Table 1 Demographic and clinical characteristics of patients in the Development and External validation cohorts

Age, median (IQR), year

29.0 (25.0–33.0)

28.0 (25.0–32.0)

0.211

30.0 (28.0–34.3)

30.0 (27.0–32.0)

0.118

Mild preeclampsia, No. (%)

 No

305 (98.7)

108 (97.3)

0.331

213 (94.2)

45 (95.7)

0.683

 Yes

4 (1.3)

3 (2.7)

13 (5.8)

2 (4.3)

Severe preeclampsia, No. (%)

 No

268 (86.7)

84 (75.7)

0.007

184 (81.4)

34 (72.3)

0.161

 Yes

41 (13.3)

27 (24.3)

42 (18.6)

13 (27.7)

Eclampsia with pregnancy/delivery, No. (%)

 No

281 (90.9)

88 (79.3)

0.002

198 (87.6)

44 (93.6)

0.247

 Yes

28 (9.1)

23 (20.7)

28 (12.4)

3 (6.4)

Eclampsia with pre-existing HTN, No. (%)

 No

298 (96.4)

98 (88.3)

0.003

215 (95.1)

43 (91.5)

0.325

 Yes

11 (3.6)

13 (11.7)

11 (4.9)

4 (8.5)

Postpartum haemorrhage, No. (%)

 No

296 (95.8)

105 (94.6)

0.270

206 (91.2)

46 (97.9)

0.149

 Yes

13 (4.2)

6 (5.4)

20 (8.8)

1 (2.1)

Multiple pregnancies, No. (%)

 No

294 (95.1)

104 (93.7)

0.557

197 (87.2)

42 (89.4)

0.679

 Yes

15 (4.9)

7 (6.3)

29 (12.8)

5 (10.6)

Premature rupture of membranes, No. (%)

 No

293 (94.8)

105 (94.6)

0.927

208 (92.0)

44 (93.6)

0.712

 Yes

16 (5.2)

6 (5.4)

18 (8.0)

3 (6.4)

Type I respiratory failure, No. (%)

 No

306 (99.0)

85 (76.6)

< 0.001

220 (97.3)

30 (63.8)

< 0.001

 Yes

3 (10.0)

26 (23.4)

6 (2.7)

17 (36.2)

Type II respiratory failure, No. (%)

 No

309 (100.0)

108 (97.3)

0.999

225 (99.6)

46 (97.9)

0.265

 Yes

0 (0.0)

3 (2.7)

1 (0.4)

1 (2.1)

Arrhythmia, No. (%)

 No

208 (67.3)

52 (46.8)

 < 0.001

151 (66.8)

23 (48.9)

0.022

 Yes

101 (32.7)

59 (53.2)

75 (33.2)

24 (51.1)

Patent ductus arteriosus, No. (%)

 No

297 (96.1)

104 (93.7)

0.297

217 (96.0)

44 (93.6)

0.469

 Yes

12 (3.9)

7 (6.3)

9 (4.0)

3 (6.4)

Ventricular septal defect, No. (%)

 No

258 (83.5)

88 (79.3)

0.318

204 (90.3)

42 (89.4)

0.850

 Yes

51 (16.5)

23 (20.7)

22 (9.7)

5 (10.6)

Atrial septal defect, No. (%)

 No

213 (68.9)

99 (89.2)

< 0.001

181 (80.1)

44 (93.6)

0.037

 Yes

96 (31.1)

12 (10.8)

45 (19.9)

3 (6.4)

Pulmonary embolism, No. (%)

 No

305 (98.7)

107 (96.4)

0.143

224 (99.1)

47 (100.0)

0.999

 Yes

4 (1.3)

4 (3.6)

2 (0.9)

0 (0.0)

Endocarditis, No. (%)

 No

307 (99.4)

110 (99.1)

0.786

226 (100.0)

46 (97.9)

1.000

 Yes

2 (0.6)

1 (0.9)

0 (0.0)

1 (2.1)

Myocardiopathy, No. (%)

 No

301 (97.4)

