Supplemental information Supplementary table S1. Distribution of offspring cardio-metabolic biomarkers by sex at follow up (n=308). Men (n=121) Mean s.d Women (n=187) Mean s.d BMI (kg/m2) Waist (cm) Systolic BP (mm Hg) Diastolic BP (mm Hg) Resting pulse (bpm) Fasting plasma glucose (mmol/L) HbA1c (%) 22.6 2.9 22.2 3.1 82.9 7.7 80.2 8.4 118.1 9.2 105.2 7.8 64.8 6.9 66.0 5.7 60.9 10.6 62.8 8.7 5.15 0.41 4.77 0.37 5.20 0.24 5.16 0.23 Median IQR Median IQR Total cholesterol (mmol/L) 4.00 1.00 4.50 1.00 Triglyceride (mmol/L) 0.80 0.50 1.00 0.60 LDL (mmol/L) 2.28 0.90 2.43 0.90 HDL (mmol/L) 1.30 0.40 1.50 0.30 HOMA-IR 1.50 0.90 1.50 0.80 Insulin (ug/l) 38.00 23.80 42.50 22.00 Leptin (ug/l) 2.13 3.10 13.06 11.50 Adiponectin (ug/l) 6.92 3.80 9.24 4.70 Abbreviations: DBP, diastolic blood pressure; HbA1c, glycated haemoglobin; HDL, high density lipoprotein, Homa-IR, homeostasis model assessment-estimated insulin resistance; LDL, low density lipoprotein; SBP, systolic blood pressure. 1 Supplementary table S2. Mean difference (95% CI) in offspring cardio-metabolic risk factors at follow up by Institute of Medicine categories of maternal gestational weight gain (n=308). Outcome HOMA-IR (%) P for trend4 Insulin (%) P for trend4 Leptin (%) P for trend4 Total cholesterol (%) P for trend4 LDL (%) P for trend4 HDL (%) P for trend4 Triglyceride (%) P for trend4 SBP (mm Hg) P for trend4 DBP (mm Hg) P for trend4 Resting pulse (bpm) P for trend4 Weight gain1 Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive Suboptimal Optimal Excessive All (n=308)2 -10 (-20, 2) ref. 3 (-8, 16) 0.05 -10 (-20, 1) ref. 3 (-8, 15) 0.05 -7 (-25, 15) ref. 42 (15, 75) <0.01 0.6 (-4, 6) ref. -5 (-9, -0.1) 0.05 3 (-5, 11) ref. -7 (-14, 0.0) 0.02 -1 (-7, 5) ref. -3 (-8, 3) 0.52 0.3 (-11, 13) ref. 4 (-7,16) 0.60 -1 (-3, 1) ref. 0.0 (-2, 2) 0.50 0.0 (-2, 2) ref. 1 (-1, 3) 0.30 -2 (-4, 1) ref. -0.8 (-3, 2) 0.53 Men (n=121)3 -18 (-32, 6) ref. 5 (-15, 30) 0.09 -16 (-31, 3) ref. 6 (-14, 29) 0.05 -18 (-45, 20) ref. 93 (30, 186) <0.01 1 (-6, 9) ref. 2 (-5, 10) 0.76 0.0 (-11, 12) ref. 3 (-8, 16) 0.62 7 (-2, 17) ref. -0.9 (-9, 9) 0.14 -4 (-19, 14) ref. 13 (-5, 35) 0.11 -0.6 (-5, 4) ref. 0.0 (-4, 4) 0.82 0.3 (-3, 3) ref. 2 (-1, 5) 0.43 -4 (-9, 1) ref. 1 (-4, 6) 0.07 Women (n=187)3 -10 (-24, 5) ref. 0.1 (-13, 17) 0.18 -10 (-23, 5) ref. -0.4 (-14, 15) 0.23 -2 (-24, 26) ref. 23 (-3, 57) 0.08 1 (-6, 9) ref. -8 (-14, -1) 0.02 5 (-6, 18) ref. -11 (-20, -1) <0.01 -5 (-12, 3) ref. -4 (-10, 4) 0.73 3 (-12,20) ref. -2 (-16, 13) 0.56 -2 (-5, 1) ref. -0.6 (-3, 2) 0.44 -0.5 (-3, 2) ref. 0.4 (-2, 2) 0.44 0.1 (-3, 3) ref. -2 (-5, 1) 0.26 Abbreviations: DBP, diastolic blood pressure; HDL, high density lipoprotein, Homa-IR, homeostasis model assessment-estimated insulin resistance; LDL, low density lipoprotein; SBP, systolic blood pressure. 