Cord-Blood Derived Chemistry Reference Values in Preterm Infants for Sodium, Chloride, Potassium, Glucose, and Creatinine

OBJECTIVE

International guidelines recommend that preterm infants should be supported to maintain their serum electrolytes within "normal" ranges. In term babies, cord blood values differed in pathological pregnancies from healthy ones.

STUDY DESIGN

We examined cord blood sodium, chloride, potassium, glucose, and creatinine to derive maturity-related reference intervals. We examined associations with gestational age, delivery mode, singleton versus multiple, and prenatal maternal adverse conditions. We compared preterm cord values to term, and to adult reference ranges.

RESULTS

There were 591 infants, 537 preterm and 54 term. Preterm cord glucose levels were steady (3.7 ± 1.1 mmol/L), while sodium, chloride, and creatinine increased over GA by 0.17, 0.14 mmol/L/week, and 1.07 µmol/L/week, respectively (p < 0.003). Average preterm cord potassium and chloride were higher than the term (p < 0.05). Compared with adult reference intervals, cord preterm reference intervals were higher for chloride (100-111 vs. 98-106 mmol/L), lower for creatinine (29-84 vs. 62-115 µmol/L), and more variable for potassium (2.7-7.9 vs. 3.5-5.0 mmol/L) and sodium (130-141 vs. 136-145 mmol/L). Cesarean section was associated with higher potassium and lower glucose, multiple births with higher chloride and creatinine and lower glucose, and SGA with lower glucose.

CONCLUSION

Cord blood values varied across the GA range with increases in sodium, chloride, and creatinine, while glucose remained steady. Average preterm reference values were higher than term values for potassium and chloride. Preterm reference values differed from published adults' reference values. The changes across GA and by delivery mode, SGA, and being a multiple, which may have direct implications for neonatal care and fluid management.

KEY POINTS

· Cord blood electrolyte, creatinine, and glucose values vary across neonatal gestational age.. · Average preterm cord values of potassium and chloride were higher than term values.. · Cord reference values differ by delivery mode, growth, and multiple impacting neonatal care decisions..

Relationship between the serum creatinine concentrations of preterm neonates within 24 h of birth and their mothers before delivery

BACKGROUND

Neonatal serum creatinine (n-sCr) concentrations during the first few days of life have been reported to correlate with the maternal serum Cr (m-sCr) concentrations. We aimed to derive a regression equation to describe the relationship between n-sCr within 24 h of birth in preterm neonates and m-sCr before delivery, and to perform multiple regression analysis to identify factors related to n-sCr and the difference between n-sCr and m-sCr.

METHODS

We recruited preterm neonates who were treated at the University of the Ryukyus Hospital between March 2012 and October 2022. Patients with underlying diseases or conditions that might affect hemodynamics were excluded, as were patients whose n-sCr and m-sCr were not measured in pairs. A total of 278 cases were included in the analysis.

RESULTS

The median (interquartile range) gestational age, birth weight, n-sCr, and m-sCr were 33.9 weeks (32.0-35.1 weeks), 1901 g (1579-2284 g), 0.55 mg/dL (0.48-0.64 mg/dL), and 0.47 mg/dL (0.42-0.57 mg/dL), respectively. The regression equation derived was n-sCr = 0.092 + 0.970 × m-sCr (R2 = 0.768, p < 0.001). The multiple regression analysis showed that m-sCr was the most potent influencer of n-sCr, and the ratio of placental weight to birth weight (PW/BW ratio) was the most potent influencer of the difference between n-sCr and m-sCr.

CONCLUSIONS

We have obtained an approximate equation of n-sCr = 0.1 + m-sCr for preterm neonates. In addition, the high PW/BW ration may reduce the difference between n-sCr and m-sCr.

Fetal Physiologically Based Pharmacokinetic Models: Systems Information on Fetal Blood Components and Binding Proteins

BACKGROUND

Fetal blood and plasma volume and binding components are critical parameters in a fetal physiologically based pharmacokinetic model. To date, a comprehensive review of their changes during fetal development has not been reported.

OBJECTIVE

The objective of this work was to collate and analyze physiological information on fetal blood and plasma volume and binding component data during development and to provide a mathematical description of these parameters that can be integrated within a fetal physiologically based pharmacokinetic model.

