A Comprehensive Approach to Neonatal Peripheral Blood Findings of Preterm and Full-term Infants: an Updated Review.

BACKGROUND: Peripheral blood film morphology in neonates is significantly different from the adults as neonatal erythrocytes show a marked heterogeneity. Moreover, there seem to be a more significant numbers of irregular shaped red blood cells such as stomatocytes, keratocytes, schistocytes, and acantocytes in newborns, particularly in preterm infants. This review study focused on the red blood cell morphology in term and preterm neonates to detect clues to distinguish between the peripheral blood film of newborns under physiological and pathological conditions. METHODS: The peripheral blood findings and blood cell counts in preterm and term neonates were studied and compared to each other using available scientific databases and indexing systems such as PubMed and Google Scholar. RESULTS: This approach is a simple, cost-effective, quick, and informative method to distinguish between physiological and pathological conditions in neonates and detect hematological disorders. CONCLUSIONS: Peripheral blood film plays a crucial role in diagnosing anemia and blood-related diseases, determining the type of anemia, and identifying specific morphological abnormalities of red cell membrane disorders.

Associations of High-Sensitive Cardiac Troponin T in Healthy Newborns and Prolonged Second Stage of Labor, Neonatal and Maternal Factors: A Prospective Study.

INTRODUCTION: High-sensitivity cardiac troponin T (hs-cTnT) is not used routinely as a diagnostic biomarker in newborns. The high precision of hs-cTnT assays increases the ability to determine small differences in cTnT over time and to detect troponin T elevation; thus, we believe that hs-cTnT assays might improve clinical care. We explored the plausible association between hs-cTnT levels (ng/L) in healthy newborns and prolonged second stage of labor, neonatal, and maternal factors. METHODS: A prospective study was performed among healthy newborns in the Obstetrics and Gynecology Department at Hillel Yaffe Medical Center in Israel in January-June 2021. The sociodemographic characteristics of the participants, maternal age, gravidity, parity, Pitocin use, epidural analgesia, and neonatal anemia were obtained from the electronic medical records. Gestational age was determined by ultrasound biometric measurements. We classified second-stage labor as normal or prolonged using the WHO guidelines. Samples from umbilical cord blood were drawn using syringes rinsed with anticoagulant by a specialist in pediatrics. The remaining blood was used to determine hs-cTnT levels (ng/L), which was defined as a continuous quantitative variable with the median value and the 25th-75th percentiles. RESULTS: Overall, 184 cord blood samples were performed from healthy newborns (60.6% males) with a median hs-cTnT of 39.03 (25th-75th percentiles = 30.53-54.09) ng/L. A multivariable linear regression model showed no significant association between neonatal anemia and hs-cTnT levels (ng/L) (p = 0.8). Gestational age (B coefficient -4.24, p < 0.001) and gravidity (B coefficient -2.41, p = 0.03) were negatively associated with hs-cTnT levels (ng/L), while Pitocin use (B coefficient 6.91, p = 0.04) and prolonged second stage of labor (B coefficient 18.07, p = 0.02) were positively associated with hs-cTnT levels (ng/L). CONCLUSIONS: High hs-cTnT levels (ng/L) were documented in the cord blood of healthy newborns. Hs-cTnT levels were positively correlated with a prolonged second stage of labor and Pitocin use and negatively correlated with longer gestational age and higher gravidity. Hs-cTnT may signify labor-related fetal distress. A larger surveillance study is mandatory to establish this correlation and assess for possible prognostic significance of elevated hs-cTnT in this context.

