Nucleated red blood cells: a marker for fetal asphyxia?

NRBC concentrations over time in neonates with moderate to severe neonatal encephalopathy with and without sentinel events

OBJECTIVE

To study the serum concentrations of nucleated red blood cells (NRBC) over time in neonates with moderate to severe neonatal encephalopathy (NE).

STUDY DESIGN

A retrospective cohort study with subjects subdivided into three groups: definite sentinel events (n = 52), probable sentinel events (n = 20) and no history of sentinel events (n = 63). Peak absolute NRBC and NRBC/100 WBC were compared between groups and with MRI Injury score, cord and admission pH/base deficit.

RESULTS

Absolute NRBC peaked at 24.05 h after birth (CI: 15.30-32.79), 17.56 h after birth (CI: 7.35-27.77), and 39.81 h after birth (CI: 28.73-50.89) in each respective group. The peak in absolute NRBC correlated with the severity of injury in the grey matter in group 2 and white matter in groups 1 and 2. Higher peak absolute NRBC value correlated to a lower admission ABG pH.

CONCLUSION

NRBC peak at 24 h after birth in neonates with sentinel events.

Effects of ketamine on the fetal transcriptomic response to umbilical cord occlusion: comparison with hypoxic hypoxia in the cerebral cortex

KEY POINTS

The cerebral response to fetal asphyxia is characterized by an upregulation of nucleic acid and chromatin modification processes, as well as a downregulation of metabolic processes at 1 h post-umbilical cord occlusion (UCO). Twenty-four hours post UCO, there was an upregulation of metabolic processes and protein modifications. UCO did not alter bacterial gene expression levels, nor did it produce a robust inflammatory response compared to maternal hypoxia. The administration of ketamine produced minimal effects on the fetal response to UCO in the cerebral cortex.

ABSTRACT

Umbilical cord occlusion (UCO) is known to cause neurological disorders in the neonate. Previously, we have reported that hypoxic hypoxia (HH) stimulates the appearance of bacteria in the fetal brain and upregulates the expression of inflammatory markers in fetal cerebral cortex (CTX) and also that ketamine attenuates these responses. In the present study, we aimed to test the hypothesis that UCO, similar to HH, produces an inflammatory response in the fetal CTX and also that treatment with ketamine reduces these effects. In chronically instrumented fetal sheep (∼125 days), 30 min of partial UCO decreased fetal P a O 2 levels by ∼50%. Half of the fetuses received ketamine (3 mg kg^-1 ) 10 min prior to UCO (n = 4 per group). Fetal brains were collected 1 and 24 h after the experiment and mRNA was extracted and hybridized for microarray analyses. Differentially-expressed genes were analysed for significant association with gene ontologies and pathways. After 1 h, UCO upregulated nucleic acid processing and chromatin modification and downregulated metabolic processes compared to control. After 24 h, UCO upregulated metabolic and protein modification processes. Ketamine produced minimal effects. UCO did not alter the abundance of bacterial DNA in fetal brain, nor did it upregulate inflammation pathways compared to HH. We conclude that UCO produced time-dependent responses that did not include bacterial invasion or upregulation of inflammation pathways in fetal CTX. This contrasts with the response to HH, which resulted in the appearance of bacteria in the CTX and upregulated inflammation pathways. These responses in fetal CTX to oxygen deprivation are therefore modified by the maternal or placental response to the stimulus.

Nucleated Red Blood Cells as a Marker of Acute and Chronic Fetal Hypoxia in a Rat Model

OBJECTIVE

To examine the relationship between duration of fetal hypoxia, nucleated red blood cell (NRBC) count, and fetal growth.

METHODS

Pregnant rats were exposed to a severe hypoxia (9.5%-10% O₂) for varying time intervals (2, 6, 12, 24, 48, and 120 hours; n=4 for each time interval) immediately prior to delivery at term. Normoxic controls were exposed to room air (21% O₂) and matched for all other study variables (n=4 rats for each time interval). Pups were delivered via hysterotomy while maintaining exposure gas concentrations. Blood gas analysis and NRBC counts were performed, and fetal body and liver weights were recorded. Student's t test and simple regression were used for statistical analysis.

RESULTS

As the duration of hypoxia increased, fetal weight, liver weight, blood bicarbonate, and base excess levels decreased significantly; concomitantly, NRBC counts increased. This increase in NRBCs became statistically significant after 24 hours of exposure. After 48 hours of hypoxia there was a 2.5-fold rise in NRBC count, and after 120 hours of hypoxia there was a 4.5-fold rise in NRBC count over control levels. After 12 or more hours of hypoxia, fetal body weights were significantly reduced; 120 hours of hypoxia resulted in a 35% reduction in fetal body weight, a 34% reduction in fetal liver weight, and 356% increase in NRBC count.

CONCLUSION

In a pregnant rat model, chronic maternal hypoxia (≥24 hours) results in a significant increase in fetal NRBC counts as well as reduced fetal body weight and organ growth.

Hematological changes in severe early onset growth-restricted fetuses with absent and reversed end-diastolic flow in the umbilical artery

BACKGROUND

Erythropoietin seems to play an important role in the regulation of fetal hypoxemia. The present prospective study was designed to determine if changes in erythropoietin levels can be found in fetuses with severe early-onset growth restriction and hemodynamic compromise.

METHODS AND RESULTS

Erythropoietin, hemoglobin, hematocrit, platelet counts, normoblasts, lacate, arterial and venous blood gasses in the umbilical cord were determined in 42 fetuses with fetal growth restriction (IUGR) with absent (zero-flow) and 26 IUGR fetuses with retrograde end-diastolic flow (reverse-flow) in the umbilical artery. Color Doppler measurements were performed on the middle cerebral artery (PI) and ductus venosus [(S-a)/D and (S-a)/Vmean]. Erythropoietin concentrations were significantly lower in the zero-flow group (median: 128.0 mU/mL; range: 60.3-213 mU/mL) compared with the reverse-flow group (median: 202.5 mU/mL; range: 166-1182 mU/mL). Significant differences in median lactate concentrations were observed between the zero-flow group: 3.28 mmol/L (range; 2.3-4.7 mmol/L), and reverse-flow group: 5.6 mmol/L (range: 3.8-7.5 mmol/L). Fetuses with reverse-flow had significantly lower median platelet counts than fetuses with zero-flow (74 vs. 155/μL) and significantly lower normoblast counts (63 vs. 342/100 WBC).

CONCLUSIONS

Fetuses with severe IUGR due to chronic placental insufficiency and absent or reversed flow in the umbilical artery show increased erythropoietin levels.

Nucleated red blood cells count as a prognostic biomarker in predicting the complications of asphyxia in neonates

OBJECTIVE

Nucleated-red-blood-cells (NRBC) count in umbilical cord of newborns is been suggested as a sign of birth asphyxia. The present study was conducted to explore the value of NRBC count in prognosis of asphyxiated neonates.

METHODS

Sixty-three neonates with asphyxia were followed up for two years. Maternal and neonatal information was recorded follow by clinical and laboratory evaluation. NRBC-level was determined per 100 white-blood-cells (WBC). After discharge, follow-up of asphyxiated infants was performed using Denver II test at 6, 12, 18 and 24 months. Neonates were divided into two groups, with favorable and unfavorable outcome based on developmental delay or death.

