Table 3 Overall and subgroup/sensitivity analysis estimates from studies that carried out a meta-analysis on the association between pregnancy complications and risk of future T2DM and hypertension. Estimates (adjusted or unadjusted) presented alongside 95% confidence intervals, 95% prediction intervals, the number of studies included in the meta-analysis and the measures of inconsistency (I²) and heterogeneity (tau²)

Alonso-Ventura 2020 [16]

Exposure: preeclampsia/eclampsia^c

Common adjustment factors: the review only provided information on matching variables for controls which were gestational age, age, parity, time of delivery, ethnicity, weight, BMI, smoking habits and family history of DM, CVD and preeclampsia, contraceptive intake, alcohol consumption

Hypertension

Outcome measured at least 3 months after delivery

Hypertension: OR 3.76 (2.87 to 4.94), PI = (2.34 to 6.05), studies = 12, n = 2261, I² = 0%, tau² = 0.03

SBP: MD 8.28 mmHg (6.85 to 9.71), PI = (1.00 to 15.56), studies = 38, n = 17,267, I² = 78%, tau² = 12.37

DBP: MD 6.79 mmHg (5.62 to 7.96), PI = (0.55 to 13.03), studies = 37, n = 17,232, I² = 83%, tau² = 9.10

Hypertension

Time of follow-up

Up to 5 years: OR 19.03 (2.47 to 146.49), studies = 2, n = 171, I² = 0%, tau² = 0

Up to 5 to 15 years: OR 4.13 (2.47 to 6.90), n = 1041, studies = 6, I² = 0%, tau² = 0.09

Above 15 years: OR 3.41 (2.41 TO 4.82), studies = 4, n = 1039, I² = 0%, tau² = 0.01

SBP

Time of follow-up

Up to 5 years: MD 9.88 (7.69 to 12.08), studies = 13, n = 1177, I² = 58%, tau² = 8.69

Up to 5 to 15 years: MD 6.82 (5.60 to 8.04), studies = 14, n = 3356, I² = 0%, tau² = 0

Above 15 years: MD 8.28 (4.99 to 11.58), studies = 11, n = 12,734, I² = 92%, tau² = 23.33

DBP

Time of follow up

Up to 5 years: MD 8.05 (6.50 to 9.60), studies = 12, n = 1142, I² = 52%, tau² = 3.53

Up to 5 to 15 years: MD 6.54 (4.85 to 8.23), studies = 14, n = 3356, I² = 71%, tau² = 6.30

Above 15 years: MD 5.78 (3.30 to 8.26), studies = 11, n = 12,734, I² = 92%, tau² = 14.24

Bellamy 2007 [17]

Exposure: preeclampsia^d

Common adjustment factors: BMI, smoking, socioeconomic status, hypercholesterolaemia, type 2 diabetes

Hypertension

Outcome measured at least 3 months after delivery

OR 6.20 (3.74 to 10.28), PI = (1.19 to 32.35), studies = 13, n = 19,758, I² = 83%%, tau² = 0.50

Parity

Preeclampsia in any pregnancy: RR 5.96 (3.42 to 10.38), studies = 4, n = np, I² = np, tau² = np

Preeclampsia in first pregnancy only: RR 3.23 (2.32 to 4.52), n = np, studies = 9, I² = NP, tau² = np

Brown 2013 [116]

Exposure: preeclampsia^d

Common adjustment factors: Not provided

Hypertension

Outcome measured at least 6 weeks after delivery

OR 3.90 (3.16 to 4.82), PI = (1.80 to 8.43), studies = 30, n = 822,555, I² = 80%, tau² = 0.13

Dall’Asta 2021 [117]

Exposure: preeclampsia^d

Common adjustment factors: Not provided

Hypertension

No restriction

OR 3.93 (3.08 to 5.02), PI = (1.40 to 11.05), studies = 21, n = 2711443, I² = 99%, tau² = 0.23

OR_adj 3.74 (2.87 to 4.87), PI = 1.28 to 10.95, studies = 15, n = 2,695,024, I² = 99%, tau² = 0.23

Giorgione 2021 [14]

Exposure: hypertensive disorders of pregnancy (including gestational hypertension, preeclampsia, eclampsia and HELLP syndrome)^a

Common adjustment factors: not provided, however, the systematic review compares population statistics between controls and exposed groups by maternal age, ethnicity (black ethnicity), BMI and smoking

Hypertension

Outcome measured 6 weeks to 2 years after delivery

HDP: OR 5.75 (3.92 to 8.44), PI = 2.08 to 15.87, studies = 14, n = 7580, I² = 49%, tau² = 0.18

Preeclampsia: OR 6.83 (4.25 to 10.96), PI = (1.96 to 23.79), studies = 12, n = 7238, I² = 53%, tau² = 0.26

HDP: Follow-up duration

First 6 months: OR 13.39 (1.27 to 141.04), studies = 3, n = 392, I² = 72%, tau² = 3.05

