickness (p < 0.001).

CONCLUSIONS:

This study shows that the uptake of cfDNA testing increases with the risk for trisomies, maternal age and is higher in nulliparous, whereas the uptake of invasive testing increases with the risk for trisomies and NT thickness.