Frequency of red blood cell transfusions in preterm neonates in Brazil: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: Red blood cell transfusions are frequent in preterm neonates. The proportion of preterm neonates transfused in Brazil remains unknown. We systematically reviewed the literature to estimate the frequency of red blood cell transfusions in preterm neonates in Brazil. MATERIALS AND METHODS: The LILACS, EMBASE, Cochrane, SciELO, MEDLINE (PubMed), Web of Science, Scopus, BDTD and 27 national university institutional databases were searched for studies that analysed red blood cell transfusion in preterm neonates in Brazil without period restriction. The Preferred Reporting Items in Systematic Reviews and Meta-Analyses guidelines were followed, and the GRADE methodology was applied. A random-effects model along with the restricted maximum likelihood method was used, and the Freeman-Tukey transformed proportion was used to estimate effect size. RESULTS: Nine studies, representing 6548 preterm neonates, were included in the qualitative and quantitative analyses. The mean gestational age ranged from 26.0 to 31.6 weeks. Most of the studies were from the Southeast region. The pooled estimated frequency of red blood cell transfusions was 58.0% (95% confidence interval = 52.0%-64.0%, p < 0.001) with low certainty. There was statistically significant heterogeneity among studies (I2 = 92.5%, p < 0.001). CONCLUSION: In this current meta-analysis of the evidence available, which included moderate and extremely preterm neonates, the observed frequency of red blood cell transfusions in preterm neonates in Brazil was 58.0% and this estimate can help health programming. Some Brazilian regions were not included in this study, and further research is needed to provide a more representative overview of Brazil.

Blood Donor Sex and Outcomes in Transfused Infants.

Red blood cell transfusion is common in neonatal intensive care. Multiple trials have evaluated different thresholds for when to administer red blood cell transfusion. In contrast, there has been less focus on studies of the characteristics of red blood cells transfused into neonates. In this review, the authors summarize the emerging literature on the potential impact of the sex of blood donors on outcomes in transfused neonates using a systematic search strategy. The authors review the uncertainty generated from studies with conflicting findings and discuss considerations regarding the impact of blood donor sex and other characteristics on neonatal outcomes.

Anemia, Iron Supplementation, and the Brain.

The developing brain is particularly vulnerable to extrinsic environmental events such as anemia and iron deficiency during periods of rapid development. Studies of infants with postnatal iron deficiency and iron deficiency anemia clearly demonstrated negative effects on short-term and long-term brain development and function. Randomized interventional trials studied erythropoiesis-stimulating agents and hemoglobin-based red blood cell transfusion thresholds to determine how they affect preterm infant neurodevelopment. Studies of red blood cell transfusion components are limited in preterm neonates. A biomarker strategy measuring brain iron status and health in the preanemic period is desirable to evaluate treatment options and brain response.

Erythrocyte transfusions are associated with retinopathy of prematurity in extremely low gestational age newborns.

AIM: Retinopathy of prematurity (ROP) is a major morbidity in preterm infants causing visual impairment including blindness. Prevention and timely treatment are critical. We investigated the potential role of red blood cell (RBC) transfusions as risk factor for ROP development. METHODS: Retrospective cohort study of data from 68 tertiary level neonatal intensive care units in Germany. Preterm infants born at 22 + 0 to 28 + 6 weeks of gestation between January 2009 and December 2021 were enrolled. RESULTS: We included n = 12 565 infants. Prevalence of any ROP was 49.2% with most infants being diagnosed with stage 1 (21.5%) and 2 disease (17.2%). ROP stage 3 was present in 10.2%, stage 4 in 0.3%, and ROP requiring treatment in 6.6%. Infants with ROP had significantly more frequently a history of RBC transfusions. Adjusting for confounders, RBC transfusions were associated with increased odds of ROP (OR 1.4, p < 0.001), ROP progression (OR 2.1, p < 0.01) and ROP requiring treatment (OR 3.6, p < 0.001). Restrictive transfusion approaches correlated with decreased (OR 0.7, p < 0.001), liberal regimes with increased odds (OR 1.2, p = 0.001). CONCLUSION: The present study confirmed an association of RBC transfusions and ROP. Our findings emphasise the need for anaemia prevention and critical re-evaluation of transfusion practices in preterm infants.

Trial-related blood sampling and red blood cell transfusions in preterm infants.

