Introduction
Methods
Study population
Candidate predictor variables
Basic preconception characteristics
Socio-demographic characteristics
Lifestyle characteristics
Medical history characteristics
Early-pregnancy clinical characteristics
Paternal characteristics
Outcomes
Primary outcomes
Secondary outcomes
Statistical analyses
Results
Study population
No adverse birth outcomea(n = 6333) | Preterm birth/small-for-gestational-agea (n = 1207) | Large-for-gestational-agea (n = 834) | |
---|---|---|---|
Maternal preconception characteristics | |||
Gestational age at enrolment, | 13.9 (9.9 to 22.9) | 14.1 (8.7 to 23.2) | 13.6 (10.2 to 23.2) |
Age, mean (SD), years | 29.7 (5.2) | 28.9 (5.7) | 30.9 (4.7) |
Ethnicity | |||
Dutch or European, n (%) | 3475 (57.7) | 549 (48.5) | 536 (67.1) |
Surinamese, n (%) | 509 (8.4) | 178 (15.7) | 36 (4.5) |
Turkish, n (%) | 571 (9.5) | 103 (9.1) | 60 (7.5) |
Moroccan, n (%) | 441 (7.3) | 49 (4.3) | 53 (6.6) |
Cape Verdean or Dutch Antilles, n (%) | 433 (7.2) | 138 (12.2) | 38 (4.8) |
Other, n (%) | 1099 (18.2) | 189 (16.7) | 131 (16.4) |
Body Mass Index, median (95%), kg/m2 | 22.6 (18.0 to 34.9) | 22.2 (17.5 to 36.6) | 23.8 (19.1 to 38.8) |
Parity, n nulliparous (%) | 3474 (55.4) | 809 (67.9) | 338 (41.0) |
Education, n higher education (%) | 2458 (42.3) | 380 (35.0) | 404 (52.3) |
Smoking, n yes (%) | 1477 (26.6) | 374 (35.5) | 143 (19.6) |
Income, n high (%) | 2694 (54.9) | 3801 (45) | 431 (64.8) |
Occupational status, employed n (%) | 3405 (72.8) | 546 (67.8) | 496 (78.0) |
Planning of pregnancy, n no (%) | 1574 (28.3) | 380 (36.8) | 162 (22.4) |
Presence of any chronic disease, n no (%) | 1922 (34.7) | 390 (32.3) | 236 (20.4) |
Alcohol consumption, n > 1x/week (%) | 991 (18.2) | 158 (15.5) | 146 (20.4) |
Vegetable consumption, n < 250 g/day (%) | 4185 (90.1) | 775 (89.8) | 566 (87.8) |
Fatty fish consumption, n < 1x/week, (%) | 91 (2.0) | 15 (1.7) | 1 (0.2) |
Caffeine consumption, median (95%), units/dayb | 1.5 (0.0 to 6.0) | 1.5 (0.0 to 6.0) | 1.5 (0.0 to 6.0) |
Multivitamin supplementation, n no (%) | 1546 (29.5) | 256 (26.7) | 152 (35.5) |
Mean systolic blood pressure, mean (SD), mmHg | 115 (12) | 115 (13) | 117 (13) |
Mean diastolic blood pressure, mean (SD), mmHg | 68 (9) | 69 (10) | 68 (10) |
Hb concentrations, mean (SD), mmol/L | 7.5 (0.6) | 7.5 (0.6) | 7.6 (0.6) |
Glucose, mean (SD), mmol/L | 4.4 (0.8) | 4.4 (0.8) | 4.6 (0.9) |
Triglycerides concentrations, mean (SD), mmol/L | 1.36 (0.52) | 1.35 (0.51) | 1.45 (0.56) |
Ferritin concentrations, median (95%), ug/L | 52.9 (9.8 to 210.1) | 52.2 (9.7 to 212.4) | 48.9 (11.2 to 191.5) |
Vitamin D concentrations, median (95%), nmol/L | 47.5 (7.0 to 122.2) | 38.5 (7.0 to 113.1) | 31.7 (7.9 to 121.7) |
