Table 2

Comparison of perinatal factors between cases and controls with statistically significant ORs shown in italics

Perinatal factorsCases N=176, %Controls N=704, %Unadjusted OR (95% CI)Age and smoking adjusted OR (95% CI)—listwise deletionAge and smoking adjusted OR (95% CI)—imputation of missing value
Pre-eclampsia11 (6.3)23 (3.3)1.98 (0.94 to 4.18)1.94 (0.88 to 4.28)1.92 (0.91 to 4.09)
Gestational hypertension19 (10.8)71 (10.1)1.09 (0.62 to 1.89)1.21 (0.67 to 2.17)1.13 (0.64 to 2.01)
Placenta praevia3 (1.7)4 (0.6)3.00 (0.67 to 13.40)3.46 (0.76 to 15.65)3.45 (0.76 to 15.62)
Abruption1 (0.6)4 (0.6)1.00 (0.11 to 8.95)1.31 (0.14 to 12.66)1.04 (0.12 to 9.41)
Other APH19 (10.8)77 (10.9)0.99 (0.58 to 1.68)0.98 (0.56 to 1.72)0.96 (0.56 to 1.65)
Previous miscarriage18 (10.2)103 (14.6)0.67 (0.39 to 1.13)0.83 (0.48 to 1.43)0.70 (0.41 to 1.19)
Preterm birth24 (13.6)47 (6.7)2.23 (1.31 to 3.79)2.09 (1.16 to 3.76)2.23 (1.29 to 3.85)
Low birth weight17 (9.7)38 (5.4)1.87 (1.03 to 3.39)1.81 (0.94 to 3.45)1.78 (0.97 to 3.28)
Low Apgar at 1 min30 (17.1)107 (15.4)1.14 (0.73 to 1.78)1.14 (0.71 to 1.84)1.15 (0.73 to 1.81)
Low Apgar at 5 min8 (4.6)7 (1.0)5.01 (1.73 to 14.54)4.91 (1.46 to 16.51)5.70 (1.93 to 16.78)
Delivery by caesarean55 (31.3)143 (20.4)1.77 (1.23 to 2.56)2.25 (1.50 to 3.36)2.07 (1.41 to 3.05)
Instrumental delivery26 (14.8)144 (20.5)0.66 (0.41 to 1.04)0.68 (0.41 to 1.13)0.67 (0.42 to 1.08)
Intrauterine growth restriction23 (13.4)71 (10.3)1.41 (0.85 to 2.36)1.20 (0.68 to 2.12)1.35 (0.80 to 2.23)
  • APH, antepartum haemorrhage.