RESULTS

We observed that NRBC count with more than 11 per 100 WBC, had sensitivity of 85% and specificity of 90% in predicting complications of asphyxia, while in absolute NRBC count with more than 1554, the sensitivity and specificity were 85% and of 87%, respectively. Combination of NRBC + HIE (hypoxic ischemic encephalopathy) grade had a high-predictive power for determining the prognosis of asphyxia in neonates.

CONCLUSION

We demonstrate that NRBC/100 WBC and absolute NRCB count can be used as prognostic marker for neonatal asphyxia, which in combination with the severity of asphyxia could indicate high infant mortality, and complications of asphyxia. Further studies in a larger and multi center setting trail are warranted to investigate the value of NRBC and HIE in asphyxiate term infants.

Persistent increase in red cell size distribution width after acute diseases: A biomarker of hypoxemia?

BACKGROUND

A biomarker of hypoxic exposure would be useful in clinical diagnosis and prognosis. Acute hypoxia stimulates large increases in serum erythropoietin (EPO), and EPO induces formation of characteristic enlarged red blood cells (RBCs). The presence of large RBCs perturbs red cell distribution width (RDW).

METHODS

Using a >2M patient medical claims database, the human pathome was scanned for diseases where RDW rose 0-50days following a new diagnosis. The course of RDW after selected diagnoses was visualized by registering RDW measurements by diagnosis date.

RESULTS

Acute hemorrhage, which provokes EPO-driven erythropoiesis, is followed by increases in RDW but not mean cell volume (MCV). Similar RDW increases follow many acute diseases with risk of hypoxia, including heart failure, pneumonia, atelectasis, pulmonary embolism, pneumothorax, and sepsis. Elevations reach maximum within 1month after onset and subside to pre-disease levels about 6months later. Unlike the case with iron-deficiency anemia (IDA), RDW elevations after hypoxia-associated diseases are unaccompanied by discernible change in average RBC size.

CONCLUSIONS

As predicted by a model risk pathway linking hypoxia to formation of enlarged RBCs via EPO, acute hypoxemia-related disease episodes induce change in RBC size distribution. Further study is needed to explore whether a more sensitive and specific signal can be extracted from the fine structure of the RBC size distribution routinely measured in automated hemocytometers.

Nucleated red blood cell counts: an early predictor of brain injury and 2-year outcome in neonates with hypoxic-ischemic encephalopathy in the era of cooling-based treatment

BACKGROUND

Raised nucleated red blood cell (NRBC) counts in neonates may indicate in utero hypoxia and brain damage.

OBJECTIVE

The study aimed to examine the use of NRBC counts as a predictor of brain injury and neurodevelopmental outcomes in neonates with hypoxic-ischemic encephalopathy (HIE) treated under current cooling-based strategy.

METHODS

Forty-three neonates with asphyxia between 2004 and 2010 were retrospectively investigated. Twenty neonates with moderate/severe HIE underwent hypothermia (HT), and 23 with mild HIE were treated in normothermia (NT). Neonates were divided into groups according to the presence of cerebral parenchymal lesions on magnetic resonance imaging (MRI) at 2 weeks after birth. All patients were followed-up neurologically for ⩾ 24 months. NRBC counts during the first 3 days were compared between groups.

RESULTS

Eleven HT (HT-N) and 21 NT (NT-N) neonates had normal MRI, and 9 HT (HT-L) and 2 NT (NT-L) neonates had parenchymal lesions. NRBC counts, both absolute and /100 white blood cells (WBC) counts, during the first 3 days in HT-L and NT-L were significantly higher than those in HT-N and NT-N, particularly within 6 hours after birth (HT-N: 502 [0-3060]/mm(3) vs HT-L: 2765 [496-6192]; 0 [0-3417] vs NT-L: 4384 [3978-4789], median [range]). Neonates with /100 white blood cells ⩾ 6/mm(3) and absolute NRBC counts ⩾ 1324/mm(3) within 6 hours of birth had high risks of abnormal MRIs and 2-year outcomes.

CONCLUSIONS

NRBC counts can predict brain injury and neurological outcomes in cooled and non-cooled asphyxiated neonates.

Follow-up study of lympho-histiocytic villitis and incidental retroplacental hematoma

Placentas are usually submitted for pathologic examination based on obstetrical indications. We hypothesized that the placenta may have diagnostic value to the infant independent of obstetrical events. We specifically tested whether lymphohistiocytic villitis (noninfectious) would predict autoimmune or alloimmune disease based on transfer of activated maternal T-cells to the fetus and whether clinically silent placental separations (retroplacental hematomas, RPH) would predict neurologic injury in the infant. All placentas from consecutive deliveries had a routine pathologic examination of the placenta. The infants with placentas demonstrating inflammation of >1% of villi or RPH >2 cm and matched controls had their hospital charts reviewed and parental interviews by telephone at 5 to 7 years of age. The children of consented patients were also searched for in the office visits of the University of Louisville Pediatric Neurology and Rheumatology divisions. One thousand six hundred eighty-four patients consented to the follow-up study. We found no cases of autoimmune disease among 17 children with villitis >1%. Of 16 infants with RPH, 1 had cerebral palsy but with other placental findings, 1 had lethal hydranenecephaly, and the remainder had no adverse outcome. Of 15 children seen by a pediatric neurologist, none had the same placental lesion. The specific lesions of lymphohistiocytic villitis or asymptomatic RPH do not predict significant pediatric disease by 7 years of age. At least for these 2 lesions, the placenta does not have diagnostic value to the infant.

Nucleated red blood cell in cord blood as a marker of perinatal asphyxia

BACKGROUND

Perinatal asphyxia is a major cause of neurological morbidity and mortality in India. The purpose of this study was to investigate variations in nucleated red blood cell (NRBC) in blood associated with perinatal asphyxia and its relationship to both the severity and short term prognosis of asphyxia.

METHODS

A prospective (case-control) study was undertaken at Gandhi Medical College and Associated Hospitals. A total of 100 neonates were included in the study. Levels of NRBC/100 white blood cells (WBC) and absolute NRBC counts in cord blood were compared for 50 asphyxiated (case group) and 50 normal neonates (control group). These parameters were also related to the severity of asphyxia and clinical outcome.

RESULTS

The number of NRBC/100 WBC in the blood of 50 newborns each in the asphyxiated and in the control group were mean 29.5 ± 26.0, range 7-144 NRBCs/100 WBC and mean ± standard deviation 5.9 ± 2.6, range 3-14 NRBCs/100 WBC respectively (P < 0.01). Using quartile deviation, staging of hypoxic ischemic encephalopathy (HIE) was done on basis of NRBC count and there was 80% agreement between clinical and NRBC staging of HIE. There was a significant (P < 0.01) correlation of the number of NRBC\100 WBC with Apgar scoring, HIE staging and mortality.

CONCLUSIONS

The NRBCs/100 WBCs can be used as a simple marker for the assessment of severity and early outcome of perinatal asphyxia.

Third trimester fetal demise occurring at time of delivery: correlation of autopsy findings and placental pathology with emphasis on antenatal central nervous system injury

OBJECTIVE

Third trimester fetal deaths occurring in the hospital at the time of delivery are unusual. We report an autopsy series of such cases with emphasis on neuropathological injury and other lesions predating delivery.

