Table 1

Characteristics of women with and without a history of pre-eclampsia during the study period of January 2002 to March 2020

CharacteristicWomen with pre-eclampsia
(n=42 252)		Women without pre-eclampsia
(n=1 359 122)		Standardised difference between women with versus without pre-eclampsia
At the index birth   
 Mean (SD) age, years31.1 (5.7)30.6 (5.5)0.09
 Income quintile (Q)   
  Q1 (lowest)9702 (23.0)300 310 (22.1)0.02
  Q28509 (20.1)273 950 (20.2)0.0
  Q38777 (20.8)277 962 (20.5)0.01
  Q48556 (20.2)278 771 (20.5)0.01
  Q5 (highest)6465 (15.3)223 323 (16.4)0.03
  Missing243 (0.6)4806 (0.4)0.03
 Rural residence5455 (12.9)125 209 (9.2)0.12
 Unknown residence35 (0.1)1281 (0.1)0.0
 Median (IQR) parity1 (0–1)1 (0–1)NR
 Singleton pregnancy40 096 (94.9)1 331 386 (98.0)0.17
 Mean (SD) prepregnancy body mass index, kg/m2*26.0 (6.4)24.4 (5.1)0.27
Conditions ≤365 days before the index date   
 Prepregnancy diabetes mellitus5526 (13.1)105 565 (7.8)0.17
 Chronic hypertension8377 (19.8)35 993 (2.6)0.57
 Dyslipidaemia387 (0.9)10 478 (0.8)0.02
 Renal disease774 (1.8)4710 (0.3)0.14
 Drug dependence or tobacco use690 (1.6)19 774 (1.5)0.01
Conditions at the index birth   
 Preterm birth <37 weeks’ gestation11 426 (27.0)91 354 (6.7)0.56
 Stillbirth464 (1.1)6440 (0.5)0.07
Median (IQR) no. years of follow-up, from time zero10 (4–15)9 (4-14)NR
Total no. person-years of follow-up, from time zero410 25912 754 500NR
Total no. receiving coronary angiography during follow-up474 (1.1)5238 (0.4)0.09
Median (IQR) no. years to coronary angiography, if received, from time zero10.1 (5.8–13.5)9.9 (6.3–13.4)NR
Total no. deaths, from time zero309 (0.7)6821 (0.5)0.03
Total no. followed to end of study of 31 December 202040 189 (95.1%)1 291 538 (95.0%)0.0
Total no. lost to follow-up before end of study of 31 December 20201280 (3.0%)55 525 (4.1%)0.06

  • All data are presented as number (%) unless otherwise indicated.

  • *Body mass index was known among 7995 women with and 286 836 women without pre-eclampsia.

  • NR, not reportable.