6 months–1 year: OR 4.13 (2.82 to 6.07), studies = 3, n = 6741, I² = 54%, tau² = 0.06

1–2 years: OR 8.73 (4.66 to 16.35), studies = 8, n = 1364, I² = 23%, tau² = 0.18

Preeclampsia: follow-up duration

First 6 months: OR 43.95 (5.72 to 338.04), studies = 2, n = 144, I² = 0%, tau² = 0

6 months–1 year: OR 4.46 (2.76 to 7.21), studies = 3, n = 5998, I² = 56%, tau² = 0.10

1–2 years: OR 8.91 (4.33 to 18.33), studies = 7, n = 1096, I² = 33%, tau² = 0.28

Estimates including cases with pre-existing chronic hypertension

HDP: OR 6.28 (4.18 to 9.43), PI = (1.99 to 19.85), studies = 15, n = 8041, I² = 56%, tau² = 0.24

Preeclampsia: OR 7.49 (4.58 to 12.26), PI = (1.88 to 29.86), studies = 13, n = 7699, I² = 60%, tau² = 0.33

HDP: follow up duration

First 6 months: OR 18.33 (1.35 to 249.48), studies = 3, n = 392, I² = 84%, tau² = 4.32

6 months–1 year: OR 4.36 (2.81 to 6.76), studies = 4, n = 7106, I² = 56%, tau² = 0.10

1–2 years: OR 7.24 (4.44 to 11.80), studies = 8, n = 1364, I² = 9%, tau² = 0.05

Preeclampsia: follow up duration

First 6 months: OR 57.08 (11.00 to 296.07), studies = 2, n = 248, I² = 0%, tau² = 0

6 months–1 year: OR 4.83 (2.78 to 8.37), studies = 4, n = 6307, I² = 58%, tau² = 0.16

1–2 years: OR 7.44 (4.19 to 13.21), studies = 7, n = 1144, I² = 20%, tau² = 0.12

Pathirana 2021 [15]

Exposure: gestational diabetes mellitus

Common adjustment factors: BMI, parity, age, history of diabetes, other pregnancy complications

Hypertension

No restriction

DBP: MD 1.89 mmHg (1.32 to 2.46), PI = (− 1.12 to 4.90), studies = 48, n = 49,495, I² = 83%, tau² = 2.18

SBP: MD 2.47 mmHg (1.74 to 3.4), PI = (− 2.22 to 7.36), studies = 48, n = 50118, I² = 79%, tau² = 5.56

Follow-up duration (DBP)

 < 1 year: MD 2.48 mmHg (0.58 to 4.37), studies = np, n = 1749, I² = 64%, tau² = np

1–5 years: MD 1.37 mmHg (0.20 to 2.54), studies = np, n = 19,676, I²⁼89%, tau² = np

5–10 years: MD 7.17 mmHg (1.69 to 16.03), studies = np,n = 2184, 99%, tau² = np

 > 10 years: MD 1.23 mmHg (1.03 to 1.96), studies = np,n = 4948, I² = 97%, tau² = np

Follow-up duration (SBP)

 < 1 year: MD 3.47 mmHg (1.26 to 5.68), studies = np, n = 1826, I² = 50%, tau² = np

1–5 years: MD 2.26 mmHg (0.27 to 4.25), studies = np, n = 19,701, I² = 93%, tau² = np

5–10 years: MD 3.96 mmHg (2.36 to 5.56), studies = np, n = 1965, I² = 17%, tau² = np

 > 10 years: MD 2.58 mmHg (1.05 to 4.11), studies = np, n = 4941, I² = 23%, tau² = np

Sukmanee 2022 [113]

Exposure: hypertensive disorders of pregnancy (including gestational hypertension and preeclampsia)^b

Common adjustment factors: age, ethnicity, socioeconomic status, time of delivery, smoking status, BMI, family history of cardiovascular diseases, parity, history of diabetes mellitus and maternal education

Hypertension

Outcome measured at least 6 weeks after delivery

OR 4.33 (3.51 to 5.33), PI = (1.47 to 12.74), studies = 37, n = 1,517,583, I² = 99%, tau² = 0.27

Follow-up duration

 ≤ 5 years: OR 6.05 (3.55 to 10.30), studies = 7, n = 321,971, I² = 98%, tau² = 0.35

6–10 years: OR 5.95 (4.69 to 7.54), studies = 6, n = 285,947, I² = 82%, tau² = 0.05

11–15 years: OR 4.22 (2.44 to 7.32), studies = 7, n = 786,479, I² = 93%, tau² = 0.41

 > 15 years: OR 2.44 (1.93 to 3.08), studies = 2, n = 4535, I² = 65%, tau² = 0.02

Duration unspecified: OR 3.74 (2.50 to 5.58), studies = 15, n = 118,651, I² = 97%, tau² = 0.40

Preeclampsia with severe features

OR 7.43 (2.85 to 19.35), studies = 4, n = 751,128, I² = 90%, tau² = 0.66

Xu 2022 [112]

