Effects of drug use in pregnancy ... Anticoagulants ...

An increased risk of thromboembolism and a risk to the fetus from oral anticoagulant use makes management of anticoagulant treatment in pregnancy difficult. Such treatment is most often used for the treatment and prophylaxis of deep vein thrombosis and pulmonary embolus and anticoagulation in patients with artificial heart valves.

Warfarin is associated with chondrodysplasia punctata, cartilage and bone abnormalities, and the asplenia syndrome in Infants of mothers taking the drug in the first trimester. Effects appear to be dose-related. eNS abnormalities such as hydrocephalus, microcephaly, optic atrophy and cranial nerve palsies have also been reported. Postpartum wound haematoma and haemorrhage may also occur in the mother. Adverse effects from phenindione have been reported to be less common than those associated with warfarin use but inadequate data supports this claim. Phenindione, unlike warfarin, is excreted in breast milk and has caused neonatal bleeding.

Heparin, unlike warfarin, does not appear to cross the placenta, and is not associated with birth defects, but maternal bleeding and bone demineralisation may occur, while thrombocytopenia is a rare idiosyncratic reaction. Dosage alteration is required in renal dysfunction.

Streptokinase and urokinase may cause bleeding, premature labour and incoordinate uterine action, possibly associated with the release of fibrin degradation products Their use in pregnancy has not been recently studied.

In conclusion ' ... anticoagulant treatment should not be undertaken lightly in pregnancy. It poses additional risks to both the mother and the fetus'.

de Swiet M British Medical Journal 294 428-430. 14 Feb 1987

0156-2703/87/0314-0003/0$01.00/0 © ADIS Press Reactions" 14 Mar 1987 3