Table 2

Characteristics of children with an ASD diagnosis and their mothers, Denmark 1995–2003

No ASDASDp Value
Maternal age<0.001
 20–2481 996 (14.0)550 (15.2)
 25–29218 242 (37.3)1259 (34.8)
 30–34199 901 (34.2)1218 (33.7)
 35–3974 442 (12.7)508 (14.0)
 40+10 749 (1.8)84 (2.3)
Parity<0.001
 Primiparous248 429 (42.4)1801 (49.8)
 Multiparous336 896 (57.6)1818 (50.2)
Educational level (years)<0.001
 Lower (9–10)115 139 (22.7)906 (27.0)
 Intermediate (11–16)349 884 (69.0)2145 (63.8)
 Higher (17+)42 283 (8.3)310 (9.2)
 Smoking<0.001
 Non-smoker454 685 (78.0)2713 (75.3)
 Smoker or stopped in pregnancy128 009 (22.0)889 (24.7)
Multiplicity0.028
 Singletons561 598 (96.1)3501 (96.9)
 Twins22 389 (3.8)107 (3.0)
 Triplets703 (0.1)7 (0.1)
 Quadruplets21 (0.0)0 (0.0)
Gestational age (weeks)<0.001
 20–271624 (0.3)20 (0.5)
 28–314114 (0.7)29 (0.8)
 32–3631 268 (5.4)228 (6.4)
 37–41496 232 (85.3)2996 (83.5)
 42+48 158 (8.3)315 (8.8)
Birth weight (g)<0.001
 500–1499500 (0.9)44 (1.2)
 1500–249924 414 (4.2)196 (5.5)
 2500+550 889 (94.9)3346 (93.3)
  • Data shown as numbers (percentages). Children without autism spectrum disorders (ASD) compared with children with ASD.