Characteristics and pregnancy outcomes by maternal blood pressure at 11–14 weeks in the NORA cohort
| Variables | Normal BP (n=750) | Elevated BP (n=98) | Hypertension (stage 1 and stage 2) (n=75) | P value |
| Maternal age (year), median (IQR) | 30.0 (26.0–34.0) | 30.0 (26.0–35.0) | 32.0 (29.0–35.0) | <0.001 |
| Race, n (%) | 0.012 | |||
| Chinese | 393 (52.3) | 38 (38.8) | 37 (49.3) | |
| Indian | 88 (11.7) | 6 (6.1) | 6 (8.0) | |
| Malay | 186 (24.8) | 41 (41.8) | 23 (30.7) | |
| Others | 84 (11.2) | 13 (13.3) | 9 (12.0) | |
| Parity, n (%) | 0.091 | |||
| 0 | 419 (55.9) | 49 (50.0) | 33 (44.0) | |
| 1 | 236 (31.5) | 32 (32.7) | 25 (33.3) | |
| ≥2 | 95 (12.7) | 17 (17.3) | 17 (22.7) | |
| Maternal education levels, n (%) | 0.044 | |||
| Less than high school | 166 (22.2) | 28 (28.6) | 25 (33.3) | |
| High school | 299 (40.0) | 44 (44.9) | 23 (30.7) | |
| College and above | 282 (37.8) | 26 (26.5) | 27 (36.0) | |
| Married, n (%) | 699 (93.2) | 90 (91.8) | 72 (96.0) | 0.544 |
| Smoking during pregnancy, n (%) | 19 (2.5) | 4 (4.1) | 0 (0) | 0.230 |
| Maternal BMI at 11–14 weeks of gestation (kg/m2), n (%) | <0.001 | |||
| <18.5 | 62 (8.3) | 2 (2.0) | 0 (0) | |
| 18.5–24.9 | 475 (63.5) | 32 (32.7) | 16 (21.3) | |
| 25.0–29.9 | 162 (21.7) | 35 (35.7) | 32 (42.7) | |
| ≥30.0 | 49 (6.6) | 29 (29.6) | 27 (36.0) | |
| Diabetes mellitus, n (%) | 7 (0.9) | 2 (2.0) | 5 (6.7) | <0.001 |
| ART conception, n (%) | 31 (4.1) | 4 (4.1) | 2 (2.7) | 0.826 |
| Antihypertensive medication, n (%) | 0 (0) | 0 (0) | 3 (4.0) | <0.001 |
| Pregnancy outcomes | ||||
| Delivery age (weeks), median (IQR) | 39.0 (38.1–39.7) | 38.7 (38.0–39.6) | 38.3 (37.6–39.1) | 0.001 |
| Birth weight (kg), median (IQR) | 3.1 (2.9–3.4) | 3.1 (2.9–3.5) | 3.1 (2.8–3.4) | 0.324 |
| Gestational hypertension, n (%) | 10 (1.3) | 3 (3.1) | 5 (6.7) | 0.004 |
| Preeclampsia, n (%) | 6 (0.8) | 3 (3.1) | 12 (16.0) | <0.001 |
| Preterm preeclampsia, n (%) | 4 (0.5) | 0 (0) | 5 (6.7) | <0.001 |
| Term preeclampsia, n (%) | 2 (0.3) | 3 (3.1) | 7 (9.3) | <0.001 |
ART, assisted reproductive technology; BMI, body mass index; BP, blood pressure.