Table 1.

Concordance analysis of the foetal sex detected by cffDNA and the traditional prenatal approaches

Gestational week (wa) of blood sampling	cffDNAb	CVSc	Amniocentesis	Concordance (%)
	(Foetal sex)	(Foetal sex)	(Foetal sex)
12	44	32	12	100
	(Md = 24; Fe = 20)	(M = 17; F = 15)	(M = 7; F = 5)
13	44	20	24	100
	(M = 22; F = 22)	(M = 8; F = 12)	(M = 14; F = 10)
14	44	9	35	100
	(M = 24; F = 20)	(M = 5; F = 4)	(M = 19; F = 16)

^aGestational week

^bCell-free foetal DNA

^cChorionic villous sampling

^dMales

^eFemales