AIM: To determine if trial-related blood sampling increases the risk of later red blood cell (RBC) transfusion in very preterm infants, we compared the volume of clinical- and trial-related blood samples, in a specific trial and correlated to subsequent RBC transfusion. METHODS: For 193 very preterm infants, participating in the FortiColos trial (NCT03537365), trial-related blood volume drawn was in accordance with ethical considerations established by the European Commission. Medical records were reviewed to assess the number and accumulated volume (mL/kg) of blood samples (both clinical- and trial-related). Data were compared with the need of RBC transfusions during the first 28 days of life. RESULTS: Mean (SD) gestational age and birth weight was 28 ± 1 weeks and 1168 ± 301 g. In total, 11% of total blood volume was drawn for sampling (8.1 ± 5.1 mL/kg) and trial-related sampling accounted for 1.6 ± 0.6 mL/kg. Trial-related blood sampling had no impact on RBC transfusion (p = 0.9). CONCLUSION: Clinical blood sampling in very preterm infants is associated with blood loss and subsequent need for RBC transfusions. In a specific trial requiring blood samples, we found no additional burden of trial-related blood sampling. The study suggests that trial-related sampling is safe if European criteria are followed.

Effect of Early Erythropoietin on Retinopathy of Prematurity: A Stratified Meta-Analysis.

BACKGROUND: Recombinant human erythropoietin (rhEPO) lost its role in minimizing red blood cell transfusion in very preterm infants after it had been associated with severe retinopathy of prematurity (ROP). Previous systematic reviews did not stratify ROP by gestation and birth weight (BW). OBJECTIVES: The aim of this study was to investigate the effect of early prophylactic rhEPO on ROP in a stratified meta-analysis of randomized controlled trials (RCTs). METHODS: The databases EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched in January 2022 and complemented by citation searching. RCTs comparing early rhEPO treatment with no treatment or placebo were selected if they were published in a peer-reviewed journal and reported ROP outcomes. Previously unpublished data were requested from the study authors to allow stratified analyses by gestational age (GA) and BW. Data were extracted and analyzed using the standard methods of the Cochrane Neonatal Review Group. Pre-specified outcomes were "ROP stage ≥3" (primary outcome) and "any ROP." RESULTS: Fourteen RCTs, comprising 2,040 infants of <29 weeks of GA, were included for meta-analysis. Data syntheses showed no effects of rhEPO on ROP stage ≥3 or on any ROP, neither in infants of <29 weeks GA, nor in infants of <1,000 g BW, nor in any GA strata. The risk ratio (95% confidence interval) for ROP stage ≥3 in infants of <29 weeks of GA was 1.13 (0.84, 1.53), p = 0.41 (quality of evidence: moderate). CONCLUSIONS: The present meta-analysis detected no effects of early rhEPO on ROP in any comparison, but most stratified analyses were limited by low statistical power.

Case Comparison of Preterm Infant Stability During Packed Red Blood Cell Transfusions.

BACKGROUND: Very preterm infants (less than 32 weeks gestational age) experience acute morbidity during their stay in a neonatal intensive care unit. Because of their prematurity and frequent laboratory testing, they experience anemia, requiring correction with packed red blood cell (PRBC) transfusion(s). PRBC transfusions have been linked to neonatal morbidity, such as necrotizing enterocolitis, but never signs and symptoms of physiological stability. OBJECTIVE: The secondary data analysis aimed to examine very preterm infants' physiological stability before, during, and after PRBC transfusions. METHODS: A within-case, mixed-methods design was used in a secondary data analysis for 16 transfusion cases from 13 very preterm infants. RESULTS: The findings showed very preterm infants with physiological variables falling within defined limits based on gestational age during the transfusion. Two contrasting case exemplars will be presented. DISCUSSION: PRBC transfusions are necessary and prevent morbidity in very preterm infants. Observing instability during transfusions and prospectively studying hypothermia, cardiac instability, and thermal gradients is essential to design interventions to decrease morbidity associated with PRBC transfusions.

Risk factors for anemia of prematurity among 30-35-week preterm infants.

