A study of oxidative stress in neonates delivered through meconium-stained amniotic fluid

Oxidative stress biomarkers for fetal growth restriction in umbilical cord blood: A scoping review

Fetal growth restriction and underlying placental insufficiency are associated with increased oxidative stress. Current diagnostics fail to identify all growth restricted fetuses and newborns, due to focus on small size. This scoping review aims to summarize the available evidence on usefulness of cord blood oxidative stress biomarkers for identification of growth restricted newborns in need of monitoring and support because of associated health risks. MEDLINE and EMBASE were searched from inception to May 2024. Studies were included if oxidative stress biomarkers were measured in cord blood collected immediately after delivery in newborns suspected to be growth restricted. Biomarkers were categorized based on the origin and/or biological function and their interrelationships. Oxidative stress was determined for each individual biomarker and category. Literature search identified 78 studies on 39 different biomarkers, with a total of 2707 newborns with suspected growth restriction, and 4568 controls. Total oxidant/antioxidant status, catalase, glutathione, ischemia-modified albumin, and nucleated red blood cells were most consistently associated with suspected growth restriction. Reactive oxygen species/reactive nitrogen species, factors in their production, antioxidant enzymes, non-enzymatic antioxidants, and products of oxidative stress were not consistently associated. This review collates the evidence of associations between cord blood oxidative stress biomarkers and growth restriction. Total oxidant/antioxidant status, catalase, glutathione, ischemia-modified albumin, and nucleated red blood cells could potentially be candidates for developing a cord blood diagnostic tool for future clinical use.

Correlation of Meconium-Stained Amniotic Fluid and Adverse Pregnancy Outcomes between 37 to 39 and 40 to 42 Weeks of Gestational Age

OBJECTIVE

We aimed at assessing the association between meconium-stained amniotic fluid (MSAF) and adverse maternal and neonatal outcomes in early-term versus late-term pregnancies.

STUDY DESIGN

Early-term pregnancies (37-39 weeks of gestation) presented with MSAF were compared with late-term (40-42 weeks of gestation) pregnancies with MSAF. The groups were compared with respect to background characteristics, maternal outcomes, and neonatal outcomes. The composite neonatal outcome was the primary outcome of the study, and secondary outcomes included maternal and neonatal outcomes.

RESULTS

The early-term group comprised 239 women, compared with 362 women in the late-term group. The primary outcome did not differ between groups. We found a higher prevalence of gestational diabetes (8.37 vs. 3%, p < 0.05), a shorter second stage of labor (45.61 ± 54.67 vs. 65.82 ± 62.99 minutes, p < 0.05), and a longer hospital stay (2.84 ± 2.21 vs. 2.53 ± 1.26 days, p < 0.05) in the early-term group. Other maternal and neonatal characteristics and outcomes were not significantly different between the two groups.

CONCLUSION

In term pregnancies complicated by MSAF, adverse neonatal and maternal delivery outcomes are equivalent, regardless of gestational age, and therefore, any term pregnancy complicated by MSAF should be considered high risk and managed appropriately.

KEY POINTS

· In term pregnancies complicated by MSAF, adverse neonatal and maternal delivery outcomes are equivalent, regardless of gestational age.. · Any term pregnancy complicated by MSAF should be considered high risk and managed appropriately.. · Deliveries presented with MSAF are typically considered to be high risk and require close fetal surveillance by a certified team with resuscitation skills.. · Our study may help to reduce the need for a close fetal surveillance and delivery interventions if MSAF is not identified as a risk factor for adverse outcomes in late-term pregnancies..

