Treatment of deep venous thrombosis in pregnant women

Abstract

The recommended dosage of tinzaparin in the treatment of thromboembolism during pregnancy is 175 IU/kg/day, as for non-pregnant subjects. In clinical practice, we have experienced a need for a higher dosage, especially in the initial phase of the treatment of deep vein thrombosis, based on four-hour post-dose measurements of anti-Xa activity. Twenty-two pregnant patients with a confirmed deep venous thrombosis were treated with tinzaparin either in a once- or twice-daily regimen. Four-hour post-dosage plasma anti-Xa activity was measured in 357 sequential blood samples during treatment. An higher dosage than recommended, was required to maintain anti-Xa activity in the target range. We suggest that the starting dosage should be 250 IU/kg/day in a twice-daily regimen, and that the dose in the initial phase be adjusted by daily monitoring of anti-Xa.

Anti-Xa Monitoring of Low-Molecular-Weight Heparin during Pregnancy: A Systematic Review

“…48,49 Therapeutic anti-Xa-adjusted LMWHs were applied in 15 studies. 37,39,40,[43][44][45][46][47][50][51][52][53][54][55][56] The initial dose was weight based, 37,40,43,44,46,47,51,53,54 not reported, 45,55 or based on preference by the treating physician. 39,50,52,56 One study used weight-adjusted LMWH for both prophylaxis and therapeutic dosing of LMWH, and the treatment was adjusted at the discretion of the treating physician.…”

“…36 Twenty-three out of 33 studies timed blood sampling to 3 to 4 hours following LMWH administration. 24,[27][28][29][30][31][35][36][37][39][40][41][42]44,46,47,49,[51][52][53][54][55][56] Four studies, investigating the pharmacokinetic profile of LMWH, used multiple blood samplings to establish 12-hour anti-Xa profiles, 33,34 or 24-hour anti-Xa profiles. 26,32 Four studies had no specific protocol for timing of blood sampling.…”

“…48 The other study reported minor bleeding complications in relation to four obstetric complications at delivery, but no bleeding above 1,000 mL. 49 Fourteen out of 17 cohort studies evaluated therapeutic anti-Xa-adjusted LMWH 37,39,40,[44][45][46][47][50][51][52][53][54][55][56] (►Tables 4 and 5). The adjustments led to both reduced and increased doses of LMWH, both within studies and when compared between studies.…”

“…Eleven studies had no loss to followup, [28][29][30]33,34,44,45,47,49,51,54 eight studies had less than 10% loss to follow-up, 32,[37][38][39][40][41][42]46 nine studies had loss to follow-up of 10 to 25%, 31,35,36,43,48,50,52,53,55 and one study had loss to follow-up of 36%. 56…”

Anticoagulant Therapy During Pregnancy for Maternal and Fetal Acquired and Inherited Thrombophilia

“…Both UFH and LMWH have shorter half-lives and lower peak plasma concentrations, usually necessitating higher doses and more frequent administration in order to maintain effective concentrations [44][45][46][47][48]. The duration and doses of subcutaneous heparin LMWH during pregnancy vary depending on guidelines and studies.…”