Reduced platelet count as a risk factor for intraventricular hemorrhage

The role of thrombocytopenia as a risk factor for intraventricular hemorrhage in infants of very low birth weight is unclear. This study investigates the relationship between the lowest platelet count and the occurrence of intraventricular hemorrhage in 302 consecutively admitted infants with birth weights under 1500 g. Intraventricular hemorrhage, which occurred in 90 infants (29.8%), was correlated with the lowest platelet count obtained during the first 4 days of life. In 27 infants with intraventricular hemorrhage, the lowest platelet count was less than 100 X 10(9)/L. Statistical analysis of the data demonstrated that reduced platelet count was not associated significantly with intraventricular hemorrhage. Similarly, the severity of intraventricular hemorrhage did not correlate with the lowest platelet count. These data suggest that a reduced platelet count does not play a major role in the pathogenesis of intraventricular hemorrhage in infants of very low birth weight.     

Thrombocytopenia related neonatal outcome in preterms

Objective To investigate the thrombocytopenia and platelet transfusion related outcome in very preterm infants. Methods Cases (n=94) with at least one episode of thrombocytopenia (platelet counts <150X10⁹/L) and controls (n=70) were identified from a database of 1054 neonates with gestational age ≤32 weeks admitted to a level III NICU. Thrombocytopenia and platelet transfusion related morbidity (IVH, sepsis, NEC, and bleeding) and mortality were analyzed with respect to gestational age (<28 weeks and 28–32 weeks), severity of thrombocytopenia (mild if platelet count ≥ 100 and <150X10⁹/L, moderate if count ≥ 50 and <100X10⁹/L, and severe if platelets <50X10⁹/L), age of thrombocytopenia onset (early <72 hours and late ≥72 hours). Results The majority of thrombocytopenia (67.0%) was diagnosed after 72 hours of age, and was mild in 12.8%, moderate in 36.2% and severe in 51.0% of the cases. Neonates with severe and moderate thrombocytopenia were more frequently born at lower gestational age and birth weight. NEC and sepsis especially that caused by Candida infection, were associated with severe thrombocytopenic events. The development of IVH was strongly associated with lower gestational age but not the severity and age of thrombocytopenia onset. Mucocutaneous bleeding complicated 18.4% of cases with severe and late-onset thrombocytopenia (7/38). Platelets were transfused to 85.4% of infants with severe and 64.7% of infants with moderate thrombocytopenia (P<0.02). The gestational age of the majority of the platelet transfused neonates (49/60, 81.7%) was <28 weeks. Mean gestational age and birth weight, and rates of severe thrombocytopenia, IVH, sepsis and mortality were comparable in transfused vs not-transfused infants with gestational age 28–32 weeks. Platelet transfused neonates with gestational age <28 weeks had lower birth weights, were more often severely thrombocytopenic, and died more frequently than infants of a similar gestational age who were not transfused. Conclusion Platelet transfusions did not lower mortality in very premature born infants with moderate and severe thrombocytopenia during the NICU admission.     

Transfusion-associated fall in platelet count in very low birthweight infants

Thirty-three infants with a birthweight of less than 1500 g were investigated retrospectively for the incidence and aetiology of thrombocytopenia occurring during the first week of life. The platelet count fell below 100 x 10(9)/l in 16 infants (48%). There was a moderately strong inverse correlation between the platelet count at its nadir during the first week or the first value below 100 x 10(9)/l and the percentage of blood volume transfused prior to this (r = -0.61; P less than 0.0001). When the platelet count was expressed as a percentage of the initial count the correlation was -0.74 (P less than 0.0001). The results were not affected by the elimination of the 10 infants with clinical conditions regarded as a probable cause of thrombocytopenia. The fitted least-squares regression line suggests that a transfusion equal to 10% of the blood volume on average reduced the platelet count by 19 x 10(9)/l or by 7% in these very low birthweight infants during the first week of life.     

