Table 1 Basic Characteristics of the participants (n = 8776)
Characteristics | Total (n = 8776) | No HDP (n = 8336) | HDP (n = 440) | P value |
|---|---|---|---|---|
Gestational age at enrollment (days) | 104.0 ± 8.7 | 104.0 ± 8.6 | 104.3 ± 8.9 | 0.46 |
Maternal age at enrollment (year) | 30.2 ± 3.6 | 30.2 ± 3.6 | 30.4 ± 3.7 | 0.14 |
Maternal height (centimeters) | 161.7 ± 4.8 | 161.7 ± 4.8 | 161.7 ± 5.0 | 0.85 |
Maternal weight before pregnancy (kg) | 54.8 ± 7.8 | 54.6 ± 7.5 | 59.8 ± 10.9 | < 0.01 |
Pre - conception BMI (kg m− 2) | ||||
 Underweight (< 18.5) | 1408 (16.0) | 1372 (16.5) | 36 (8.2) |  |
 Normal (18.5–23) | 5706 (65.0) | 5486 (73.6) | 220 (50.0) |  |
 Overweight (23–27.5) | 1436 (16.4) | 1298 (15.6) | 138 (31.4) |  |
 Obesity (≥27.5) | 226 (2.6) | 180 (2.2) | 46 (10.5) | < 0.01 |
Season of conception | ||||
 Spring | 3136 (35.7) | 2951 (35.4) | 185 (42.1) |  |
 Summer | 1778 (20.3) | 1695 (20.3) | 83 (18.9) |  |
 Autumn | 1541 (17.6) | 1492 (17.9) | 49 (11.1) |  |
 Winter | 2321 (26.5) | 2198 (26.4) | 123 (27.9) | < 0.01 |
Parity | ||||
 Nulliparous | 7117 (81.1) | 6735 (80.8) | 382 (86.8) |  |
 Multiparous | 1659 (18.9) | 1601 (19.2) | 58 (13.2) | < 0.01 |
Sex of foetus | ||||
 Male | 4510 (51.4) | 4284 (51.4) | 226 (51.4) |  |
 Female | 4266 (48.6) | 4085 (48.6) | 214 (48.6) | 0.99 |
Parental history of chronic diseases | ||||
 No | 6027 (68.7) | 5777 (69.3) | 250 (56.8) |  |
 Yes | 2749 (31.3) | 2559 (30.7) | 190 (43.2) | < 0.01 |
Prenatal care insurance type | ||||
 Government-sponsored | 6900 (78.6) | 6535 (78.4) | 365 (83.0) |  |
 Self-pay | 1876 (21.4) | 1801 (21.6) | 75 (17.0) | 0.02 |