BACKGROUND: The risk factors for anemia of prematurity (AOP) among late preterm infants are unelucidated. We identified risk factors for declining hemoglobin (Hb) concentration and triggering factors for AOP treatment in infants born at 30-35 gestational weeks. METHODS: From 2012 to 2020, we conducted a single-center retrospective study of infants born at 30-35 weeks of gestation without congenital anomalies or severe hemorrhage. The primary outcome was AOP development, defined by initiation of treatments including red blood cell transfusion, subcutaneous injections of erythropoietin, and iron supplementation. A multivariable logistic regression model was used to investigate potential risk factors for AOP. RESULTS: A total of 358 infants were included. Lower gestational age (odds ratio, 0.19; 95% confidence interval 0.11-0.32), small for gestational age (SGA; 7.17, 2.15-23.9), low maternal Hb level before birth (0.66, 0.49-0.87), low Hb at birth (0.71, 0.57-0.89), and multiple large blood samplings (1.79; 1.40-2.29) showed significantly higher odds for AOP development. CONCLUSIONS: Gestational age, SGA, low maternal Hb before birth, Hb at birth, and high number of large blood samplings were positively associated with AOP development in infants born at 30-35 gestational weeks.

Red Blood Cell Transfusion Thresholds for Anemia of Prematurity.

Anemia of prematurity affects the majority of preterm infants, particularly extremely low birthweight infants. Anemia of prematurity arises from both innate and iatrogenic causes and results in more than 80% of extremely preterm infants receiving red blood cell transfusions during the first month after birth. Multiple randomized controlled trials were conducted to evaluate the effect of using lower versus higher transfusion thresholds based on hemoglobin levels. These trials showed no difference in the primary outcome of neurodevelopmental impairment at 2 years of age between lower and higher thresholds. However, some uncertainties about transfusion thresholds remain. This review elaborates the following: 1) the etiology, prevention, and treatment of anemia of prematurity with a focus on red blood cell transfusions, 2) the history of randomized controlled trials on the treatment of anemia of prematurity, and 3) limitations of the evidence and remaining questions about thresholds for red blood cell transfusions in preterm infants.

Diagnosing Anemia in Neonates: An Evidence-Based Approach.

It is important for clinicians who render neonatal care to precisely and reproducibly diagnose anemia; however, confusion arises from various definitions. For the simplicity and consistency of detection, we advocate defining neonatal anemia as a hemoglobin level or hematocrit below the 5th percentile of the reference population, which is highly dependent on gestational and postnatal ages. Thus, a newborn infant delivered at 24 weeks' gestation will have anemia with a blood hemoglobin concentration much lower than a hemoglobin concentration defining anemia at term. Moreover, a hemoglobin concentration defining anemia at term birth is higher than that defining anemia in the same infant 60 days after birth. Diagnosing neonatal anemia can be evidence-based and consistent by using reference intervals derived from large neonatal databases. To do this, we advocate defining anemia as a hemoglobin level that plots below the 5th percentile lower reference interval, defining moderately severe anemia as a hemoglobin value between the 1st and 5th percentile, and defining severe anemia as a hemoglobin level that plots below the 1st percentile. The information provided in this review can easily be adopted by clinical laboratories and individual neonatal care units, thereby fostering application of these definitions for all infants whose hemoglobin levels are measured. Additional normative values included in this review describing various other erythrocyte metrics can likewise be easily adopted. Doing so will codify and standardize the diagnosis of neonatal anemia and will facilitate identifying the cause of the anemia, thus pointing the way to proper additional diagnostic testing and treatment.

Placental abruption and neonatal anemia.

OBJECTIVE: Placental abruption can cause maternal blood loss and maternal anemia. It is less certain whether abruption can cause fetal blood loss and neonatal anemia. STUDY DESIGN: Retrospective multi-hospital 24-month analysis of women with placental abruption and their neonates. RESULTS: Of 55,111 births, 678 (1.2%) had confirmed abruption; 83% of these neonates (564) had one or more hemoglobins recorded in the first day. Four-hundred-seventy (83.3%) had a normal hemoglobin (≥5th% reference interval) while 94 (16.7%) had anemia, relative risk 3.26 (95% CI, 2.66-4.01) vs. >360,000 neonates from previous reference interval reports. The relative risk of severe anemia (<1st% interval) was 4.96 (3.44-7.16). When the obstetrician identified the abruption as "small" or "marginal" the risk of anemia was insignificant. CONCLUSIONS: Most abruptions do not cause neonatal anemia but approximately 16% do. If an abruption is not documented as small, it is important to surveille the neonate for anemia.

