3 Platelets, or thrombocytes (from Greek θρόμβος — «clot» and κύτος — «cell»)
4 Platelets produced in bone marrow from megakaryocytes platelets produced per megakaryocyte35,000-50,000 platelets/microL produced daily8-10 day survival
5 Normal Platelet Count150, ,000/microLMay be slightly decreased in pregnancy (Platelet count at term pregnancy: a reappraisal of the threshold. Boehlen F; Hohlfeld P; Extermann P; Perneger TV; de Moerloose P Obstet Gynecol Jan;95(1):
6 Causes of Thrombocytopenia in Pregnancy Benign Thrombocytopenia of PregnancyITPPreeclampsiaOther (Drug related, SLE, HIV, Antiphospholipid syndrome, Viral, TTP, HIT, pseudothrombocytopenia, DIC, Giant Cavernous Hemangioma (Kasabach-Merritt syndrome)
7 Benign Thrombocytopenia of Pregnancy Usually platelet count greater than 70,0005% occurrence rateDoes not increase incidence of thrombocytopenia in newbornNo effect on pregnancy management with exception of possible steroid boost near term to allow for regional anesthesia
8 Benign Thrombocytopenia of Pregnancy Mild and asymptomatic thrombocytopeniaNo past history of thrombocytopeniaOccurrence during late gestationNo association with fetal thrombocytopeniaSpontaneous resolution after delivery
9 Immune Thrombocytopenic Purpura (ITP) Mild cases clinically difficult to differentiate from benign thrombocytopenia of pregnancy
10 Immune Thrombocytopenic Purpura (ITP) Acquired disorderDecreased platelet count – otherwise normal CBC and smearNo obvious alternative clinical condition or drug related etiology
11 Immune Thrombocytopenic Purpura (ITP) Antiplatelet antibodies not required for diagnosisNot demonstrable in all patients with ITPDo not affect management decisions
13 Immune Thrombocytopenic Purpura (ITP) Surgically significant bleeding <50,000Significant bleeding rare if platelets >10,000Spontaneous remission common in children, rare in adults
14 Immune Thrombocytopenic Purpura (ITP) TreatmentTreat in 30,000-50,000 rangeGoal – Safe platelet count to prevent major bleed, not normalized countMortality < 1%Increased bleeding risks in pregnancy – lower treatment threshold
15 Prednisone 1mg/kg/dayMost respond within one weekSupplement with Calcium and Vitamin D if greater than 3 months RxUnresponsive – IVIG 1 gr/kg/day over 1-2 daysUnresponsive to medical therapy - splenectomy
16 SplenectomyRemoves primary site of destruction of antibody coated plateletsDecreases antiplatelet antibody productionIf successful remission usually within two weeks of surgery65% long term remission
17 Immune Thrombocytopenic Purpura (ITP) C-Section for obstetric indicationsPoor correlation with maternal platelet count or fetal scalp platelet countPUBS is contraindicated – procedure related mortality significantly greater than disease related mortality
18 Preeclampsia 15% develop thrombocytopenia HELLP syndrome Delivery is treatmentPlatelet nadir may occur post delivery – usually begins rising by day 3 after delivery
19 Avoid aspirin and NSAID’s in patients with thrombocytopenia Inhibits
20 Life threatening thrombocytopenia Platelet transfusionConcurrent IVIGMethylprednisoloneIf no response – recombinant factor VIIa
21 Neonatal Alloimmune Thrombocytopenia (NAIT) Maternal IgG crosses placenta and attacks foreign platelet antigen in fetusCan occur in first pregnancy1/ birthsMother is asymptomatic – normal platelet count75-90% recurrence rate with increased severity
22 Neonatal Alloimmune Thrombocytopenia (NAIT) 200 cases NAITAnti-HPA-1a — 75 percentAnti-HPA-5b — 16 percentAnti-HPA-15b — 4 percentManagement and outcome of 200 cases of fetomaternal alloimmune thrombocytopenia. Ghevaert C; Campbell K; Walton J; Smith GA; Allen D; Williamson LM; Ouwehand WH; Ranasinghe E Transfusion May;47(5):
23 Neonatal Alloimmune Thrombocytopenia (NAIT) Table 2. Risk Stratification and Treatment ProtocolHigh Risk Standard RiskStratification Initial fetal platelet count 20,000/mL3, orsibling with a perinatal intracranialhemorrhageInitial platelet count 20,000 /mL3,and no sibling intracranialFirst fetal bloodsampling20 wk estimated gestational age 20 wk estimated gestational ageTreatment After sampling, randomize between:IVIG 1 g/kg/wk plus prednisone 1 mg/kg/dor IVIG 1 g/kg/wkAfter sampling, randomize between:IVIG 1 g/kg/wk or prednisone0.5 mg/kg/dStudy definition ofresponse to therapyFetal platelet count 25,000/mL3 at the time of the second sampling, provided that it hadincreased by 10,000/mL3 from the value obtained at the first sampling or Fetal plateletcount 40,000/mL3 provided that it had not decreased by 10,000/mL3 from the previousvalueIntensification IVIG prednisone arm: increase IVIG to2 g/kg/wk and continue prednisoneIVIG arm: add prednisone 1 mg/kg/dPrednisone arm: add IVIG 1 g/kg/dIVIG arm: A) add prednisone 1 mg/kg/d; B) ifno response to IVIG and prednisone, thenincrease IVIG to 2 g/kg/wk and continueprednisoneIf no response to IVIG and prednisonein either arm, then increase IVIG to
24 Neonatal Alloimmune Thrombocytopenia (NAIT) The standard-risk group appears to respond well to either IVIG 1 gm/kg/wk or prednisone 0.5 mg/kg/d.Substantial number of patients in the high-risk group with an initial count of less than 10,000/mL3 for whom IVIG 1 gm/kg/wk was shown to be inadequate.
25 Neonatal Alloimmune Thrombocytopenia (NAIT) Empiric therapy without knowing the fetal platelet count may be either unnecessary or inadequate. The former needlessly overtreats the mother while the latter allows the fetal platelet count to remain dangerously low.The fetal-neonatal morbidity and mortality associated with fetal blood sampling was substantial (14% emergent delivery or death in utero due to serious PUBS complication)
26 Neonatal Alloimmune Thrombocytopenia (NAIT) Obstet Gynecol Jan;107(1):91-6.Parallel randomized trials of risk-based therapy for fetal alloimmune thrombocytopenia.Berkowitz RL, Kolb EA, McFarland JG, Wissert M, Primani A, Lesser M, Bussel JB.
27 Neonatal Alloimmune Thrombocytopenia (NAIT) 73 women with documented alloimmune thrombocytopenia, patients were randomized to receive either intravenous immunoglobulin (IVIG) 2 g/kg/wk (group A) or IVIG 1 g/kg/wk plus prednisone 0.5 mg/kg/d (group B), starting at approximately 20 weeks of gestation. Fetal blood sampling was performed at approximately 32 weeks of gestation, and those with fetal platelet counts less than 30,000/mL(3) were given salvage therapy (IVIG 2 g/kg/wk plus prednisone 0.5 mg/kg/day)
28 Neonatal Alloimmune Thrombocytopenia (NAIT) Obstet Gynecol Aug;110(2 Pt 1):Antepartum treatment without early cordocentesis for standard-risk alloimmune thrombocytopenia: a randomized controlled trial.Berkowitz RL, Lesser ML, McFarland JG, Wissert M, Primiani A, Hung C, Bussel JB.
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