Antithrombin III concentrate (Kybernin)

[danilatou]

A woman with antithrombin deficiency and recent sinus venous thrombosis during her last pregnancy is under LMWH treatment. Cesarean section is programmed for next week and she is going to be treated with antithrombin III concentrates pre and postpartum for a few days. Is antithrombin III concentrate safe for breastfeeding? Since it is necessary to continue anticoagulation after delivery, and LMWH is not a treatment of choice for her, we plan to continue treatment with acenocoumarol (sintrom) or rivaroxaban. I know that acenocoumarol is safer for breastfeeding but since she prefers rivaroxaban what is your opinion concerning breastfeeding? Should she stop breastfeeding if she chooses rivaroxaban?
Thank you in advance.

[admin]

Danilatou:

Antithrombin concentrate is derived from human plasma and is used to replace missing antithrombin in human plasma. It is 58,000 Daltons in size and would be unable to enter milk compartment after 4 days and is unlikely to be a problem even early postpartum. Basically, the treatment is to re-establish the normal levels found in the human.

Acenocoumarol is another anticoagulant similar to warfarin and is probably safe to use in a breastfeeding mother.


Rivaroxaban is a Factor Xa inhibitor with a crucial role in the coagulation cascade. In a single case report of a postpartum woman with a PE given rivaroxaban 15 mg twice daily, milk samples were taken on day 3 at 3, 6 and 10 hours after the morning dose. The peak milk concentration was 86.4 µg/L at 3 hours post-dose, the average milk concentration was 38.4 µg/L and the milk/plasma ratio was 0.4. The relative infant dose was 1.3% using the Cavg from the 10 hour collection period. At this dose, it is probably safe to use in a breastfeeding mother.

Tom Hale Ph.D.
InfantRisk Center