coagulation defects in pregnancy

Coagulation Defects in Pregnancy

Coagulation Disorders in Pregnancy

• 1.Disseminated intravascular coagulation:• 2. Others:a. Inherited: b. b. Non-inherited:

Disseminated Intravascular Coagulation (DIC)

Pathogenesis Extensive vessels and tissues damage ? release of

thromboplastins ? utilisation of the fibrinogen and other clotting factors in an aimless coagulation process ? fibrin .? stimulates fibrinolytic system ? breaks fibrin and fibrinogen into FDP which have an anticoagulant effect ? aggravates haemorrhage and shock ? ischaemia ? more tissue damage ? viscious circle.

The anticoagulant effect of FDP is due to:

a. Inhibition of platelet function.b.Interference with thrombin/ fibrinogen

reaction.c. Interference with fibrin polymerisation.d. Interference with myometrial contraction.

Predisposing factors

a. Abruptio placentae.b.Amniotic fluid embolism.c. Endotoxic shock.d. Eclampsia and pre-eclampsia.e. Hydatidiform mole.f.. IUFD and missed abortion.g. Intra amniotic hypertonic saline or urea for induction of abortion.h. Incompatible blood transfusion or transfusion of massive banked • blood which is deficient in factor V and VIII.• i. Prolonged shock of whatever the cause.• g. Placenta accreta.• h. Rupture uterus.

Clinical features

• a. oozing of blood,• b. bruising,• c epistaxis,• d. haematuria,• e. haematoma formation especially at wound

and venepuncture site,• f. postpartum haemorrhage.

Investigations

a. Clot observation test: + 5-10 C.C. of blood in a test tube will be clotted

normally within 10 minutes. In case of DIC no clot will be formed or a clot is formed but it undergoes dissolution within one hour in 37oC.

b. Fibrindex test: + 0.5 C.C. of fibrindex which contains thrombin is

added to 0.5 C.C. of plasma in a test tube. Normally, a visible clot will be formed within 5-10 seconds. In DIC, clot formation is delayed up to 30 seconds (hypofibrinogenaemia) or it will not form at all (afibrinogenaemia).

c. Schneider test:d. Thrombin is added to serial dilutions of the patient’s plasma 1:2, 1: 4, 1:8,......1:128.

> Clot formation in all tubes: Normal.> No clot in all tubes: Afibrinogenaemia.> No clot in dilutions 1: 16 onwards:

Hypofibrinoginaemia.

Laboratory tests

a. Plasma fibrinogen level: > During pregnancy the normal level is

4-6 gm/L. Failure of coagulation occurs when its level drops to 1 gm/L.

b. Fibrinogen degradation products FDP: increased.

c. Platelet count: decreased.

Management

a Elimination of the underlying cause.b. Fresh blood transfusion: contains clotting factors

particularly F II, V and VIII.c. Fresh frozen plasma: contains 3 gm fibrinogen/L in

addition to FV and VIII.d. Fibrinogen: 4-6 gm IV may be given if there is no

fresh frozen plasma. However, it is not recommended as it may aggravate the coagulation process (fuel on fire) and cause hepatitis B.

e. Heparin: to inhibit fibrin production and consumption of the clotting factors but it is contraindicated if there is current bleeding.

f. Antifibrinolytic agents: as EACA, trasylol or tranexamic acid may be given to suppress the fibrinolytic process. However, this may enhance thrombosis formation.

DEEP VEIN THROMBOSIS (DVT)