Plasma transforming growth factor beta1 levels in thrombocytopenic and nonthrombocytopenic neonates

In this study, we determined the plasma TGF-beta1 levels in healthy and thrombocytopenic and nonthrombocytopenic neonates who had perinatal risk factors and examined the association between plasma TGF-beta1 levels and platelet counts in these newborns to investigate the role of TGF-beta1 in the pathogenesis of neonatal thrombocytopenia. Three groups were defined in this prospective study: group 1, thrombocytopenic neonates (n=22) who had perinatal risk factors; group 2, nonthrombocytopenic neonates who had similar perinatal risk factors for thrombocytopenia (n=20); group 3, healthy and nonthrombocytopenic neonates without any risk factors (n=20). Plasma TGF-beta1 levels were measured with ELISA. Plasma TGF-beta1 levels of the thrombocytopenic neonates were significantly lower than those of healthy nonthrombocytopenic neonates but did not differ significantly from nonthrombocytopenic neonates who had similar perinatal risk factors for thrombocytopenia. There was a significant positive correlation between plasma TGF-beta1 levels and platelet counts. Further studies are needed to determine the cause of low plasma TGF-beta1 levels in thrombocytopenic neonates and to investigate the role of plasma TGF-beta1 levels in the pathogenesis of neonatal thrombocytopenia.     

Neonatal thrombocytopenia: new insights into pathogenesis and implications for clinical management

The healthy fetus has a platelet count of greater than 150 x 10(9)/L by the second trimester of pregnancy and only 2% of term infants are thrombocytopenic at birth. Severe thrombocytopenia (platelets < 50 x 10(9)/L) occurs in fewer than three per 1000 term infants, the most important cause being alloimmune thrombocytopenia. In contrast, in infants admitted to neonatal intensive care units, thrombocytopenia develops in 25% and in up to half of sick preterm infants. Recent evidence shows that these infants mostly have evidence of underlying impaired fetal megakaryocytopoiesis and platelet production following pregnancy complications characterized by placental insufficiency or fetal hypoxia. The mechanism of this is unknown. However, many neonatal complications exacerbate this thrombocytopenic potential and 20% of thrombocytopenias in neonatal intensive care unit patients are severe. Evidence-based guidelines for platelet transfusion therapy in these patients are yet to be defined, but as platelet underproduction underlies most neonatal thrombocytopenias, recombinant hemopoietic growth factors, including thrombopoietin and interkeukin-11, may be useful future therapies.     

Association of Neonatal Thrombocytopenia and Maternal Anti-HLA Antibodies

In order to evaluate the influence of maternal anti-HLA antibody on neonatal thrombocytopenia, clinical features and maternal anti-HLA antibody of three groups of infants (19 thrombocytopenic and low birth weight, 27 nonthrombocytopenic and low birth weight, and 80 healthy full-term) were investigated. The incidence of positive maternal anti-HLA antibodies in the three groups was 73.7%, 29.6% and 27.5%, respectively. Thrombocytopenia in small-for-gestational-age (SGA) infants was closely related to the presence of maternal anti-HLA antibodies. Among 20 SGA infants (11 thrombocytopenic, 9 non-thrombocytopenic), anti-HLA antibody was detected in 10 mothers (90.9%) of thrombocytopenic SGA infants, while it was positive in only one mother (11.1%) of nonthrombocytopenic SGA infants. Investigation of the SGA infants revealed that in those whose mothers were sensitized to HLA antigen, not only the platelet count but also the leukocyte and lymphocyte counts in the first week of life were significantly lower than in infants whose mothers were not sensitized. The results suggest that the presence of maternal anti-HLA antibody is a cause of neonatal thrombocytopenia especially in SGA infants.     

Hematologic abnormalities in severe neonatal necrotizing enterocolitis.

Serial determinations of the absolute granulocyte and platelet counts were performed in 40 infants with severe neonatal necrotizing enterocolitis. Fourteen of the 38 infants had absolute granulocyte counts less than 1,500 nm3, the mean absolute granulocyte count was significantly lower in the group of infants who died during the acute episode of NEC as compared to that of the infants who survived. Thrity-five of 40 infants had nadir platelet counts less than 150,000/nm3, clinical bleeding occurred in 12 of the thrombocytopenic infants. Fourteen thrombocytopenic infants were evaluated for disseminated intravascular coagulation by additional coagulation studies; six were noted to have laboratory evidence of DIC. We conclude that (1) a low absolute granulocyte count in severe NEC is associated with a poor prognosis and (2) thrombocytopenia is a significant problem in severe NEC and may occur with or without evidence of fulminant intravascular coagulation.     