Bloody Amniotic Fluid and Neonatal Outcomes

Information on the effect of bloody amniotic fluid during labor at term is scarce. This study assessed risk factors and adverse outcomes in labors with bloody amniotic fluid. During the six years of this study, all nulliparas in our institution, with a trial of labor, were included. Multiple pregnancies and preterm deliveries were excluded. Outcomes were compared between the bloody amniotic fluid group and the clear amniotic fluid group. Overall, 11,252 women were included. Among them, 364 (3.2%) had bloody amniotic fluid and 10,888 (96.7%) had clear amniotic fluid. Women in the bloody amniotic fluid group were characterized by shorter duration of the second stage and higher rate of cesarean section due to non-reassuring fetal heart rate. In addition, there were higher rates of low cord pH (<7.1) and NICU admissions in the bloody amniotic fluid group. In multivariate logistic regression analysis, cesarean delivery, cord blood pH < 7.1, and NICU admission were independently associated with increased odds ratio for bloody amniotic fluid. Bloody amniotic fluid at term is associated with adverse outcomes and must be considered during labor.

Women with preeclampsia exposed to air pollution during pregnancy: Relationship between oxidative stress and neonatal disease - Pilot study

Oxidative imbalance as a pathophysiological mechanism has been reported as an adverse outcome in pregnant women who develop preeclampsia and in their newborns. Furthermore, emerging evidence suggests the same mechanism by which air pollutants may exert their toxic effects. Therefore, the objective of the study was to evaluate the biomarkers of oxidative stress and their relationship with neonatal disease in premature newborns from mothers with preeclampsia exposed to air pollution during pregnancy. The data of air pollutants (PM_2.5, PM₁₀ and ozone) were collected at fixed monitoring stations. Oxidative and antioxidant status markers were obtained through special techniques in women with preeclampsia and in umbilical cord blood of their premature newborns. The oxidative stress markers were significantly higher in women with preeclampsia and their newborns who were exposed to higher levels of ambient air pollutants in the first and second trimester of pregnancy. Neonatal diseases are associated with preeclampsia in pregnancies, specifically intrauterine growth restriction (IUGR) and necrotizing enterocolitis (NEC). A significant correlation was identified in the levels of prooxidant agents and antioxidant enzyme activity in the presence of neonatal diseases associated with preeclampsia. There is increased oxidative damage in both the maternal and fetal circulation in women who develop preeclampsia exposed to air pollution during pregnancy. Therefore, these pregnancies complicated by preeclampsia have a greater adverse outcome as neonatal disease in the preterm infant.

Impact of Thin Meconium on Delivery and Early Neonatal Outcomes

Several reports regarding the effects of thin meconium on maternal and neonatal outcomes are contradictory. This study evaluated the risk factors and obstetrical outcomes during deliveries complicated with thin meconium. This retrospective cohort study included all women with a singleton pregnancy, who underwent trial of labor >24 weeks of gestation, in a single tertiary center, over a six-year period. Obstetrical, delivery, and neonatal outcomes were compared between deliveries with thin meconium (thin meconium group) to deliveries with clear amniotic fluid (control group). Included in the study were 31,536 deliveries. Among them 1946 (6.2%) were in the thin meconium group and 29,590 (93.8%) were controls. Meconium aspiration syndrome was diagnosed in eight neonates in the thin meconium group and in none of the controls (0.41%, p < 0.001). In multivariate logistic regression analysis, the following adverse outcomes were found to be independently associated with increased odds ratio (OR) for thin meconium: intrapartum fever (OR 1.37, 95% CI 1.1-1.7), instrumental delivery (OR 1.26, 95% CI 1.09-1.46), cesarean delivery for non-reassuring fetal heart rate (OR 2.0, 95% CI 1.68-2.46), and respiratory distress requiring mechanical ventilation (OR 2.06, 95% CI 1.19-3.56). Thin meconium was associated with adverse obstetrical, delivery, and neonatal outcomes that should receive extra neonatal care and alert the pediatrician.

