Circulating levels of fibrin/fibrinogen degradation fragment E measured by radioimmunoassay in pre-eclampsia

Changes in coagulation and fibrinolysis during pregnancy: evidence of activation of coagulation preceding spontaneous abortion

In order to monitor physiological changes in coagulation and fibrinolysis that occur during normal pregnancy, blood samples were collected in each trimester of pregnancy from 17 volunteers. Control samples were collected from 12 non-pregnant female volunteers. As pregnancy advanced there was a rise in the basal levels of fibrinopeptide A, cross linked D-dimer fragment and the B beta 15-42 fragment and an increase in the in vitro rate of fibrinopeptide A generation. These results were consistent with an increased activation of coagulation during normal pregnancy, compensated for by a concomitant rise in fibrinolytic activity. In two patients who spontaneously aborted, evidence of uncompensated activation of coagulation could be detected before the manifestation of any clinical signs. In a second pregnancy in one of these patients similar changes were observed, but were reversed by heparin treatment and the pregnancy progressed to full-term delivery of a normal infant.

Alterations in platelet concentration and aggregation in normal pregnancy and preeclampsia

Platelets were evaluated in normal pregnant women and in pregnant subjects with mild and severe preeclampsia, nonpregnant control subjects, and pregnant subjects with chronic hypertension. The parameters studied included platelet count, presence of circulating platelet aggregates, and in vitro platelet aggregability by means of a variety of agonists of platelet aggregation. When subjects with a normal pregnancy were compared to nonpregnant controls, they demonstrated a significantly lower platelet count and an increase in circulating platelet aggregates and in vitro hypoaggregability. Significant differences among the groups of pregnant subjects could not be found. These studies suggest the occurrence of platelet activation in pregnancy. This activation causes in vivo platelet aggregation followed by exhaustion of platelets.

Coagulation problems in human pregnancy

Coagulation problems in pregnancy are primarily associated with overactivity of the intrinsic clotting system. This accounts for the increased incidence of thrombo-embolism during pregnancy. Where specific obstetric complications cause clotting problems the common underlying feature is usually placental pathology as in abruptio placentae, pre-eclampsia or hydatidiform mole. Abnormal activation of the clotting system is an early, and occasionally the first detectable feature of pre-eclampsia, but there is no evidence that this is a primary change. Therefore the role of anticoagulant treatment in the management of pre-eclampsia remains questionable. A new test for estimating factor VIII consumption is proving to be a sensitive index of early activation of the clotting system and can be used for the diagnosis of early pre-eclampsia.

Post-partum intracranial subdural haematoma. A possible complication of epidural analgesia

A case is reported of bilateral chronic subdural haematomas in a 29-year-old woman 1 month after childbirth under attempted epidural analgesia. The possible link between leakage of cerebrospinal fluid through a hole in the lumbar theca and the later development of an intracranial chronic subdural haematoma is discussed, with a review of eleven previous reported cases.

Early platelet consumption in pre-eclampsia

One hundred and thirty-one women with chronic hypertension were studied serially during pregnancy to determine the sequence of events in the development of superimposed pre-eclampsia and to discover the time of onset. Twenty-seven women developed a sustained rise in plasma urate concentrations, which began at about 28 weeks' gestation and which is characteristic of pre-eclampsia. The mean platelet count was already significantly reduced and continued to fall until delivery, which was on average at 36 weeks' gestation. A comparable but smaller decrease in platelet count was seen in 55 women who had borderline but consistent increases in plasma urate concentrations. In 49 women whose plasma urate concentrations remained steady the platelet count did not change significantly before delivery. The reduced platelet count in women who develop pre-eclampsia suggests that increased platelet consumption is an early feature of the disorder.

Factor-VIII consumption in pre-eclampsia

In 50 women with high-risk pregnancies, increased factor-VII consumption, as estimated by the difference between the levels of factor-VIII-related antigen and factor-VIII clotting activity, correlated with the severity of pre-eclampsia, particularly when measured by increases in plasma-urate. Longitudinal studies of the evolution of pre-eclampsia demonstrated that increased factor-VIII consumption usually but not always developed before hyperuricaemia. The earliest time that abnormal factor-VIII consumption was demonstrated was at 18 weeks' gestation in a woman who had had two previous stillbirths. Subcutaneous heparin and oral dipyridamole failed to reverse the coagulation abnormality, and the fetus died in utero at 28 weeks' gestation. The renal and coagulation changes characteristic of pre-eclampsia were also seen in a patient without hypertension. This suggests that the concept of pre-eclampsia may need to be widened to include a non-hypertensive syndrome characterised by these changes in clotting and renal function.

Coagulation and the hypertensive diseases of pregnancy

The coagulation and fibrinolytic systems were investigated in a group of patients with essential hypertension during pregnancy, and the findings were compared with those of normal gravid women. Patients with essential hypertension exhibited the following significant differences: shortened partial thromboplastin times, thrombocytopenia, and decreased antithrombin III levels. Euglobulin lysis times and assays for fibrin breakdown products suggest that essential hypertension is not associated with changes in the fibrinolytic mechanism. Until more sophisticated studies can be performed on such patients, it cannot be concluded that the increased coagulability observed in pregnant patients with essential hypertension represents a state of intravascular coagulation.

The association of maternal and neonatal thrombocytopenia in high-risk pregnancies

In this study of 136 women with pre-eclampsia, eclampsia, placenta previa, or abruptio placentae, 21 mothers were noted to have thrombocytopenia. Seventeen of the 21 were in the pre-eclampsia group. Of the 21 thrombocytopenic mothers, nine were associated with thrombocytopenia in the children, seven children had normal platelet counts, and five had no counts performed. Eight of the nine thrombocytopenic neonates were associated with pre-eclampsia in the mother, and five of these were not believed to have disseminated intravascular coagulation as the etiology of the platelet defect. The results suggest that thrombocytopenia is common in high-risk pregnancies in both the mother and the baby. However, the etiology of the platelet defect cannot be easily explained on the basis of a hypercoagulable state.