Table 3. Distribution of the mean transcerebellar diameter in the population.

GA: gestational age; TCD: transcerebellar diameter; SD: standard deviation

GA (in weeks)	TCD (mm) mean ± SD	Frequency	Percentage
18	18.5 ± 0.4	25	5.0
19	20.7 ± 0.3	35	7.0
20	21.1 ± 0.2	40	8.0
21	21.8 ± 0.2	25	5.0
22	22.6 ± 0.3	32	6.4
23	24.3 ± 0.3	15	3.0
24	25.2 ± 0.4	10	2.0
25	27.0 ± 0.3	8	1.6
26	29.5 ± 0.4	10	2.0
27	30.3 ± 0.4	11	2.2
28	33.4 ± 0.5	48	9.6
29	34.8 ± 1.2	24	4.8
30	35.6 ± 1.5	22	4.4
31	37.2 ± 1.5	14	2.8
32	38.4 ± 1.6	41	8.2
33	40.2 ± 1.5	22	4.4
34	42.4 ± 1.5	10	2.0
35	43.8 ± 1.6	14	2.8
36	45.6 ± 1.8	35	7.0
37	47.4 ± 1.8	11	2.2
38	48.5 ± 1.9	30	6.0
39	50.2 ± 2.2	10	2.0
40	51.5 ± 2.5	8	1.6
Total		500	100