METHODS

We identified autopsies performed on third trimester fetuses documented to be alive shortly before delivery, but that expired during, or very close to, time of delivery, and we correlate autopsy and placental findings. Fetuses with major congenital anomalies were excluded.

RESULTS

Ten cases were identified (6 term, 4 preterm). All were delivered by cesarean section and had attempted resuscitation. Established or recent brain injury was identified in 9 of 10 cases, including 3 with established neuronal damage and 1 with periventricular leukomalacia. Additional autopsy findings included thymic involution in eight (five mild; three severe), myocardial infarcts in two; intrathoracic petechiae in five, and ascites or pleural or pericardial effusions in six. Severe thymic involution and myocardial infarcts correlated with established brain injury. Placental lesions adaptive to decreased oxygenation (increased nucleated red blood cells or villous hypervascularity) were seen in five cases and correlated with established brain injury. Acute chorioamnionitis with funisitis was present in one, and chronic inflammatory placental lesions were present in six.

CONCLUSIONS

These findings indicate brain injury predated the time period immediately before delivery in 9 of 10 fetuses, and in the fetuses with established brain injury the onset of acute illness was possibly >72 h before delivery.

Understanding cardiotocographic patterns associated with intrapartum fetal hypoxia and neurologic injury

Widespread use of fetal heart rate monitoring for intrapartum fetal surveillance preceded our detailed understanding of the behaviour and regulation of the fetal cardiovascular system during labour. The fetal heart rate is sensitive to fetal hypoxaemia and hypoxia, but lacks specificity for fetal acidosis, the end point of unmitigated hypoxaemia and hypoxia. Original interpretations of fetal heart rate patterns equated decelerations to 'fetal distress' and mandated operative intervention. Since then, obstetricians have been trained to focus on the morphological appearances of fetal heart rate decelerations rather than to understand the underlying physiological mechanisms, how the fetus compensates and defends itself, and those patterns that suggest progressive loss of compensation. Consequently, operative interventions are commonly undertaken to 'rescue' fetuses that display benign signs of fetal heart rate adaption to events in labour. Failure to recognise abnormal fetal heart rate patterns remains the leading cause of avoidable brain injury and litigation. In this chapter the general characteristics of the fetal heart rate, the changes in fetal heart rate pattern that may occur during labour, and the patterns that suggest failure of the fetal compensatory mechanisms leading to injury are discussed.

Early assessment of the severity of asphyxia in term newborns using parameters of blood count

Acute perinatal asphyxia is a major cause of death and neurological injury in newborn infants. Severe asphyxia can occur in infants around the time of birth for several reasons. The aim of our study was to find the most sensitive, easily obtainable and fast assessable parameter of the presence and quantification of asphyxia.

In our study 39 term newborns (15 healthy term newborns and 24 asphyxial term newborns), from vaginal deliveries admitted within 24 hours of life were monitored and parameters of blood count from venous blood were assessed. Laboratory findings of blood count parameters revealed significant differences between term asphyxial and healthy newborns in erythrocyte count and hemoglobin and hematocrit values.

Hematological changes observed early after delivery can determine the duration of hypoxemia (acute vs. chronic) and asphyxia of short duration may be accompanied without occurrence of polyglobulia.

Nucleated red blood cells and early EEG: predicting Sarnat stage and two year outcome

AIMS

Hypoxic Ischaemic Encephalopathy (HIE) causes characteristic changes of the electroencephalogram (EEG), and a raised Nucleated Red Blood Cell (NRBC) count compared to controls. We wished to examine whether combining these markers could improve their ability to predict HIE severity in the first 24h.

METHODS

Term infants with HIE were recruited. NRBC count and continuous multi-channel EEG were recorded within the first 24h. Neurological assessment was carried out at 24 months. A control population with NRBC counts in the first 24h was recruited.

RESULTS

44 infants with HIE and 43 control infants were recruited. Of the HIE population 39 completed a 2 year follow-up. The median NRBC count differed significantly between the controls and those with HIE (3/100 WBC [range of 0-11] vs 12.3/100 WBC [0-240]) (p<0.001). Within the HIE population the median NRBC count was significantly greater in infants with moderate/severe HIE than mild (16/100 WBC [range of 0-240] vs 8/100 WBC [1-23]) (p=0.016), and among infants with abnormal outcome compared to normal (21.3/100 WBC [1-239.8] vs 8.3/100 WBC [0-50])(p=0.03). The predictive ability of EEG changed with time post-delivery, therefore results are given at both 12 and 24h of age. At both time points the combined marker had a stronger correlation than EEG alone; with HIE severity (12h: r=0.661 vs r=0.622), (24h: r=0.645 vs r=0.598), and with outcome at 2 years (12h: r=0.756 vs r=0.652), (24h: r=0.802 vs r=0.746).

CONCLUSION

Combining early EEG and NRBC count to predict HIE severity and neurological outcome, improved the predictive ability of either in isolation.

Perinatal asphyxia is associated with the umbilical cord nucleated red blood cell count in pre-eclamptic pregnancies

Nucleated red blood cells are commonly present in the blood of newborns. Our objective was to investigate the value of umbilical cord nucleated red blood cell (NRBC) count in predicting fetal asphyxia in pre-eclamptic women. NRBCs were counted in umbilical cord blood samples of neonates born to 43 pre-eclamptic and 25 healthy pregnant women. Pre-eclamptic women were further subgrouped based on the presence or absence of intrauterine growth restriction. The NRBC count differed significantly between pre-eclamptic women with and without intrauterine growth restriction, and controls (26.3 +/- 7.5; 17.1 +/- 6.8; and 9.9 +/- 2.7; p < 0.001). A NRBC count of 18.5 or above could predict fetal asphyxia with a sensitivity of 94.4% and a specificity of 80.0%. The umbilical cord NRBC count is effective in predicting fetal asphyxia in pre-eclamptic women.

Response of leukocytes and nucleated red blood cells in very low-birth weight preterm infants after exposure to intrauterine inflammation

OBJECTIVES

To test the hypothesis if very immature preterm infants exposed to chorioamnionitis would exhibit increased numbers of leukocytes, neutrophils, and nucleated red blood cells (NRBC) in peripheral blood.

STUDY DESIGN

Preterm infants with birth weight <1500 g were prospectively evaluated. Blood cells were counted within the first hour of life in infants exposed to histological chorioamnionitis and controls.

RESULTS

Birth weight, gestational age, and sex did not differ between the groups (n = 71). Seventeen infants who were exposed to chorioamnionitis had significantly higher counts of leukocytes, neutrophils, and immature neutrophils after birth. However, there was no difference in the number of circulating NRBCs between both groups. In contrast, there was a tendency towards an increased NRBC count in the control group.

CONCLUSION

Preterm infants exposed to chorioamnionitis elicited a strong inflammatory response as reflected by increased numbers of leukocytes and neutrophils. However, chorioamnionitis did not induce an increase in numbers of NRBC.

Nucleated red blood cell and platelet counts in asphyxiated neonates sufficient to result in permanent neurologic impairment

OBJECTIVE

Recent research has suggested that a nucleated red blood cell (NRBC) count >or=26 per 100 white blood cells (%) or the development of a platelet count <or=100,000 per mm(3) within five days of birth is characteristic of neonates who have experienced acute birth asphyxia.