Bleeding disorders: A common cause of menorrhagia in adolescents

OBJECTIVE: To determine the frequency of underlying bleeding disorders in adolescents with menorrhagia. STUDY DESIGN: We retrospectively reviewed the charts of all girls, aged 10 to 19 years, who presented to our children's hospital for inpatient or outpatient evaluation of menorrhagia between January 1990 and November 1998. RESULTS: At presentation, 9 of the 71 girls (13%) had thrombocytopenia (platelet count <150,000/microL; range, 5000-106,000/microL). The most common causes for thrombocytopenia were immune thrombocytopenic purpura (n = 5) and myelosuppression caused by chemotherapy (n = 2). Of 14 girls who underwent a more detailed hemostatic evaluation, 8 were given a diagnosis of a hereditary coagulation disorder: 6 had platelet function defects and 2 had type 1 von Willebrand disease. Excessive menstrual bleeding commonly results in anemia. One half of the total group had anemia (hemoglobin <12.0 g/dL). Seven girls (10%) had potentially life-threatening anemia (hemoglobin <5.0 g/dL). CONCLUSIONS: Acquired and congenital bleeding disorders are common causes of menorrhagia in adolescent girls. Severe anemia is a frequent complication of menorrhagia. We recommend that adolescents without thrombocytopenia who present with menorrhagia receive a comprehensive hemostatic evaluation, including testing for von Willebrand disease and platelet function defects.     

Thrombopoietin has a primary role in the regulation of platelet production in preterm babies.

Thrombocytopenia in the first days of life, in association with evidence of reduced megakaryocytopoiesis and platelet production at birth, is common in sick preterm babies. Thrombopoietin (Tpo) is the major regulator of platelet production in adults. However, these babies have low Tpo levels at birth, suggesting that the Tpo response to thrombocytopenia may be impaired. To test this hypothesis we 1) measured Tpo levels, 2) measured circulating megakaryocyte progenitors serially over the first 12 d of life in 13 preterm babies with early onset thrombocytopenia and in 14 control babies with evidence of normal megakaryocytopoiesis, and 3) measured Tpo levels in thrombocytopenic children (n = 13). In control babies, platelet counts and progenitor numbers remained normal and Tpo levels were consistently low-d 1:160+/-23 pg/mL (mean+/-SEM), d 4/5: 154+/-18 pg/mL and d 12: 150+/-58 pg/mL. In thrombocytopenic babies, platelet counts and megakaryocyte progenitor numbers were significantly lower than controls at d 1: platelets 130+/-14 x 10(9)/L versus 255+/-20 x 10(9)/L (p < 0.001) and megakaryocyte progenitors 552 versus 3907 colonies/mL (mean, p < 0.001), and fell further to nadir on d 4/5: platelets 76+/-6 X 10(9)/L versus 259+/-21 x 10(9)/L (p < 0.001) and MK progenitors 479 versus 2742 colonies/mL (p < 0.05). Tpo levels were only slightly raised on d 1:247+/-52 pg/mL (p = 0.24), but then rose sharply by d 4/5: 425+/-75 pg/mL (p < 0.001). By d 12, platelet count, megakaryocyte progenitors and Tpo level (145+/-29 pg/mL) had returned to control levels. Tpo levels at platelet nadir in thrombocytopenic babies were significantly lower than in thrombocytopenic children: mean 425 versus 1383 pg/mL (p < 0.001). These data show that Tpo is important in platelet homeostasis in preterm babies, with a close reciprocal relationship with platelet count and progenitor numbers during thrombocytopenia. However, the increase in Tpo levels seen in these babies was modest, despite significantly impaired megakaryocytopoiesis, and when compared with that seen in children with thrombocytopenia. This offers further evidence that preterm babies have an impaired Tpo response to thrombocytopenia and suggests that recombinant human Tpo may have a role in the prevention/treatment of preterm thrombocytopenia.     

Assessment of clinical impact and predisposing factors for neonatal thrombocytopenia

Thrombocytopenia is a common hemostatic abnormality in the newborn infant. The early diagnosis of thrombocytopenia and the underlying primary pathology process play an important role in reducing the risk of severe complications and mortality. We performed a 2-year prospective study of 643 neonates admitted to our neonatology unit to determine the frequency, predisposing factors, and clinical impact of thrombocytopenia. Thrombocytopenia developed in 18.2% of the preterm neonates and 0.8% of the term neonates. Prematurity, sepsis, hypoxia, intrauterine growth retardation, and disseminated intravascular coagulation were identified as predisposing factors for thrombocytopenia. The incidence of complications and mortality were higher in thrombocytopenic infants. Especially the prognosis was worse in cases who had mucosal hemorrhage, without a relation with the degree of thrombocytopenia. The thrombocytopenia occurred by day 2 in 43% of the infants, and resolved by day 8 in 61%. The platelet count nadir occurred by day 2. Since thrombocytopenic infants are at greater risk for bleeding, and the thrombocytopenia itself may have contributed to the high mortality, predisposing factors such as prematurity, infections, hypoxia must be eliminated by prividing better care, giving adequate hygiene of both mother and the baby during the prenatal, natal, and neonatal period.     

