Intracranial hemmorhage in alloimmune thrombocytopenia: stratified management to prevent recurrence in the subsequent pregnancy. In almost all cases of NAIT, the human platelet antigen (HPA) system is involved. During pregnancy, these antibodies cross the placenta (afterbirth) and attach to the platelets in the baby’s blood. In those cases, the procedure would be performed after 32 weeks of gestation to document that the fetal platelet response to therapy has been adequate enough to safely permit a vaginal delivery to occur, and late enough in gestation to deliver a viable newborn if any complications occur. In this case, the liquid part of the mother’s blood is put in the same tube as her partner’s platelets to see if there are antibodies present that will attack them. Perform an amniocentesis (the process of getting a fluid sample from the amniotic sac) to check the baby’s platelet type. When their blood is tested, the test will return as HPA-1a/1a or HPA-1a/1b. Together a unique embryo (future baby) is formed. What Is The Evidence For Specific Management and Treatment Recommendations Definition of neonatal alloimmune thrombocytopenia in the Definitions.net dictionary. If the fetal platelet count is found to be low (< 50,000/mm3), a cesarean section can be performed. In this condition, patients previously sensitized against certain platelet antigens (the same ones that lead to NAIT) develop acute, severe thrombocytopenia 5–14 days after transfusion. Typically, the mother is negative for HPA-1a and often, but not always, positive for anti-HPA-1a antibodies (Kjeldsen-Kragh et al., 2007). No. Additional cases of NAIT can be identified in neonates without bleeding symptoms who have thrombocytopenia detected incidentally on blood counts obtained for sepsis or other non-hemorrhagic evaluations. Neonatal alloimmune thrombocytopenia affects 0.1% of births, with maternal antibodies crossing the placenta as early as 14 weeks’ gestation. The antibodies cross the placenta and attach to the antigen on fetal platelets, which are then removed from circulation by the reticuloendothelial system of the fetus. What is the term for what the mother has that causes NAIT? This situation occurs in about 75% of individuals that are HPA-1 positive. These blood components contain platelet microparticles that express the offensive platelet antigen, leading to an anamnestic production of antibodies. It occurs in 1:2000 to 1:3000 live births among Caucasians. In most protocols, pregnancies are categorized by risk. Most people are familiar with the red blood cells that make up the majority of the blood in our bodies, but may not be aware of a second type … The incompatibility is due to a single nucleotide The use of cordocentesis in alloimmune thrombocytopenia is controversial. Physicians take several steps to diagnose this disease. The second most common antigen to be involved in whites is HPA-5b.164 In Asians, the most common antigen involved is HPA-4.165 The HPA-3a antigen may also be involved.166, NAIT is not commonly diagnosed despite the severe thrombocytopenia that can occur and the large number of HPA-1a– negative women who become pregnant every year. This chapter focuses on the neonatal alloimmune thrombocytopenia (NAIT) which is mentioned to be secondary to maternal alloimmunization to fetal platelet antigens and subsequent fetal thrombocytopenia to maternal red blood cell alloimmunization and hemolytic disease of the fetus and newborn. If a previous unborn child had bleeding into the brain before seven months of pregnancy, then intravenous immune globulin is started as early as 10 weeks of pregnancy at a higher dose (two grams per kilogram of body weight). Alloantibodies against HPA-1a have been implicated in the majority of cases of NAIT (75%) with HPA-5b being the second most frequent target. In this case, the delivery should be spontaneous and not assisted with forceps or vacuum extraction. One of two approaches can be taken: Your baby will be watched very closely and his or her blood will be checked several times to measure the platelet count. Additional information about NAIT is given in Chapter 80. Bleeding symptoms in the neonate with NAIT can include petechiae, hematoma, melena, hematuria, hematemesis, hemoptysis or, most significantly, intracranial hemorrhage. The dose and the timing for the start the intravenous immune globulin typically depend on how severely a previous child was affected by Neonatal Alloimmune Thrombocytopenia. This can happen with blood transfusion, or during a miscarriage, abortion, or after the delivery of a child, when the baby’s blood mixes with the mother’s. If