Birth outcomes | |||
Sex, n female (%) | 3168 (50.0) | 578 (47.9) | 410 (49.2) |
Gestational age at birth, median (95%), weeks | 40.1 (37.4 to 42.4) | 39.0 (30.4 to 42.0) | 40.3 (35.8 to 42.4) |
Birthweight, mean (SD), grams | 3458 (353) | 2571 (459) | 4270 (382) |
Model selection and performance for preterm birth/SGA and LGA
Preterm birth/SGA | LGA | ||||
---|---|---|---|---|---|
Variable | Categories | Odds Ratio (original) | Odds Ratio (shrunk) | Odds Ratio (original) | Odds Ratio (shrunk) |
Intercept | 0.04 | 0.07 | 0.10 | 0.11 | |
Age | < 25 | 0.93 | 0.95 | 0.79 | 0.84 |
25–35 | Reference | Reference | Reference | Reference | |
> 35 | 1.16 | 1.12 | 0.83 | 0.88 | |
Ethnicity | Dutch or European | Reference | Reference | Reference | Reference |
Surinamese | 1.65 | 1.44 | 0.46 | 0.57 | |
Turkish | 0.86 | 0.89 | 0.65 | 0.73 | |
Moroccan | 0.56 | 0.65 | 0.64 | 0.73 | |
Cape Verdian or Dutch Antilles | 1.51 | 1.35 | 0.62 | 0.71 | |
Other | 0.95 | 0.96 | 0.77 | 0.83 | |
Missing | 1.03 | 1.02 | 0.63 | 0.72 | |
Prepregnancy BMI | < 25 kg/m2 | Reference | Reference | Reference | Reference |
25.0–30.0 kg/m2 | 0.83 | 0.87 | 1.61 | 1.41 | |
30.1–35.0 kg/m2 | 0.76 | 0.81 | 2.09 | 1.71 | |
> 35.0 kg/m2 | 0.77 | 0.83 | 3.48 | 2.46 | |
Missing | 1.05 | 1.04 | 1.44 | 1.30 | |
Parity | Nulliparity | 1.89 | 1.59 | 0.57 | 0.67 |
Multiparous | Reference | Reference | Reference | Reference | |
Missing | 1.50 | 1.35 | 1.15 | 1.11 | |
Smoking status | No | Reference | Reference | Reference | Reference |
Yes | 1.32 | 1.23 | 0.76 | 0.82 | |
Missing | 0.78 | 0.83 | 0.97 | 0.98 | |
Educational level | Low | 1.30 | 1.21 | ||
High | Reference | Reference | |||
Missing | 0.77 | 0.82 | |||
Household income | Low | 1.27 | 1.19 | 0.81 | 0.86 |
High | Reference | Reference | Reference | Reference | |
Missing | 1.37 | 1.26 | 0.91 | 0.93 | |
Occupational status | Currently employed | Reference | Reference | ||
Applying for a job | 0.81 | 0.86 | |||
Unemployed and not applying for a job | 1.16 | 1.12 | |||
Missing | 1.28 | 1.20 | |||
Pregnancy planning | Planned pregnancy | Reference | Reference | ||
Unplanned pregnancy | 1.11 | 1.08 | |||
Missing | 1.06 | 1.05 | |||
Alcohol consumption | Never or < 1 drink/week | Reference | Reference | ||
> 1 drinks/week | 0.87 | 0.90 | |||
Missing | 1.07 | 1.05 | |||
Vegetable intake | < 250 g/day | 0.69 | 0.77 | ||
≥250 g/day | Reference | Reference | |||
Missing | 0.65 | 0.73 | |||
Weekly fatty fish consumption | <1x/week | 1.15 | 1.11 | ||
1-2x/week | Reference | Reference | |||
>2x/week | 2.59 | 2.01 | |||
Missing | 1.05 | 1.04 | |||
Daily caffeine consumption | < 2/day | Reference | Reference | ||
