[Absence of transplacental passage of Fraxiparin (low molecular weight heparin) during the 3d trimester of pregnancy].

Using low molecular weight fractions of heparin (HBPM) can be at least potentially useful in pregnant women for certain indications. After animal studies had been carried out for toxic effects, one HBPM, CY216, which has been put on the market under the name of Fraxiparin, was studied to see whether it crosses the placenta in pregnant women by analysing fetal blood directly. Seven women who had fetal indications for terminating their pregnancies in the third trimester received a subcutaneous injection of 17,500 Choay units of Fraxiparin (0.7 ml). The haemostatic state was assessed in the mothers before the injection and three hours after it, and in the fetus approximately three hours after the injection into the mother. The fetal blood was taken in the uterus by direct aspiration using ultrasound guidance techniques. Anti Xa, anti IIa, and cephalin-kaolin time (TCK) were estimated. The anti Xa, anti IIa and the TCK were not changed in the 7 fetuses that were studied, 3 hours after the subcutaneous injection of a large dose of CY 216 although marked changes were noted in the mothers.