Table 4.
Rate of first antepartum venous thromboembolism (VTE) during hospital admission/after discharge stratified by trimester, age, calendar year and BMI
| Variable | No of VTE | Rate* (95%CI) | IRR (95% CI) | |
|---|---|---|---|---|
| Adjusted 1† | Adjusted 2‡ | |||
| Variation by antepartum trimester | ||||
| Trimester 1 and 2: | ||||
| Time outside hospital | 60 | 60 (46 to 77) | 1.00 | 1.00 |
| Admission/after discharge | 5 | 449 (186 to 1078) | 7.61 (3.03 to 19.0) | 8.43 (3.27 to 21.7) |
| Trimester 3: | ||||
| Time outside hospital | 90 | 162 (134 to 203) | 1.00 | 1.00 |
| Admission/after discharge | 21 | 961 (426 to 1473) | 5.93 (3.64 to 9.65) | 5.57 (3.32 to 9.34) |
| Variation by calendar year in admission/after discharge | ||||
| 1997-2003: | ||||
| Time outside hospital | 62 | 96 (74 to 123) | 1.00 | 1.00 |
| Admission/after discharge | 8 | 550 (275 to 1100) | 5.82 (2.76 to 12.2) | 4.59 (2.08 to 10.1) |
| 2004-10: | ||||
| Time outside hospital | 88 | 98 (79 to 121) | 1.00 | 1.00 |
| Admission/after discharge | 18 | 975 (614 to 1548) | 10.1 (6.03 to 16.9) | 8.51 (4.94 to 14.6) |
| Variation by maternal age (years) | ||||
| 15-24: | ||||
| Time outside hospital | 34 | 93 (66 to 131) | 1.00 | 1.00 |
| Admission/after discharge | 4 | 363 (136 to 967) | 3.88 (1.37 to 10.9) | 3.80 (1.25 to 11.5) |
| 25-34: | ||||
| Time outside hospital | 90 | 101 (82 to 124) | 1.00 | 1.00 |
| Admission/after discharge | 13 | 771 (447 to 1328) | 7.61 (4.24 to 13.6) | 6.15 (3.24 to 11.7) |
| 35-44: | ||||
| Time outside hospital | 26 | 89 (60 to 131) | 1.00 | 1.00 |
| Admission/after discharge | 9 | 1756 (913 to 3376) | 19.6 (9.20 to 42.0) | 21.7 (9.62 to 49.0) |
| Variation by BMI | ||||
| Normal BMI (18.5-24.9) | ||||
| Time outside hospital | 51 | 72 (55 to 95) | 1.00 | 1.00 |
| Admission/after discharge | 10 | 766 (412 to 1423) | 6.24 (2.41 to 16.1) | 4.72 (1.71 to 13.0) |
| Overweight (25-29.9): | ||||
| Time outside hospital | 34 | 113 (81 to 158) | 1.00 | 1.00 |
| Admission/after discharge | 3 | 474 (153 to 1472) | 10.3 (5.15 to 20.8) | 9.42 (4.38 to 20.5) |
| Obese (≥30): | ||||
| Time outside hospital | 30 | 157 (109 to 224) | 1.00 | 1.00 |
| Admission/after discharge | 5 | 974 (405 to 2341) | 4.30 (1.30 to 14.1) | 4.50 (1.23 to 16.4) |
IRR=incidence rate ratio.
*Rate calculated per 100 000 person years.
†Adjusted for maternal age and calendar year when not stratified by them.
‡Adjusted for maternal age, calendaryear, BMI, gestational infection, cardiac disease, varicose vein, gestational diabetes, and hyperemesis when not stratified by them.