Neonatal Anemia.

All neonates experience a downtrend in their hematocrit values immediately following the birth through normal falls in erythropoietin (Epo) production, transition to adult hemoglobin, and hemodilution with somatic growth. However, this drop is more pronounced in critically ill and preterm neonates and can lead to potentially pathologic anemia that impairs tissue oxygen delivery. In this review, we highlight the mechanisms underlying physiologic anemia and anemia of prematurity and briefly review the evidence for the treatment of anemia in the neonatal population, including the use of red blood cell transfusions, erythropoietic stimulating agents, and iron supplementation.

BORN study: a multicenter randomized trial investigating cord blood red blood cell transfusions to reduce the severity of retinopathy of prematurity in extremely low gestational age neonates.

BACKGROUND: Extremely low gestational age neonates (ELGANs, i.e., neonates born before 28 weeks of gestation) are at high risk of developing retinopathy of prematurity (ROP), with potential long-life visual impairment. Due to concomitant anemia, ELGANs need repeated red blood cell (RBC) transfusions. These produce a progressive replacement of fetal hemoglobin (HbF) by adult hemoglobin (HbA). Furthermore, a close association exists between low levels of HbF and severe ROP, suggesting that a perturbation of the HbF-mediated oxygen release may derange retinal angiogenesis and promote ROP. METHODS/DESIGN: BORN (umBilical blOod to tRansfuse preterm Neonates) is a multicenter double-blinded randomized controlled trial in ELGANs, to assess the effect of allogeneic cord blood RBC transfusions (CB-RBCs) on severe ROP development. Recruitment, consent, and randomization take place at 10 neonatology intensive care units (NICUs) of 8 Italian tertiary hospitals. ELGANs with gestational age at birth comprised between 24+0 and 27+6 weeks are randomly allocated into two groups: (1) standard RBC transfusions (adult-RBCs) (control arm) and (2) CB-RBCs (intervention arm). In case of transfusion need, enrolled patients receive transfusions according to the allocation arm, unless an ABO/RhD CB-RBC is unavailable. Nine Italian public CB banks cooperate to make available a suitable amount of CB-RBC units for all participating NICUs. The primary outcome is the incidence of severe ROP (stage 3 or higher) at discharge or 40 weeks of postmenstrual age, which occurs first. DISCUSSION: BORN is a groundbreaking trial, pioneering a new transfusion approach dedicated to ELGANs at high risk for severe ROP. In previous non-randomized trials, this transfusion approach was proven feasible and able to prevent the HbF decrease in patients requiring multiple transfusions. Should the BORN trial confirm the efficacy of CB-RBCs in reducing ROP severity, this transfusion strategy would become the preferential blood product to be used in severely preterm neonates. TRIAL REGISTRATION: ClinicalTrials.gov NCT05100212. Registered on October 29, 2021.

Immunologic effects of red blood cell and platelet transfusions in neonates.

PURPOSE OF REVIEW: Premature neonates are frequently transfused red blood cells (RBCs) or platelets to raise hemoglobin or platelet counts. However, these transfusions may have unintended effects on the immune system. This review will summarize the newest discoveries on the immunologic effects of RBC and platelet transfusions in neonates, and their potential impact on neonatal outcomes. RECENT FINDINGS: Neonatal RBC transfusions are associated with increases in plasma pro-inflammatory cytokines, but recent findings suggest sex-specific differential responses. At least one cytokine (monocyte chemoattractant protein-1) rises in females receiving RBC transfusions, but not in males. These inflammatory responses correlate with poorer neurodevelopmental outcomes in heavily transfused female infants, while preterm male infants seem to be more sensitive to severe anemia. Platelet transfusions in preterm neonates are associated with increased neonatal mortality and morbidity. The underlying mechanisms are unknown, but likely related to the immune/inflammatory effects of transfused platelets. Adult platelets are different from neonatal platelets, with the potential to be more pro-inflammatory. Early preclinical data suggest that platelet transfusions alter the neonatal systemic inflammatory response and enhance immune cell migration. SUMMARY: RBC and platelet transfusions alter neonatal immune and inflammatory responses. Their pro-inflammatory effects might worsen neonatal disease or affect neurodevelopmental outcomes.

