Controls n = 163

Cases n = 121

p-value

Developmental delay at 3 years old

4.3% (7)

6.6% (8)

0.429

Developmental characteristics

Pervasive developmental disorder

0.6% (1)

1.7% (2)

0.577

Attention deficit hyperactivity disorder

0% (0)

0.8% (1)

0.426

Language difficulty

2.5% (4)

0.8% (1)

0.398

Motor difficulty

0% (0)

1.7% (2)

0.181

Intellectual disability

1.2% (2)

1.7% (2)

0.763

Gestational weeks at delivery

34 (n = 31)

9.7% (3)

35 (n = 31)

3.2% (1)

36 (n = 59)

6.8% (4)

38 (n = 68)

2.9% (2)

39 (n = 46)

8.7% (4)

40 (n = 49)

2.0% (1)