Abstract

Platelet counts, fibrinogen levels, thrombotest, thromboplastin generation screening test, thrombin ratio, and titre of circulating fibrin degradation products, were measured in 30 infants with Rh isoimmunization, of whom 5 had a bleeding tendency clinically, and 8 had laboratory evidence of disturbed haemostasis.

At necropsy intravascular fibrin deposits were found in the tissues of 3 out of 4 babies who died with haemorrhage.

An additional retrospective survey indicated that haemorrhage had been a major factor in causing death in 10 out of 18 newborn babies who died with rhesus isoimmunization in the period 1967-69.

Sites of haemorrhage at necropsy were mainly intracranial (subarachnoid and intracerebral) and intrapulmonary, with microscopical evidence of intravascular fibrin deposits in 5 cases.

It is concluded that disseminated intravascular coagulation is a major cause of haemostatic failure in babies with rhesus isoimmunization, but that disturbed hepatic synthesis of coagulation factors may also play a part.

Babies at risk from haemostatic failure are those with cord Hb below 7 g/100 ml. It is suggested that a platelet count should be performed as an initial investigation on all such infants.