Effect of placenta previa on umbilical cord hematocrit value.

OBJECTIVE: Placenta previa is one of the causes of neonatal anemia. This condition is mainly explained by antenatal hemorrhage and incision of the anteriorly located placenta during cesarean section. However, the mechanism of neonatal anemia in placenta previa has not been extensively studied or well elucidated. This study investigates whether placenta previa is associated with lower hematocrit levels in newborns with no antenatal hemorrhage and placental incision. KEY FINDINGS: This prospective study investigated 47 patients with previa and 43 control patients who gave birth with a cesarean section at 34-38 weeks of gestation. Blood samples were obtained from the fetal end of the umbilical vein. The mean umbilical cord hematocrit value was 49.3% in the control patients and 46.7% in the patients with previa, and the difference was statistically significant (p = .029). No significant association was observed between hematocrit value and birth weight, gestational age, newborn gender, placenta position, or preoperative maternal hemoglobin level. CONCLUSION: The study findings reveal that even if not complicated by antepartum or intrapartum hemorrhage, placenta previa may be associated with lower hematocrit values in newborns. Although in none of the cases, the umbilical cord hematocrit value was not as low as to be defined as anemia, this effect of previa on newborns should be considered because of the importance of iron status.

Packed red blood cell transfusion in preterm infants.

Premature infants commonly receive adult packed red blood cells (pRBCs) during their hospital stay. As adult erythrocytes differ substantially from those of preterm infants, transfusion of adult pRBCs into preterm infants can be considered inappropriate for the physiology of a preterm infant. An absence of standardisation of transfusion protocols makes it difficult to compare and interpret pertinent clinical data, as reflected by unclear associations between pRBC transfusion and complications related to prematurity, such as bronchopulmonary dysplasia, neurodevelopmental impairment, retinopathy of prematurity, or necrotising enterocolitis. The difficulty in interpreting clinical data is further increased by differences in study designs that either overestimate pRBC-associated complications of prematurity or have not yet been designed to directly link pRBC transfusions to their respective complications. Thus, neonatal transfusion practice has become an ongoing difficulty, in which differences in transfusion guidelines hinder the ability to generate comparable clinical data, and heterogeneity in clinical data prevents the implementation of standardised transfusion protocols. To overcome these issues, novel approaches with biochemical-clinical translational designs could enable clinicians to gather causal evidence instead of circumstantial correlation.

Does placental abruption cause neonatal anemia?

INTRODUCTION: Placental abruption can result in serious perinatal morbidity and mortality. However, it is not clear whether placental abruption could lead to neonatal anemia, as a direct relation has not been described yet. The objective of this study is to investigate whether there is a relation between occurrence of placental abruption and neonatal anemia. MATERIAL AND METHODS: All women with a clinical diagnoses of placental abruption between January 2016 and April 2021 in Amsterdam UMC, from both the VU University Medical Center and Amsterdam Medical Center, were included. Demographic data and delivery outcomes were collected retrospectively using the medical files. The primary outcome was neonatal anemia, defined as hemoglobin levels less than the fifth percentile for gestational age. RESULTS: A total of 65 mothers and 65 neonates were included in our study. Average gestational age was 30 + 5 weeks. Mean hemoglobin level of the neonates at birth was 16.5 g/dl (10.2 mmol/L) with hemoglobin levels comparable to the reference curve. Two neonates (3.6%) were diagnosed with anemia based on their hemoglobin level at birth, and six (9.2%) neonates received a blood transfusion within 24 h after birth. CONCLUSIONS: With this study, we found that the hemoglobin levels of the neonates born after placental abruption are comparable to the reference curve and do not show more neonates than expected below the fifth percentile for gestational age. It remains unclear whether there is fetal blood loss during a placental abruption but our results suggest that at least a big amount of fetal blood is not lost, since we did not found a large number of anemic neonates. Severe neonatal anemia in the case of placental abruption does not need to be expected.