Table 1: Maternal characteristics: maternal country of birth: 1: Sweden, 2: Mediterranean countries. Year of birth of infant with neuronal migration disorder. BMI: weight in kg/length in cmX2, “—”: missing information in length or weight. Smoking: 1: no, 2: 1–9 cigarettes/day, 3: ≥10/day, “—”: missing information. Delivery: Vag: normal vaginal delivery, Cs: Cesarean section, Ve: vacuum extraction.

Age Origin Year of birth of infant BMI Smoking Delivery 29 1 1982 — — Cs 34 1 1982 19.6 1 Vag 28 1 1982 20.8 2 Cs 29 1 1986 21.7 1 Vag 26 1 1986 — 2 Vag 20 1 1987 17.6 1 Vag 23 1 1988 19.5 2 Vag 32 1 1988 — 1 Vag 30 1 1991 — 1 Vag 19 1 1991 19.7 3 Ve 25 1 1993 23.7 1 Ve 34 1 1993 19.8 1 Cs 37 1 1993 28.5 1 Vag 30 1 1994 20.2 1 Cs 31 2 1998 20.0 1 Vag 23 2 1998 24.4 1 Vag 35 2 1999 — 1 Vag