101 (91.0)

0.007

226 (100.0)

44 (93.6)

0.999

 Yes

8 (2.6)

10 (9.0)

0 (0.0)

3 (6.4)

Rheumatic heart disease, No. (%)

 No

280 (90.6)

97 (87.4)

0.338

217 (96.0)

45 (95.7)

0.938

 Yes

29 (9.4)

14 (12.6)

9 (4.0)

2 (4.3)

Congenital heart disease, No. (%)

 No

127 (41.1)

62 (55.9)

< 0.001

140 (61.9)

35 (74.5)

0.107

 Yes

182 (58.9)

49 (44.1)

86 (38.1)

12 (25.5)

Eisenmenger syndrome, No. (%)

 No

294 (95.1)

90 (81.1)

< 0.001

215 (95.1)

44 (93.6)

0.669

 Yes

15 (4.9)

21 (18.9)

11 (4.9)

3 (6.4)

Gestational diabetes mellitus, No. (%)

 No

281 (90.9)

88 (79.3)

0.002

193 (85.4)

44 (93.6)

0.142

 Yes

28 (9.1)

23 (20.7)

33 (14.6)

3 (6.4)

Infection, No. (%)

 No

281 (90.9)

76 (68.5)

< 0.001

181 (80.1)

24 (51.1)

< 0.001

 Yes

28 (9.1)

35 (31.5)

45 (19.9)

23 (48.9)

Systemic lupus erythematosus, No. (%)

 No

301 (97.4)

106 (95.5)

0.324

216 (95.6)

41 (87.2)

0.034

 Yes

8 (2.6)

5 (4.5)

10 (4.4)

6 (12.8)

Liver insufficiency, No. (%)

 No

303 (98.1)

109 (98.2)

0.926

217 (96.0)

44 (93.6)

0.469

 Yes

6 (1.9)

2 (1.8)

9 (4.0)

3 (6.4)

Left to right shunt, No. (%)

 No

293 (94.8)

107 (96.4)

0.506

211 (93.4)

44 (93.6)

0.949

 Yes

16 (5.2)

4 (3.6)

15 (6.6)

3 (6.4)

Right-to-left shunt, No. (%)

 No

301 (97.4)

107 (96.4)

0.584

220 (97.3)

46 (97.9)

0.836

 Yes

8 (2.6)

4 (3.6)

6 (2.7)

1 (2.1)

Premature delivery, No. (%)

 No

130 (42.1)

37 (33.3)

0.803

93 (59.3)

17 (59.6)

0.193

 Yes

112 (36.2)

49 (44.1)

100 (11.9)

18 (23.4)

PH classification, No. (%)

 Group 1

265 (85.8)

84 (75.7)

0.132

199 (88.1)

40 (85.1)

0.760

 Group 2

37 (12.0)

20 (18.0)

17 (7.5)

4 (8.5)

 Group 3

1 (0.3)

1 (0.9)

3 (1.3)

0 (0.0)

 Group 4

1 (0.3)

2 (1.8)

0 (0.0)

0 (0.0)

 Group 5

5 (1.6)

4 (3.6)

7 (3.1)

3 (6.4)

Pregnancy outcome, No. (%)

 Termination of pregnancy

67 (21.7)

25 (22.5)

< 0.001

33 (14.6)

12 (25.5)

0.017

 Vaginal delivery

20 (6.5)

8 (7.2)

15 (6.6)

1 (2.1)

 Spinal and/or epidural for C-section

204 (66.0)

46 (41.4)

172 (76.1)

29 (61.7)

 General anaesthesia for C-section

18 (5.8)

32 (28.8)

6 (2.7)

5 (10.6)

Cardiac surgery, No. (%)

 No

292 (94.5)

109 (98.2)

0.127

204 (90.3)

46 (97.9)

0.171

 Single lung transplantation

0 (0.0)

0 (0.0)

5 (2.2)

0 (0.0)

 Repair of heart defect

17 (5.5)

2 (1.8)

17 (7.5)

1 (2.1)

