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Background: Intravenous immunoglobulins (IVIGs) are the cornerstone in the treatment of pregnancies at risk for fetal and neonatal alloimmune thrombocytopenia (FNAIT). The most commonly used dose is 1.0 g/kg/week, not based on any dose-finding study. IVIG is an expensive multidonor human blood product with dose-related side effects. Our aim was to describe the amount of severe thrombocytopenia according to two different doses of IVIG., Study Design and Methods: We performed a cohort study, where two dosage regimes of IVIG were evaluated in the treatment of pregnant women suffering from FNAIT with a previous affected child without intracranial hemorrhage (ICH). Cases, treated with 0.5 or 1.0 g/kg/week, were selected from the international multicenter No IntraCranial Hemorrhage (NOICH) registry. Outcome was neonatal platelet (PLT) count at birth and amount of severe thrombocytopenia. Furthermore the appearance of ICH was analyzed., Results: A total of 109 women were included in the study, 46 in the 0.5 IVIG group and 63 in the 1.0 IVIG group. There was no difference in PLT count at birth (mean, 112 vs. 119; crude difference, 7; confidence interval [CI], -37.4 to 23.7]) and incidence of severe thrombocytopenia (<30 × 10(9) /L; n = 7/46 vs. n = 7/63; odds ratio, 1.43 [CI, 0.46-4.42]). No ICH occurred., Conclusion: In pregnancies with FNAIT with a previous affected child without ICH, treatment with IVIG in a weekly dose of 0.5 or 1.0 g/kg results in comparable neonatal PLT count at birth and degree of thrombocytopenia., (© 2016 AABB.)

Objective: The objective of the study was to evaluate the incidence of fetal thrombocytopenia and association with hydrops in Rhesus D alloimmunization., Study Design: The study was a retrospective chart review of 914 intrauterine transfusions in 314 pregnancies performed between 1988 and 2005 in a single institution. The incidence of thrombocytopenia and severity of hydrops at cordocentesis were assessed and correlated with perinatal mortality., Results: Thrombocytopenia (less than 150 x 10(9)/L) was found in 241 of 914 (26%) and severe thrombocytopenia (less than 50 x 10(9)/L) in 25 of 914 (3%) cordocentesis. Twenty-three percent of severely hydropic fetuses had severe thrombocytopenia, compared with 3% and 1% of mildly hydropic and nonhydropic fetuses, respectively. Thrombocytopenia was an independent risk factor for perinatal mortality. Mortality in fetuses that were severely thrombocytopenic and severely hydropic was 67%., Conclusion: Thrombocytopenia is common in hydropic anemic fetuses. Severe thrombocytopenia is associated with a poor prognosis, irrespective of the presence of hydrops. The option of platelet transfusion in severely hydropic anemic fetuses needs further study.

Fetal thrombocytopenia is most often caused by maternal alloantibodies against fetal platelets crossing the placenta and resulting in platelet destruction. This condition, known as fetal and neonatal alloimmune thrombocytopenia, is usually detected after the birth of a symptomatic child who shows signs of bleeding in the skin or in the brain. In the most severe cases, intracranial hemorrhage leads to severe handicap or death. The challenge for the clinician is to provide preventive treatment in the next pregnancy. The current cornerstone of this treatment is maternal intravenous administration of immunoglobulins during the second half of pregnancy.

Objective: To examine (1) the incidence of fetal thrombocytopenia in hydropic fetuses with congenital B19 virus infection, (2) the effect of intrauterine platelet transfusions and (3) the correlation between fetal B19 viral load and severity of thrombocytopenia., Design: Retrospective analysis of data from prospectively collected fetal blood samples., Setting: Leiden University Medical Centre, the national centre for management of intrauterine fetal disease in the Netherlands., Population: Thirty hydropic fetuses treated with intrauterine red blood cell and platelet transfusions for human B19 virus-induced severe fetal anaemia and thrombocytopenia over a 10-year period., Methods: Fetal blood samples (n= 30) taken before and after intrauterine transfusion were investigated. No cases were excluded, and there was no loss to follow up., Main Outcome Measures: Parameters recorded were gestational age, experienced fetal movements, gravidity and parity, severity of fetal hydrops, severity of fetal anaemia and thrombocytopenia and megakaryocyte and reticulocyte counts. Survival and procedure-associated complications were documented. Quantitative B19 viral load measurements were performed on all fetal samples., Results: Forty-six percent of all hydropic fetuses showed severe thrombocytopenia. No antenatal intracerebral haemorrhage or procedure-associated bleeding occurred. Overall, survival was 77%. Platelet counts increased following platelet transfusion and decreased significantly following red blood cell transfusion alone. No correlation was found between fetal viral loads and platelet counts., Conclusion: Thrombocytopenia was frequently encountered in fetal B19V infection, but fetal bleeding complications were not noted. Absence of a direct relationship between fetal B19 viral load and platelet counts suggests a temporal dissociation between these findings. Dilutional thrombocytopenia is frequently seen in the fetus following red blood cell transfusion alone. The clinical significance of this phenomenon is unclear. The risk of fluid overload by fetal platelet transfusion in a severely hydropic fetus should be weighed against the low incidence of fetal bleeding complications.