METHODS

A comprehensive literature search was conducted on fetal blood and plasma volume and binding component parameters and their changes during growth from apparently healthy fetuses from uncomplicated pregnancies. Collated data were assessed, integrated, and analyzed to establish continuous mathematical functions describing their growth trends with fetal age and weight.

RESULTS

Data were available from 14 studies for blood, ten studies for hematocrit, 12 studies for albumin, and four studies for alpha-1-acid glycoprotein, while plasma and red blood cell volumes were described based on blood and hematocrit data. Fetal physiologically based pharmacokinetic parameters, including blood, plasma and red blood cell volumes, hematocrit, serum albumin, and acid glycoprotein were quantified as a function of fetal age and weight. Variability around the mean parameters at different fetal ages was also investigated. The growth of each of these parameters was different (with respect to direction and monotonicity).

CONCLUSIONS

Despite the limitations identified in the availability of some values, the collected data presented in this article provide a useful resource for fetal physiologically based pharmacokinetic modeling. Potential applications include predicting xenobiotic exposure and risk assessment in the fetus following maternally administered drugs or unintended exposure to environmental toxicants.

Copenhagen Baby Heart Study: a population study of newborns with prenatal inclusion

Congenital heart diseases (CHDs) are reported in 0.8% of newborns. Numerous factors influence cardiovascular development and CHD prevalence, and possibly also development of cardiovascular disease later in life. However, known factors explain the probable etiology in only a fraction of patients. Past large-scale population-based studies have made invaluable contributions to the understanding of cardiac disease, but none recruited participants prenatally and focused on the neonatal period. The Copenhagen Baby Heart Study (CBHS) is a population-based study of the prevalence, spectrum, and prognosis of structural and functional cardiac abnormalities. The CBHS will also establish normal values for neonatal cardiac parameters and biomarkers, and study prenatal and early childhood factors potentially affecting later cardiovascular disease risk. The CBHS is an ongoing multicenter, prospective study recruiting from second trimester pregnancy (gestational weeks 18-20) (expected n = 25,000). Information on parents, pregnancy, and delivery are collected. After birth, umbilical cord blood is collected for biochemical analysis, DNA purification, and biobank storage. An echocardiographic examination, electrocardiography, and post-ductal pulse oximetry are performed shortly after birth. Infants diagnosed with significant CHD are referred to a specialist or admitted to hospital, depending on CHD severity. CBHS participants will be followed prospectively as part of specific research projects or regular clinical follow-up for CHD. CBHS design and methodology are described. The CBHS aims to identify new mechanisms underlying cardiovascular disease development and new targets for prevention, early detection, and management of CHD and other cardiac diseases presenting at birth or developing later in life.

Pediatric reference intervals for alkaline phosphatase

BACKGROUND

Interpretation of alkaline phosphatase activity in children is challenging due to extensive changes with growth and puberty leading to distinct sex- and age-specific dynamics. Continuous percentile charts from birth to adulthood allow accurate consideration of these dynamics and seem reasonable for an analyte as closely linked to growth as alkaline phosphatase. However, the ethical and practical challenges unique to pediatric reference intervals have restricted the creation of such percentile charts, resulting in limitations when clinical decisions are based on alkaline phosphatase activity.

METHODS

We applied an indirect method to generate percentile charts for alkaline phosphatase activity using clinical laboratory data collected during the clinical care of patients. A total of 361,405 samples from 124,440 patients from six German tertiary care centers and one German laboratory service provider measured between January 2004 and June 2015 were analyzed. Measurement of alkaline phosphatase activity was performed on Roche Cobas analyzers using the IFCC's photometric method.

RESULTS

We created percentile charts for alkaline phosphatase activity in girls and boys from birth to 18 years which can be used as reference intervals. Additionally, data tables of age- and sex-specific percentile values allow the incorporation of these results into laboratory information systems.

CONCLUSIONS

The percentile charts provided enable the appropriate differential diagnosis of changes in alkaline phosphatase activity due to disease and changes due to physiological development. After local validation, integration of the provided percentile charts into result reporting facilitates precise assessment of alkaline phosphatase dynamics in pediatrics.