Duration and morbidity of newly diagnosed idiopathic thrombocytopenic purpura in children: A prospective Nordic study of an unselected cohort

OBJECTIVE: To determine the duration of the risk period with platelet counts <20 x 10(9)/L and the frequency of bleeding episodes in unselected children with idiopathic thrombocytopenic purpura (ITP). STUDY DESIGN: We established a registry for patients with newly diagnosed ITP in the five Nordic countries, enrolling children aged 0 to 14 years with platelet counts <30 x 10(9)/L. Treatment centers prospectively reported presenting features, management details, and disease-related events during the first six months after diagnosis. RESULTS: At presentation (n=501), more than half of the children had a platelet count <10 x 10(9)/L, but only 15 (3.0%) had a hemorrhage requiring blood transfusion. During follow-up of 409 patients, thrombocytopenia resolved uneventfully in 277. A risk period was present in 376 cases. Among 283 with self-limiting ITP, 26 were at risk >1 month and 25 had 30 events. Among 93 patients with chronic ITP, 73 were at risk >1 month and 44 had 111 events. Events occurred with an average frequency of 0.39 per month at risk. Life-threatening hemorrhages did not occur in the first six months after diagnosis. CONCLUSION: Most children with ITP are at risk for serious bleeding for less than one month. Continuing severe thrombocytopenia is associated with little morbidity, bleeding episodes being infrequent and very rarely serious.     

The Prevalence and Outcomes of Thrombocytopenia in a Neonatal Intensive Care Unit: A Three-Year Report

Neonatal thrombocytopenia is one of the most common hematologic disorders in neonatal intensive care units (NICUs). The purpose of this study was to determine the prevalence of thrombocytopenia and whether thrombocytopenia has an effect on the occurrence of intraventricular hemorrhage (IVH) ≥ grade 2 and on mortality rate. This study was carried out retrospectively in neonates admitted to NICU of Cumhuriyet University in Sivas, Turkey, between 2009 and 2012. Among 2218 neonates evaluated, 208 (9.4%) developed thrombocytopenia. The prevalence of IVH ≥ grade 2 was more in infants with thrombocytopenia (7.2%) than in those without thrombocytopenia (4.4%), although this was not statistically significant (P = .08). In univariate analysis, IVH ≥ grade 2 was higher in cases with very severe thrombocytopenia (35.7%, n = 5) than in those with mild (2.1%, n = 2), moderate (4.7%, n = 3), and severe thrombocytopenia (15.2%, n = 5) (P = .04). Multivariate logistic regression analysis showed that birth weight <1500 g (OR 6.2, 95% CI 3.4–9.8; P = .0001), gram-negative sepsis (OR 2.5, 95% CI 1.8–4.2; P = .01), very severe thrombocytopenia (OR 1.3, 95% CI 1.1–2.1; P = .03), and platelet transfusion ≥2 (OR 7.3, 95% CI 4.1–12.1; P = .001) were significant risk factors for mortality. The results of our study suggest that outcomes of neonates with thrombocytopenia depend not only on platelet count but also on decreased gestational age or birth weight, prenatal factors, and sepsis.     

Neonatal thrombocytopenia: what we do and don't know

The evaluation and management of thrombocytopenia is a frequent challenge for neonatologists, as it affects 22-35% of infants admitted to the neonatal intensive care unit. Multiple disease processes can cause neonatal thrombocytopenia, and these can be classified as those inducing early thrombocytopenia (72 h). Most cases of neonatal thrombocytopenia are mild to moderate, and do not warrant intervention. In approximately 25% of affected neonates, however, the platelets count is <50x10(9)/L, and therapy with platelet transfusions is considered to decrease the risk of hemorrhage. The existing evidence to establish platelet transfusion triggers in neonates is very limited, but it suggests that transfusing platelets to non-bleeding neonates with platelet counts >50x10(9)/L does not decrease the risk of intraventricular hemorrhage (IVH), and that 30x10(9)/L might be an adequate threshold for stable non-bleeding neonates. However, adequately powered multi-center studies are needed to conclusively establish the safety of any given set of neonatal transfusion guidelines.     

