Absolute and relative rates of VTE by risk factors in the antepartum period
| Variable . | Events . | Rate* . | IRR† (Model 1) . | IRR‡ (Model 2) . |
|---|---|---|---|---|
| Maternal characteristics | ||||
| Maternal age, y | ||||
| 15-24 | 45 | 73 (54-98) | 0.87 (0.61-1.24) | 0.89 (0.62-1.27) |
| 25-34 | 120 | 79 (66-95) | 1.00 | 1.00 |
| 35-44 | 50 | 112 (85-148) | 1.42 (1.01-1.93) | 1.40 (0.99-1.96) |
| Body mass index | ||||
| Underweight (<18.5 kg/m2) | 3 | 34 (11-1074) | 0.48 (0.15-1.54) | 0.48 (0.15-1.53) |
| Normal (18.5-24.9 kg/m2) | 86 | 73 (59-90) | 1.00 | 1.00 |
| Overweight (25-29.9 kg/m2) | 49 | 103 (75-136) | 1.41 (0.99-2.00) | 1.40 (0.98-2.00) |
| Obese (≥30 kg/m2) | 30 | 109 (76-156) | 1.50 (0.99-2.28) | 1.40 (0.90-2.16) |
| No BMI recorded before conception | 47 | 85 (63-113) | 1.18 (0.82-1.71) | 1.16 (0.85-1.69) |
| Cigarette smokers | 55 | 89 (68-116) | 1.15 (0.83-1.58) | 1.16 (0.84-1.60) |
| Pregnancy-associated characteristics and complication§ | ||||
| Previous live births | ||||
| None | 127 | 90 (75-107) | 1.00 | 1.00 |
| 1 | 60 | 72 (56-93) | 0.76 (0.56-1.03) | 0.72 (0.53-0.98) |
| 2 | 19 | 78 (50-123) | 0.79 (0.49-1.28) | 0.71 (0.43-1.16) |
| 3 or more | 9 | 103 (53-198) | 0.97 (0.48-1.93) | 0.89 (0.45-1.78) |
| Multiple gestation | 3 | 73 (23-227) | 0.83 (0.26-2.61) | 0.83 (0.26-2.60) |
| Eclampsia/preeclampsia | 0 | — | — | — |
| Gestational hypertension | 4 | 95 (35-254) | 1.01 (0.37-2.76) | 0.99 (0.36-2.72) |
| Gestational diabetes | 3 | 165 (53-514) | 1.71 (0.54-5.41) | ‖ |
| Acute respiratory tract infection | 13 | 142 (82-245) | 1.70 (0.97-2.99) | 1.65 (0.94-2.90) |
| Urinary tract infection | 31 | 145 (102-206) | 1.88 (1.28-2.77) | 1.80 (1.22-2.67) |
| Medical comorbidities§ | ||||
| Preexisting diabetes | 8 | 282 (141-565) | 3.08 (1.42-6.39) | 3.54 (1.13-11.0) |
| Preexisting hypertension | 7 | 82 (39-173) | 0.90 (0.42-1.94) | 0.74 (0.32-1.71) |
| Varicose veins | 13 | 216 (125-373) | 2.69 (1.53-4.70) | 2.21 (1.55-4.76) |
| Nephrotic syndrome | 0 | — | — | — |
| Systemic lupus erythematosus | 0 | — | — | — |
| Cancer | 6 | 169 (76-373) | 1.97 (0.87-4.44) | 1.95 (0.86-4.41) |
| Inflammatory bowel disease | 3 | 288 (93-895) | 3.46 (1.11-10.7) | 3.50 (1.12-10.9) |
| Cardiac disease | 0 | — | — | — |
| Variable . | Events . | Rate* . | IRR† (Model 1) . | IRR‡ (Model 2) . |
|---|---|---|---|---|
| Maternal characteristics | ||||
| Maternal age, y | ||||
| 15-24 | 45 | 73 (54-98) | 0.87 (0.61-1.24) | 0.89 (0.62-1.27) |
| 25-34 | 120 | 79 (66-95) | 1.00 | 1.00 |
| 35-44 | 50 | 112 (85-148) | 1.42 (1.01-1.93) | 1.40 (0.99-1.96) |
| Body mass index | ||||
| Underweight (<18.5 kg/m2) | 3 | 34 (11-1074) | 0.48 (0.15-1.54) | 0.48 (0.15-1.53) |
| Normal (18.5-24.9 kg/m2) | 86 | 73 (59-90) | 1.00 | 1.00 |
| Overweight (25-29.9 kg/m2) | 49 | 103 (75-136) | 1.41 (0.99-2.00) | 1.40 (0.98-2.00) |
| Obese (≥30 kg/m2) | 30 | 109 (76-156) | 1.50 (0.99-2.28) | 1.40 (0.90-2.16) |
| No BMI recorded before conception | 47 | 85 (63-113) | 1.18 (0.82-1.71) | 1.16 (0.85-1.69) |
| Cigarette smokers | 55 | 89 (68-116) | 1.15 (0.83-1.58) | 1.16 (0.84-1.60) |
| Pregnancy-associated characteristics and complication§ | ||||
| Previous live births | ||||
| None | 127 | 90 (75-107) | 1.00 | 1.00 |
| 1 | 60 | 72 (56-93) | 0.76 (0.56-1.03) | 0.72 (0.53-0.98) |
| 2 | 19 | 78 (50-123) | 0.79 (0.49-1.28) | 0.71 (0.43-1.16) |
| 3 or more | 9 | 103 (53-198) | 0.97 (0.48-1.93) | 0.89 (0.45-1.78) |
| Multiple gestation | 3 | 73 (23-227) | 0.83 (0.26-2.61) | 0.83 (0.26-2.60) |
| Eclampsia/preeclampsia | 0 | — | — | — |
| Gestational hypertension | 4 | 95 (35-254) | 1.01 (0.37-2.76) | 0.99 (0.36-2.72) |
| Gestational diabetes | 3 | 165 (53-514) | 1.71 (0.54-5.41) | ‖ |
| Acute respiratory tract infection | 13 | 142 (82-245) | 1.70 (0.97-2.99) | 1.65 (0.94-2.90) |
| Urinary tract infection | 31 | 145 (102-206) | 1.88 (1.28-2.77) | 1.80 (1.22-2.67) |
| Medical comorbidities§ | ||||
| Preexisting diabetes | 8 | 282 (141-565) | 3.08 (1.42-6.39) | 3.54 (1.13-11.0) |
| Preexisting hypertension | 7 | 82 (39-173) | 0.90 (0.42-1.94) | 0.74 (0.32-1.71) |
| Varicose veins | 13 | 216 (125-373) | 2.69 (1.53-4.70) | 2.21 (1.55-4.76) |
| Nephrotic syndrome | 0 | — | — | — |
| Systemic lupus erythematosus | 0 | — | — | — |
| Cancer | 6 | 169 (76-373) | 1.97 (0.87-4.44) | 1.95 (0.86-4.41) |
| Inflammatory bowel disease | 3 | 288 (93-895) | 3.46 (1.11-10.7) | 3.50 (1.12-10.9) |
| Cardiac disease | 0 | — | — | — |
Absolute rate calculated as per 100 000 person-years.
Adjusted for age, parity, BMI, and smoking status when not stratified by them.
Adjusted for age, parity, BMI, preexisting diabetes, IBD, varicose veins, acute systemic infection, and smoking status when not stratified by them.
IRR compared with women without risk factor under study.
Gestational diabetes was dropped from model 2 because of colinearity.