Fetal and neonatal alloimmune thrombocytopenia: evidence based antenatal and postnatal management strategies

Abstract

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a relatively rare but potentially lethal disease, leading to severe bleeding complications in 1 in 11.000 newborns. It is the leading cause of thrombocytopenia in healthy term-born neonates. Areas covered: This review summarizes the antenatal as well as postnatal treatment, thus creating a complete overview of all possible management strategies for FNAIT. Expert commentary: The optimal antenatal therapy in order to prevent bleeding complications in pregnancies complicated by FNAIT is non-invasive treatment with weekly intravenous immunoglobulin (IVIG). Based on risk stratification, weekly doses of IVIG of 0.5 or 1.0g/kg should be administered started early in the second in high risk cases or at the end of the second trimester in low risk cases. The optimal postnatal treatment depends on the platelet count and the clinical condition of the newborn. Prompt administration of compatible platelet transfusion is the first treatment of choice in case of severe thrombocytopenia or active bleeding. In case matched platelets are not directly available, random platelets can also be administered initially to gain time until matched platelets are available. In case of persistent thrombocytopenia despite transfusions, IVIG 1.0-2.0g/kg can be administered.

Neonatal Alloimmune Neutropenia

“…Further investigation will be necessary to explain the presence of granulocyte-specific antibodies in never allo-exposed women and primiparous women. Expression of the human platelet antigen 1a (HPA-1a) on glycoprotein αvβ3 on placental endothelial cells is one of the reasons for alloimmunization against HPA-1a already in the first pregnancy [19]. However, most of the involved granulocyte antigens are not expressed on placental tissue, and therefore, only exposure of these antigens on fetal granulocytes seems to be the immunizing trigger during pregnancy.…”

Management and Neonatal Outcomes of Pregnancies with Fetal/Neonatal Alloimmune Thrombocytopenia: A Single-Center Retrospective Cohort Study

“…Comparison with other studies is relatively difficult due to the fact that the majority of authors have calculated FBS-related fetal loss and adverse outcome rates in relation to the total number of treated fetuses, rather than the total number of procedures performed in this population, which, by definition, would result in an higher reported rate of such complications [9, 12, 16, 18-21] (Appendix 1). Two reports did calculate the risk compared to the total number of procedures: Berkowitz et al [21] reported a rate of pregnancy loss similar to our data (0.6 vs. 0.8%) with, however, a rate of other adverse outcomes five times higher than in our series (6 vs. 0.8%), and Overton et al [19] reported a fetal loss rate of 2.4% (2/84 procedures) in a small series of 12 cases, including an unexplained fetal death occurring 7 days after an uncomplicated PLT IUT.…”

“…In this case, labor occurred 5 days after the procedure, while in 2 cases, induction of labor was planned because of severe maternal pre-eclampsia with HELLP syndrome at 29 and 32 +2 weeks, and in one case spontaneous labor occurred at 33 +5 weeks, 2 weeks after the second FBS, in a woman with a history of premature labor at 35 weeks’ gestation (Table 2). Bussel and Primiani [12] reported a similar rate of premature birth (2.1%) in the subgroup undergoing FBS, while in the majority of the other studies, the prematurity rate was reported as being between 7.8 and 75%, reflecting a higher rate of FBS-related adverse pregnancy outcome or, in one series, delivery was undertaken at 32 weeks routinely [19]. We suggest that a detailed discussion of the potential risks associated with FBS (in very experienced hands only), and the role it may play in allowing a safe vaginal delivery, should be discussed with these patients, many of whom have had previous vaginal deliveries.…”

“…We defined responders (R) as medically treated patients in whom fetal PLTs were normal (> 50 × 10 9 /L), and non-responders (NR) as medically treated patients in whom fetal PLT count was < 50 × 10 9 /L, requiring serial PLT IUTs. The expected CS rate was calculated based on those high-risk cases which, in a non-invasive protocol, would have been offered CS (as an alternative to FBS) [12]. Continuous variables were compared using the Student t test and categorical variables were compared using the χ 2 test.…”

Alloimmunization and Role of HLA in Pregnancy

“…In many of the FNAIT instance, the illness presents as, petechiae, hematomas, haemoptysis, retinal bleeding and haematuria [57,67]. Occasionally, the bleeding due to FNAIT is diagnosed during foetal life in ultrasound abnormalities [68]. Without routine screening for HPA antibodies the disease is mostly detected after the delivery of the first affected child.…”