Table 5.
Contribution of the individual risk factors to the occurrence of ‘Adverse Outcome’
| A Forward approach | |||||
|---|---|---|---|---|---|
| Multiple imputed dataset 1 | Multiple imputed dataset 2 | Multiple imputed dataset 3 | |||
| Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI |
| Neighbourhood deprivation | NI | Neighbourhood deprivation | NI | Neighbourhood deprivation | NI |
| Age <20 years | NI | Age <20 years | NI | Age <20 years | NI |
| Ethnicity Afro-African | NI | Ethnicity Afro-African | NI | Ethnicity Afro-African | NI |
| Ethnicity non-Western other | 1.20 (1.05; 1.37) | Ethnicity non-Western other | 1.20 (1.05; 1.38) | Ethnicity non-Western other | 1.19 (1.03; 1.36) |
| Net income Euro <1,200 | 1.39 (1.20; 1.62) | Net income Euro <1,200 | 1.19 (1.02; 1.40) | Net income Euro <1,200 | 1.23 (1.05; 1.44) |
| Occupation non-working | NI | Occupation non-working | NI | Occupation non-working | NI |
| Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI |
| Marital status single | NI | Marital status single | NI | Marital status single | NI |
| BMI intake <20 | 1.34 (1.11; 1.61) | BMI intake <20 | 1.34 (1.11; 1.61) | BMI intake <20 | 1.34 (1.11; 1.61) |
| Smoking during pregnancy | 1.21 (1.06. 1.37) | Smoking during pregnancy | 1.22 (1.08; 1.39) | Smoking during pregnancy | 1.17 (1.03; 1.33) |
| Recreational drug use | NI | Recreational drug use | NI | Recreational drug use | NI |
| Nullipara | 1.81 (1.59; 2.07) | Nullipara | 1.83 (1.61; 2.09) | Nullipara | 1.84 (1.61; 2.10) |
| Unplanned pregnancy | NI | Unplanned pregnancy | NI | Unplanned pregnancy | NI |
| No folic acid use | NI | No folic acid use | 1.18 (1.02; 1.35) | No folic acid use | NI |
| Complications previous pregnancy | 1.33 (1.05; 1.69) | Complications previous pregnancy | 1.33 (1.05; 1.69) | Complications previous pregnancy | 1.33 (1.04; 1.68) |
| Gestational age booking ≥14 weeks | NI | Gestational age booking ≥14 weeks | NI | Gestational age booking ≥14 weeks | NI |
| Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI |
| Comorbidity | NI | Comorbidity | NI | Comorbidity | NI |
| Sexual transmittable diseases | NI | Sexual transmittable diseases | NI | Sexual transmittable diseases | NI |
| Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | |||
| Afro-African | 1.37 (1.17; 1.59) | Afro-African | 1.40 (1.20; 1.63) | Afro-African | 1.39 (1.19; 1.62) |
| Interaction: single marital status × age <20 years | NI | Interaction: single marital status × age <20 years | NI | Interaction: single marital status × age <20 years | NI |
| Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI |
| Interaction: net income Euro <1,200 × folic acid | NI | Interaction: net income Euro <1,200 × folic acid | NI | Interaction: net income Euro <1,200 × folic acid | NI |
| A Forward approach | |||||
|---|---|---|---|---|---|
| Multiple imputed dataset 4 | Multiple imputed dataset 5 | Combined estimate/Median | |||
| Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI |
| Neighbourhood deprivation | NI | Neighbourhood deprivation | 1.13 (1.00; 1.28) | Neighbourhood deprivation | NI |
| Age <20 years | NI | Age <20 years | NI | Age <20 years | NI |
| Ethnicity Afro-African | NI | Ethnicity Afro-African | NI | Ethnicity Afro-African | NI |
| Ethnicity non-Western other | 1.24 (1.08; 1.41) | Ethnicity non-Western other | 1.22 (1.07; 1.39) | Ethnicity non-Western other | 1.20 (1.05; 1.37) |
| Net income Euro <1,200 | 1.22 (1.05; 1.42) | Net income Euro <1,200 | NI | Net income Euro <1,200 | 1.22 (1.05; 1.42) |
| Occupation non-working | NI | Occupation non-working | NI | Occupation non-working | NI |
| Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI |
| Marital status single | NI | Marital status single | NI | Marital status single | NI |
| BMI intake <20 | 1.35 (1.12; 1.62) | BMI intake <20 | 1.34 (1.12; 1.62) | BMI intake <20 | 1.34 (1.11; 1.61) |