Effects of continuous prenatal and postnatal global system for mobile communications electromagnetic waves (GSM-EMW) exposure on the oxidative stress biomarkers in female rat liver

In light of the increased use of communication technologies, the harm caused by continuous exposure to emitted radiation on pregnancy and developing newborns is among the public concerns. Using Sprague-Dawley rats, our study investigates the effects of 24 h/day prenatal and postnatal 900 MHz radiofrequency electromagnetic radiation (RF-EMR) exposure of female rats on liver oxidative stress (OS) and other hepatic parameters at postnatal days (PND) 1, 9, and 21. Our results showed that RF-EMR exposure led to an increase in oxidative stress status as indicated by a significant elevation in MDA level at PND9 and PND21, a decrease in catalase (CAT) activity at all ages, a reduction (PND1 and PND9) in catalase amounts and mRNA expression, in addition to a decrease in GPx activity at PND21 in the exposed group. Current findings also showed a significant increase in cytoSOD at PND9 and 21 and a reduction in mitoSOD at PND21 in the exposed groups compared to the control groups. However, significant increases in glutathione peroxidase (GPx) level and mitoSOD activity were observed at all studied ages. Furthermore, cytoSOD activity showed a significant reduction in PND1, whereas in PND9 the value of this parameter increased compared to the non-exposed group. Moreover, while SOD1 mRNA expression increased at PND1, it decreased at PND9 and 21. However, GPx1 expression was shown to be always decreased in the exposed group. In addition, at PND1 and 9, exposed rats showed a similar response on Akt1, nuclear factor erythroïd 2-related factor 2 (Nrf-2), and intercellular adhesion molecule-1 (ICAM-1) expression. Therefore, an increased oxidative stress status produced from a continuous (24 h/day) GSM-modulated 900 MHz radiofrequency electromagnetic radiation (RF-EMR) exposure during the prenatal and postnatal periods may result in adverse health effects during future life stages.

Neonatal diseases and oxidative stress in premature infants: an integrative review

OBJECTIVE

To describe the relationship of oxidative stress and antioxidant biomarkers in cord blood of premature newborns and the prognosis of diseases in the neonatal period.

SOURCES

This study consists of an integrative review. Searches were conducted in electronic databases Scopus, PubMed, Web of Science, and Medline/Lilacs through the Virtual Library on Health Issues, using the descriptors: "premature infants", "preterm infants", "preterm birth", "preterm", "oxidative stress", "antioxidants", "infant, premature, diseases" and "cord blood". Original articles published between 2016 and 2021 in Portuguese, English, or Spanish, which analyzed oxidative stress and/or antioxidant levels through cord blood of premature newborns and evaluated clinical outcomes, were included.

SUMMARY OF THE FINDINGS

Of the 1,003 studies reviewed, after exclusion of duplicate articles, analysis of titles, abstracts, and full texts, 18 articles were included. 72.2% (n = 13) of analyzed studies reported a positive association between oxidative stress and the development of prematurity-related diseases; 27.7% (n = 5) showed no significant relation. Outcomes that showed a positive association were: intrauterine growth restriction, necrotizing enterocolitis, bronchopulmonary dysplasia, intraventricular hemorrhage, fetal inflammatory response syndrome, early-onset neonatal sepsis, retinopathy of prematurity, morbidity, and mortality.

CONCLUSION

The analysis of oxidative stress and antioxidants in cord blood of premature newborns may be useful in the prognosis of some pathologies. The consequences of oxidative damage are known to be associated with increased morbidity in the short and long term. Further investigation is needed in this population in order to define normality parameters of biomarkers, clinical manifestations, diagnosis and treatment of these conditions.

Exposure to Meconium-Stained Amniotic Fluid and Long-Term Neurological-Related Hospitalizations throughout Childhood

OBJECTIVE

This study aimed to investigate the possible impact of meconium-stained amniotic fluid (MSAF) on the occurrence of neurological-related hospitalizations throughout childhood and adolescence.

STUDY DESIGN

In this population-based cohort analysis, all singleton deliveries occurring between 1991 and 2014 at the Soroka University Medical center were included and the long-term neurological-related hospitalizations were compared between children with and without MSAF during their delivery. A Kaplan-Meier survival analysis was constructed for the evaluation of cumulative hospitalization rate due to neurological morbidity over the 18 years of follow-up, and a Cox proportional hazards model was used to study the independent association between MSAF and childhood neurological morbidity while controlling for potential confounders.