you continue to use this site we will assume that you are happy with it. However, paradoxically, these patients develop antibodies directed against their own platelets, either by fusion of the exogenous microparticles with their own platelets, or by a process in which exposure to foreign platelets leads to formation of autoantibodies. Prednisone is added at around 20 weeks and the dose of intravenous immune globulin is increased to two grams/kilogram at around 28 weeks of the pregnancy. Catherine E. McGuinn MD, ... James B. Bussel MD, in Transfusion Medicine and Hemostasis (Second Edition), 2013. In cases of severe thrombocytopenia or bleeding, platelet transfusion is appropriate. Platelet transfusions to the baby in the womb are not typically used as the primary treatment for Neonatal Alloimmune Thrombocytopenia is during pregnancy. Information and translations of neonatal alloimmune thrombocytopenia in the most comprehensive dictionary definitions resource on the web. mothers are also at risk of thrombocytopenia), principally from ITP and SLE. Not usually. Neonatal Autoimmune Thrombocytopenia is due to maternal platelet autoantibodies (i.e. To understand platelet alloimmunization, you must first understand about different platelet types. Neonatal alloimmune thrombocytopenia (NAITP, NAIT, NATP or NAT) is a disease that affects babies in which the platelet count is decreased. Fetal neonatal alloimmune thrombocytopenia (FNAIT), also known as neonatal alloimmune thrombocytopenia (NAIT) or fetomaternal alloimmune thrombocytopenia (FMAIT), is a There are other platelet antigen systems found in humans that are associated with Neonatal Alloimmune Thrombocytopenia, including HPA-3, HPA-4 (present in people of Asian descent), HPA-5, HPA-9 and HPA-15. Fetal neonatal alloimmune thrombocytopenia (FNAIT), also known as neonatal alloimmune thrombocytopenia (NAIT) or fetomaternal alloimmune thrombocytopenia (FMAIT), is a rare condition which affects a baby's platelets. Cordocentesis – also called fetal blood sampling or percutaneous umbilical blood sampling (PUBS) 3. This is repeated weekly. Neonatal alloimmune thrombocytopenia (NAT) is a life-threatening bleeding disorder caused by maternal platelet antibodies produced in response to fetal platelet antigens inherited from the father. In addition, platelets do not last more than seven to ten days in the baby once they are given. Neonatal alloimmune thrombocytopenia or fetal and neonatal alloimmune thrombocytopenia (FNAIT) is similar to hemolytic disease of the fetus and newborn (HDFN) in that it is due to an incompatibility between mother and fetus, but of platelets, not red cells. Prednisone is usually well-tolerated, although it can be associated with diabetes in pregnancy, weight gain, mood changes and an increase in appetite. Neonatal alloimmune thrombocytopenia (NAIT) is a rare (1 of 1200 pregnancies) but potentially serious condition. Moreover, the neonate may need to receive IVIg and platelet transfusions after delivery to increase fetal platelet counts to prevent intracerebral hemorrhage at a dose of 1.0 g/kg (Chapter 131). Once at 32 weeks of gestation, the IVIg dose is increased to 2.0 g/kg weekly with corticosteroids. Required fields are marked *. Around 10% of infants will be affected. Bussel JB, Berkowitz RL, Hung C, Kolb EA, Wissert M, Primiani A, Tsaur FW, MacFarland JG. If bleeding occurred into the brain of a previous unborn child after seven months of the pregnancy and before 36 weeks’ gestation, intravenous immune globulin is usually started by 12 weeks of pregnancy at a dose of one gram/kilogram and repeated weekly. 4. Intravenous immune globulin is very expensive, however most insurance companies pay for its use in Neonatal Alloimmune Thrombocytopenia after it has been pre-approved. Since red blood cells that are stored after donation contain very little of the liquid portion of the blood that contains the antibodies, mothers with these antibodies should be able to donate blood. If bleeding occurred into the brain of a previous unborn child after 36 weeks of the pregnancy or after the child was born, intravenous immune globulin (one gram/kilogram/week) is started at around 12 weeks of the pregnancy. The exposure to antigen-positive fetal platelets results in maternal alloimmunization with subsequent production of immunoglobulin G (IgG) alloantibodies. We hope this booklet has answered many of the questions that you or your family may have concerning Neonatal Alloimmune Thrombocytopenia. Neonatal alloimmune thrombocytopenia (NAIT) is a rare disorder that can led to severe bleeding, including intracranial hemorrhage, in