Objective: To describe the outcome of pregnancies with fetal and neonatal alloimmune thrombocytopenia (FNAIT) in relation to the invasiveness of the management protocol., Design: Retrospective analysis of prospectively collected data from a national cohort., Setting: Leiden University Medical Centre, the national centre for management of severe red cell and platelet alloimmunisation in pregnancy., Population: Ninety-eight pregnancies in 85 women with FNAIT having a previous child with thrombocytopenia with (n= 16) or without (n= 82) an intracranial haemorrhage (ICH)., Methods: Our management protocol evolved over time from (1) serial fetal blood samplings (FBS) and platelet transfusion (n= 13) via (2) combined FBS with maternal intravenous immunoglobulins (n= 33) to (3) completely noninvasive treatment with immunoglobulins only (n= 52 pregnancies, resulting in 53 neonates). Perinatal outcome was assessed according to the three types of management., Main Outcome Measures: Occurrence of ICH, perinatal survival, gestational age at birth and complications of FBS., Results: All but one of 98 pregnancies ended in a live birth; none of the neonates had an ICH. The median gestational age at birth was 37 weeks (range 32-40). In groups 1 and 2, three emergency caesarean sections were performed after complicated FBS, resulting in two healthy babies and one neonatal death., Conclusion: Noninvasive antenatal management of pregnancies complicated by FNAIT appears to be both effective and safe.

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 x 10(9)/l (range, 4-252 x 10(9)/l), with severe thrombocytopenia (<50 x10(9)/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.

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]

Objective To evaluate the incidence and severity of and risk factors for thrombocytopenia at birth in neonates with red cell alloimmunization. Study design All neonates with haemolytic disease of the foetus/newborn (HDFN) due to red cell alloimmunization admitted to our centre between January 2000 and September 2010 were included in this retrospective study. We measured platelet counts at birth and determined the incidence of thrombocytopenia (platelet count < 150 × 109/l) and severe thrombocytopenia (platelet count < 50 × 109/l). Risk factors for thrombocytopenia at birth were evaluated. Results Thrombocytopenia was present in 26% (94/362) of included neonates with HDFN at birth. Severe thrombocytopenia was found in 6% (20/362) of neonates. Three risk factors were found to be independently associated with thrombocytopenia at birth: treatment with intrauterine red cell transfusion (IUT) (OR 3·32, 95% CI 1·67-6·60, P = 0·001), small for gestational age (SGA) below the 10th percentile (OR 3·32, 95% CI 1·25-8·80, P = 0·016) and lower gestational age at birth (OR 1·22/week, 95% CI 1·02-1·44, P = 0·025). Conclusions Thrombocytopenia at birth occurs in 26% of neonates with HDFN due to red cell alloimmunization and is independently associated with IUT treatment, SGA and lower gestational age at birth. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Scheffer P, Ait Soussan A, Verhagen O, Page-Christiaens G, Oepkes D, de Haas M, van der Schoot C. Noninvasive fetal genotyping of human platelet antigen-1a. BJOG 2011;118:1392-1395. We describe a reliable noninvasive fetal human platelet antigen (HPA)-1a genotyping assay on a real-time polymerase chain reaction (PCR) platform using cell-free fetal DNA isolated from maternal blood. Nonspecific amplification of maternal cell-free DNA is overcome by pre-PCR digestion of the cell-free DNA with the Msp1 restriction enzyme. Noninvasive fetal HPA-1a genotyping offers a safe method for alloimmunised pregnant women to determine whether their fetus is at risk of fetal or neonatal alloimmune thrombocytopenia (FNAIT) and whether interventions to prevent intracranial haemorrhage are required. The availability of this test is relevant to the ongoing debate on screening pregnancies for HPA-1a-mediated FNAIT. [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]

Objective To examine (1) the incidence of fetal thrombocytopenia in hydropic fetuses with congenital B19 virus infection, (2) the effect of intrauterine platelet transfusions and (3) the correlation between fetal B19 viral load and severity of thrombocytopenia. Design Retrospective analysis of data from prospectively collected fetal blood samples. Setting Leiden University Medical Centre, the national centre for management of intrauterine fetal disease in the Netherlands. Population Thirty hydropic fetuses treated with intrauterine red blood cell and platelet transfusions for human B19 virus-induced severe fetal anaemia and thrombocytopenia over a 10-year period. Methods Fetal blood samples ( n= 30) taken before and after intrauterine transfusion were investigated. No cases were excluded, and there was no loss to follow up. Main outcome measures Parameters recorded were gestational age, experienced fetal movements, gravidity and parity, severity of fetal hydrops, severity of fetal anaemia and thrombocytopenia and megakaryocyte and reticulocyte counts. Survival and procedure-associated complications were documented. Quantitative B19 viral load measurements were performed on all fetal samples. Results Forty-six percent of all hydropic fetuses showed severe thrombocytopenia. No antenatal intracerebral haemorrhage or procedure-associated bleeding occurred. Overall, survival was 77%. Platelet counts increased following platelet transfusion and decreased significantly following red blood cell transfusion alone. No correlation was found between fetal viral loads and platelet counts. Conclusion Thrombocytopenia was frequently encountered in fetal B19V infection, but fetal bleeding complications were not noted. Absence of a direct relationship between fetal B19 viral load and platelet counts suggests a temporal dissociation between these findings. Dilutional thrombocytopenia is frequently seen in the fetus following red blood cell transfusion alone. The clinical significance of this phenomenon is unclear. The risk of fluid overload by fetal platelet transfusion in a severely hydropic fetus should be weighed against the low incidence of fetal bleeding complications. [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]