Neonatal Hemostasis Research Articles

Report of Scientific and Standardization Subcommittee on Neonatal Hemostasis Diagnosis and Treatment of Neonatal Thrombosis

SummaryThrombotic disease in newborn infants is common and serious enough to require effective and safe intervention (1). Flowever, neonatal thrombosis is also sufficiently rare to prompt anecdotal observations rather than controlled clinical trials. While there is an abundance of case reports in the pediatric literature, there is a conspicuous paucity of well-designed studies to guide clinical decision-making (2).The Subcommittee on Neonatal Hemostasis of the Scientific and Standardization Committee recognizes the need for multicenter controlled clinical trials to determine the risks and benefits of different treatment modalities for neonatal thrombosis. Until such data becomes available, the following recommendations may assist clinicians in the management of newborn infants with thrombotic disease. These recommendations were endorsed by the Subcommittee after careful review of the literature and several consensus meetings.

Severe neonatal protein C deficiency: Prevalence and thrombotic risk

Severe deficiencies of protein C, a pivotal coagulation-regulatory protein, have been reported in neonates as an apparently transient condition. In this prospective study, cord blood was collected at 193 deliveries and assays of protein C were correlated with clinical status, other coagulation results, and outcome. Protein C levels of less than 0.1 unit/ml were found most frequently in preterm infants with respiratory distress, infants of diabetic mothers, and infants of twin gestations. Levels of protein C correlated with levels of factor VIII activity but did not correlate with markers of consumptive coagulopathy. A protein C level less than 0.1 unit/ml was significantly correlated with the subsequent onset of thrombosis, even when the effects of gestational age and birth weight were excluded. Low cord blood levels of protein C may reflect delayed maturation or increased turnover in certain infants and appear to convey an independent risk of thrombosis, but the critical concentration of protein C necessary to maintain neonatal hemostasis is not known.

Report of Scientific and Standardization Subcommittee on Neonatal Hemostasis

Report of Scientific and Standardization Subcommittee on Neonatal Hemostasis

Recommendations for the Evaluation and Treatment of Neonatal Autoimmune and Alloimmune Thrombocytopenia

The following recommendations of the Neonatal Hemostasis Subcommittee of the Scientific and Standardization Committee of the ISTH for the management of neonatal immune thrombocytopenia were prepared by the working party on neonatal immune thrombocytopenia. Evaluation, diagnosis, and treatment of the mother and neonate with alloimmune and autoimmune thrombocytopenia are discussed and current recommendations provided. This document is likely to require frequent future revision(s).

Coagulation Parameters in Maternal and Cord Blood at Delivery

A wide range of hemostatic variables were studied in 300 maternal/neonatal pairs at the time of delivery and also in 375 healthy nonpregnant women who served as controls. There was significant prol...

The comparison of the pharmacokinetics of a low molecular weight heparin in the newborn and adult pig

Standard heparin (SH) is frequently used in the sick neonate to prevent catheter related thrombosis. SH can cause significant bleeding complications in the adult and its use in the neonate is linked to an increased incidence of intraventricular hemorrhage. Recently available low molecular weight heparins (LMWH) offer potential advantages over SH in the adult by exhibiting a longer half life and decreased bleeding side effects compared to SH. Whether LMWHs would offer similar therapeutic advantages to the sick neonate is unknown. Using the porcine model of neonatal hemostasis we measured the pharmacokinetics of a LMWH (Choay 222) in the pig (ATIII level: 100%), in the piglet (ATIII level:50% of adult) and in the piglet given exogenous ATIII. All pigs were bolused with 125I-LMWH (5, 25 or 100 anti-factor Xa units/kg) and blood samples collected for the measurement of 125I-radioactivity, and anti-factor Xa activity. The half life of LMWH, measured as either 125I-radioactivity or as anti-factor Xa activity, was not dose dependent and was similar in pigs and piglets; however, the volume of distribution was greater in the piglet resulting in an increased total clearance compared to the pig. As well, the supplementation of the piglet with exogenous ATIII did not influence the pharmacokinetics of LMWH. The half life of the LMWH in both pigs and piglets was approximately twice as long as previously reported values for SH in the same animal model. Thus the longer half life of LMWH in the piglet, and the similarity of the half life in piglets and pigs suggest that LMWH may have a therapeutic advantage in the newborn over SH.

Haemostatic factors in infants of preeclamtic mothers

Top of pageAbstract To investigate a possible influence of maternal pre-eclampsia on haemostasis in the neonate, blood coagulation and fibrinolysis were tested in 21 preterm infants (27-36 weeks gestation) born after maternal pre-eclampsia and in 16 healthy neonates, 10 preterm (32-36 weeks gestation), of uncomplicated pregnancies. A peripheral venous blood sample (1.5-2 ml) was taken within 8 hours after birth and analysed for activated partial thromboplastin time and plasma levels of fibrinogen, antithrombin III, prekallikrein, C1 esterase inhibitor, alpha-2-antiplasmin, plas-minogen, protein C and D dimer. The levels of the various factors well agreed with normal reference values for the age and did not differ significantly between the two groups of preterm infants. Thus an influence of maternal pre-eclampsia on neonatal haemostasis could not be demonstrated. Significantly (P <0.01) lower levels of prekallikrein (29.2/37.7%), plasminogen (53.4/84.2%) and protein C (21/38%) in the preterm than in the term controls confirms a gestational age dependency of haemostatic factors.

