Excretion of low molecular weight heparin in human milk

Aims The excretion of low molecular weight heparin (LMWH) in breast milk wa s investigated in 15 lactating mothers after Caesarean section. Methods Blood and milk samples were collected before and 3-4 h after once d aily routine subcutaneous injection of 2500 IU dalteparin. Anti-Xa activity was measured by in assay utilizing prolonged clotting times in plasma or b reast milk as an index of LMWH activity. Results Plasma anti-Xa activities ranged from 0.074 to 0.308 IU ml(-1) of p lasma. Anti-Xa activities in breast milk ranged from <0.005-0.037 IU ml(-1) of milk. This is equivalent to a milk/plasma ratio of <0.025-0.224. Conclusions Therefore, it appears highly unlikely that puerperal thrombopro phylaxis with LMWH has any clinically relevant effect on the nursing infant .