RESULTS

During the study period, 243,725 deliveries met the inclusion criteria; 35,897 of the cohort (15%) constituted the exposed group (MSAF), while the rest of the cohort (n = 207,828) constituted the unexposed group (no MSAF). A total of 7,543 hospitalizations due to neurological-related morbidity were documented with a rate of 3.2% (1,152) in children exposed to MSAF as compared with 3.1% (6,391) in the unexposed group (OR 1.1, 95% confidence interval 0.9-1.1, p = 0.149). The survival curve showed a comparable cumulative hospitalization rate in the MSAF-exposed group compared with the unexposed group (log rank p = 0.349). The Cox analysis, controlled for gestational diabetes and hypertension, gestational and maternal ages, demonstrated MSAF exposure not to be an independent risk factor for neurological-related hospitalizations during childhood (adjusted hazard ratio = 1.03, 0.96-1.09).

CONCLUSION

Fetal exposure to MSAF, at any gestational age, does not appear to be an independent risk factor for later neurological-related hospitalizations throughout childhood and adolescence.

KEY POINTS

· MSAF is associated with several short-term complications such as low Apgar scores.. · The long-term implications of MSAF exposure are yet to be clearly defined.. · Fetal exposure to MSAF is not a risk factor for neurological morbidity throughout childhood..

Oxidative stress biomarkers in the preterm infant

Oxidative stress (OS) plays a key role in the pathophysiology of preterm infants. Accurate assessment of OS remains an analytical challenge that has been partially addressed during the last few decades. A plethora of approaches have been developed to assess preterm biofluids to demonstrate a link postnatally with preterm OS, giving rise to a set of widely employed biomarkers. However, the vast number of different analytic methods and lack of standardization hampers reliable comparison of OS-related biomarkers. In this chapter, we discuss approaches for the study of OS in prematurity with respect to methodologic considerations, the metabolic source of different biomarkers and their role in clinical studies.

Correlations between the Status of the Umbilical Cord and Neonatal Health Status

Purpose: This study aimed to identify correlations between the status of the umbilical cord and neonatal health status.Methods: In total, 172 newborns were enrolled who were admitted to the newborn nursery with a gestational age of 35 weeks or older and a body weight of 2 kg or above. Data were collected on the basic personal information of the newborns, the diameter and soft tissue status of the umbilical cord, and neonatal health status after birth. Analyses were performed using t-test, analysis of variance, <i>x</i>² test, and Fisher exact test.Results: Umbilical cord diameter exhibited a statistically significant difference by sex (t=2.71, <i>p</i>=.007). A thin umbilical cord diameter was associated with a 1-minute Apgar score less than 8 points (t=2.47, <i>p</i>=.015) and with being transferred to the intensive care unit (t=2.45, p=.015). Poor soft tissue status of the umbilical cord was associated with a 1-minute Apgar score of less than 8 points (<i>x</i>²=16.68, <i>p</i><.001) and with oxygen being supplied (<i>x</i>²=4.81, <i>p</i>=.028).Conclusion: Assessing the umbilical cord diameter and status in newborns is an important tool for evaluating neonatal health status after birth, and this point also underscores the importance of professionals' careful observations in the newborn nursery.

Free radicals and neonatal encephalopathy: mechanisms of injury, biomarkers, and antioxidant treatment perspectives

Neonatal encephalopathy (NE), most commonly a result of the disruption of cerebral oxygen delivery, is the leading cause of neurologic disability in term neonates. Given the key role of free radicals in brain injury development following hypoxia-ischemia-reperfusion, several oxidative biomarkers have been explored in preclinical and clinical models of NE. Among these, antioxidant enzyme activity, uric acid excretion, nitric oxide, malondialdehyde, and non-protein-bound iron have shown promising results as possible predictors of NE severity and outcome. Owing to high costs and technical complexity, however, their routine use in clinical practice is still limited. Several strategies aimed at reducing free radical production or upregulating physiological scavengers have been proposed for NE. Room-air resuscitation has proved to reduce oxidative stress following perinatal asphyxia and is now universally adopted. A number of medications endowed with antioxidant properties, such as melatonin, erythropoietin, allopurinol, or N-acetylcysteine, have also shown potential neuroprotective effects in perinatal asphyxia; nevertheless, further evidence is needed before these antioxidant approaches could be implemented as standard care.