≥2/day | 1.14 | 1.10 | |||
Missing | 0.86 | 0.90 | |||
Multivitamin supplementation | Yes | Reference | Reference | ||
No | 1.26 | 1.18 | |||
Missing | 1.27 | 1.19 | |||
History of a chronic disease | No | Reference | Reference | Reference | Reference |
Yes | 1.13 | 1.10 | 0.85 | 0.89 | |
Missing | 1.37 | 1.26 | 0.86 | 0.90 | |
Systolic blood pressure | Per 10 mmHg increase | 1.08 | 1.06 | ||
Diastolic blood pressure | Per 10 mmHg increase | 1.10 | 1.07 | 0.92 | 0.94 |
Hb concentrations | First quintile (3.9 to 7.0 mmol/l) | 1.17 | 1.12 | 1.15 | 1.11 |
Second quintile (7.1 to 7.4 mmol/l) | 1.10 | 1.07 | 0.97 | 0.98 | |
Third quintile (7.5 to 7.6 mmol/l) | Reference | Reference | Reference | Reference | |
Fourth quintile (7.7 to 8.0 mmol/l) | 1.15 | 1.11 | 1.25 | 1.18 | |
Fifth quintile (8.10 to 11.30 mmol/l) | 1.33 | 1.23 | 0.92 | 0.94 | |
Missing | 1.25 | 1.17 | 1.09 | 1.06 | |
Random glucose concentrations | Per mmol/L increase | 1.16 | 1.12 | ||
Triglyceride concentrations | Per mmol/L increase | 1.18 | 1.13 | ||
Ferritine concentrations | First quintile (1.5 to 26.4 μg/l) | 1.18 | 1.13 | ||
Second quintile (26.4 to 42.5 μg/l) | 0.87 | 0.91 | |||
Third quintile (42.5 to 62.8 μg/l) | Reference | Reference | |||
Fourth quintile (62.8 to 95.8 μg/l) | 0.69 | 0.77 | |||
Fifth quintile (95.9 to 390.4 μg/l) | 0.86 | 0.89 | |||
Missing | 0.87 | 0.91 | |||
Vitamin D concentrations | Per 10 nmol/l increase | 0.94 | 0.96 |
Paternal analyses
Clinical applicability of the maternal prediction models
Models | AUC (95% CI) | Sensitivity at specificity (%) | ||
---|---|---|---|---|
70% | 80% | 90% | ||
Maternal pregnancy complications | ||||
Gestational hypertension | ||||
Preterm birth/SGA-modela | 0.80 (0.78 to 0.83) | 75 | 63 | 45 |
LGA-modelb | 0.81 (0.79 to 0.83) | 77 | 63 | 44 |
Pre-eclampsia | ||||
Preterm birth/SGA-modela | 0.77 (0.74 to 0.80) | 70 | 58 | 33 |
LGA-modelb | 0.77 (0.74 to 0.81) | 72 | 59 | 40 |
Delivery complications | ||||
Fetal distress | ||||
Preterm birth/SGA-modela | 0.68 (0.66 to 0.70) | 53 | 40 | 25 |
LGA-modelb | 0.68 (0.66 to 0.70) | 55 | 41 | 23 |
Caesarian section | ||||
Preterm birth/SGA-modela | 0.65 (0.64 to 0.67) | 50 | 37 | 23 |
LGA-modelb | 0.66 (0.64 to 0.67) | 51 | 39 | 24 |
Neonatal complications | ||||
Low Apgar | ||||
Preterm birth/SGA-modela | 0.70 (0.65 to 0.76) | 60 | 50 | 36 |
LGA-modelb | 0.72 (0.66 to 0.77) | 65 | 48 | 35 |
Low birthweight | ||||
Preterm birth/SGA-modela | 0.70 (0.67 to 0.73) | 59 | 45 | 29 |
LGA-modelb | 0.70 (0.67 to 0.72) | 59 | 44 | 27 |
Macrosomia | ||||
Preterm birth/SGA-modela | 0.71 (0.67 to 0.74) | 61 | 50 | 34 |
LGA-modelb | 0.71 (0.67 to 0.75) | 62 | 54 | 35 |