Table 1 Details of candidate predictors of women in the PREP study and the proportion with missing values

 Maternal age (years), mean (SD)

30.2 (6.1)

2 (0.2%)

 Gestational age at diagnosis (weeks), mean (SD)

30.5 (2.9)

–

 Number of fetuses in pregnancy^a

  Singleton

866 (91%)

  Twins

83 (9%)

–

  Triplets

5 (1%)

 Parity

–

  0

551 (58%)

  1

207 (22%)

  2

109 (11%)

  3

55 (6%)

  4

20 (2%)

  5 – 9

12 (1%)

 Medical history^b

1 (0.1%)

  None

601 (63%)

  At least one condition

251 (26%)

  Two or more conditions

101 (11%)

  Chronic hypertension

139 (15%)

10 (1.0%)

  Renal disease

30 (3%)

10 (1.0%)

  Previous history of pre-eclampsia

169 (43%)

558^b

  Autoimmune disease

18 (2%)

32 (3.4%)

  Diabetes mellitus

109 (11%)

6 (0.6%)

 Symptoms of headache and/or visual disturbance

382 (41%)

28 (2.9%)

 Symptoms of epigastric pain, nausea and/or vomiting

202 (22%)

47 (4.9%)

 Symptoms of chest pain and/or breathlessness

60 (7%)

126 (13.2%)

 Systolic blood pressure (mmHg), mean (SD)

159 (19)

5 (0.5%)

 Diastolic blood pressure (mmHg), mean (SD)

99 (12)

5 (0.5%)

 Clonus

95 (17%)

403 (42.2%)

 Exaggerated tendon reflexes

147 (24%)

353 (37%)

 Oxygen saturation by pulse oximetry (%), mean (SD)

98 (2)

521 (54.6%)

 Oxygen saturation: abnormal (< 94%)

4 (1%)

521 (54.6%)

Urine dipstick

  None/Trace

39 (4%)

  1+

170 (18%)

  2+

314 (34%)

19 (2%)

  3+

306 (33%)

   ≥ 4

106 (11%)

 Haemoglobin (g/L), mean (SD)

11.9 (1.3)

37 (3.9%)

 Platelet count (× 10⁹/L), mean (SD)

226 (78)

41 (4.3%)

 Alanine transaminase (U/L), mean (SD)

31.0 (71.0)

75 (7.9%)

 Serum uric acid (μmol/L), mean (SD)

0.6 (2.7)

165 (17.3%)

 Serum urea (mmol/L), mean (SD)

4.6 (4.4)

70 (7.3%)

 Serum creatinine (μmol/L), mean (SD)

61.0 (17.8)

38 (4%)

 Urine PCR (mg/mmol), mean (SD)

273 (492)

109 (11.4%)

 Any anti-hypertensive therapy^c

753 (79%)

6 (0.6%)

 Oral anti-hypertensive therapy

734 (77%)

6 (0.6%)

 Parenteral anti-hypertensive therapy

111 (12%)

6 (0.6%)

 Parenteral magnesium sulfate^d

144 (15%)

6 (0.6%)