2 1 Increase in the outcome variable by the Institute of Medicine guidelines; suboptimal (<11.5 kg), optimal (11.5- 16) and excessive (>16 kg) weight gain. 2 Adjusted for maternal pre-pregnancy BMI, age, parity, smoking status and educational level, offspring´s sex and whether offspring thinks their father is overweight. 3 Same covariates as in 2 but without offspring sex. 4 T-test with gestational weight gain entered as dichotomous variable. 3 Supplementary table S3. Associations of maternal gestational weight gain during the first 30 weeks of gestation with offspring cardio-metabolic risk factors at follow up adjusted additionally for offspring smoking, alcohol consumption and BMI at follow up (n=308). Adjusted I1 Outcome3 BMI (kg/m2) HOMA_IR (%) Insulin (%) Leptin (%) Adiponectin (%) Total cholesterol (%) LDL (%) HDL (%) Triglyceride (%) Systolic BP (mm Hg) Diastolic BP (mm Hg) Resting pulse (bpm) Men (n=121) 0.2 (0.0, 0.3) 3.1 (0.5, 5.9) 3.5 (1.0, 6.0) 10.8 (5.6, 16.3) -0.9 (-3.1, 1.3) 0.0 (-0.9, 0.9) 0.3 (-1.0, 1.7) -1.2 (-2.2, -0.0) 1.9 (-0.3, 4.2) 0.4 (-0.1, 1.0) 0.4 (0.1, 0.8) 1.0 (0.4, 1.6) Women (n=187) 0.1 (-0.0, 0.2) -0.4 (-2.2, 1.5) -0.4 (-2.2, 1.3) 0.4 (-2,5, 3.4) 1.7 (0.2, 3.1) -1.5 (-2.3, -0.6) -2.2 (-3.5, -1.0) -0.2 (-1.1, 0.7) -1.3 (-3.0, 0.5) 0.3 (-0.1, 0.6) 0.1 (-0.2, 0.3) -0.2 (-0.6, 0.2) Adjusted II2 Men (n=121) 2.7 (0.0, 5.4) 3.0 (0.5, 5.6) 8.3 (3.6, 13.2) -0.2 (-2.3, 2.0) -0.1 (-1.0, 0.9) 0.2 (-1.2, 1.7) -0.9 (-2.0, 0.1) 1.2 (-1.0, 3.4) 0.2 (-0.3, 0.6) 0.4 (-0.0, 0.8) 1.0 (0.3, 1.6) Women (n=187) -0.9 (-2.6, 0.9) -0.9 (-2.6, 0.8) -1.3 (-3.4, 0.9) 1.9 (0.4, 3.4) -1.5 (-2.3, -0.7) -2.3 (-3.6, -1.1) -0.1 (-1.0, 0.8) -1.3 (-3.0, 0.5) 0.2 (-0.3, 0.6) 0.0 (-0.2, 0.3) -0.2 (-0.6, 0.1) Abbreviations: BMI, body mass index; DBP, diastolic blood pressure; HDL, high density lipoprotein, Homa-IR, homeostasis model assessment-estimated insulin resistance; LDL, low density lipoprotein; SBP, systolic blood pressure. 1 Adjusted for maternal pre-pregnancy BMI, age, parity, smoking status and educational level, offspring´s sex, whether offspring thinks their father is overweight, offspring smoking and alcohol consumption. 2 Same covariates as in 1 but additionally adjusted for offspring BMI 3 Showing increase in the outcome variable per 1-kg increase in gestational weight gain and the 95% confidence interval. 4