STUDY DESIGN

Study cases were from the population defined in a prior publication (Prenat Neonat Med 1997;2:286). The impaired neonates were separated into three groups: group 1, persistent non-reactive fetal heart rate (FHR) pattern from admission until delivery; group 2, reactive FHR pattern on admission followed by a tachycardia, non-reactivity, repetitive variable or late decelerations, and usually a loss of variability; group 3, cases with a reactive FHR pattern on admission followed by a sudden, rapid and sustained deterioration of the FHR usually in response to a hypoxic sentinel event that lasted until delivery or a bradycardia on admission. The FHR pattern in group 3 is considered most consistent with acute birth asphyxia. We then examined these FHR groups with respect to the presence of hematologic injury. Chi-square testing was used to describe differences among the study populations.

RESULTS

Of the original 52 cases, sufficient hematologic data were available for 47. Of these, the proportion of cases with NRBC >or=26% was: group 1, 10/21 (47.6%); group 2, 0/14 (0%); group 3, 0/12 (0%). Those with a platelet count <or=100,000 per mm(3): group 1, 11/21 (52.4%); group 2, 2/14 (14.3%); group 3, 0/12 (0%). Group 1 was significantly more likely to have an NRBC count >or=26% than group 3 (p = 0.0135). A platelet count <or=100,000 per mm(3) within five days of birth was also significantly more likely to be encountered in group 1 as compared with group 3 (p = 0.0072).

CONCLUSION

In cases of acute birth asphyxia, hematologic injury was infrequently encountered. Our findings suggest that a neonatal NRBC count >or=26% and/or a platelet count <or=100,000 per mm(3) within five days of birth is inconsistent with acute birth asphyxia.

The combined detection of umbilical cord nucleated red blood cells and lactate: early prediction of neonatal hypoxic ischemic encephalopathy

OBJECTIVE

To establish a simple and quick method that could be used to predict the occurrence of hypoxic ischemic encephalopathy (HIE) as early as possible by investigating the variations of nucleated red blood cells per 100 white blood cell (NRBC/100 WBC) counts and lactate levels in cord blood.

METHODS

In 46 cases of acute fetal distress (AFD) and 54 cases of chronic fetal distress (CFD) neonates we measured the percentage (NRBCs/100 WBC) and lactate in the umbilical blood.

RESULTS

Both lactate levels and NRBC/100WBC counts were higher in CFD and AFD groups than in controls (both P<0.01). The numbers of NRBC/100 WBC and the values of lactate in moderate-severe HIE group were higher than in mild-HIE group (P=0.002 and P=0.042, respectively). The combined sensitivity and specificity was 94% and 96% at 15NRBC/100WBC and 4.25 mmol/L level by combined detecting NRBC and lactate to predict HIE. Three infants (including 1 death and 2 survivors) had the highest levels of NRBC/100WBC and lactate in cord blood, and the 2 survivors had the lowest mental development index (MDI) and psychomotor development index (PDI).

CONCLUSIONS

Combined detection with NRBC/100WBC and lactate allows early prediction of development and severity of HIE. The levels of these parameters are related to the neurodevelopment outcome of HIE infants.

Birthweights in sickle cell trait pregnancies

OBJECTIVES

Available evidence on the effect of sickle cell trait (SCT) on birthweight is conflicting, not gestational age specific, and does not account for maternal and infant factors. The objectives of this study are to determine the contemporary mean birthweight, mean customised birthweight centile, and to analyse the risk of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) babies in SCT pregnancies.

DESIGN

Large retrospective cohort study.

SETTING

London hospital.

POPULATION

Singleton pregnancies between 24 and 42 completed weeks delivered between 2000 and 2005 in parturient with body mass index between 18.0 and 35.0 kg/m(2).

METHODS

All qualifying pregnancies were identified on Terra Nova Healthware. Birthweight centiles of these cases were computed with Gardosi customised bulk centile calculator using collected data on maternal height, weight, ethnicity and parity, and the infant's gender, gestational age and birthweight. Birthweight and birthweight centiles of SCT and pregnancies with no haemoglobinopathy (control) were compared. Statistical analysis was performed using Stata version 9.2.

MAIN OUTCOME MEASURES

Birthweight and birthweight centiles.

RESULTS

Five hundred and five SCT and 16 320 controls were analysed. The mean birthweight of SCT pregnancies was 3223 g, 57 g lower than controls (P = 0.024). However, its mean birthweight centile was 49.0% similar to that of controls' 47.5% (P = 0.320). There is an apparent risk of LGA babies in SCT pregnancies, but logistic regression analysis suggests that the odds are related to being an older non-white parturient and a male infant rather than SCT status.

CONCLUSIONS

SCT is not a risk factor for SGA or LGA infants.

Nucleated red blood cells are a direct response to mediators of inflammation in newborns with early-onset neonatal sepsis

OBJECTIVE

The objective of the study was to test the hypothesis that inflammation modulates fetal erythroblastosis and/or the release of nucleated red blood cells (NRBCs) independent of hypoxia or fetal stress. We sought to determine whether fetal inflammation is associated with an elevation in neonatal NRBC count in the setting of inflammation-associated preterm birth.

STUDY DESIGN

The relationships between peripheral NRBC count, histological chorioamnionitis, umbilical cord interleukin (IL)-6, erythropoietin (EPO), cortisol, and acid-base status were analyzed in 68 preterm singletons, born to mothers who had an amniocentesis to rule out infection. Proteomic profiling of amniotic fluid identified presence of intraamniotic inflammation according to established parameters. NRBC counts were assessed within 1 hour of birth. Early-onset neonatal sepsis (EONS) was established based on hematological and microbiological indices. IL-6, EPO, and cortisol levels were measured by immunoassays. Fetal acid-base status was determined within 10 minutes of delivery. Parametric or nonparametric statistics were used.

RESULTS

Fetuses with EONS (n = 19) were delivered at earlier gestational ages (mean +/- SD: 27.1 +/- 2.8 weeks, P = .001) and more often by mothers with intraamniotic inflammation (P = .022) and histological chorioamnionitis (P < .001). Neonates with EONS had higher absolute NRBC counts (P = .011). NRBC counts were directly correlated with cord blood IL-6 levels (P < .001) but not with EPO, cortisol or parameters of acid-base status levels regardless of EONS status. These relationships remained following correction for gestational age, diabetes, intrauterine growth restriction, and steroid exposure.

CONCLUSION

In the setting of inflammation-associated preterm birth and in the absence of hypoxia, elevations in NRBCs in the early neonatal period may be a direct response of exposure to inflammatory mediators in utero.

Nucleated red blood cell counts in the first week of life: a critical appraisal of relationships with perinatal outcome in preterm growth-restricted neonates

OBJECTIVE

Nucleated red blood cells (NRBC) are fetal hematologic markers for placental dysfunction, hypoxemia, and asphyxia. NRBC count elevation at birth or persistence is linked statistically to adverse outcome, but clinical predictive value is variable. We studied novel indices to better define overall magnitude of NRBC response.