The Animal Models for Hemorrhage and Thrombosis in the Neonate

Animal models have added significantly to our understanding of adult hemorrhagic and thrombotic diseases. Few models, however, have been developed for studies of the hemostatic disorders in the fetus and newborn. This report reviews the current information on animal models of fetal and neonatal hemostasis. The requirements of a relevant model are addressed and previous studies using fetal and neonatal animal models are reviewed. A recommendation of a single animal for all studies of fetal and neonatal hemostasis is not possible. However, the lamb has been the most frequently studied and appears to provide relevant information regarding normal development and the factors which may adversely influence hemostasis in the fetus and newborn. Animal models, in contrast to in vitro experiments, provide a means of studying the entire spectrum of biologic consequences that results from a single experimentally induced alteration. In the "Introduction to the Study of Experimental Medicine" Claude Bernard commented "I not only conclude that experiments made on animals from the physiological, pathological, and therapeutic points of view have results that are applicable to theoretic medicine, but I think that without such comparative study of animals, practical medicine can never acquire a scientific character". In the area of blood coagulation, animal models have added significantly to our understanding of the pathophysiology of hemorrhage and thrombosis. There are animal models for both congenital and acquired bleeding disorders including factor VII, VIII, IX, X, XI, and fibrinogen deficiency; as well as von Willebrand's disease and disorders of platelet function.(ABSTRACT TRUNCATED AT 250 WORDS)

ICTH Subcommittee on Neonatal Hemostasis

ICTH Subcommittee on Neonatal Hemostasis

Effects of Acetylsalicylic-acid Ingestion on Maternal and Neonatal Hemostasis

In a case-control study, we evaluated the effects of maternal ingestion of acetylsalicylic acid (aspirin) within 10 days of delivery on maternal and neonatal hemostasis. Only one of 34 control maternal-neonatal pairs (3 per cent) had hemostatic abnormalities. In 10 pairs, when maternal aspirin ingestion occurred within five days of delivery, 6 of 10 mothers and 9 of the 10 infants had bleeding tendencies. Seven maternal-neonatal pairs in which aspirin was ingested 6 to 10 days before delivery were free of clinical bleeding. Among seven other mothers who ingested aspirin in the immediate post-partum period four of the seven (57 per cent) also had impaired hemostasis. Neonatal hemostatic abnormalities included numerous petechiae over the presenting part, hematuria, a cephalhematoma, subconjunctival hemorrhage, and bleeding from a circumcision. Maternal bleeding was confined to excessive intrapartum or post-partum blood loss. We conclude that aspirin should be avoided during pregnancy. If ingestion has occurred within five days of delivery, the neonate should be evaluated for the presence of bleeding.

Effects of Acetylsalicylic-Acid Ingestion on Maternal and Neonatal Hemostasis

In a case-control study, we evaluated the effects of maternal ingestion of acetylsalicylic acid (aspirin) within 10 days of delivery on maternal and neonatal hemostasis. Only one of 34 control maternal-neonatal pairs (3 per cent) had hemostatic abnormalities. In 10 pairs, when maternal aspirin ingestion occurred within five days of delivery, 6 of 10 mothers and 9 of the 10 infants had bleeding tendencies. Seven maternal-neonatal pairs in which aspirin was ingested 6 to 10 days before delivery were free of clinical bleeding. Among seven other mothers who ingested aspirin in the immediate post-partum period four of the seven (57 per cent) also had impaired hemostasis. Neonatal hemostatic abnormalities included numerous petechiae over the presenting part, hematuria, a cephalhematoma, subconjunctival hemorrhage, and bleeding from a circumcision. Maternal bleeding was confined to excessive intrapartum or post-partum blood loss. We conclude that aspirin should be avoided during pregnancy. If ingestion has occurred within five days of delivery, the neonate should be evaluated for the presence of bleeding.

Effects of Acetylsalicylic Acid Ingestion on Maternal and Neonatal Hemostasis

In a case-control study, we evaluated the effects of maternal ingestion of acetylsalicylic acid (aspirin) within 10 days of delivery on maternal and neonatal hemostasis. Only one of 34 control maternal-neonatal pairs (3 per cent) had hemostatic abnormalities. In 10 pairs, when maternal aspirin ingestion occurred within five days of delivery, 6 of 10 mothers and 9 of the 10 infants had bleeding tendencies. Seven maternal-neonatal pairs in which aspirin was ingested 6 to 10 days before delivery were free of clinical bleeding. Among seven other mothers who ingested aspirin in the immediate post-partum period four of the seven (57 per cent) also had impaired hemostasis. Neonatal hemostatic abnormalities included numerous petechiae over the presenting part, hematuria, a cephalhematoma, subconjunctival hemorrhage, and bleeding from a circumcision. Maternal bleeding was confined to excessive intrapartum or post-partum blood loss. We conclude that aspirin should be avoided during pregnancy. If ingestion has occurred within five days of delivery, the neonate should be evaluated for the presence of bleeding.

Current Problems in Pediatric Hematology

This compact, 180-page monograph, reprinted from the April and July 1975 issues of<i>Seminars in Hematology</i>, is an eclectic collection of 11 definitive review articles by acknowledged experts within pediatric hematology. Although taken from a hematological seminar series, this book is for the practicing pediatrician and not a collection of esoterica of interest only to other hematologists. Each chapter is extensively referenced with both current and classic papers; the tables and illustrations are appropriate in number and of high quality and excellent organization. The areas covered represent those with the greatest progress in recent years. Four reviews are devoted to neonatal hematological problems and include discussions of the anemia of prematurity, bleeding problems, Rh erythroblastosis, and erythrocyte metabolism. Hemostasis is represented by two papers on the therapy of hemophilia and a discussion of inherited defects of platelet function, in addition to the neonatal hemostasis chapter. The field of hemoglobinopathies includes