Clinical results after the implementation of cell-free fetal DNA detection in maternal plasma

Detection of cell-free fetal DNA in maternal blood is a type of noninvasive prenatal diagnosis test (NIPT), which has already been known for some time but has not yet been introduced in most of public hospitals in Spain. How the implementation of cell-free fetal DNA (cffDNA) in a contingent protocol has influenced the aneuploidy screening in our hospital is described.

Two cohorts of patients with positive combined screening were compared: the first one (years 2012-2013, 5747 patients) from a period of time in which the protocol valid until March 2016 - that included the use of invasive procedures - was applied; and the second one in which the current protocol - that included NIPT versus invasive procedures - was applied (first 7 months after protocol implementation, 898 patients).

Comparison of both periods resulted in a 60.5% reduction of invasive procedures (P < 0,001) preserving the same chromosomopathy detection rate. The ratio of positive invasive procedures-indicated invasive procedures was improved by 15% in the first period to 50% in the second period (P = 0.01).

NIPT introduction has caused a significant reduction of 60.5% of IP in high chromosomopathy risk patients after combined screening without modifying detection rate.