Coagulation disorders in Pregnancy

Coagulation Disorders in Pregnancy

Dr.Zahraa’ Muhmmed Jameel
Physiology
Pregnancy is a hypercoagulable state, which returns to normal around 4 weeks after delivery.
Increase in
Factors VII, VIII, IX, X, &XII, von Willebrand factor
Fibrinogen concentration, D- dimer
Activated protein C resistance
Factor XI slightly falls, protein s activity decrease while factor V remains unchanged.
The fibrinolytic activity diminishes
Increase in procoagulants, potential for vascular damage & increase in venous stasis explain increase VTE 5 times during pregnancy.
Platelet count remains stable throughout pregnancy, but may be lower than non-pregnant state due to increase aggregation. increase in platelet count in the 1st few weeks post-partum may lead to increase VTE complications

Bleeding disorders during pregnancy & delivery

Inherited
Acquired
Vascular abnormalities
Platelet disorders
Coagulation disorders


Thrombocytopenia
Disseminated intra-vascular coagulation (DIC)
Acquired coagulation disorders
Marrow disorders

Thrombocytopenia

Is defined as a platelet count <150×109 /L.
Is common & found in 7-8% of pregnant women
Bleeding is rarely a complication unless count <50×109 /L.
Gestational thrombocytopenia is diagnosis of exclusion when autoimmune & other causes have been excluded. Usually occur late in pregnancy. No association with fetal thrombocytopenia & spontaneous resolution occur only after delivery.
Causes OF THROMBOCYTOPENIA in pregnancy
Idiopathic
Increased destruction or consumption
Pre-eclampsia, HELLP syndrome.
Thrombotic thrombocytopenic purpura
Auto immune thrombocytopenic purpura (ITP)
Anti-phospholipid antibody syndrome , SLE
DIC
Hypersplenism
Decreased production
Sepsis
HIV infection
Malignant marrow infiltration


Autoimmune thrombocytopenia

Occurs because of platelet destruction mediated by platelet autoantibodies directed against cell surface antigens. The reticuloendothelial system destroys platelet/antibody complexes.
The incidence in preg is 1 in 5000.
Maternal platelet count may fall at any stage of preg, & can reach level of <50×109 /L
Maternal hemorrhage at delivery is very unlikely if the platelet count is >50×109 /L
Spontaneous bleeding during preg very unlikely if the platelet count is >20×109 /L
5-10% chance of associated fetal thrombocytopenia (50), which cannot be predicted using maternal count or antigen.
Management
Serial monitoring of plt count provided the count > 80×109 /L, no complications are likely. If the count fall below 50×109 /L approaching term, treatment should be considered
Corticosteroids (1st line treatment in stable patient) act by suppressing abs, however, high doses are often required, take 2-3 weeks to have significant effect & associated with wt gain, HT, DM
IV immunoglobuline (IgG) :rapid response, is preferred option where a rapid plt increase is required close to term, if the duration of treatment is likely to be prolonged, or if high dose of prednisolone platelet is required
If plt count < 80×109 /L vaginal delivery should be facilitated, regional anesthesia avoided, fetal bl sampling & instrumental delivery by venous are best avoided b/c of risk of fetal thrombocytopenia
Splenectomy is an appropriate treatment for women with ITP with severe thrombocytopenia that is refractory to medical therapy. If indicated, it should be performed in the 2nd trimester
A cord bl sample must be collected for plt counting, but nadir of neonatal bl count occurs 2-5 day after delivery

Inherited coagulation disorders

Hemophilia A (FVIII def) & hemophilia B (FIX def) are x-linked recessive
Von willebrand dis is the most common inherited bleeding disorder ( prev 1%). The inheritance is usually autosomal dominant & result from either quantitative or qualitative defect in VWF
FXI def is a rare autosomal dominant bl disorder
Management
Women with hemophilia A, B &VWD should be identified & counseled prior to preg. Baseline coag factor assay should be done as soon as preg confirmed & repeated in the 3rd trim
In hemophilia carriers, fetal sex should be determined either by US or by fetal DNA in maternal blood
Invasive procedures during preg may require clotting factors cover
Planning for delivary is based on 3rd trim clotting factor levels taking into accounts the individual’s bleeding tendency
Low factor level should receive prophylactic treatment (factor concentrate, tranexamic acid, desmopressin) to cover labor and delivery
Clotting factor level > 40 IU/L is usually safe for VD & a level greater than 50 IU/L is adequate for CS
In hemophilia carriers, epidurals may be permitted if the clotting factor is > 40IU/L
Invasive fetal monitoring, ventous & forceps should be avoided if the fetus may be affected, & cord bl samples collected for coag test
They are At significant risk for 1ary & 2ndary PPH & can be minimized by appropriate prophylactic treatment
IV desmopressin (DAVPP) to increase FVIII &VWF in those known to be responders pre- preg, usually reserved for post-partum treatment due to concern about uterine contraction or causing vasoconstriction in preg