| Smoking during pregnancy | 1.19 (1.05; 1.35) | Smoking during pregnancy | 1.20 (1.06; 1.36) | Smoking during pregnancy | 1.20 (1.06; 1.36) |
| Recreational drug use | NI | Recreational drug use | NI | Recreational drug use | NI |
| Nullipara | 1.81 (1.58; 2.06) | Nullipara | 1.82 (1.60; 2.08) | Nullipara | 1.82 (1.60; 2.08) |
| Unplanned pregnancy | NI | Unplanned pregnancy | NI | Unplanned pregnancy | NI |
| No folic acid use | NI | No folic acid use | 1.21 (1.05; 1.39) | No folic acid use | NI |
| Complications previous pregnancy | 1.31 (1.03; 1.66) | Complications previous pregnancy | 1.32 (1.04; 1.68) | Complications previous pregnancy | 1.33 (1.04; 1.68) |
| Gestational age booking ≥14 weeks | 1.14 (1.00; 1.30) | Gestational age booking ≥14 weeks | NI | Gestational age booking ≥14 weeks | NI |
| Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI |
| Comorbidity | NI | Comorbidity | NI | Comorbidity | NI |
| Sexual transmittable diseases | NI | Sexual transmittable diseases | NI | Sexual transmittable diseases | NI |
| Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | |||
| Afro-African | 1.41 (1.21; 1.65) | Afro-African | 1.49 (1.30; 1.71) | Afro-African | 1.40 (1.20; 1.63) |
| Interaction: single marital status × age <20 years | NI | Interaction: single marital status × age <20 years | NI | Interaction: single marital status × age <20 years | NI |
| Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI |
| Interaction: net income Euro <1,200 × folic acid | NI | Interaction: net income Euro <1,200 × folic acid | NI | Interaction: net income Euro <1,200 × folic acid | NI |
| B Backward approach | |||||
|---|---|---|---|---|---|
| Multiple imputed dataset 1 | Multiple imputed dataset 2 | Multiple imputed dataset 3 | |||
| Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI |
| Neighbourhood deprivation | NI | Neighbourhood deprivation | NI | Neighbourhood deprivation | NI |
| Age <20 years | 1.37 (1.02; 1.84) | Age <20 years | 1.34 (1.00; 1.79) | Age <20 years | 1.37 (1.02; 1.83) |
| Ethnicity Afro-African | 1.34 (1.11; 1.63) | Ethnicity Afro-African | 1.36 (1.11; 1.65) | Ethnicity Afro-African | 1.33 (1.09; 1.62) |
| Ethnicity non-Western other | 1.23 (1.07; 1.42) | Ethnicity non-Western other | 1.25 (1.08; 1.44) | Ethnicity non-Western other | 1.22 (1.06; 1.41) |
| Net income Euro <1,200 | 1.35 (1.15; 1.58) | Net income Euro <1,200 | 1.17 (0.99; 1.37) | Net income Euro <1,200 | 1.22 (1.04; 1.43) |
| Occupation non-working | NI | Occupation non-working | NI | Occupation non-working | NI |
| Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI |
| Marital status single | NI | Marital status single | NI | Marital status single | NI |
| BMI intake <20 | 1.37 (1.13; 1.64) | BMI intake <20 | 1.36 (1.13; 1.63) | BMI intake <20 | 1.36 (1.13; 1.63) |
| Smoking during pregnancy | 1.23 (1.08; 1.39) | Smoking during pregnancy | 1.24 (1.09; 1.41) | Smoking during pregnancy | 1.18 (1.04; 1.34) |
| Recreational drug use | NI | Recreational drug use | NI | Recreational drug use | NI |
| Nullipara | 1.85 (1.62; 2.11) | Nullipara | 1.85 (1.62; 2.11) | Nullipara | 1.86 (1.63; 2.12) |
| Unplanned pregnancy | NI | Unplanned pregnancy | NI | Unplanned pregnancy | NI |
| No folic acid use | NI | No folic acid use | 1.17 (1.01; 1.34) | No folic acid use | 1.16 (1.01; 1.34) |
| Complications previous pregnancy | 1.33 (1.05; 1.69) | Complications previous pregnancy | 1.31 (1.03; 1.66) | Complications previous pregnancy | 1.31 (1.03; 1.66) |
| Gestational age booking ≥14 weeks | 1.14 (0.99; 1.30) | Gestational age booking ≥14 weeks | NI | Gestational age booking ≥14 weeks | NI |
| Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI |
| Comorbidity | NI | Comorbidity | 1.23 (0.98; 1.55) | Comorbidity | 1.23 (0.98; 1.54) |
| Sexual transmittable diseases | NI | Sexual transmittable diseases | NI | Sexual transmittable diseases | NI |
| Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | |||
