Table 1.
Characteristics of the study cohort (N=4,099).
| Characteristic | No hypertensive disorder | Preterm preeclampsia | Preeclampsia with severe features* | Preeclampsia without severe features* | Gestational hypertension |
|---|---|---|---|---|---|
| n (%) | 3,751 (91.5%) | 26 (0.6%) | 111 (2.7%) | 128 (3.1%) | 83 (2.0%) |
| Maternal characteristics | |||||
| Age, years | 30 (27 to 33) | 29 (25 to 34) | 30 (26 to 34) | 29 (26 to 33) | 29 (25 to 33) |
| Age stopped FTE†, years | 21 (18 to 23) | 18 (16 to 21) | 19 (17 to 22) | 21 (18 to 23) | 21 (17 to 22) |
| Missing | 105 (2.8) | 1 (3.9) | 4 (3.6) | 7 (5.5) | 5 (6.0) |
| Height, cm | 165 (161 to 170) | 163 (158 to 167) | 165 (160 to 168) | 165 (161 to 168) | 165 (160 to 168) |
| Deprivation quartile | |||||
| 1 (lowest) | 917 (24) | 7 (27) | 26 (23) | 27 (21) | 20 (24) |
| 2 | 899 (24) | 2 (7.7) | 28 (25) | 33 (26) | 14 (17) |
| 3 | 897 (24) | 12 (46) | 26 (23) | 28 (22) | 21 (25) |
| 4 (highest) | 889 (24) | 5 (19) | 28 (25) | 34 (27) | 18 (22) |
| Missing | 149 (3.7) | 0 (0.0) | 3 (2.7) | 6 (4.7) | 10 (12) |
| Ethnicity | |||||
| Non-white | 211 (5.6) | 2 (7.7) | 5 (4.5) | 4 (3.1) | 5 (6.0) |
| White | 3478 (93) | 23 (88) | 105 (95) | 124 (97) | 73 (88) |
| Missing | 62 (1.7) | 1 (3.9) | 1 (0.9) | 0 (0.0) | 5 (6.0) |
| Married | 2558 (68) | 21 (81) | 74 (67) | 80 (63) | 56 (67) |
| Smoker | 182 (4.9) | 1 (3.9) | 3 (2.7) | 7 (5.5) | 8 (9.6) |
| Any alcohol consumption | 172 (4.6) | 0 (0.0) | 4 (3.6) | 4 (3.1) | 6 (7.2) |
| Missing | 1 (<0.1) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Body mass index, kg/m2 | 24 (22 to 27) | 28 (26 to 30) | 25 (23 to 32) | 28 (23 to 32) | 27 (24 to 31) |
| Missing | 1 (<0.1) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Type 1 or type 2 DM† | 7 (0.2) | 3 (12) | 0 (0.0) | 2 (1.6) | 2 (2.4) |
| Chronic hypertension | 95 (2.5) | 9 (35) | 34 (31) | 74 (58) | 0 (0.0) |
| Renal disease | 28 (0.8) | 1 (3.9) | 3 (2.7) | 8 (6.3) | 0 (0.0) |
| UtA mean PI† highest decile | 335 (8.9) | 11 (42) | 23 (21) | 21 (16) | 9 (11) |
| Missing | 91 (2.4) | 2 (7.7) | 1 (0.9) | 7 (5.5) | 3 (3.6) |
| Birth outcomes | |||||
| Birth weight, g | 3425 (3110 to 3735) | 2210 (1650 to 2660) | 3425 (3050 to 3750) | 3383 (3100 to 3785) | 3501 (3190 to 3830) |
| Birth weight, z score | -0.15 (-0.71 to 0.41) | -0.61 (-1.15 to 0.06) | -0.14 (-0.73 to 0.63) | -0.03 (-0.69 to 0.40) | -0.15 (-0.59 to 0.71) |
| Birth weight, centile | 44 (24 to 66) | 28 (13 to 52) | 45 (23 to 73) | 49 (25 to 66) | 44 (28 to 76) |
| Missing | 1 (<0.1) | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Gestational age, weeks | 40 (39 to 41) | 35 (34 to 36) | 40 (39 to 41) | 40 (39 to 41) | 40 (39 to 41) |
| Induction of labor | 1115 (30) | 6 (23) | 70 (63) | 82 (64) | 37 (45) |
| Mode of delivery | |||||
| Spontaneous vaginal | 1896 (51) | 6 (23) | 25 (23) | 42 (33) | 31 (37) |
| Assisted vaginal | 873 (23) | 0 (0.0) | 29 (26) | 41 (32) | 23 (28) |
| Intrapartum caesarean | 616 (16) | 3 (12) | 43 (39) | 31 (24) | 21 (25) |
| Pre-labor caesarean | 356 (9.5) | 17 (65) | 13 (12) | 14 (11) | 8 (10) |
| Missing | 10 (0.3) | 0 (0.0) | 1 (0.9) | 0 (0.0) | 0 (0.0) |
| sFlt-1:PlGF ratio | |||||
| At 20wkGA | 6.5 (4.4 to 9.4) | 9.1 (5.1 to 15.9) | 6.9 (5.0 to 9.1) | 6.9 (4.5 to 10.6) | 6.3 (4.2 to 8.4) |
| Missing | 125 (3.3) | 4 (15) | 6 (5.4) | 7 (5.5) | 4 (4.8) |
| At 28wkGA | 2.7 (1.7 to 4.2) | 6.5 (3.4 to 22.5) | 3.9 (2.4 to 7.8) | 3.9 (2.3 to 6.9) | 2.6 (1.8 to 4.3) |
| Missing | 101 (2.7) | 0 (0.0) | 4 (3.6) | 3 (2.3) | 2 (2.4) |
| At 36wkGA | 11.2 (5.1 to 22.6) | 126.2 (64.5 to 187.7) | 42.3 (22.6 to 88.2) | 35.3 (18.4 to 65.3) | 20.2 (8.2 to 38.3) |
| Missing | 274 (7.3) | 20 (77) | 9 (8.1) | 11 (8.6) | 9 (11) |
Confined to women delivering ≥37wkGA.
Abbreviations: FTE denotes full time education, DM denotes diabetes mellitus, UtA denotes uterine artery and PI denotes pulsatility index.
Data are expressed as median (IQR) or n (column %) as appropriate. For fields where there is no category labelled "missing", data were 100% complete.
Maternal age was defined as age at recruitment. All other maternal characteristics were defined by self-report at the 20wkGA interview, from examination of the clinical case record, or linkage to the hospital’s electronic databases. Deprivation was quantified using the Index of Multiple Deprivation 200710, which is based on census data from the area of the mother’s postcode. Birth weight percentiles and z scores were calculated using a population-based UK reference.11 Gestational hypertension was defined as development of hypertension in the second half of pregnancy in a previously normotensive woman who did not fulfill the diagnostic criteria for preeclampsia. See Supplemental Material for details.