Relationship between Irisin Concentration and Serum Cytokines in Mother and Newborn

Introduction

Irisin is considered to be a myokine and adipokine that may also participate in reproductive functions, as it increases significantly throughout pregnancy. However, the regulation of circulating irisin and its relationship with other cytokines has not been assessed thus far in pregnant women and their offspring.

Objective

The aim of this study was to evaluate differences in irisin and cytokine concentrations between women at the end of pregnancy and their offspring, as well as the relationship between maternal and newborn irisin and maternal and newborn biomarkers.

Methods

Twenty-eight mother/newborn pairs were included in this study. The following biomarkers were evaluated in maternal venous and arterial umbilical cord blood samples: irisin, 27 cytokine panel, total antioxidant capacity (TAC), total plasma protein, and free fatty acid concentration.

Results

The newborns had significantly lower irisin concentrations compared to their mothers (p = 0.03), but this difference was present only in babies born from mothers without labor prior to cesarean section delivery (p = 0.01). No significant differences in maternal and newborn irisin concentrations were found between diabetic and non-diabetic mothers or between overweight/obese and normal weight mothers. A significant positive correlation was found between TAC level and irisin concentration in newborns. Maternal and newborn interleukin (IL)-1β, IL-1RA, IL-5, IL-7, and interferon gamma-induced protein (IP)-10 levels were significantly positively correlated with irisin concentrations in both study groups. In addition, maternal IL1β, IL-5, IL-7, and IP-10 levels positively predicted maternal irisin concentrations. Furthermore, arterial cord blood TAC and IL-1β and IL1-RA levels positively predicted newborn irisin concentrations. Multiple regression analyses showed that maternal IL-13 negatively predicted offspring irisin levels (p = 0.03) and that maternal IL-1β positively predicted newborn irisin concentrations (p = 0.046).

Conclusion

No evidence was found that serum irisin concentrations in mothers at pregnancy termination or those of their newborns correlated with maternal body mass index, the presence of diabetes mellitus, or free fatty acid levels. However, the results of this study indicated that cytokines might predict irisin concentration in mothers and their offspring, although interactions between irisin levels during pregnancy and the newborn have not yet been fully elucidated.

Evaluation of creatine kinase, lactate dehydrogenase, and amylase concentrations in umbilical blood of preterm infants after long-term tocolysis

Creatine kinase (CK), lactate dehydrogenase (LDH), and amylase levels of preterm infants following long-term tocolysis in pregnant women are limited. The objective of this study was to determine if the tocolytic therapy affects CK, LDH, and amylase levels in the umbilical blood. This study included 215 preterm infants born to women treated with and without ritodrine hydrochloride. CK, LDH, and amylase levels in the umbilical blood at delivery were determined. Infants were divided according to the ritodrine tocolysis, as follows: Group A (n = 91), not exposed to ritodrine; Group B (n = 44), IV ritodrine for <1 week; Group C (n = 80), IV ritodrine for ≥1 week. The CK concentration in cord blood of Group C (198.8 ± 14.2 IU/L) was significantly higher in comparison with Group A (155.0 ± 7.3 IU/L, P < 0.05). There was no significant difference in LDH and amylase levels in the three groups. The CK significantly correlated with gestational age (r = 0.42, P < 0.01) and birth weight (r = 0.38, P < 0.01). LDH and amylase levels did not change with gestational age nor birth weight. In conclusion, long-term ritodrine tocolysis leads to increased umbilical blood CK level.

Maternal-fetal-infant dynamics of the C3-epimer of 25-hydroxyvitamin D

BACKGROUND

Poor vitamin D status (i.e. low serum 25-hydroxyvitamin D (25(OH)D)) has been associated with adverse clinical outcomes during pregnancy and childhood. However, the interpretation of serum 25(OH)D levels may be complicated by the presence of the C3-epimer of 25(OH)D. We aimed to quantify C3-epi-25(OH)D3 in pregnant women and fetuses, to explore the relationship of the C3-epimer between maternal and cord samples, and to establish whether infant C3-epimer abundance is explained by prenatal formation.

METHODS

In a sub-study of a randomized trial of prenatal vitamin D3, 25(OH)D3 and C3-epi-25(OH)D3 were quantified by LC-MS/MS in 71 sets of mother-fetus-infant serum samples, including maternal delivery specimens, cord blood, and infant specimens acquired at 3-28 weeks of age.