STUDY DESIGN

Peripheral NRBC count was obtained from preterm (<34 weeks of gestation) growth-restricted neonates within 2 hours of life. Daily counts and duration of NRBC count >30/100 white blood cells were determined. Mean counts (NRBC-mean), area under the curve (NRBC-AUC), and declination (NRBC-slope) were analyzed over week 1. NRBC parameters were related to major morbidity (bronchopulmonary dysplasia, grade III/IV intraventricular hemorrhage, necrotizing enterocolitis included) and neonatal death (NND).

RESULTS

Twenty-two of 176 patients (12.5%) had acidosis. Complications included bronchopulmonary dysplasia (n = 36; 20.5%), intraventricular hemorrhage (n = 18; 10.2%), necrotizing enterocolitis (n = 18; 10.2%), NND (n = 18; 10.2%). NRBC-AUC and NRBC-mean correlated most strongly with pH, birthweight, and gestational age (Pearson coefficient -0.45 to -0.18; all P < .001). NRBC-AUC varied most between nonmorbid and morbid; NRBC-mean varied most between survivors and NND (all P < .001). NRBC persistence strongly predicted NND: clearance by day 4 was achieved by 80% of survivors and only 35% of NNDs. Logistic regression identified prematurity and persistent NRBC counts as primary morbidity determinants (r2 = 0.56; P < .01). Although the importance of individual NRBC counts varied, day-4 NRBC counts of >70 predicted morbidity best (sensitivity, 82%; specificity, 96%). Presence of morbidity and birthweight were prime determinants of death (r2 = 0.42; P < .01).

CONCLUSION

Simple daily NRBC counts provide clinical information that is equivalent to more complicated methods. The importance of prematurity and growth are emphasized, but elevated NRBC counts beyond day 3 are relevant independent predictors of adverse outcome.

The Timing of Neonatal Brain Damage

Although neonatal morbidity and mortality are less than in the past, the risk of pre-natal and neonatal brain damage has not been eliminated. In order to optimize pre-natal, perinatal and neonatal care, it is necessary to detect factors responsible for brain damage and obtain information about their timing. Knowledge of the timing of asphyxia, infections and circulatory abnormalities would enable obstetricians and neonatologists to improve prevention in pre-term and full-term neonates. Cardiotocography has been criticized as being too indirect a sign of fetal condition and as having various technical pitfalls, though its reliability seems to be improved by association with pulse oximetry, fetal blood pH and electrocardiography. Neuroimaging is particularly useful to determine the timing of hypoxic-ischemic brain damage. Cranial ultrasound has been used to determine the type and evolution of brain damage. Magnetic resonance has also been used to detect antenatal, perinatal and neonatal abnormalities and timing on the basis of standardized assessment of brain maturation. Advances in the interpretation of neonatal electroencephalograms have also made this technique useful for determining the timing of brain lesions. Nucleated red blood cell count in cord blood has been recognized as an important indication of the timing of pre-natal hypoxia, and even abnormal lymphocyte and thrombocyte counts may be used to establish pre-natal asphyxia. Cord blood pH and base excess are well-known markers of fetal hypoxia, but are best combined with heart rate and blood pressure. Other markers of fetal and neonatal hypoxia useful for determining the timing of brain damage are assays of lactate and markers of oxidative stress in cord blood and neonatal blood. Cytokines in blood and amniotic fluid may indicate chorioamnionitis or post-natal infections. The determination of activin and protein S100 has also been proposed. Obstetricians and neonatologists can therefore now rely on various methods for monitoring the risk of brain damage in the antenatal and post-natal periods.

Umbilical cord nucleated red blood cell counts: normal values and the effect of labor

OBJECTIVE

To determine the umbilical cord blood nucleated red blood cell (UC-nRBC) count in uncomplicated pregnancies delivered by elective cesarean section or delivered vaginally.

METHODS

A total of 57-term singleton pregnancies were studied: 33 with elective cesarean sections and 24 with vaginal deliveries. UC-nRBC was analyzed for its nucleated red blood cell counts. A logarithmic transformation of the data was used for statistical analysis.

RESULTS

The mean+/-standard deviation (s.d.) for nucleated red blood cell per 100 white blood cells (nRBC/100WBC) from the elective cesarean section group was 7.8+/-7.4. The vaginal delivery group had a mean value of 9.3+/-10.5, which was not significantly different. A value of 22 nRBC/100WBC defined the upper 95% confidence limit. The correlation between absolute nRBC and nRBC/100 WBC was 0.97.

CONCLUSION

Although chronic hypoxia is associated with elevated nRBC, the stress of uncomplicated labor does not change the level. This adds credence to its use as a marker for hypoxia preceding labor and delivery.

Influence of perinatal factors on hematological variables in umbilical cord blood

OBJECTIVE

The purpose of our study was to investigate any possible relationship between the duration of labor, the mode of delivery and the duration of rupture of membranes and hematological parameters in cord blood.

MATERIAL AND METHODS

We studied 298 pregnant women who delivered term normal infants. The patients were divided into three groups according to the route of delivery: vaginal (n = 165), cesarean section after labor (n = 27) and elective cesarean section (n = 106). Immediately after delivery, umbilical cord blood samples were collected.

RESULTS

The mode of delivery influenced white blood cells, hemoglobin, hematocrit, red blood cell distribution, platelets count and nucleated red blood cells. There was no correlation between the cord blood hematological values and the duration of labor, as well as the duration of rupture of membranes before delivery.

CONCLUSION

The influence of mode of delivery, duration of labor and duration of ruptured membranes on hematological parameters in umbilical cord blood is limited.

Fetal "nonreassuring status" is associated with elevation of nucleated red blood cell counts and interleukin-6

OBJECTIVE

Previous studies have established the association between fetal hypoxia and elevated nucleated red blood cells (NRBCs). Animal studies have demonstrated that a rise in plasma erythropoietin (EPO) is not detectable until 4 to 6 hours after the initiation of hypoxia. In contrast, interleukin-6 (IL-6) has the capacity to directly induce erythroid maturation. Therefore, we set forth to evaluate the role of EPO and IL-6 as potential mediators of elevated fetal NRBCs in response to acute hypoxia.

STUDY DESIGN

Low-risk pregnancies with a normal fetal heart rate at admission to labor and delivery were eligible for participation. Deliveries for "nonreassuring fetal status" comprised the study group. All other deliveries served as controls. Umbilical cord blood was prospectively collected for blood gas analysis, NRBC counts, EPO, and IL-6.

RESULTS

One hundred women participated in the study. Nonparametric univariate analysis demonstrated a significant association between elevated NRBC counts and Apgar scores, arterial cord blood pH, base excess, EPO, and IL-6 levels (all P values <.01). Stepwise regression analysis identified only pH, IL-6, and EPO as independent variables associated with elevated NRBC counts at birth (all P values <.0001 with R2 of 0.27, 0.42, and 0.46, respectively). A significant increase in NRBC counts was noted in study patients. IL-6 was significantly increased in study patients, whereas there was no difference in EPO between groups.

CONCLUSION

The fact that NRBC counts were elevated in fetuses who were delivered for "nonreassuring fetal status" with EPO being normal and IL-6 being elevated implies that IL-6 may have a unique, short-term role in elevating fetal NRBC counts.

Combination of early perinatal factors to identify near-term and term neonates for neuroprotection

OBJECTIVE

To determine early predictors of abnormal outcome at > or =24 months' age in neonates at risk for hypoxic-ischemic brain injury.

