Aberrant Hematopoiesis and Morbidity in Extremely Preterm Infants With Intrauterine Growth Restriction

Assessment of Hemostatic Profile in Neonates with Intrauterine Growth Restriction: A Systematic Review of Literature

Intrauterine growth restriction (IUGR) affects nearly 10 to 15% of pregnancies and is responsible for many short- and long-term adverse consequences, including hemostatic derangement. Both thrombotic and hemorrhagic events are described in the perinatal period in these neonates. The aim of this study was to systematically review the literature on the laboratory studies used to evaluate the hemostatic system of the IUGR small for gestational age neonate. We reviewed the current literature via PubMed and Scopus until September 2022. Following our inclusion/exclusion criteria, we finally included 60 studies in our review. Thrombocytopenia, characterized as hyporegenerative and a kinetic upshot of reduced platelet production due to in utero chronic hypoxia, was the main finding of most studies focusing on growth-restricted neonates, in most cases is mild and usually resolves spontaneously with the first 2 weeks of life. In regard to coagulation, growth-restricted newborns present with prolonged standard coagulation tests. Data regarding coagulation factors, fibrinolytic system, and anticoagulant proteins are scarce and conflicting, mainly due to confounding factors. As thromboelastography/rotational thromboelastometry (TEG/ROTEM) provides a more precise evaluation of the in vivo coagulation process compared with standard coagulation tests, its use in transfusion guidance is fundamental. Only one study regarding TEG/ROTEM was retrieved from this population, where no difference in ROTEM parameters compared with appropriate for gestational age neonates was found. Despite the laboratory aberrations, no correlation could be achieved with clinical manifestations of bleeding or thrombosis in the studies included. More studies are needed to assess hemostasis in IUGR neonates and guide targeted therapeutic interventions.

Hemostatic Profile of Intrauterine Growth-Restricted Neonates: Assessment with the Use of NATEM Assay in Cord Blood Samples

BACKGROUND

Intrauterine growth restriction (IUGR) is associated with hemorrhagic and thrombotic complications during the perinatal period. Thrombocytopenia, platelet dysfunction, and prolonged standard coagulation tests are observed in this population. The aim of this study is to examine the hemostatic profile of IUGR neonates with the use of a non-activated assay (NATEM) in cord blood samples.

METHODS

During an 18 month period, a NATEM ROTEM assay was performed on cord blood samples of 101 IUGR neonates. A total of 189 appropriate for gestational age (AGA) neonates were used as a control group. The NATEM variables recorded include the following: clotting time (CT); clot formation time (CFT); clot amplitude at 5, 10, and 20 min (A5, A10, A20); α-angle (a°); maximum clot firmness (MCF); lysis index at 30 and 60 min (LI30, LI60); and maximum clot elasticity (MCE).

RESULTS

IUGR neonates demonstrate a hypocoagulable state, with lower A5, A10, A2, MCF, and MCE values when compared to AGA. Using multiple linear regression, we determined IUGR as an independent factor influencing all NATEM parameters (except CT and LI30) exhibiting a hypocoagulable and hypofibrinolytic profile. Platelet count was positively correlated with A5, A10, A20, MCF, alpha angle, and MCE, and negatively correlated with CFT.

CONCLUSION

IUGR neonates appear with lower clot strength and elasticity and prolonged clot kinetics, as illustrated by ROTEM variables.

Hyper high haemoglobin content in red blood cells and erythropoietic transitions postnatally in infants of 22 to 26 weeks' gestation: a prospective cohort study

OBJECTIVE

Blood cell populations, including red blood cells (RBC) unique to the extremely preterm (EPT) infant, are potentially lost due to frequent clinical blood sampling during neonatal intensive care. Currently, neonatal RBC population heterogeneity is not described by measurement of total haemoglobin or haematocrit. We therefore aimed to describe a subpopulation of large RBCs with hyper high haemoglobin content, >49 pg (Hyper-He) following EPT birth.

DESIGN

Prospective observational cohort study.

SETTING

Two Swedish study centres.

PARTICIPANTS

Infants (n=62) born between gestational weeks 22+0 to 26+6.

METHODS

Prospective data (n=280) were collected from March 2020 to September 2022 as part of an ongoing randomised controlled trial. Blood was sampled from the umbilical cord, at postnatal day 1-14, 1 month, 40 weeks' postmenstrual age and at 3 months' corrected age.