RESULTS

Without supplementation, median concentrations of C3-epi-25(OH)D₃ were higher in infants (6.80 nmol/L) than mothers (0.45 nmol/L) and cord blood (0 nmol/L). However, there was substantial variation such that C3-epi-25(OH)D₃ accounted for up to 11% (maternal), 14% (cord), and 25% (infant) of the total 25(OH)D₃. Supplemental vitamin D₃ significantly increased maternal-fetal C3-epi-25(OH)D₃, and was a preferential source of C3-epi-25(OH)D₃ compared to basal vitamin D, possibly due to C3-epi-cholecalciferol in the supplement. Multivariate regression did not suggest transplacental transfer of C3-epi-25(OH)D₃, but rather indicated its generation within the fetal-placental unit from maternally-derived 25(OH)D₃. Neither maternal nor fetal C3-epi-25(OH)D₃ is accounted for the relatively high concentrations of infant C3-epi-25(OH)D₃, suggesting rapid postnatal generation.

CONCLUSIONS

C3-epi-25(OH)D₃ is present in some pregnant women and fetuses, but does not appear to be efficiently transferred transplacentally. High C3-epimer concentrations in infancy are probably due to postnatal formation rather than fetal stores.

Establishing reference intervals for electrolytes in newborns and infants using direct ISE analyzer

BACKGROUND

To generate clinically applicable reference intervals (RIs) for commonly requested electrolytes in Ethiopian newborns and infants that can help in early detection, close monitoring and correction of electrolyte abnormalities. Cord blood (from newborns, n = 60) and venous blood samples (from infants, n = 57) were collected and analyzed using direct ISE analyzer, AVL (9181). MedCalc® software was applied to determine the robust upper and lower end points covering 95% of the reference values of each electrolyte with respective 90% CIs.

FINDINGS

This is an extension report of our recent study; and hence is resulted from the same data source. The level of Na+ and K+ showed difference in newborns and infants even though combined RIs were suggested by the Haris and Boyd rule as 126-143 mmol/l and 4.0-7.9 mmol/l respectively. However, Cl- values failed to show such a difference and thus a combined RI was determined to be 100-111 mmol/l. Almost all maternal, neonatal and infantile factors were not able to affect the values of the electrolytes.

CONCLUSION

Combined RIs are suggested for the interpretation of electrolyte values in newborns and infants without taking the effect of maternal, neonatal and infantile factors into account. Since the RIs were different from previously reported values, it will be appropriate to apply such RIs for the interpretation of electrolyte values in Ethiopian pediatric population.

Pharmacokinetics of high-dose weekly oral vitamin D3 supplementation during the third trimester of pregnancy in Dhaka, Bangladesh

A pharmacokinetic study was conducted to assess the biochemical dose-response and tolerability of high-dose prenatal vitamin D3 supplementation in Dhaka, Bangladesh (23°N). Pregnant women at 27–30 weeks gestation (n = 28) were randomized to 70,000 IU once + 35,000 IU/week vitamin D3 (group PH: pregnant, higher dose) or 14,000 IU/week vitamin D3 (PL: pregnant, lower dose) until delivery. A group of non-pregnant women (n = 16) was similarly administered 70,000 IU once + 35,000 IU/week for 10 weeks (NH: non-pregnant, higher-dose). Rise (∆) in serum 25-hydroxyvitamin D concentration ([25(OH)D]) above baseline was the primary pharmacokinetic outcome. Baseline mean [25(OH)D] were similar in PH and PL (35 nmol/L vs. 31 nmol/L, p = 0.34). A dose-response effect was observed: ∆[25(OH)D] at modeled steady-state was 19 nmol/L (95% CI, 1 to 37) higher in PH vs. PL (p = 0.044). ∆[25(OH)D] at modeled steady-state was lower in PH versus NH but the difference was not significant (−15 nmol/L, 95% CI −34 to 5; p = 0.13). In PH, 100% attained [25(OH)D] ≥ 50 nmol/L and 90% attained [25(OH)D] ≥ 80 nmol/L; in PL, 89% attained [25(OH)D] ≥ 50 nmol/L but 56% attained [25(OH)D] ≥ 80 nmol/L. Cord [25(OH)D] (n = 23) was slightly higher in PH versus PL (117 nmol/L vs. 98 nmol/L; p = 0.07). Vitamin D3 was well tolerated; there were no supplement-related serious adverse clinical events or hypercalcemia. In summary, a regimen of an initial dose of 70,000 IU and 35,000 IU/week vitamin D3 in the third trimester of pregnancy was non-hypercalcemic and attained [25(OH)D] ≥ 80 nmol/L in virtually all mothers and newborns. Further research is required to establish the safety of high-dose vitamin D3 in pregnancy and to determine if supplement-induced [25(OH)D] elevations lead to maternal-infant health benefits.