STUDY DESIGN

A prospective cohort study with developmental follow-up of > or =24 months. Infants were selected based on risk factors, and neurologic outcome was determined. Variables affecting the outcome were evaluated with univariate and multivariate methods, and a scoring system was devised to predict adverse outcome.

RESULTS

A total of 41 infants born > or =35 weeks' gestational age with possibility of hypoxic-ischemic insult were enrolled. In all, 39 (95%) had known outcomes, of whom 17 (48%) had an abnormal neurologic outcome, including five deaths. The variables within the first hour of life correlating with the adverse outcome were 1- and 5-minute Apgar scores, intubation in the delivery room and cord/initial base-deficit > or =20 mmol/l. A scoring system was derived based on significant variables, and a score > or =5 had a 90% positive predictive value for abnormal outcome. Seizures, multiorgan failure and abnormal imaging studies were also significantly associated with abnormal outcome.

CONCLUSIONS

The proposed scoring system, being highly predictive of outcome at 24 months' age, may be potentially useful in selecting subjects for preventive or therapeutic interventions to prevent or minimize neurologic morbidity due to hypoxic brain injury.

Birth asphyxia and cerebral palsy

There has been a societal presumption that most, if not all, cases of hypoxic ischemic encephalopathy-induced cerebral palsy occur during the 3 hours that are related to the events of labor and delivery; society has tended to overlook the remaining 7000 hours of the pregnancy. As a result of this societal perspective, often times the obstetrician has been targeted unfairly as the person who is responsible for a given child's neurologic injuries. Rather, the entire pregnancy, labor, delivery, and well beyond birth require examination to understand fully the pathophysiologic mechanisms that are responsible for an infant's brain injuries, and their long-term impact on the child.

Timing of fetal nucleated red blood cell count elevation in response to acute hypoxia

We determined the effect of an acute episode of severe hypoxia on peripheral nucleated red blood cell (RBC) counts in the fetal rat. Timed pregnant rats were randomized to a 2-hour exposure to hypoxia (placement in a chamber containing a gas mixture with 9% O2 +3% CO2 + balanced N2) or to a 2-hour exposure to a sham chamber containing room air. Two maternal animals per group underwent cesarean section immediately after the 2-hour period and then 4, 12, 24, 36, 48, and 60 h after exposure. Fetal nucleated RBC counts were compared between groups at each time interval. The nucleated RBC counts were not significantly different in the hypoxia group until 12 h (mean +/- SEM 158.0 +/- 22.4 RBC/10 high-power fields vs. 90.6 +/- 11.0; p = 0.03) and 24 h (133.2 +/- 16.0 vs. 84.1 +/- 9.0; p = 0.04) after exposure. There were no differences between groups 36, 48, and 60 h after exposure. In the near-term rat fetus, acute hypoxia was associated with a delayed but transient increase in peripheral nucleated RBC counts.

Nucleated red blood cell counts: not associated with brain injury or outcome

The objective was to determine whether an elevated nucleated red blood cell count at birth after perinatal depression is associated with brain injury as measured by (1) proton magnetic resonance spectroscopy and (2) abnormal neurodevelopmental outcome at 30 months of age. The nucleated red blood cell counts from the first 24 hours of life were statistically analyzed in 33 term infants enrolled in a prospective study of the value of magnetic resonance imaging for the determination of neurodevelopmental outcome after perinatal depression. Nucleated red blood cell counts were elevated in 13/33 (39%). Abnormal outcome (19/33, 54%) was associated with Score for Neonatal Acute Physiology-Perinatal Extension (P = 0.04), decreased N-acetylaspartate to choline ratio in the basal ganglia (P = 0.009), and increased lactate to choline ratio in the basal ganglia (P = 0.02), but not with cord pH, Apgar score, or nucleated red blood cell value. In a logistic regression model, increasing nucleated red blood cell counts did not increase the odds of an abnormal outcome at 30 months of age (OR 1.02, P = 0.17). In a population of neonates with perinatal depression, the nucleated red blood cell count at birth does not correlate with magnetic resonance spectroscopy or 30-month neurodevelopmental outcome. The nucleated red blood cell count should not be used as a surrogate marker for subsequent brain injury.

Fine-needle aspiration in the evaluation of nucleated red blood cells in the human placenta

OBJECTIVE

The purpose of this study was to evaluate the correlation between placental and umbilical cord nucleated red blood cell counts.

STUDY DESIGN

Eighty placentas and their matched umbilical cord blood samples were collected prospectively immediately after delivery. In vitro fine-needle aspiration biopsy specimens were used to obtain placental tissue samples. Nucleated red blood cells were counted by both manual microscopy and flow cytometry. Statistical analysis included Wilcoxon signed rank test and Spearman correlation.

RESULTS

The median nucleated red blood cell counts/100 white blood cell counts for manual microscopy in umbilical cord blood; placental samples were 7.5 and 3.0, respectively (P <.0001). The median nucleated red blood cell counts for flow cytometric determination in umbilical cord blood and placental samples were 11.3 and 8.6, respectively (P <.0001). The Spearman correlation between manually counted umbilical cord blood samples and the placental tissue specimens was 0.66 (P <.0001). The Spearman correlation between flow cytometrically counted umbilical cord blood nucleated red blood cell and nucleated red blood cell counts that were obtained from the placenta was statistically significant (r = 0.74, P <.0001). The Spearman correlation between manual microscopy and flow cytometry for umbilical cord samples and their matched placental tissue specimens were 0.80 and 0.58, respectively, with all probability values at <.0001.

CONCLUSION

Previous studies have reported an association between acute and chronic hypoxia and elevated nucleated red blood cells. Our results indicate that in vitro placental nucleated red blood cell counts correlate with umbilical cord nucleated red blood cell counts and suggest that antenatal evaluation of fetal nucleated red blood cells could be achieved by placental fine-needle aspiration biopsy.

Prediction of perinatal asphyxia with nucleated red blood cells in cord blood of newborns

OBJECTIVE

To determine normal level of nucleated red blood cells (NRBC) per 100 white blood cells (WBC) in cord blood of term non-asphyxiated newborns and to investigate variations in NRBC counts in perinatal asphyxia.

METHODS

A total of 75 cases were studied. Levels of NRBC per 100 WBC in umbilical venous blood were compared between 26 asphyxiated newborns (group I) and 49 non-asphyxiated newborns (group II). Correlation with neonatal outcome was also evaluated.

RESULTS

The mean (+/-S.D.) NRBC per 100 WBC level in umbilical blood of newborns in group I was 16.5+/-6.4, range 3-25; whereas that in group II was 8.6+/-7.01, range 1-26. This difference was statistically significant (P<0.001). A statistically significant negative correlation existed between NRBC level and markers of acute intrapartum asphyxia, Apgar score and umbilical arterial pH (r=-0.50, P<0.001 and r=-0.48, P<0.001, respectively). Positive correlation was demonstrated with evidence of chronic antepartum asphyxia, presence of pregnancy induced hypertension and intrauterine growth restriction (r=2.66, P=0.02). A high NRBC count in umbilical blood correlated with poor early neonatal outcome.