Disseminated Intravascular Coagulations (DIC)
is a thrombo-haemorrhagic disorder
-due to abnormal activation of the coag. cascade
-seen in asso. with well-defined clinical situations
Etiology –DIC seen in following clinical situations:
Abruptio placentae
Amniotic fluid embolism
Retained intrauterine dead fetus
Sepsis and endotoxic shock
Severe pre-eclampsia and eclampsia
Induced abortion, especially using hypertonic saline
Acute fatty liver of pregnancy
Molar pregnancy
Excessive blood loss & shock due to any cause

Pathogensis

DIC occurs when fibrin gets deposited in the small vessels of virtually every organ in the body. Consumptive coagulopathy results due to consumption of coagulation factors and platelets
Intrinsic pathway
Triggered where ever there is loss of endothelial integrity

Extrinsic pathway

Triggered by tissue destruction: Eg: In abruptio & IUD Thromboplastin is liberated from the placenta & dead fetus. In septicaemia bacterial endotoxins activate the extrinsic clotting system


Clinical Presentation
1. Persistent bleeding from venepuncture sites , surgical wounds.
2.Bleeding from episiotomy incisions, perineal lacerations
3.Bleeding gums and nose
4.Blood stained urine -haematuria
Investigations
Bed side tests:
Clotting time Take 5ml of blood in a glass tube, If a clot forms in 10mts & remains firm it is unlikely that the pt has a DIC & also means that the fibrinogen levels are normal.
Clot retraction time: Is another bed side test where in the clot retracts at the end of 1 hour. This means that the platelets are adequate.
Clot stability is indicated when a stable clot forms .A fragile or unstable clot indicates presence of FDP and hence it gets lysed
Prothrombin time P.T. 11-16 secs (extrinsic pathway)
Partial thromboplastin time 30-45 secs(intrinsic pathway)
Serum fibrinogen 300-600mg% (<100-severe hypofibrinogenaemia )
Platelet ( decreases as it is consumed)
D.Dimer <0.5mg/L (increases when FDP levels increase)
Fibrinogen degradation products <10micro/dl ( DIC unlikely with normal FDP)
Increased Decreased
PT Platelets
APTT Fibrinogen
FDP
No single test establishes the diagnosis of DIC, Serial clotting assays are more useful, Therefore repeat coagulation tests after 6-8hours
The three corner stones In the Management of DIC
•Correct the underlying problem; Eg:-in case of abruptio , prolonged retention of dead fetus and HELLP syndrome immediate delivery is indicated
•Maintain circulating blood volume
•Replace clotting factors & red blood cells
First priority is to replace intravascular compartment
colloids (starch -haestrel 3.5%, voluven 6%)(Avoid dextran as it interferes with subsequent cross match)
If crystalloids give 3 times est. blood loss (eg: for 1 liter blood loss give 3 liters of normal saline or ringer lactate
Replace blood volume
•The only indication for whole blood transfusion is MASSIVE Obst. He. Only give fresh blood- as stored blood is deficient in all labile clotting factors and platelets. (Hb takes about 24-72 hours to reach a constant after transfusion . Therefore check accordingly )
Fresh frozen plasma –FFP: Contains labile and stable clotting factors including fibrinogen
Cryo precipitate: is rich in fibrinogen and factor VIII ,XIII and V
Platelet transfusion: when platelet count is below 50,000/cc and when surgical intervention is required. For a vag. delivery less than 20,000 platelets
Recombinant VII a ( Nova-7 ) Only indicated in massive , intractable haemorrhage when other measures fail.
Anesthesia & Surgery in DIC
•Correct the coagulation abnormality
•Avoid regional anesthesia
•Use vertical incisions
•Put in drains where required before completion