Perinatal risk factors and intraventricular hemorrhage in newborn infants of birth weight less than or equal to 1,500 g

In a retrospective study in 113 preterm newborns (birth weight less than or equal to 1500 g, gestational age less than 35 weeks) intraventricular hemorrhage (IVH I-IV) determined by serial sonographic examinations was correlated to a number of maternal and neonatal risk factors. While there was no significant correlation to bleeding during the gestation, premature rupture of the membranes, mode of delivery, and age of the mother, incidence of IVH was significantly lower in newborns born to mothers with EPH-gestoses (p less than 0.05). A significant high incidence of IVH was found in very premature newborns (p less than 0.025) and in newborns with hyaline membrane disease (p less than 0.005). No single risk factor for a high incidence of IVH was found. IVH in very low birth weight infants probably is caused by summation of several different perinatal risk factors.     

Intraventricular hemorrhage in extremely small premature infants

The incidence, timing, severity, and outcome of intraventricular hemorrhage (IVH) were studied in extremely small premature infants with birth weights (BWs) between 500 and 700 g; 366 infants with BWs between 701 and 1500 g, admitted during the same period, served as a comparison group. Intraventricular hemorrhage occurred in 34 (62%) of 55 infants with BWs less than 700 g vs 91 (25%) of the 366 comparison infants. In the group with BWs less than 700 g, IVH occurred in the first 18 hours, from 19 to 72 hours, and after 72 hours of life in 62%, 20%, and 18% of the infants, respectively. In the comparison group, the occurrence for these periods was 13%, 82%, and 5%, respectively. The severity of IVH in infants with BWs less than 700 g was grade III (with or without intraparenchymal hemorrhage) in 97% of the lesions, but in the comparison group such severe IVH accounted for only 32% of the lesions. Intraventricular hemorrhage was a common contributor to death in the infants with BWs less than 700 g. Thus, in 24 infants who died before 72 hours of life, 21 infants (88%) had severe IVH. In addition, intracranial hemorrhage (four infants with IVH and two infants with intracerebellar hemorrhage) occurred late (days 8 to 25) and contributed to death in six of the infants with BWs less than 700 g. These data indicate that in comparison with larger premature infants, infants with BWs less than 700 g exhibit a higher incidence of IVH, which is more severe, occurs earlier, and is associated more often with a fatal outcome. In addition, late and lethal intracranial hemorrhage is also more likely to occur in these smaller infants.     

Idiopathic thrombocytopenic purpura: predictors of chronic disease.

We studied the extent to which patient characteristics influenced outcome in childhood idiopathic thrombocytopenic purpura in a historical cohort of 289 children over a 20 year period (1968-87). Outcome was classified as acute or chronic depending on whether the platelet count had returned to normal (150 X 10(9)/l) by six months after diagnosis. Fifty three cases (18%) had chronic idiopathic thrombocytopenic purpura. The likelihood of chronic disease was determined by logistic regression analysis of five patient variables: age, sex, season of onset of symptoms, history of recent viral illness, and duration of symptoms at presentation. A history of symptoms of greater than 14 days at presentation, adjusted for the other variables, was strongly predictive of chronic idiopathic thrombocytopenic purpura; the other variables did not significantly affect outcome. At 28 days after diagnosis 138 (47%) of the study cohort had normal platelet counts. Children whose platelet counts were less than 150 X 10(9)/l had a threefold risk of progressing to chronic idiopathic thrombocytopenic purpura, which increased to fivefold if counts were less than 50 X 10(9)/l. Two thirds of patients in the chronic group, irrespective of treatment, remained thrombocytopenic two years after diagnosis. We conclude that a history of symptoms for greater than two weeks at presentation is strongly predictive of chronic idiopathic thrombocytopenic purpura. If platelet counts are subnormal 28 days after diagnosis the risk of chronic idiopathic thrombocytopenic purpura is increased with prolonged thrombocytopenia being very likely if platelet counts remain low three months after diagnosis.     