Robust reference intervals for liver function test (LFT) analytes in newborns and infants

Background

Reference intervals (RIs) are ranges of upper and lower limits of a given analyte which are used for a laboratory test to determine whether a disease is present or absent or to know if the patient is at risk for future disease states. In Ethiopia, a country with highly diversified population groups and geographical sites, there are no established RIs to metabolic analytes including the liver function test (LFT) analytes for the pediatric population though it has been known that liver function assessment in this population is vital as a result of varied vulnerability to both endogenous and xenobiotic substances.

Methods

A cross sectional study was conducted in Tikur Anbessa Specialized Hospital (TASH) and Teklehaymanot Health Center (THC) from November 2010 to April 2011. 117 cord blood (from newborns) and venous blood samples (from infants) were collected and analyzed using HumaStar 300. All pre-analytical, analytical and post-analytical aspects were thoroughly controlled. A robust, CLSI/ IFCC recommended, method was used for the determination of upper and lower end points covering 95% of the reference values of each analyte with respective 90% CIs using MedCalc® software.

Results

Combined RIs for newborns and infants were established for albumin, AST, ALP, direct bilirubin and total bilirubin to be 3.88-5.82 g/dl, 16.1-55.4U/l, 130-831U/l, <0.41 mg/dl and <1.37 mg/dl respectively. But, separated RIs were indicated for ALT and GGT as 1.2-23.1U/l and 6.94-24.8U/l ALT; and 30.6-160.7U/L and 10–28.2U/l GGT for newborns and infants respectively. Some maternal and infantile factors were identified to affect the values of analytes.

Conclusion

Almost all analytes were different from previously reported values for other target population of similar age group, kit insert values and adult values. So, interpretation of values of these analytes in newborns and infants of Ethiopian population sounds better to be performed by using such RIs taking the effect of some maternal and infantile factors in to account.

Effect of vitamin D supplementation during pregnancy on neonatal mineral homeostasis and anthropometry of the newborn and infant

Hypovitaminosis D is common in India. In the present prospective partially randomised study of vitamin D (D₃) supplementation during pregnancy, subjects were randomised in the second trimester to receive either one oral dose of 1500 μg vitamin D₃ (group 1, n 48) or two doses of 3000 μg vitamin D₃ each in the second and third trimesters (group 2, n 49). Maternal 25-hydroxyvitamin D (25(OH)D) at term, cord blood (CB) alkaline phosphatase (ALP), neonatal serum Ca and anthropometry were measured in these subjects and in forty-three non-supplemented mother-infant pairs (usual care). Median maternal 25(OH)D at term was higher in group 2 (58·7, interquartile range (IQR) 38·4-89·4 nmol/l) v. group 1 (26·2, IQR 17·7-57·7 nmol/l) and usual-care group (39·2, IQR 21·2-73·4 nmol/l) (P = 0·000). CB ALP was increased (>8.02 μkat/l or >480 IU/l) in 66·7 % of the usual-care group v. 41·9 % of group 1 and 38·9 % of group 2 (P = 0·03). Neonatal Ca and CB 25(OH)D did not differ significantly in the three groups. Birth weight, length and head circumference were greater and the anterior fontanelle was smaller in groups 1 and 2 (3·08 and 3·03 kg, 50·3 and 50·1 cm, 34·5 and 34·4 cm, 2·6 and 2·5 cm, respectively) v. usual care (2·77 kg, 49·4, 33·6, 3·3 cm; P = 0·000 for length, head circumference and fontanelle and P = 0·003 for weight). These differences were still evident at 9 months. We conclude that both 1500 μg and two doses of 3000 μg vitamin D₃ had a beneficial effect on infant anthropometry, the larger dose also improving CB ALP and maternal 25(OH)D.

