Table 1.
Characteristics of the study population (N = 814)
| Maternal characteristics | Mean (SD) or N (%) |
|---|---|
| Pre-pregnancy risk factorsa | |
| Maternal age at delivery, years | 33.3 (5.8) |
| Below 20 years, yes | 22 (3.0%) |
| Above 40 years, yes | 115 (14.1%) |
| Pre-eclampsia in previous pregnancy, yes | 178 (21.9%) |
| Intrauterine growth estriction in previous pregnancy, yes | 85 (10.4%) |
| Gestational diabetes in previous pregnancy, yes | 84 (10.3%) |
| Diet treated | 75 (9.2%) |
| Insulin treated | 9 (1.1%) |
| Pre-pregnancy body mass index kg/m2 | 27.4 (6.4) |
| ≥30 kg/m2 | 287 (35.3%) |
| Pre-pregnancy chronic hypertension, yes | 109 (13.4%) |
| Pre-pregnancy type 1 diabetes, yes | 12 (1.5%) |
| Pre-pregnancy systemic lupus erythematosus, yes | 2 (0.3%) |
| Sjögren’s syndrome, yes | 11 (1.4%) |
| Previous pregnancy with fetal demise (>22 gestational weeks or over 500 g), yes | 28 (3.4%) |
| Number of known pre-pregnancy risk factors | |
| No known pre-pregnancy risk factors | 79 (9.7%) |
| 1 or 2 pre-pregnancy risk factors | 696 (85.5%) |
| 3 or more pre-pregnancy risk factors | 31 (3.8%) |
| Data not available | 8 (1.0%) |
| Pregnancy disorders | |
| Gestational diabetes, yes | 183 (22.5%) |
| Diet treated | 147 (18.1%) |
| Insulin treated | 36 (4.4%) |
| Data not available on gestational diabetes treatment | 2 (0.2%) |
| Data not available on gestational diabetes diagnosis | 1 (0.1%) |
| Hypertension spectrum pregnancy disorders, yes | |
| Gestational hypertension | 80 (9.8%) |
| Pre-eclampsia | 61 (7.5%) |
| Early pre-eclampsia (diagnosis <34 weeks of gestation) | 53 (6.5%) |
| Late pre-eclampsia (diagnosis ≥34 weeks of gestation) | 8 (1.0%) |
| Non-severe pre-eclampsia | 42 (5.2%) |
| Severe pre-eclampsia | 19 (2.3%) |
| Chronic hypertension | 134 (16.5%) |
| Data not available | 1 (0.1%) |
| Other characteristics | |
| Education level | |
| Lower secondary or less | 359 (44.1%) |
| Upper secondary | 184 (22.6%) |
| Tertiary | 248 (30.5%) |
| Data not available | 23 (2.8%) |
| Parity | |
| Primiparous | 247 (30.3%) |
| Multiparous | 566 (69.5%) |
| Data not available | 1 (0.1%) |
| Smoking during pregnancy | |
| Non-smoker | 780 (95.8%) |
| Quit during first trimester | 26 (3.2%) |
| Smoked throughout the pregnancy | 8 (1.0%) |
| Data not available | 0 |
| Alcohol use during pregnancy | |
| No | 588 (72.2%) |
| Yes | 117 (14.4%) |
| Data not available | 109 (13.4%) |
| Mode of delivery | |
| Vaginal | 640 (78.6%) |
| Cesarean | 173 (21.3%) |
| Data not available | 1 (0.1%) |
| Antenatal betamethasone treatment | |
| No | 750 (92.1%) |
| Yes (n = 1 for 12 mg/24 h, n = 22 for 24 mg/24 h, n = 1 for 48 mg/24 h, n = 11 for no information on dose) | 35 (4.3%) |
| Timing of antenatal betamethasone treatment, number of days before birth | 33.4 (27.1) |
| 30 days or less before delivery | 14 (1.7%) |
| 30 days or more before delivery | 13 (1.6%) |
| Data not available | 29 (3.6%) |
| Neonatal characteristics | |
| Sex | |
| Girls | 384 (47.2%) |
| Boys | 430 (52.8%) |
| Data not available | 0 |
| Gestational age at birth, weeks | 39.76 (1.60) |
| Data not available | 0 |
| DNA methylation gestational age, weeks | 38.45 (2.05) |
| Data not available | 0 |
| Raw epigenetic gestational age difference, DNA methylation gestational age-gestational age | −1.32 (1.85) |
| Data not available | 0 |
| Absolute epigenetic gestational age difference, DNA methylation gestational age-gestational age in absolute values | 1.78 (1.41) |
| Data not available | 0 |
| Horvath DNA methylation age at birth, weeks | 9.77 (19.51) |
| Data not available | 0 |
| Birth weight, g | 3549 (546) |
| Small for gestational age, yesb | 23 (2.8%) |
| Data not available | 1 (0.1%) |
| Birth length, cm | 50 (2) |
| Small for gestational age, yesb | 21 (2.6%) |
| Data not available | 1 (0.1%) |
| Head circumference, cm | 35 (2) |
| Small for gestational age, yesb | 14 (1.7%) |
| Data not available | 2 (0.3%) |
| Ponderal index, kg/m3 | 27.8 (2.7) |
| Data not available | 1 (0.1%) |
| Placenta weight, g | 615 (134) |
| Cord blood pH | |
| Arterial | 7.26 (0.09) |
| Venous | 7.31 (0.08) |
| Apgar score | |
| 9–10 | 611 (75.1%) |
| 7–8 | 145 (17.8%) |
| ≤6 | 47 (5.8%) |
| Data not available | 11 (1.4%) |