REVIPARIN

Fetal Risk Summary

Reviparin is a low-molecular-weight heparin prepared by depolymerization of heparin obtained from porcine intestinal mucosa (1). It is not available in the United States (see also Dalteparin and Enoxaparin). Reviparin has an average molecular weight of 3500–4500 (range 2000–8000) (1). Because this is a relatively large molecule, it probably does not cross the placenta and, thus, presents a low risk to the fetus.

An abstract published in 1997 described the use of reviparin and aspirin (100 mg/day) in 50 women with unexplained recurrent fetal loss and autoantibodies (2). Reviparin was administered either as 4900 units SC once daily or as 2800 units SC twice daily. The once-daily injection produced comparable plasma anti-factor Xa levels to the twice-daily regimen. No maternal bleeding, thrombocytopenia, or decreased bone density was noted and no placental pathology was found in the 43 women who had completed their pregnancies (7 pregnancies were still in progress). The outcomes of the 43 completed pregnancies were 35 normal newborns (no premature deliveries), 7 spontaneous abortions, and 1 ectopic pregnancy. No congenital malformations or low-birth-weight newborns were observed.

Breast Feeding Summary

No reports describing the use of reviparin during lactation or breast feeding have been located. Reviparin, a low-molecular-weight heparin, still has a relatively high molecular weight (average 3500–4500) and, as such, should not be expected to be excreted into human milk. Because reviparin would be inactivated in the gastrointestinal tract, the risk to a nursing infant from ingesting the drug appears to be negligible.

References

1. Reynold JEF, ed. Martindale. The Extra Pharmacopoeia. 30th ed. London: The Pharmaceutical Press, 1993:232.
2. Laskin C, Ginsberg J, Farine D, Crowther M, Spitzer K, Soloninka C, Ryan G, Seaward G, Ritchie K. Low molecular weight heparin and ASA therapy in women with autoantibodies and unexplained recurrent fetal loss (U-RFL). Society of Perinatal Obstetricians abstracts. Am J Obstet Gynecol 1997;176:S125.