Fetal gender and cocaine exposure as determinants of cord blood gamma-glutamyl transferase activity

OBJECTIVE

The serum activity of the hepatic enzyme gamma-glutamyl transferase (GGT) is elevated in the newborn relative to older age groups. Few reports to date have studied the influence of perinatal factors on neonatal serum GGT and no study has assessed the influence of maternal drug ingestion.

STUDY DESIGN

Cord blood was randomly collected from 234 liveborn infants and correlated with a range of maternal and fetal perinatal variables to assess influences on cord blood GGT.

RESULTS

Our study showed that the range of cord blood GGT activity in 234 randomly selected term newborns was 22 to 556 IU/l. In a subgroup of 75 newborns, GGT activity was independently influenced by only two of the variables studied - cocaine exposure and fetal gender (p=0.009, r=0.39). Females had a lower GGT than males (95+/-66 vs 130+/-90 IU/l, p<0.001) while GGT activity in cocaine-exposed newborns was lower than in cocaine-nonexposed newborns (96+/-48 vs 142+/-109, p<0.01). Birth weight, race, gestational age, and maternal serum GGT were not found to significantly influence cord blood GGT activity. Maternal GGT was uniformly normal and was not affected by any of the variables tested.

CONCLUSION

Our findings demonstrate that the reference range for cord blood GGT activity is wide and appears to be influenced by fetal gender and cocaine exposure.

Glutathione S-transferase Alpha 1-1 and aminotransferases in umbilical cord blood

Recent data suggest that levels of glutathione S-transferase Alpha 1-1 in umbilical cord plasma may be a good indicator of neonatal hepatocellular integrity. In order to fully understand the significance of this new marker we compared the values of glutathione S-transferase Alpha 1-1 (GSTA1-1) with that of the well known liver function markers alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in arterial and corresponding venous umbilical cord blood of 93 patients. In addition, in 49 of these patients maternal venous blood was also studied. Both arterial and venous umbilical cord GSTA1-1 and AST levels were significantly higher than corresponding maternal venous levels, whereas ALT levels were not. Arterial umbilical cord GSTA1-1 correlated significantly with the corresponding AST and ALT levels (R = 0.46, P < 0.0001 and R = 0.41, P < 0.0001, respectively). Arterial umbilical cord AST correlated significantly with corresponding ALT levels (R = 0.58, P < 0.0001). Arterial umbilical cord plasma GSTA1-1 levels were significantly lower in the cesarean delivery group as compared to the vaginal birth group, whereas no difference was noted for AST or ALT. Arterial umbilical cord AST and GSTA1-1 levels correlated significantly with base deficit (R = 0.29, P = 0.005; R = 0.29, P = 0.005, respectively), whereas ALT did not (R = 0.06, P = 0.54). Arterial umbilical cord AST, ALT, and GSTA1-1 levels correlated significantly with birthweight. In conclusion, GSTA1-1 levels as assessed in neonatal umbilical cord blood, being unrelated to maternal levels, seem to be a more sensitive marker for early neonatal hepatocellular integrity as compared to ALT or AST and even might detect impaired hepatocellular integrity due to the vaginal birth process. Umbilical cord GSTA1-1 may provide a valuable indicator of neonatal condition immediately after birth, the clinical relevance of which needs to be further established.

Biochemical diagnosis in prenatal uropathy

Thirty-two fetuses, six with prune-belly syndrome, seven with renal cyst, 19 with obstructive uropathy, underwent intrauterine fluid aspiration during weeks 15-37 of gestation. Fluid samples were analysed for Na, K, creatinine, urea, alpha 1-, and beta 2-microglobulin. Aspirate concentrations of sodium below 130 mmol/L and creatinine above 115 mumol/L indicate an active kidney and exclude a renal cyst. However, aspirates from fetal cysts or fetuses with obstructive uropathy showed analyte concentrations for sodium, potassium, creatinine, and urea corresponding to extracellular fluid (ECF). In conclusion fluid aspirates of fetuses with ultrasonographically detectable cystic cavities in the abdomen should be examined for sodium and creatinine to assess remaining renal function for planning of obstetric management.