Table 1.

Distribution of fetal and maternal characteristics

	Full dataset (n = 2022)			Restricted to medical cards, or medical cards and logs (n = 1180)
	Missing measurement (%)	Mean/median (minimum, maximum)	1st quartile/3rd quartile	Missing measurement (%)	Mean/median (minimum, maximum)	1st quartile/3rd quartile
Head circumference (cm)	1104 (54.6)	35.55/36 (26, 59)	35/36	262 (22.2)	35.55/36 (26, 59)	35/36
Chest circumference (cm)	1109 (54.8)	34.67/35 (24, 57)	34/36	267 (22.6)	34.67/35 (24, 57)	34/36
Neonatal length (cm)	239 (11.8)	51.73/52 (34, 64)	50/53	54 (4.6)	51.68/52 (34, 64)	50/53
Birthweight (kg)	59 (2.9)	3.40/3.10 (0.00, 5.70)	0.95/3.80	33 (2.8)	3.40/3.10 (0.00, 5.70)	0.95/3.80
Gestation length (weeks)	470 (23.2)	39.75/40 (27, 48)	40/40	77 (6.5)	39.72/40 (27, 48)	39/40
Trimester of exposure (1–3)	75 (3.7)	2.07/2 (1, 3)	1/3	58 (4.9)	2.10/2 (1, 3)	1/3
Baby sex (male = 0, female = 1)	242 (12.0)	0.51/1 (0, 1)	0/1	37 (3.1)	0.51/1 (0, 1)	0/1
Singleton versus twin (singleton = 1, twin = 2)	52 (2.6)	1.02/1 (1, 2)	1/1	30 (2.5)	1.02/1 (1, 2)	1/1
Maternal height (cm)	1361 (67.3)	162.49/162 (145, 182)	158/166	519 (44.0)	162.49/162 (145, 182)	158/166
Maternal weight at 1st clinic visit (kg)	1756 (86.8)	69.15/67 (45, 115)	61/76	914 (77.5)	69.15/67 (45, 115)	61/76
Fetal dose (Gy)	54 (2.7)	0.061/0.009 (0.000, 2.263)	0.001/0.046	41 (3.5)	0.046/0.007 (0.000, 1.594)	0.001/0.031