Table 1. Characteristics of women (n = 8271).
| Characteristics | <20 years n = 338 | 20–24.9 years n = 1391 | 25–29.9 years n = 2256 | 30–34.9 years n = 3045 | 35–39.9 years n = 1102 | ≥ 40 years n = 139 |
|---|---|---|---|---|---|---|
| Maternal characteristics | ||||||
| Age, years (median, IQR) | 19.0 (18.2–19.5) | 22.8 (21.6–24.0) | 27.8 (26.4–28.9) | 32.4 (31.2–33.6) | 36.6 (35.7–37.9) | 41.2 (40.5–42.3) |
| Height, mean (SD) (cm) | 165.1 (6.4) | 165.3 (7.1) | 166.4 (7.4) | 168.3 (7.3) | 168.2 (7.5) | 167.9 (8.2) |
| Weight, mean (SD) (kg) | 65.3 (13.4) | 67.8 (13.8) | 69.7 (14.2) | 69.6 (12.5) | 71.0 (12.1) | 72.3 (13.6) |
| Body Mass Index, mean (SD) (kg/m2) | 23.9 (4.6) | 24.8 (4.7) | 25.1 (4.9) | 24.6 (4.3) | 25.1 (4.1) | 25.6 (4.6) |
| Parity, No. nulliparous (%) | 295 (88.9) | 985 (71.9) | 1341 (60.1) | 1538 (51.0) | 370 (33.9) | 49 (36.0) |
| Education, No. higher education (%) | 2 (0.7) | 101 (8.2) | 718 (35.1) | 1686 (59.2) | 611 (58.9) | 73 (57.1) |
| Race / Ethnicity, No. (%) | ||||||
| Dutch or European, No. (%) | 75 (25.0) | 389 (30.3) | 1107 (51.8) | 2105 (71.6) | 725 (67.9) | 81 (60.0) |
| Surinamese, No. (%) | 61 (20.3) | 192 (15.0) | 210 (9.8) | 165 (5.6) | 74 (6.9) | 9 (6.7) |
| Turkish, No. (%) | 32 (10.6) | 236 (18.4) | 253 (11.8) | 155 (5.3) | 49 (4.6) | 6 (4.4) |
| Moroccan, No. (%) | 19 (6.3) | 157 (12.2) | 192 (9.0) | 118 (4.0) | 50 (4.7) | 12 (8.9) |
| Cape Verdian or Dutch Antilles, No. (%) | 72 (23.9) | 190 (14.8) | 154 (7.2) | 132 (4.6) | 49 (4.6) | 6 (4.4) |
| Smoking, No. (%) | ||||||
| None, No. (%) | 161 (55.9) | 747 (61.8) | 1454 (73.8) | 2110 (78.0) | 717 (73.8) | 89 (77.4) |
| Early-pregnancy only, No. (%) | 27 (9.4) | 102 (8.4) | 172 (8.7) | 238 (8.8) | 74 (7.4) | 7 (6.1) |
| Continued, No. (%) | 100 (34.7) | 360 (29.8) | 343 (17.4) | 358 (13.2) | 181 (18.6) | 19 (16.5) |
| Folic acid use No. used (%) | 71 (30.5) | 809 (83.4) | 1156 (70.0) | 1942 (82.1) | 637 (76.7) | 73 (71.6) |
| 2nd trimester uterine artery RI, mean (SD) | 0.56 (0.09) | 0.54 (0.09) | 0.54 (0.09) | 0.54 (0.09) | 0.55 (0.09) | 0.56 (0.09) |
| 2nd trimester umbilical artery PI, mean (SD) | 1.24 (0.19) | 1.23 (0.19) | 1.21 (0.18) | 1.19 (0.18) | 1.18 (0.19) | 1.17 (0.19) |
| 3rd trimester uterine artery RI, mean (SD) | 0.48 (0.08) | 0.48 (0.07) | 0.48 (0.08) | 0.48 (0.08) | 0.50 (0.08) | 0.51 (0.07) |
| 3rd trimester umbilical artery PI, mean (SD) | 0.99 (0.16) | 0.99 (0.17) | 0.99 (0.17) | 0.98 (0.17) | 0.98 (0.17) | 0.97 (0.19) |
| 3rd trimester uterine artery notching, No. (%) | 40 (22.5) | 113 (14.8) | 137 (10.8) | 146 (7.9) | 50 (7.6) | 6 (8.1) |
| Birth characteristics | ||||||
| Males, No.(%) | 164 (48.5) | 713 (51.3) | 1131 (50.1) | 1536 (50.4) | 572 (51.9) | 72 (51.8) |
| Gestational age at delivery, weeks (IQR) | 39.9 (38.7–40.8) | 40.0 (39.1–40.9) | 40.1 (39.0–41.0) | 40.1 (39.4–41.0) | 40.3 (39.3–41.0) | 40.3 (38.7–41.1) |
| Birth weight, mean (SD) grams | 3184 (516) | 3315 (522) | 3399 (551) | 3461 (576)4 | 3487 (549) | 3424 (656) |
| Small-size for gestational age, No. (%) | 53 (15.7) | 191 (13.7) | 214 (9.5) | 254 (8.3) | 97 (8.8) | 13 (9.4) |
| Large-size for gestational age, No. (%) | 16 (4.7) | 75 (5.4) | 209 (9.3) | 379 (12.4) | 122 (11.1) | 20 (14.4) |
| Preterm birth | 27 (8.0) | 65 (4.7) | 128 (5.7) | 153 (5.0) | 50 (4.5) | 9 (6.5) |
| Assisted vaginal delivery | 29 (9.8) | 156 (12.4) | 301 (14.6) | 409 (14.7) | 128 (12.7) | 10 (7.7) |
| Cesarean delivery | 28 (9.5) | 111 (8.8) | 249 (12.1) | 363 (13.0) | 142 (14.0) | 32 (24.6) |
| Gestational hypertension | 13 (4.1) | 42 (3.2) | 80 (3.8) | 117 (4.1) | 41 (3.9) | 4 (3.1) |
| Preeclampsia | 10 (3.2) | 23 (1.8) | 58 (2.8) | 57 (2.0) | 15 (1.5) | 3 (2.3) |
| APGAR <7 after 5 min, No. (%) | 5 (1.6) | 18 (1.3) | 27 (1.2) | 38 (1.3) | 11 (1.0) | 1 (0.7) |
| Placental weight (grams) median (IQR) | 600 (500–695) | 600 (520–700) | 620 (540–713) | 630 (545–725) | 619 (530–724) | 650 (530–732) |
Abbreviation: IQRinter quartile range. Values are observed data and represent means (SD), medians (IQR) or number of subjects (valid%).