Exposure: hypertensive disorders of pregnancy (including preeclampsia and gestational hypertension)^b

Common adjustment factors: a list of adjustment factors in each primary study is not provided, however authors mention some studies adjusted for age and BMI at recruitment, pre-pregnancy BMI, age at first delivery and other factors

Hypertension

Included studies evaluating outcome at least 1 year after delivery

HDP: OR 3.61 (2.18 to 6.00), PI = (0.62 to 20.98), studies = 11, n = 228,317, I² = 96%, tau² = 0.84

HDP_adj: OR 2.47 (1.67 to 3.64), PI = (0.71 to 8.63), studies = 5, n = 7137, I² = 79%, tau² = 0.12

Gestational hypertension: OR 6.24 (1.73 to 22.55), studies = 3, n = 933, I² = 73%, tau² = 0.90

Preeclampsia:

OR 3.19 (1.52 to 6.70), PI = (0.22 to 46.88), studies = 13, n = 341,060, I² = 97%, tau² = 1.35

Preeclampsia_adj: OR 3.78 (2.05 to 6.98), PI = (0.23 to 62.05), studies = 4, n = 2549, I² = 90%, tau² = 0.33

HDP

Region

North and South America: OR 2.11 (1.42 to 3.14), studies = 5, I² = 82%, n = 6581, tau² = 0.12

Asia: OR 4.26 (1.07 to 16.94), studies = 3, n = 1260, I² = 88%, tau² = 1.30

Europe: OR 5.52 (3.01 to 10.13), studies = 3, n = 220,476, I² = 64%, tau² = 0.17

Test of differences between regions: p-value = 0.03

Preeclampsia

Region

North and South America: OR 3.32 (1.26 to 8.74), studies = 6, n = 332,949, I² = 95%, tau² = 1.07

Asia: OR 7.54 (2.49 to 22.81), studies = 3, n = 6529, I² = 36%, tau² = 0.45

Europe: OR 2.19 (0.30 to 16.02), studies = 4, n = 1582, I² = 98%, tau² = 3.57

Vounzoulaki 2020 [114]

Exposure: gestational diabetes mellitus

Common adjustment factors: maternal age, body mass index, family history of T2DM, parity, ethnicity, and socioeconomic status

T2DM

Included studies evaluating outcome at least 1 year after delivery

RR_unadj 9.51 (7.14 to 12.67), PI = (3.31 to 27.30), studies = 20, n = 1,332,373, I² = 96.5%, tau² = 0.23

1. Ethnicity

White population: RR 16.28 (15.01 to 17.66), studies = 6, n = 187,532, I² = 0%, tau² = 0

Non-white population: RR 10.38 (4.61 to 23.39), studies = 4, n = 2538, I² = 78.2%, tau² = 0.46

Mixed populations: RR 8.31 (5.44 to 12.69), studies = 10, n = 1,142,303, I² = 97.8%, tau² = 0.34

Test of differences between ethnicities: white vs mixed p-value = 0.26, white vs non-white p-value = 0.54)

2. Length of follow-up

1 to 5 years: RR 17.06 (8.95 to 32.55), studies = 6, n = 1566, I² = 0%, tau² = 0

 > 5 to 10 years: RR 10.42 (5.68 to 19.11), studies = 7, n = 223,945, I² = 98%, tau² = 0.52

 > 10 years: RR 8.09 (4.34 to 15.08), studies = 7, n = 1,106,862, I² = 97%, tau² = 0.52

Test of differences between ethnicities: 1–5 years vs 5–10 years p-value = 0.63, 1–5 years vs > 10 years p-value = 0.38)

Zhao 2021 [115]

Exposure: hypertensive disorders of pregnancy (HDP) (including gestational hypertension and preeclampsia)^a

Common adjustment factors: maternal age, body mass index, socioeconomic status, smoking status, pre-pregnancy and current BMI, parity, ethnicity and time of delivery

T2DM

Included studies evaluating outcome at least 1 year after delivery

HDP: HR_adj 2.24 (1.95 to 2.58), PI = (1.14 to 4.40), studies = 15, n = 3,095,457, I² = 94%, tau² = 0.10

Gestational hypertension: HR_adj 2.19 (1.69 to 2.84), PI = (1.02 to 4.37) studies = 7, n = 2,735,586, I² = 87%, tau² = 0.07

Preeclampsia: HR_adj: 2.56 (2.02 to 3.24), PI = (1.07 to 5.67), studies = 11, n = 3,007,543, I² = 94%, tau² = 0.23

Preterm preeclampsia: HR_adj 3.05 (2.05 to 4.56), studies = 3, n = np, I² = 82%, tau² = 0.09

Follow-up duration

Less than 20 years: HR_adj 2.64 (2.23 to 3.12), studies = 7, n = np, I² = 95%, tau² = np

Greater or equal to 20 years: HR_adj 1.34 (1.20 to 1.50), studies = 2, n = np, I² = 0%, tau² = np