NYHA functional class, No. (%)

 I / II

215 (69.6)

23 (20.7)

< 0.001

184 (81.4)

13 (27.7)

< 0.001

 III

73 (23.6)

41 (36.9)

31 (13.7)

11 (23.4)

 IV

21 (6.8)

47 (42.3)

11 (4.9)

23 (48.9)

NT-proBNP, No. (%), ng/L

 < 1400

277 (89.6)

43 (38.7)

< 0.001

199 (88.1)

17 (36.2)

< 0.001

\(\ge\)1400

32 (10.4)

68 (61.3)

27 (11.9)

30 (63.8)

Gestation times, median (IQR), times

2.0 (1.0–3.0)

2.0 (1.0–3.0)

0.006

2.0 (1.0–3.0)

2.0 (1.0–3.0)

0.811

Parity, median (IQR), times

1.0 (1.0–2.0)

1.0 (1.0–2.0)

0.690

1.0 (1.0–2.0)

2.0 (1.0–2.0)

0.507

Troponin, median (IQR), ng/mL

0.01 (0.00–0.01)

0.03 (0.00–0.20)

0.185

0.01 (0.00–0.10)

0.02 (0.01–5.70)

0.164

Prothrombin time, median (IQR), s

10.1 (9.5–10.8)

10.4 (9.6–11.7)

< 0.001

10.4 (9.7–11.1)

10.7 (9.8–11.7)

0.009

APTT, median (IQR), s

28.9 (26.5–31.6)

30.2 (27.6–34.1)

< 0.001

27.6 (25.9–30.4)

29.8 (26.7–32.9)

0.009

Thrombin time, median (IQR), s

14.1 (12.8–16.5)

13.9 (12.9–16.3)

0.038

14.4 (13.2–16.0)

14.3 (13.1–16.1)

0.089

Fibrinogen, median (IQR), g/L

3.7 (3.1–4.3)

3.4 (2.8–4.0)

0.028

3.7 (3.3–4.3)

3.8 (3.0–4.7)

0.028

RBC, median (IQR), * 10^12/L

3.9 (3.5–4.3)

3.9 (3.3–4.3)

0.218

3.8 (3.5–4.2)

3.6 (3.2–4.3)

0.617

Haemoglobin, median (IQR), g/L

113.0 (102.0–124.0)

106.0 (93.0–123.0)

0.007

111.5 (100.0–123.0)

106.8 (90.0–118.6)

0.131

Platelet, median (IQR), * 10^9/L

196.0 (146.0–238.0)

152.0 (94.5–233.3)

< 0.001

183.5 (144.3–231.3)

166.0 (126.0–231.0)

0.136

D-Dimer, median (IQR), mg/L

0.5 (0.3–1.2)

0.8 (0.5–1.9)

0.030

0.6 (0.3–1.7)

0.8 (0.5–1.9)

0.687

RVD, median (IQR), mm

22.0 (18.0–29.0)

22.0 (17.1–29.0)

0.769

21.0 (18.0–25.0)

21.0 (18.0–25.0)

0.750

LVDs, median (IQR), mm

38.0 (29.0–46.0)

38.0 (32.5–50.5)

0.065

39.0 (32.0–45.5)

37.0 (24.8–44.5)

0.464

mPAD, median (IQR), mm

23.0 (20.0–27.8)

22.0 (21.0–26.0)

0.852

23.0 (21.0–26.0)

23.0 (23.0–28.0)

0.053

AOD, median (IQR), mm

21.8 (20.0–26.0)

25.0 (20.0–26.0)

0.234

25.0 (20.0–25.0)

25.0 (22.8–25.0)

0.230

EF, median (IQR), %

63.0 (60.0–66.0)

61.0 (57.0–64.0)

0.003

63.0 (61.0–67.0)

62.0 (56.0–66.0)

0.015

PASP, median (IQR), mm Hg

50.0 (42.0–71.5)

75.0 (50.0–100.0)

< 0.001

42.5 (37.0–56.3)

62.0 (41.0–90.0)

< 0.001