CONCLUSIONS

The level of NRBC per 100 WBC correlates both with acute as well as chronic antepartum asphyxia. Further, it can be used as a reliable index of early neonatal outcome.

The association of fetal heart rate patterns with nucleated red blood cell counts at birth

OBJECTIVE

The purpose of this study was to evaluate the relationship between fetal heart rate patterns and fetal nucleated red blood cell counts.

STUDY DESIGN

Data were collected prospectively from March through September 2000. Umbilical cord blood was used for nucleated red blood cell analysis. The fetal heart rate pattern was analyzed for reactivity; presence, duration, and type of decelerations; and time interval between the last acceleration and delivery.

RESULTS

Two hundred seventy-nine singleton term pregnancies formed the study population, 67% of which were delivered vaginally. The median nucleated red blood cells per 100 white blood cells was 7 (range, 0-158). The univariate analysis indicated that nucleated red blood cells are correlated significantly with abnormal fetal heart rate patterns, time interval between the last acceleration and delivery, fetal growth restriction, the presence of meconium, and a 1-minute Apgar score of < or =7. However, the stepwise regression analysis identified the time interval between the last acceleration and delivery as the only variable that independently predicted elevated nucleated red blood cell count at birth (P <.0001, R (2) = 0.26).

CONCLUSION

Earlier studies have demonstrated an association between adverse perinatal outcome and elevated nucleated red blood cell count. In view of the high false-positive rate that is associated with the prediction of adverse perinatal outcome by fetal heart rate abnormalities, our results support previous studies that indicate that the presence of fetal heart rate accelerations is a reliable predictor of the nonhypoxic fetus.

Nucleated red blood cell counts and erythropoietin levels in high-risk neonates

BACKGROUND

The presence of increased numbers of nucleated red blood cells (NRBC) and increased levels of erythropoietin (EPO) in the circulation of neonates has been associated with states of relative hypoxia. The aim of this study is to assess the pattern of NRBC counts and EPO levels in a group of high-risk neonates under stress conditions and determine the short-term outcome for these babies by using these parameters.

METHODS

There were 69 high-risk neonates; 14 intrauterine growth retarded (IUGR), 25 preterm infants, 18 term infants with asphyxia and 12 infants of diabetic mothers. Control groups included healthy, term infants delivered either vaginally (n = 18) or with cesarean section (n = 19). Three blood samples were obtained from each infant within 12 h (initial), 3 days and 7 days after birth to measure NRBC counts and EPO levels. Neonatal and short-term outcomes at 3 and 6 months of age were determined.

RESULTS

There was no significant difference among the groups with regard to the initial serum EPO concentrations. The initial NRBC counts were significantly lower in the control groups compared with the study groups (P = 0.002). While there was no significant difference between patients with good and poor outcome in terms of EPO concentrations of initial samples, a significant difference existed in terms of NRBC counts (P = 0.038).

CONCLUSIONS

Both serum EPO level and NRBC count provide limited clinical benefit in the detection of pathological conditions of the neonatal period, but NRBC count determination seems to be especially helpful in predicting short-term neurodevelopmental outcome.

Neonatal nucleated red blood cell counts in twins

We counted nucleated red blood cells (NRBC) per 100 white blood cells (WBC) in the umbilical cord blood from 98 twins born to 49 women with uncomplicated twin pregnancies at > or = 34 weeks of gestation to better characterize NRBC in twins. Twelve women with monochorionic (MC) placentas and 37 with dichorionic (DC) placentas gave birth at 36.7 +/- .9 and 36.5 +/- 2 weeks of gestation, respectively. All twins were born with an Apgar score of > or = 7 at 1 min. Log10 (NRBC/100 BC) in 98 twins exhibited a nearly normal distribution, and was significantly associated with gestational age for both MC (r = -0.457, p = 0.025) and DC twins (r = - 0.275, p = 0.018), and with birth weight for both MC (r = -0.682, p < 0.001) and DC twins (r = -0.336, p = 0.003). Log10 (NRBC/100 WBC) tended to be larger in smaller twins than in larger twins in the MC group, and significantly larger in smaller twins than in larger twins in the DC group (p < 0.05). Intertwin difference in Log10 (NRBC/100 WBC) was defined as the value of Log10 (NRBC/100 WBC) of the smaller twin minus Log10 (NRBC/100 WBC) of the larger twin, and became greater with increasing intertwin difference in birth weight (r = 0.411, p = 0.003). These findings suggest that neonatal NRBC reflected gestational age and birth weight in twins. This preliminary observation using a small number of twins suggests that the smaller twin may have experienced a relative lack of oxygen compared with the larger twin in utero.

Neonatal nucleated red blood cell counts in small-for-gestational-age fetuses: relationship to fetoplacental Doppler studies

OBJECTIVE

To study the influence of pathologic umbilical and middle cerebral artery and uterine artery Doppler studies on the nucleated red blood cell count in small-for-gestational-age (SGA) fetuses.

MATERIALS AND METHODS

Cord blood was prospectively collected during a 18-month period. 80 SGA fetuses (fetal abdominal circumference < 5th percentile) with Doppler ultrasound of the umbilical, the middle cerebral artery and both uterine arteries were enrolled in the study. SGA fetuses with normal Doppler flow velocity waveforms were allocated to group 1 (n = 23). Group 2 (n = 13) were fetuses with abnormal umbilical Doppler studies and group 3 (n = 44) were fetuses with both, pathologic umbilical and uterine artery Doppler studies. 2 fetuses in group 3 showed evidence of brain sparing, 3 fetuses presented absent-end-diastolic flow in the umbilical artery. Outcome measures included nucleated red blood cell count, Apgar scores, arterial pH and arterial base excess, venous pH, birth weight, gestational age at delivery, mode of delivery, rate of neonatal intensive care unit admission and length of stay in the neonatal intensive care unit.

RESULTS

Highest nucleated red blood cell counts with lowest birth weight and gestational age were found in group 3. Decelerations of the fetal heart rate were more frequent in study group 3 and caesarean section for fetal indication was performed more often in this group. Those fetuses had to be transfered more often to the neonatal intensive care unit than fetuses of the other study groups. There was a tendency in group 3 towards lower arterial pH values and arterial base excess values. Fetuses with absent-end-diastolic flow in the umbilical artery presented highest nucleated red blood cell counts.

CONCLUSION

In SGA fetuses increasing Doppler pathology seems to be correlated with increasing nucleated red blood cell count post-partum. Pathologic uterine artery flow results might have an additional impact on the number of nucleated red blood cells at birth.

Association of ABO incompatibility with elevation of nucleated red blood cell counts in term neonates

OBJECTIVE

Nucleated red blood cells in the circulation in term neonates have been associated with a wide range of pathologic conditions. We sought to examine the relationship between nucleated red blood cells in the circulation of term neonates and maternal-neonatal blood type compatibility.

STUDY DESIGN

We prospectively collected umbilical blood from all live-born neonates delivered at our institution. Venous blood was analyzed for nucleated red blood cells and is reported as the number of nucleated red blood cells per 100 white blood cells. We reviewed maternal and neonatal records for neonates born at > or =37 weeks' gestation for correlative clinical data. Statistical analysis was performed with the SAS statistical software package (version 6.12; SAS Institute, Inc, Cary, NC). Kruskal-Wallis analysis was used as a nonparametric test.

