. 2010;2(2):74–87.

Table IV. Effects and risks after exposure to ionizing radiation in utero, and spontaneous frequency (no radiation) (Kal et al., 2005).

Time after conception (w)	Effect	Risk per 0.01 Gy	Spontaneous frequency
0 - 2	Prenatal death*	0.01 - 0.001	0.3 - 0.6
8 - 15	Mental reatardation	0.004	0.005
8 - 15	IQ decrease§	0.004	0.005
16 - 25	Mental retardation	0.001	0.005
16 - 25	IQ decrease#	0.001	0.005
0 - 38	Leukemia, solid tumors	0.003 - 0.004	0.002 - 0.003
0 - 38	In childhood	0.003 - 0.004	0.002 - 0.003

Based on experimental data. ¥Above threshold dose of 0.1 - 0.2 Gy. §Reduction of 21 IQ points per 1 Gy above threshold of about 0.05 Gy. Trheshold dose for mental retardation about 0.06 Gy, #Reduction of 13 IQ points per 0.1 Gy above threshold dose of about 0.05 gy, threshold dose for mental retardation about 0.25 Gy.