Correlation of functional echocardiography and clinical parameters in term neonates with shock

BACKGROUND

To evaluate the correlation between functional echocardiography and clinical parameters in term neonates with shock.

METHOD

Cross sectional study of 30 full term newborns who were clinically detected to have shock compared to 30 full term hemodynamically stable neonates. For statistical analysis, cases were further sub classified into cardiogenic and septic shock.

RESULT

Functional echocardiography revealed inferior vena cava collapsibility index (cIVC), fractional shortening (FS), ejection fraction (EF), cardiac output and superior vena cava (SVC) flow were significantly lower whereas myocardial performance index (MPI) was significantly higher in babies with cardiogenic and septic shock as compared to the controls. Left ventricular end diastolic area (LVEDA) was significantly higher in cardiogenic shock whereas it was significantly lower in septic shock as compared to the controls. Also, cIVC was significantly lower and LVEDA was significantly higher in cardiogenic as compared to the septic shock. In cardiogenic shock SVC flow correlated significantly with capillary filling time and systolic blood pressure. The correlation between functional echocardiographic parameters of cardiogenic and septic shock showed that EF, FS and MPI were positively and significantly correlated (r 0.742, p 0.022 for EF, r 0.766, p 0.016 for FS and r 0.478, p 0.05 for MPI) whereas SVC flow and cIVC were negatively and significantly correlated between cardiogenic and septic shock (r - 0.655, p 0.045 for SVC flow and - 0.578, p 0.05 for cIVC).

CONCLUSION

In the complex environment of neonatal intensive care unit detection of shock continues to be a major challenge. Functional echocardiography provides an adjunct information to the clinical assessment of shock and helps in monitoring the response to treatment.

Non-invasive assessment of oxidative stress in preterm infants

Preterm newborns have an immature antioxidant defense system and are especially susceptible to oxidative stress. Resuscitation, mechanical ventilation, intermittent hypoxia and apneic episodes require frequently oxygen supplementation which leads to oxidative stress in preterm newborns. The consequences of oxidative damage are increased short and long-term morbidities, neurodevelopmental impairment and increased mortality. Oxidative stress biomarkers are determined in blood samples from preterm children during their stay in neonatal intensive care units especially for research purposes. However, there is a tendency towards reducing invasive and painful techniques in the NICU (Neonatal Intensive Care Unit) and avoiding excessive blood extractions procedures. In this paper, it has been described some studies that employed non-invasive samples to determine oxidative stress biomarkers form preterm infants in order to perform a close monitoring biomarker with a significant greater predictive value. Among these methods we describe a previously developed and validated high-performance liquid chromatography tandem mass spectrometry method that allow to accurately determine the most reliable biomarkers in biofluids, which are non-invasively and painlessly obtained.

Experimental Models of Acute Lung Injury in the Newborns

Acute lung injury in the preterm newborns can originate from prematurity of the lung and insufficient synthesis of pulmonary surfactant. This situation is known as respiratory distress syndrome (RDS). In the term neonates, the respiratory insufficiency is related to a secondary inactivation of the pulmonary surfactant, for instance, by action of endotoxins in bacterial pneumonia or by effects of aspirated meconium. The use of experimental models of the mentioned situations provides new information on the pathophysiology of these disorders and offers unique possibility to test novel therapeutic approaches in the conditions which are very similar to the clinical syndromes. Herewith we review the advantages and limitations of the use of experimental models of RDS and meconium aspiration syndrome (MAS) and their value for clinics.