Immune Thrombocytopenia and Pregnancy Treatment & Management

Updated: Oct 09, 2015
  • Author: Muhammad A Mir, MD, FACP; Chief Editor: Srikanth Nagalla, MBBS, MS, FACP  more...
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Treatment

Medical Care

In pregnancy, treatment for immune thrombocytopenic purpura (ITP) and neonatal alloimmune thrombocytopenia (NAIT) involves two patients: the mother and the fetus.

In cases of ITP, care of the mother centers on minimizing her risk of bleeding during pregnancy and childbirth. Check platelet counts regularly throughout gestation to verify that they are in an acceptable range. Conservatively, platelet counts should be checked monthly during pregnancy (platelet counts should be checked at least every trimester even in completely stable patients).

Spontaneous bleeding seldom occurs if the maternal platelet count is greater than 20,000/µL; therefore, treatment is not indicated in the absence of bleeding unless the platelet count falls below this level. Intraoperative or intrapartum bleeding complications are unusual if the platelet count is greater than 50,000/µL; therefore, administer treatment if the platelet count is less than this prior to delivery. [20] A history of ITP in a mother or ITP in a previous pregnancy is not a contraindication to future pregnancies. [21]

One trial evaluated the safety of breastfeeding in women with ITP and did not document thrombocytopenia developing in any breastfed infants. [16] IgG antiplatelet antibodies are transmitted through the breast milk, so consider monitoring the platelet counts in breastfed newborns of mothers with ITP.

The major neonatal concern in ITP is the risk of fetal or newborn intracranial or visceral hemorrhage due to severe thrombocytopenia. Newborn thrombocytopenia is difficult to predict because newborn platelet counts do not always correlate with maternal platelet counts [2] or antiplatelet antibody titers. [8] It does correlate with the platelet count of previous first and second siblings at birth. [22] Maternal platelet counts that fall within the reference range after previous splenectomy or corticosteroid treatment do not guarantee a fetal platelet count within the reference range. In fact, splenectomy prior to pregnancy has been reported as a risk factor for the development of newborn thrombocytopenia. [23] Splenectomy possibly increases the amount of free antiplatelet antibody in the maternal sera due to the removal of the platelet/antibody destruction site. [24]

Fetal platelet counts can be obtained by fetal scalp sampling during labor or cordocentesis at 38-39 weeks' estimated gestational age; however, neither is reliable at predicting thrombocytopenia at birth. Fetal scalp sampling is technically difficult and often unreliable. [25] Owing to the risk of hemorrhage in the fetus and possible inaccuracy of the fetal platelet count, it is best avoided. [26] In a clinical trial, platelet counts were obtained by cordocentesis in 42 women with ITP. Two of the 42 newborns had severe thrombocytopenia at birth; neither was detected with cordocentesis. [27] At present, no reliable method of determining which newborns are at risk for severe thrombocytopenia exists.

A platelet count at birth is recommended. Peripheral blood is preferred over heel sticks or cord samples because of better accuracy. A cranial ultrasound should be considered if the platelet count is less than 50,000/µL, even in the absence of symptoms. Intramuscular injections such as vitamin K are best avoided. [15]

Some investigators have recommended performing a cesarean delivery in all women with ITP to minimize the trauma to the newborn during the birth process. Cesarean delivery has not been demonstrated to prevent bleeding complications in thrombocytopenic newborns. In a review of 474 newborns born to mothers with ITP, 29% of newborns born vaginally experienced a bleeding complication, compared to 30% of newborns born via cesarean delivery. [28] Reviews published to date comparing vaginal birth to cesarean delivery in women with ITP are retrospective studies; none are randomized controlled trials. However, in the absence of any clear benefit to the neonate (given the low rate of intracranial hemorrhage in infants born to mothers with ITP), cesarean delivery should be reserved for the usual obstetrical indications.

In women with a history of delivering a significantly thrombocytopenic newborn (platelet < 50,000/µL) or a newborn with an intracranial hemorrhage (platelet count < 100,000/µL) in whom other illnesses commonly associated with thrombocytopenia have been excluded, [29] test for NAIT. Perform maternal platelet antigen typing and confirm the presence of maternal antiplatelet antibodies with specificity for paternal platelets. Perform antigen typing and zygosity testing on the father of the baby to determine if platelet antigen incompatibility between the parents exists and if all potential offspring will be at risk for NAIT. If the father is a heterozygote, each subsequent fetus has only a 50% chance of being affected. Fetal platelet typing can be performed on a chorionic villous sample, amniocytes, or fetal blood to determine if the fetus carries the significant paternally derived antigen.

Prospective screening programs have demonstrated that NAIT usually develops in babies born to women with detectable antiplatelet antibody. [9] Some investigators have suggested all pregnant women presenting for prenatal care be typed for platelet alloantigen to determine if they are at risk for NAIT. Women at risk can be tested for the presence of platelet alloantibodies twice during gestation (similar to current screening programs for Rh disease). A comparison of the effectiveness of this type of screening program estimated a cost of $45,000 per case of alloimmunization diagnosed in whites. [9] The cost would be higher if testing were initiated in women of other ethnic groups because the rate of NAIT is lower in nonwhite women. At present, universal prenatal screening is not recommended because a clear clinical benefit has not been demonstrated. [10, 30]

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Surgical Care

Splenectomy is an appropriate treatment for women with ITP with severe thrombocytopenia that is refractory to medical therapy. Approximately two thirds of patients have a positive response, generally within a few days. Splenectomy is seldom performed during pregnancy because most patients can be managed medically. If splenectomy is indicated, it should be performed in the second trimester. Surgical interventions requiring general anesthesia are avoided in the first trimester if possible to prevent fetal medication exposures during embryogenesis. Splenectomy is technically difficult in the third trimester because the enlarging uterus limits exposure to the spleen. Successful splenectomy has been reported during cesarean delivery. [31]

Women with splenectomies should be immunized against pneumococcus, meningococcus, and Haemophilus influenzae. [10]

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Consultations

Consulting a surgeon may be appropriate if splenectomy is indicated in a pregnant woman with ITP. A hematologist can be consulted if the patient with ITP or NAIT is not responding to standard therapies or requires transfusions.

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Activity

Women with ITP and severe thrombocytopenia should avoid activities that are likely to result in trauma.

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