Table 1:

Distribution of numbers of fetuses providing data as a function of the indication for neurosonography

Indication	No.	Mean Gestational Week	Min	Max	Median
CMV seroconversion	35	33.63	30	40	33
Ventricular asymmetry	54	31.78	21	37	32
Abnormal head circumference	15	34.27	29	38	35
Abnormal posterior fossa	10	31.60	26	35	32
Cystic lesions	8	33.75	31	37	33
Family history of CNS illness	6	32.33	31	34	32
Midline abnormalities	6	31.67	23	37	32
Obstetric complications and extra-CNS anatomic findings	28	31.00	23	36	32