RESULTS

At birth, there was a considerable inter-individual variation; Hyper-He ranging from 1.5% to 24.9% (median 7.0%). An inverse association with birth weight and gestational age was observed; Spearman's rho (CI) -0.38 (-0.63 to -0.07) and -0.39 (-0.65 to -0.05), respectively. Overall, Hyper-He rapidly decreased, only 0.6%-5.0% (median 2.2%) remaining 2 weeks postnatally. Adult levels (<1%) were reached at corresponding term age.

CONCLUSION

Our results point to gestational age and birth weight-dependent properties of the RBC population. Future work needs to verify results by different measurement techniques and elucidate the potential role of differing properties between endogenous and transfused RBCs in relation to neonatal morbidities during this important time frame of child development.

TRIAL REGISTRATION NUMBER

NCT04239690.

Neonatal hematological parameters: the translational aspect of developmental hematopoiesis

Hematopoiesis is a process constantly evolving from fetal life through adulthood. Neonates present with qualitative and quantitative differences in hematological parameters compared to older children and adults, reflecting developmental changes in hematopoiesis correlated with gestational age. Such differences are more intense for preterm and small-for-gestational-age neonates or neonates with intrauterine growth restriction. This review article is aimed at describing the hematologic differences among neonatal subgroups and the major underlying pathogenic mechanisms. Issues that should be taken into account when interpreting neonatal hematological parameters are also highlighted.

Implications of an Elevated Nucleated Red Blood Cell Count in Neonates with Moderate to Severe Hypoxic-Ischemic Encephalopathy

OBJECTIVES

To investigate associations between nucleated red blood cell (NRBC) count in neonates with hypoxic-ischemic encephalopathy (HIE), acute perinatal sentinel events, and neurodevelopmental outcomes and to examine the mechanism(s) causing elevated counts.

STUDY DESIGN

We included newborn infants with HIE treated with therapeutic hypothermia with ≥3 NRBC counts during their neonatal intensive care unit hospitalization and neurodevelopmental evaluations at a mean of 24 ± 6 months.

RESULTS

Ninety-five of 152 infants who met our study criteria (63%) had a normal NRBC count after birth, defined as ≤95th percentile of the upper reference interval, and the other 57 (37%) had an elevated count. Documented sentinel events during labor resulting in emergency delivery (eg, acute abruption) (n = 79) were associated with a normal NRBC count (OR, 257; 95% CI, 33-1988). Of the 152 infants evaluated, 134 (88%) survived to discharge. The odds of surviving were 3-fold greater (OR, 3.0; 95% CI, 1.1-8.3) when the first NRBC count was normal than when it was elevated. Normal counts were moderately predictive of infants without neurodevelopmental impairment at a 2-year evaluation (P < .001). NRBC half-life was longer in infants with an elevated NRBC count compared with those with a normal count (60 hours vs 39 hours; P < .01).

CONCLUSIONS

In infants with HIE, a normal NRBC count after birth was associated with acute intrapartum events necessitating emergent delivery. Normal counts were modestly predictive of a better prognosis. We speculate that the elevated NRBC counts at birth resulted from hypoxia that occurred earlier or chronically. Impaired clearance of NRBCs from the blood might be one mechanistic explanation for the high counts.

Perinatale Palliativmedizin: Wie ist der weltweite Forschungsstand?

Laut Weltgesundheitsorganisation verstarben im Jahr 2019 etwa 2,4 Millionen Kinder während der Neonatalperiode. Um Feten bzw. Neugeborene mit infauster Prognose sowie die betroffenen Familien bestmöglich betreuen zu können, ist eine gut ausgebaute perinatale Palliativversorgung, welche sowohl die prä- als auch die postnatale Periode umfasst, wichtig. Welche Forschungsanstrengungen wurden seit der Jahrtausendwende auf diesem Gebiet unternommen?

Hämatopoese und Morbidität intrauterin wachstumsretardierter Frühgeborener

Aufgrund einer uteroplazentaren Dysfunktion mangelversorgte Feten können ihr biologisches Wachstumspotenzial nicht ausschöpfen und entwickeln eine intrauterine Wachstumsrestriktion. Der chronische Sauerstoffmangel bringt zudem das blutbildende System aus dem Gleichgewicht. Welche hämatopoetischen Veränderungen weisen wachstumsretardierte, extrem unreife Frühgeborene auf? Und welche Komplikationen drohen bei dieser Konstellation?