Peri- and postnatal, teratology and reproductive studies of a low molecular weight heparin in rats.

The low molecular weight heparin (OP/LMWH) used in these studies elicited no evidence of teratogenicity when administered by subcutaneous route during the period of organogenesis to pregnant rats at doses up to 10 mg/kg/d. In reproductive studies there were no effects on conception or pregnancy in males or females rats at dosages up to 10 mg/kg/d (by s.c. route). In these studies the doses were used that in chronic toxicity had shown unremarkable toxic effects on animals. In teratologic and in peri- and postnatal experiments unfractionated heparin at doses of 1 and 10 mg/kg/d by s.c. route was used for comparison.