RESULTS

We evaluated 1661 neonates delivered during the study period and found a mean (+/-SD) of 9.29 +/- 18.56 nucleated red blood cells per 100 white blood cells (range, 0-327 nucleated red blood cells per 100 white blood cells). Nucleated red blood cell counts were lower in ABO-compatible maternal-fetal dyads (mean +/- SD, 8.29 +/- 12.84 nucleated red blood cells per 100 white blood cells; range, 0-216 nucleated red blood cells per 100 white blood cells) than in ABO-incompatible dyads (mean +/- SD, 13.16 +/- 13.16 nucleated red blood cells per 100 white blood cells; range, 0-327 nucleated red blood cells/100 white blood cells; P =.006). Neonates of mothers with blood groups A and B had significantly lower nucleated red blood cell counts (P <.05). Dyads with maternal type O and neonate type B had significantly higher nucleated red blood cell counts (P <.002). Nonparametric testing determined that type O mother and type B neonate combinations had significantly higher umbilical cord nucleated red blood cell counts (P <.001).

CONCLUSION

Maternal-fetal ABO incompatibility is associated with elevation of nucleated red blood cell count in term neonates. Nucleated red blood cell elevation does not always connote a serious pathologic process, however, because ABO incompatibility usually does not adversely affect neonatal outcome. The clinical significance of an elevated nucleated red blood cell count thus is limited.

Nucleated red blood cells as a marker in acute and chronic fetal asphyxia

OBJECTIVE

To investigate the variations of nucleated red blood cell (NRBC) counts in acute and chronic fetal hypoxia and to examine if it could be possible to establish a cutoff value for the number of NRBCs for prediction of fetal acidosis.

METHOD

We prospectively studied 77 pregnant women. Patients were grouped as acute (n=11) and chronic fetal distress (n=21) and controls (n=45). At delivery the umbilical cord was double clamped and blood samples were collected.

RESULTS

The mean NRBC counts in chronic fetal distress group was higher than acute fetal distress. NRBC counts were found to be correlated with umbilical cord pH (r=-0.57; P<0.001). The cutoff value predicting fetal acidosis was determined as 14/100 leukocytes (sensitivity 87%, specificity 81%) by using ROC analysis.

CONCLUSION

The duration and the severity of fetal asphyxia may be predicted by the number of NRBCs per leukocyte.

Can neurological injury be timed?

Our knowledge about the cause of cerebral palsy continues to expand and prenatal events are thought to play an important role. This article reviews laboratory tests, imaging studies and pathologic findings that have been used to identify the timing of neurological injury. Limitations exist for all modalities, however, imaging studies, electroencephalograms and pathologic examination provide the most useful information. Improvements in our ability to time neurological injury will better direct our efforts to prevent cerebral palsy.

Fetal heart rate observations in the brain-damaged infant

The objective of this study was to describe the fetal heart rate patterns and underlying pathophysiologic changes in the brain-damaged fetus. Fetuses with brain damage from hypoxic ischemic encephalopathy do not manifest uniform fetal heart rate patterns. However, these fetuses do show distinct fetal heart rate patterns that permit categorization based on their admission heart rate, subsequent changes in their baseline rate; and neonatal findings. Based on the observations of infants brain damaged in utero because of hypoxic ischemic encephalopathy, the intrapartum fetal management will depend on the admission fetal heart rate pattern, and the subsequent changes in the baseline rate.

The relationship between nucleated red blood cell counts and early-onset neonatal seizures

OBJECTIVE

This study was undertaken to better define the timing of neurologic insult in neonates with early-onset seizures through evaluation of neonatal nucleated red blood cell levels.

STUDY DESIGN

Medical records and the International Classification of Diseases, Ninth Revision codes were used to identify all term neonates with neonatal convulsions who were delivered at our institution (January 1, 1990-December 31, 1995). Each neonate with early-onset seizures was matched to the next 3 neonates who met the following criteria: gestational age > or =37 weeks, no early-onset seizures, birth weight > or =800 g, umbilical artery pH > or =7.25, and a 5-minute Apgar score >7. Demographic characteristics, clinical factors, and mean initial nucleated red blood cell counts were compared between groups.

RESULTS

During the 6-year study period, there were a total of 36, 490 singleton term deliveries of infants who were alive at birth. Forty-five (0.1%) of these neonates had early-onset seizures. Thirty neonates with early-onset seizures met the inclusion criteria. Mean nucleated red blood cell counts (number of nucleated red blood cells per 100 white blood cells) for neonates with early-onset seizures were significantly increased compared with those of control neonates (18.4 +/- 22.0 vs 4.6 +/- 4.5; P <.0008).

CONCLUSIONS

Our findings are suggestive of the hypothesis that neurologic injury leading to early-onset seizures often occurs before the intrapartum period.

Nucleated red blood cells in growth-restricted fetuses: associations with short-term neonatal outcome

OBJECTIVE

To determine the utility of the neonatal nucleated red blood cell (NRBC) count as an independent predictor of short-term perinatal outcome in growth-restricted fetuses.

METHODS

Hospital charts of neonates with a discharge diagnosis indicating a birth weight <10th percentile were reviewed for perinatal outcome. We studied all eligible neonates who had a complete blood count on the first day of life. After multiple gestations, anomalous fetuses and diabetic pregnancies were excluded; 73 neonates comprised the study group. Statistical analysis included ANOVA, simple and stepwise regression.

RESULTS

Elevated NRBC counts were significantly associated with cesarean section for non-reassuring fetal status, neonatal intensive care unit admission and duration of neonatal intensive care unit stay, respiratory distress and intubation, thrombocytopenia, hyperbilirubinemia, intraventricular hemorrhage and neonatal death. Stepwise regression analysis including gestational age at birth, birth weight and NRBC count demonstrated that in growth-restricted fetuses, NRBC count was the strongest predictor of neonatal intraventricular hemorrhage, neonatal respiratory distress and neonatal death.

CONCLUSION

An elevated NRBC count independently predicts adverse perinatal outcome in growth-restricted fetuses.

Nucleated red blood cells in cord blood of singleton term and post-term neonates

OBJECTIVE

This study aims to determine if nucleated red blood cells are elevated in pregnancies that continue beyond 289 days of gestation.

STUDY DESIGN

Cord blood was prospectively collected from term and post-term singleton gestations from August 1 to December 31, 1998. Umbilical artery nucleated red blood cells were counted per 100 white blood cells. The comparison was made between pregnancies ending at 261-289 days (37.1-41.2 weeks) of gestation and those ending after 289 days (> or = 41.3 weeks) of gestation.

RESULTS

Cord blood from 304 cases was obtained and evaluated for nucleated red blood cells per 100 white blood cells. The mean value of nucleated red blood cells per 100 white blood cells in the post-term neonate group was significantly higher than in the term neonate group (median 6.5, range 0-24 vs. median 3.7, range 0-14; p < 0.05). The values did not vary by fetal presentation, mode or duration of delivery. Neonatal outcome was comparable between both study groups.

CONCLUSION

In post-term gestation after 289 days nucleated red blood cells in cord blood are significantly increased. These results point towards a different fetal oxygenation in post-term pregnancies beyond 289 days of gestation and support the current practice of very close testing of fetal well-being under those circumstances.