Table 2.
Absolute risks (AR) of pregnancy associated venous thromboembolism (VTE) for each thrombophilia, for family and non-family cohort studies
| Thrombophilia | No of studies | No of women with thrombophilia with VTE/Total | No of VTE events with information on time of occurrence/Total | AR of VTE, all studies, % pregnancies (95% CrI) | % probability of AR >1%, for all studies | % probability of AR >3%, for all studies | High quality studies | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Antepartum and post partum | Antepartum | Post partum | Antepartum | Post partum | Antepartum | Post partum | No | No of women with thrombophilia with VTE/Total | AR of VTE, antepartum and post partum, % pregnancies (95% CrI) | ||||||||
| Antithrombin deficiency: | |||||||||||||||||
| Family | 4 | 23/125 | 23/23 | 16.6 (0.0 to 45.1) | 7.3 (1.8 to 15.6) | 11.1 (3.7 to 21.0) | 100 | 100 | 96 | 99 | 3 | 13/105 | 10.5 (0.0 to 30.3) | ||||
| Protein C deficiency: | |||||||||||||||||
| Family | 3 | 10/137 | 10/10 | 7.8 (0.0 to 33.8) | 3.2 (0.6 to 8.2) | 5.4 (0.9 to 13.8) | 96 | 99 | 54 | 83 | 2 | 4/123 | 2.6 (0.0 to 13.5) | ||||
| Protein S deficiency: | |||||||||||||||||
| Family | 3 | 7/135 | 7/7 | 4.8 (0.0 to 20.0) | 0.9 (0.0 to 3.7) | 4.2 (0.7 to 9.4) | 47 | 98 | 9 | 73 | 2 | 6/130 | 3.6 (0.0 to 37.0) | ||||
| Heterozygous factor V Leiden mutation: | |||||||||||||||||
| Overall | 17 | 45/3031 | 37/45 | 1.1 (0.3 to 1.9)* | 0.4 (0.1 to 0.9) | 2.0 (0.9 to 3.7) | 2 | 97 | 0 | 11 | 13 | 43/2604 | 1.3 (0.5 to 2.2) | ||||
| Family | 8 | 35/1359 | 34/35 | 2.4 (0.9 to 4.4) | 0.4 (0.0 to 0.9) | 2.5 (1.2 to 4.4) | 3 | 100 | 0 | 25 | 6 | 33/1291 | 2.4 (0.6 to 5.4) | ||||
| Non-family | 9 | 10/1672 | 3/10 | 0.4 (0.0 to 0.9) | 0.7 (0.0 to 2.6) | 0.4 (0.0 to 1.8) | 31 | 15 | 4 | 2 | 7 | 10/1313 | 0.6 (0.0 to 1.2) | ||||
| Homozygous factor V Leiden mutation: | |||||||||||||||||
| Overall | 6 | 5/58 | 5/5 | 6.2 (0.0 to 18.0) | 2.8 (0.0 to 8.6) | 2.8 (0.0 to 8.8) | 86 | 85 | 47 | 46 | 5 | 5/56 | 7.9 (0.4 to 23.0) | ||||
| Family | 3 | 4/35 | 4/4 | 8.3 (0.0 to 29.6) | NA | NA | NA | NA | NA | NA | 2 | 4/33 | 9.9 (0.0 to 39.7) | ||||
| Non-family | 3 | 1/23 | 1/1 | 5.6 (0.0 to 34.3) | NA | NA | NA | NA | NA | NA | 3 | 1/23 | 5.6 (0.0 to 34.3) | ||||
| Heterozygous prothrombin G20210A mutation: | |||||||||||||||||
| Overall | 5 | 14/1322 | 9/14 | 0.9 (0.2 to 2.0) | 0.0 (0.0 to 0.2) | 0.9 (0.2 to 2.0) | 0 | 41 | 0 | 1 | 5 | 14/1322 | 0.9 (0.2 to 2.0) | ||||
| Family | 4 | 11/998 | 9/11 | 1.0 (0.0 to 2.5) | NA | NA | NA | NA | NA | NA | 4 | 11/998 | 1.0 (0.0 to 2.5) | ||||
| Non-family | 1 | 3/324 | 0/3 | 0.8 (0.1 to 2.0) | NA | NA | NA | NA | NA | NA | 1 | 3/324 | 0.8 (0.1 to 2.0) | ||||
| Compound heterozygous factor V Leiden and prothrombin G20210A mutation: | |||||||||||||||||
| Family | 3 | 5/199 | 3/5 | 2.5 (0.0 to 9.5) | NA | NA | NA | NA | NA | NA | 3 | 5/199 | 2.5 (0.0 to 9.5) | ||||
| Non-carriers, overall: | |||||||||||||||||
| Family | 13 | 14/2330 | 13/14 | 0.5 (0.2 to 1.0) | NA | NA | NA | NA | NA | NA | 12 | 12/2293 | 0.4 (0.1 to 0.8) | ||||
| Non-family | 9 | 20/31245 | 9/20 | 0.1 (0.0 to 0.1) | NA | NA | NA | NA | NA | NA | 7 | 18/30791 | 0.1 (0.0 to 0.1) | ||||
Analyses shown are meta-analyses of absolute risks of all studies, including absolute risk of antepartum VTE and postpartum VTE, and meta-analyses of high quality studies (NOS score ≥8) only. The probability of absolute risks of pregnancy associated VTE being above the treatment thresholds of 1% and 3% are also shown. CrI=credible interval, NOS=Newcastle-Ottawa scale, NA=not available. *Significant effect of family studies as compared with non-family studies.