Transfusion-associated fall in platelet count in very low birthweight infants

Abstract Thirty-three infants with a birthweight of less than 1500 g were investigated retrospectively for the incidence and aetiology of thrombocytopenia occurring during the first week of life. The platelet count fell below 100 × 10⁹/l in 16 infants (48%). There was a moderately strong inverse correlation between the platelet count at its nadir during the first week or the first value below 100 × 10⁹/l and the percentage of blood volume transfused prior to this ( r =−0.61; P < 0.0001). When the platelet count was expressed as a percentage of the initial count the correlation was −0.74 ( P < 0.0001). The results were not affected by the elimination of the 10 infants with clinical conditions regarded as a probable cause of thrombocytopenia. The fitted least-squares regression line suggests that a transfusion equal to 10% of the blood volume on average reduced the platelet count by 19 × 10⁹/l or by 7% in these very low birthweight infants during the first week of life.     

Neuropathologic findings in short-term survivors of intraventricular hemorrhage

Intraventricular hemorrhage (IVH) occurs in 31% to 43% of infants weighing less than 1500 g. Intraventricular hemorrhage is rarely an isolated lesion at autopsy. To document associated cerebral abnormality, 24 brains of infants with a diagnosis of IVH and who survived for at least one week were examined. The diagnosis was verified in 20 infants. Choroid plexus hemorrhage and brain calcification had been misdiagnosed as IVH in two infants and in two other infants, IVH was not evident at autopsy. Eleven infants (46%) had choroid plexus hemorrhage. Twenty-two infants (92%) had additional cerebral abnormalities: periventricular leukomalacia, brainstem necrosis, hydrocephalus, or cerebellar necrosis. This study demonstrates that IVH is rarely an isolated abnormality in the preterm infant brain. The associated brain lesions should be considered in attempts to prevent or treat IVH and their presence should be suspected during clinical assessment of survivors.     

Clinical and diagnostic comparison of neonatal alloimmune thrombocytopenia to non-immune cases of thrombocytopenia

BACKGROUND: Affected patients with neonatal alloimmune thrombocytopenia (AIT) are often severely thrombocytopenic and, if so, may suffer an intracranial hemorrhage (ICH). This study was undertaken to compare the outcome of cases of AIT to cases of neonatal thrombocytopenia shown not to be AIT and to identify clinical features that would facilitate the diagnosis. PROCEDURE: Two hundred twenty two cases of neonatal thrombocytopenia for which serologic testing was obtained by the referring physician were accrued for this study from 11 testing laboratories. The relevant clinical information was pursued. RESULTS: The mean birth platelet count in 110 neonates with AIT was 26,000/mm(3) x 10(9)/L and the rate of ICH was 11% (not all neonates had head sonos). Three criteria distinguished cases of AIT from other causes of neonatal thrombocytopenia (n = 56): (1) severe thrombocytopenia <50,000/mm(3) x 10(9)/L; (2) ICH associated with 1 or more of: a 1-min Apgar score >5, birthweight >2,200 g, grade >1, antenatal occurrence, or signs of bleeding, that is, petechiae, ecchymoses; and (3) no additional, non-hemorrhagic neonatal medical problems. CONCLUSIONS: AIT is a unique type of neonatal thrombocytopenia with significant hemorrhagic consequences. Identification of AIT at the bedside should guide institution of appropriate treatment and lead to serologic testing for confirmation.     

极低出生体重儿血小板参数与脑室内出血的关系探讨

目的　 探讨极低出生体重儿血小板参数与脑室内出血 (IVH)的关系。 方法 　将 84例极低出生体重儿分为无IVH组、轻度IVH组和重度IVH组 ,分析比较其生后 2 4h内的血小板参数。 结果 　血小板计数重度IVH组低于无IVH组 (P <0 0 1)及轻度IVH组 (P <0 0 5 ) ,轻度IVH组低于无IVH组 (P <0 0 1) ;血小板压积重度IVH组低于无IVH组 (P <0 0 1) ;血小板体积分布宽度 ,重度IVH组高于无IVH组 (P <0 0 5 )。血小板减少症发生率重度IVH组高于轻度IVH组 (P <0 0 5 )及无IVH组 (P <0 0 1) ,轻度IVH组高于无IVH组 (P <0 0 5 )。 结论 　血小板参数与极低出生体重儿IVH密切相关 ,可能参与了IVH的病理过程。