Table 2

Live-birth pregnancies and risk (HRs and 95% CI) of hypertension by reproductive interval for women in the Danish National Birth Cohort

Live-birth cycleCasesPerson-yearsModel 1*Model 2†Model 3 ‡Model 3‡ - stratified by pre-pregnancy BMI
UW/normalOW/OB
Hypertension risk in each live-birth cycle
 Overall1731679 354n=44 552n=44 552n=40 177; cases=1547n=29 762; cases=865n=10 415; cases=682
 LBC 1857238 1391.53 (1.37 to 1.71)1.54 (1.38 to 1.72)1.53 (1.37 to 1.72)1.63 (1.40 to 1.89)1.45 (1.23 to 1.71)
 LBC 2668341 2661 (baseline)1 (baseline)1 (reference)1 (reference)1 (reference)
 LBC 317990 8731.08 (0.91 to 1.27)1.07 (0.91 to 1.26)1.13 (0.95 to 1.34)1.22 (0.98 to 1.53)1.02 (0.78 to 1.34)
 ≥LBC 42790761.64 (1.11 to 2.40)1.63 (1.11 to 2.40)1.72 (1.15 to 2.58)2.34 (1.48 to 3.75)0.91 (0.40 to 2.05)
Hypertension risk during live-birth pregnancies
 Overall95580 280n=44 552n=44 552n=40 177; cases=852n=29 762; cases=469n=10 415; cases=383
 LBP 161238 9762.12 (1.82 to 2.47)2.12 (1.82 to 2.47)2.10 (1.79 to 2.47)2.37 (1.90 to 2.96)1.85 (1.47 to 2.31)
 LBP 226131 0561 (reference)1 (reference)1 (reference)1 (reference)1 (reference)
 LBP 37591780.85 (0.65 to 1.10)0.85 (0.65 to 1.10)0.89 (0.68 to 1.16)1.23 (0.88 to 1.72)0.51 (0.32 to 0.84)
 ≥LBP 4710700.63 (0.30 to 1.34)0.64 (0.30 to 1.36)0.63 (0.28 to 1.43)0.80 (0.29 to 2.17)0.44 (0.11 to 1.79)
Hypertension risk in the inter-live-birth pregnancy intervals
 Overall394458 171n=44 549n=44 549n=40 174; cases=339n=29 760; cases=194n=10 414; cases=145
 Inter-LBP 1135198 8830.80 (0.64 to 1.00)0.80 (0.64 to 1.00)0.76 (0.60 to 0.97)0.75 (0.54 to 1.03)0.80 (0.55 to 1.15)
 Inter-LBP 2210214 1841 (reference)1 (reference)1 (reference)1 (reference)1 (reference)
 Inter-LBP 34341 9731.01 (0.73 to 1.41)1.01 (0.73 to 1.40)1.11 (0.79 to 1.56)0.96 (0.60 to 1.54)1.35 (0.82 to 2.21)
 ≥Inter LBP 4631311.82 (0.81 to 4.09)1.81 (0.80 to 4.09)1.56 (0.64 to 3.83)1.81 (0.57 to 5.72)1.23 (0.30 to 5.09)
  • *Age as underlying time scale, adjusted for previous hypertension diagnosis in an inter-LBP interval for analysis of LBP intervals or previous hypertension diagnosis in a LBP interval for analysis of inter-LBP intervals

  • †Adjusted for -* and for induced abortions, spontaneous abortions and stillbirths (time-dependent variables)

  • ‡Adjusted for † and for smoking status (ever/never), socio-occupational status, alcohol intake, exercise level and pre-pregnancy body mass index (underweight, normal-weight, overweight and obese)

  • BMI, body mass index; inter-LBP, inter-live-birth pregnancy; LBC, live-birth cycle; LBP, live-birth pregnancy;OB, obese; OW, overweight; UW, underweight.