Analysis of Quality of Nuchal Translucency Measurements: Its Role in Prenatal Diagnosis

Table 2

Distribution NT values, expressed in centiles, according to the different criteria (operator, number of consecutive scans, period, CRL values, FMF certification, and professional profile).

	NT
	≥ 95th centile		≤ 5th centile		Total
	𝑛	%	𝑛	%	𝑛
Operator
Obs 1	186	6,7**	52	1,9**	2.776
Obs 2	17	2,5**	9	1,3**	669
Obs 3	20	5,7	0	0,0**	352
Obs 4	62	6,3**	38	3,9	987
Obs 5	3	2,1	1	0,7**	141
Obs 6	5	2,5	41	20,6**	199
Obs 7	40	2,8**	92	6,5**	1.407
Obs 8	8	5,1	38	24,4**	156
Obs 9	200	6,7**	43	1,4**	2.968
Obs 10	107	3,6**	190	6,4**	2.969
Obs 11	15	7,0	8	3,8	213
Obs 12	79	4,6	76	4,4	1.712
Obs 13	1	1,8	9	16,4**	55
Obs 14	1	0,4**	8	3,3	243
𝑛^∘ US
First 100 US	63	4,2	117	7,9*	1.486
>100 US	686	5,1	507	3,8*	13.492
Period
2003–2006	430	6,5*	328	5,0*	6.615
2007–2009	281	3,9*	172	2,4*	7.225
CRL (mm)
≤ 60	466	5,6*	381	4,6*	8.287
>60	283	4,2*	243	3,6*	6.691
FMF
Certified	61	3,2*	42	2,2*	1.878
Noncertified	688	5,3*	582	4,4*	13.1
Profile
Dedicated	691	5,1*	500	3,7*	13.488
Nondedicated	58	3,9*	124	8,3*	1.49
Overall	749	5,0	624	4,2	14.978

Obs: observer or operator.
n° US: number of scans performed.
FMF: Fetal Medicine Foundation.
* 𝑃<0.05 (comparison between criteria).
** 𝑃<0.05 (comparison between obstetricians and expected binomial distribution).