Should Blood Tests Be Performed to Monitor LMWH Therapy in Pregnancy?
If the diagnosis of VTE is confirmed (DVT or PTE), treatment should be continued. Experience indicates that satisfactory anti-Xa levels (peak anti-Xa activity, 3 hours post-injection, of 0.5–1.2 units/mL) are obtained using a weight-based regimen and monitoring of anti-Xa is not routinely required in women with VTE on therapeutic doses of LMWH, particularly as there are concerns over the accuracy of anti-Xa monitoring. There may be a case for monitoring levels at extremes of body weight (less than 50 kg and 90 kg or more) and women with other complicating factors, including renal disease and recurrent VTE. Guideline documents recommend that routine platelet count monitoring is not required in obstetric women who have received only LMWH as there have been no cases of heparin-induced thrombocytopenic thrombosis in pregnancies managed with LMWH. If unfractionated heparin is employed, or if the obstetric patient is receiving LMWH after first receiving unfractionated heparin, or if she has
