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Objectives To evaluate the safety of vaginal delivery in pregnancies with fetal and neonatal alloimmune thrombocytopenia (FNAIT). Design Prospective data collection. Setting Leiden University Medical Centre, the national centre for management of severe red cell and platelet alloimmunisation. Population Thirty-two pregnancies with FNAIT, with a sibling with thrombocytopenia but without an intracranial haemorrhage (ICH). Methods The mode of delivery, platelet count in cord blood and neonatal outcome were analysed. All women received weekly intravenous immunoglobulin from 32 to 38 weeks of gestation. Head ultrasound scan was performed in all neonates. Main outcome measures Signs of ICH or other bleeding in the neonates. Results Twenty-three women delivered vaginally. Nine caesarean sections were performed, all for obstetric reasons. Median platelet count at birth was 142 × 109/l (range, 4–252 × 109/l), with severe thrombocytopenia (<50 ×109/l) in four neonates, of which three were born vaginally. None of the neonates showed signs of ICH or other bleeding. Conclusions In pregnancies with FNAIT and a thrombocytopenic sibling without ICH, vaginal delivery was not associated with neonatal intracranial bleeding. These initial results support our noninvasive management of these pregnancies with FNAIT. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Madani K, Kamphuis M, Lopriore E, Porcelijn L, Oepkes D. Delayed diagnosis of fetal and neonatal alloimmune thrombocytopenia: a cause of perinatal mortality and morbidity. BJOG 2012;119:1612-1616. Objective To evaluate the rate and consequences of a late or missed diagnosis of fetal and neonatal alloimmune thrombocytopenia (FNAIT). Design Retrospective analysis of prospectively collected data of a national cohort. Setting National referral centre for fetal therapy in the Netherlands. Population Twenty-six women with pregnancies complicated by FNAIT and at least one previous pregnancy with a thrombocytopenic child. Methods Retrospective analysis of data from our electronic FNAIT database. In a consecutive cohort managed between July 2008 and July 2010, timing of first diagnosis of FNAIT was correlated to severity and outcome in the subsequent pregnancies. Main outcome measures Occurrence of delayed diagnosis of FNAIT, and possibly associated intracranial haemorrhage (ICH). Results In four of 26 pregnancies, timely diagnostic testing for FNAIT was not performed despite fetal or neonatal thrombocytopenia or ICH. Down syndrome, dysmaturity and birth trauma were perceived to be the cause of the thrombocytopenia/ICH. In two of these four subsequent, untreated pregnancies, severe fetal ICH occurred. The other 22 women were treated for FNAIT using intravenous immunoglobulin, all children are alive and well. Conclusions All neonates with thrombocytopenia at birth should be evaluated for FNAIT. Missing this diagnosis can have severe consequences for subsequent pregnancies. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Kamphuis M, Paridaans N, Porcelijn L, De Haas M, van der Schoot C, Brand A, Bonsel G, Oepkes D. Screening in pregnancy for fetal or neonatal alloimmune thrombocytopenia: systematic review. BJOG 2010;117:1335–1343. Background Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, which may lead to intracranial haemorrhage (ICH), with neurological damage as a consequence. In the absence of screening, FNAIT is only diagnosed after bleeding symptoms, with preventive options limited to a next pregnancy. Objectives To estimate the population incidence of FNAIT and its consequences to prepare for study design of a screening programme. Search strategy An electronic literature search using MEDLINE, EMBASE and Cochrane database, and references of retrieved articles. No language restrictions were applied. Selection criteria Prospective studies on screening for human platelet antigen 1a (HPA-1a) alloimmunisation in low-risk pregnant women. Data collection and analysis Two reviewers independently assessed studies for inclusion and extracted data. Main outcome data were prevalence of HPA-1a negativity, HPA-1a immunisation, platelet count at birth and perinatal ICH. We aimed to compare outcome with and without intervention. Main results HPA-1a alloimmunisation occurred in 294/3028 (9.7%) pregnancies at risk. Severe FNAIT occurred in 71/227 (31%) immunised pregnancies, with perinatal ICH in 7/71 (10%). True natural history data were not found because interventions were performed in most screen-positive women. Authors’ conclusions Screening for HPA-1a alloimmunisation detects about two cases in 1000 pregnancies. The calculated risk for perinatal ICH of 10% in pregnancies with severe FNAIT is an underestimation because studies without interventions were lacking. Screening of all pregnancies together with effective antenatal treatment such as intravenous immunoglobulin may reduce the mortality and morbidity associated with FNAIT. [ABSTRACT FROM AUTHOR]

Background and Objectives Kell haemolytic disease in pregnancies has been suggested to be associated with decreased fetal platelet counts. The aim of this study was to evaluate the incidence and clinical significance of fetal thrombocytopenia in pregnancies complicated by Kell alloimmunization. Materials and Methods In this retrospective cohort study, fetal platelet counts were performed in 42 pregnancies with severe Kell alloimmunization prior to the first intrauterine blood transfusion. Platelet counts from 318 first intrauterine transfusions in RhD alloimmunized pregnancies were used as controls. Results Fetal thrombocytopenia (platelet count < 150 × 109/l) was found in 4/42 (10%) in the Kell group and in 84/318 (26%) in the RhD group. None of the fetuses in the Kell alloimmunized pregnancies, including 15 with severe hydrops, had a clinically significant thrombocytopenia defined as a platelet count < 50 × 109/l. In the RhD alloimmunized pregnancies, 2/230 (1%) of the non-hydropic fetuses and 7/30 (23%) of the severely hydropic fetuses had a clinically significant thrombocytopenia. Conclusion In contrast to fetuses with severe anaemia and hydrops due to RhD alloimmunization, fetuses with severe anaemia due to Kell alloimmunization are generally not at risk for substantial thrombocytopenia. [ABSTRACT FROM AUTHOR]

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a disease in pregnancy characterized by maternal alloantibodies directed against the human platelet antigen (HPA). These antibodies can cause intracranial hemorrhage (ICH) or other major bleeding resulting in lifelong handicaps or death. Optimal fetal care can be provided by timely identification of pregnancies at risk. However, this can only be done by routinely antenatal screening. Whether nationwide screening is cost-effective is still being debated. HPA-1a alloantibodies are estimated to be found in 1 in 400 pregnancies resulting in severe burden and fetal ICH in 1 in 10.000 pregnancies. Antenatal treatment is focused on the prevention of fetal ICH and consists of weekly maternal IVIg administration. In high-risk FNAIT treatment should be initiated at 12–18 weeks gestational age using high dosage and in standard-risk FNAIT at 20–28 weeks gestational age using a lower dosage. Postnatal prophylactic platelet transfusions are often given in case of severe thrombocytopenia to prevent bleedings. The optimal threshold and product for postnatal transfusion is not known and international consensus is lacking. In this review practical guidelines for antenatal and postnatal management are offered to clinicians that face the challenge of reducing the risk of bleeding in fetuses and infants affected by FNAIT. [ABSTRACT FROM AUTHOR]