the fetus or neonate. Ultrasound NAIT is when fetal/neonatal thrombocytopenia occurs as a consequence of maternal transplacental transmission of HPA alloantibodies that react with fetal/neonate platelets. The exact way that intravenous immune globulin prevents thrombocytopenia in the baby is unknown. All of her offspring will not be affected by Neonatal Alloimmune Thrombocytopenia no matter what partner she chooses. One of the first steps in finding out whether platelet alloimmunization is present is to check the mother’s platelet type. NAIT abbreviation stands for Neonatal Alloimmune Thrombocytopenia. Not all infants born to women with anti-HPA-1a have thrombocytopenia, but about 20% have severe thrombocytopenia associated with bleeding.80,81 FNAIT should be suspected in an otherwise healthy neonate with isolated thrombocytopenia. A small amount of fluid is withdrawn and tested to determine the baby’s platelet type. Antiplatelet antibodies cross the placenta and cause destruction of fetal platelets, leading to severe … These small cells are responsible for stopping bleeding in the human body. In about half of cases, the baby will be found to HPA-1 negative and there will be no further concerns in the pregnancy. Neonatal alloimmune thrombocytopenia (NAT) caused by antihuman platelet antigen 1a (HPA-1a) antibodies occurs in 1 : 1250 pregnancies in the Caucasian population. The antibodies can cause the unborn baby’s platelets to disappear from his or her blood stream, resulting in a low platelet count. In this case, prenatal testing to identify maternal platelet alloantibodies can be performed.80. Management: All neonates with suspected NAIT should be screened for ICH by cranial ultrasound in view of the risk of severe neurodevelopmental problems.70 Most cases of NAIT resolve within a week without long-term sequelae, and for well neonates with documented or suspected NAIT who have no evidence of hemorrhage, transfusion of HPA-compatible platelets is recommended only when the platelet count is <30×109/L.80 When there is major hemorrhage, including ICH, most guidelines recommend maintaining the platelet count >50×109/L although there are no studies to show whether or not this is effective.80,81 When appropriate HPA-negative platelets are unobtainable, random donor platelet transfusions or intravenous immunoglobulin (IVIG) can be used, as they often produce a significant platelet increment in NAIT.58,82 Since the platelet count usually falls over the first 4–7 days of life, all thrombocytopenic neonates with NAIT should be monitored until there is a sustained rise in their platelet count into the normal range.55,69 In some cases thrombocytopenia may persist for up to 8–12 weeks. If necessary, conduct a cordocentesis (the process of getting a blood sample from the unborn baby’s umbilical cord) for more information. Should I push for testing? Neonatal alloimmune thrombocytopenia is the most common cause of immune-mediated thrombocytopenia in the newborn period. Important note: Mothers who are negative for the antigen in question can develop antiplatelet antibodies that cross the placenta, leading to severe fetal thrombocytopenia. Very few of these unexplained cases have been shown to be due to antibodies against minor HPA (such as HPA-6w and HPA-9w),70 and therefore, most groups do not recommend routine screening for these very low frequency HPA antigens in unexplained NAIT except in selected severe cases. IVIG is usually a better option than repeated platelet transfusions. Giving platelets to the unborn baby is associated with a risk of bleeding from puncture of the umbilical cord. Severe hemorrhage is estimated to occur in 10 per 100,000 neonates, commonly occurring before birth (Kamphuis et al., 2014). The disease process that happens in the fetus or baby is known as Neonatal Alloimmune Thrombocytopenia. Although current guidelines recommend antigen-negative platelets,83 these products may not be readily available. However, ultrasound can be used to look at the baby’s brain for evidence of bleeding. Many maternal-fetal medicine specialists are reluctant to perform cordocentesis as a low platelet count in the baby can cause significant bleeding from the umbilical cord and other complications at the time of the procedure. The thrombocytopenia associated with NAIT is often severe and result in serious bleeding, including intracranial hemorrhage and so rapid diagnosis and management is essential to prevent the consequences of life-threatening bleeding. Copyright © 2018 naitbabies.org - All rights reserved. Though packed red cells are most commonly associated with PTP, transfusion