| Afro-African | NI | Afro-African | NI | Afro-African | NI |
| Interaction: single marital status × age <20 years | 1.29 (1.08; 1.55) | Interaction: single marital status × age <20 years | 1.35 (1.12; 1.62) | Interaction: single marital status × age <20 years | 1.36 (1.13; 1.63) |
| Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI |
| Interaction: net income Euro <1,200, × folic acid | NI | Interaction: net income Euro <1,200, × folic acid | NI | Interaction: net income Euro <1,200, × folic acid | NI |
| B Backward approach | |||||
|---|---|---|---|---|---|
| Multiple imputed dataset 4 | Multiple imputed dataset 5 | Combined estimate/Median | |||
| Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI | Risk factor | Exp (B) 95% CI |
| Neighbourhood deprivation | NI | Neighbourhood deprivation | 1.11 (0.98; 1.26) | Neighbourhood deprivation | NI |
| Age <20 years | 1.33 (1.00; 1.79) | Age <20 years | 1.34 (1.00; 1.79) | Age <20 years | 1.34 (1.00; 1.79) |
| Ethnicity Afro-African | 1.37 (1.13; 1.67) | Ethnicity Afro-African | 1.37 (1.12; 1.66) | Ethnicity Afro-African | 1.36 (1.11; 1.65) |
| Ethnicity non-Western other | 1.28 (1.12; 1.48) | Ethnicity non-Western other | 1.26 (1.09; 1.45) | Ethnicity non-Western other | 1.25 (1.08; 1.44) |
| Net income Euro <1,200 | 1.20 (1.02; 1.40) | Net income Euro <1,200 | NI | Net income Euro <1,200 | 1.20 (1.02; 1.40) |
| Occupation non-working | NI | Occupation non-working | NI | Occupation non-working | NI |
| Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI | Occupation ≥36 h/week | NI |
| Marital status single | NI | Marital status single | NI | Marital status single | NI |
| BMI intake <20 | 1.36 (1.13; 1.64) | BMI intake <20 | 1.36 (1.13; 1.63) | BMI intake <20 | 1.36 (1.13; 1.63) |
| Smoking during pregnancy | 1.20 (1.06; 1.37) | Smoking during pregnancy | 1.21 (1.06; 1.37) | Smoking during pregnancy | 1.21 (1.06; 1.37) |
| Recreational drug use | NI | Recreational drug use | NI | Recreational drug use | NI |
| Nullipara | 1.83 (1.60; 2.09) | Nullipara | 1.83 (1.61; 2.10) | Nullipara | 1.85 (1.62; 2.11) |
| Unplanned pregnancy | NI | Unplanned pregnancy | NI | Unplanned pregnancy | NI |
| No folic acid use | NI | No folic acid use | 1.19 (1.04; 1.37) | No folic acid use | NI |
| Complications previous pregnancy | 1.32 (1.04; 1.67) | Complications previous pregnancy | 1.33 (1.05; 1.68) | Complications previous pregnancy | 1.32 (1.04; 1.67) |
| Gestational age booking ≥14 weeks | 1.14 (1.00; 1.31) | Gestational age booking ≥14 weeks | NI | Gestational age booking ≥14 weeks | NI |
| Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI | Depressive or Anxiety complaints | NI |
| Comorbidity | NI | Comorbidity | NI | Comorbidity | NI |
| Sexual transmittable diseases | NI | Sexual transmittable diseases | NI | Sexual transmittable diseases | NI |
| Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | Interaction: single marital status × ethnicity | |||
| Afro-African | NI | Afro-African | NI | Afro-African | NI |
| Interaction: single marital status × age <20 years | 1.35 (1.12; 1.61) | Interaction: single marital status × age <20 years | 1.44 (1.22; 1.70) | Interaction: single marital status × age <20 years | 1.35 (1.12; 1.61) |
| Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI | Interaction: single marital status × unplanned pregnancy | NI |
| Interaction: net income Euro <1,200 × folic acid | NI | Interaction: net income Euro <1,200 × folic acid | NI | Interaction: net income Euro <1,200 × folic acid | NI |
Results from logistic regression analysis with forward and backward approach (P inclusion = P exclusion = 0.10) for all 5 imputed datasets separately. If the same association was observed across 4 or 5 datasets, this was interpreted as a significant association. In that case we report on the combined estimate given as the median size of that coefficient together with its 95% CI. NI not included in final step