of any blood component may precipitate this disorder. Neonatal alloimmune thrombocytopenia (NAIT), also referred to as fetal and neonatal alloimmune thrombocytopenia or perinatal alloimmune thrombocytopenia, is the most common cause of thrombocytopenia in an otherwise healthy newborn. The father of a previously affected fetus or neonate should also undergo platelet typing. (This report is a PDF file, click here to Download the free latest version of Adobe Reader). During the first week, the thrombocytopenia worsens. This can put them at risk of … 5. Maternal platelet alloantibody detection and newborn platelet antigen typing can aid in the diagnosis postnatally; however, treatment including platelet transfusion may be necessary before the results are available. This medication is usually taken once or twice daily. If the mother’s platelet type is negative for a certain antigen and the baby’s platelets are positive for that antigen, the mother may form antibodies against the baby’s platelets. Again, this involves drawing a special blood sample and sending it to a reference laboratory usually along with the mother’s blood sample. The management of women with previously affected neonates during subsequent pregnancies is a complex issue, which is reviewed in Chapter 46. In order to determine maternal platelet alloimmunization, rapid platelet testing is performed by ELISA on maternal serum. The condition occurs when a fetus inherits cell surface … The treatment of NAIT during pregnancy is maternal administration of 1.0 g/kg IVIg weekly as a first-line therapy beginning at 20 weeks of gestational age with the use of glucocorticosteroids, or 2.0 g/kg weekly if steroids are not used. The most serious complication of NAIT is bleeding in the brain called intracranial hemorrhage (ICH). Save my name, email, and website in this browser for the next time I comment. Diagnosis and management of the fetus and neonate with alloimmune thrombocytopenia. Often in the first pregnancy, there are no problems until the baby is born. Berkowitz RL, Bussel JB, McFarland JG. It is a direct result of the platelet alloimmunization in the mother. Neonatal alloimmune thrombocytopenia (NAITP) NAITP, the platelet equivalent of haemolytic disease of the newborn, is caused by transplacental passage of maternal alloantibodies directed against fetal platelet antigens inherited from the father but absent on maternal platelets. In whites, 80 to 90% of cases of NAIT are the result of fetomaternal HPA-1 incompatibility.163 However, other antigens may be involved. 2. The focus of the management of NAIT is on the prevention of severe bleeding. What is Neonatal Alloimmune thrombocytopenia (NAIT)? Platelet alloimmunization happens when a mother’s body forms antibodies (a protein substance that reacts to unrecognized proteins in the body) in reaction to antigens that are different from her own. Check for Maternal Antibodies A limited number of prospective screening studies showed that granulocyte-specific antibo … Diagnosis is confirmed by demonstrating a platelet antigen incompatibility and the presence of maternal antibody directed against that specific antigen (vs. nonspecific platelet alloantibodies). Kenneth J. Moise, Jr., MD. Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is characterized by the presence of transient isolated neonatal thrombocytopenia secondary to maternal antibodies against paternally inherited antigens expressed on the fetal platelets. If maternal platelets are transfused, they must be volume reduced or washed to limit the amount of antibody-containing plasma and irradiated to minimize risk of TA-GVHD. Neonatal Alloimmune Thrombocytopenia or NAIT is not common, but can have devastating complications. (Note:  Medication brand names will differ according to country, as will treatment costs, place and time taken for IVIG administration.). Additionally, NAIT mediated by antibodies against HPA-1a is more clinically severe, perhaps because these antibodies may also block platelet aggregation, since HPA-1a is an antigen expressed on platelet GPIIIa. Neonatal Alloimmune Thrombocytopenia (NAIT) results from maternal human platelet antibodies (HPA) against fetal platelet antigens inherited from the father. At around 32 weeks into the pregnancy, prednisone, a steroid pill that is taken by mouth, may be added. Neonatal Alloimmune Thrombocytopenia (NAIT) is a blood-related disease that affects expectant mothers and their babies. These antibodies, because they are IgG in nature, can cross the placenta, bind to fetal platelets, and cause thrombocytopenia. 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