Urinary oxidative stress biomarkers are associated with preterm birth: an Environmental Influences on Child Health Outcomes program study

Association between organic micropollutants in tap water and human exposure and birth outcomes: Implications for environmental health in northern Puerto Rico

The presence of micropollutants in Puerto Rico's tap water, potentially linked to nearby Superfund sites, was hypothesized to contribute to the region's higher preterm birth rate than the US mainland. This study analyzed the presence of 175 micropollutants in tap water samples collected from participant households and evaluated their association with human exposure using 14 oxidative stress and inflammation biomarkers in urine samples collected from pregnant participants, and further with the subsequent birth outcome information. Notably, three out of four oxidative stress biomarkers consistently showed negative correlations with five micropollutant categories, highlighting the oxidative stress induced by these contaminants. For the ten selected inflammation-related biomarkers, two showed positive yet not significant correlations with the five categories of micropollutants and, only one biomarker (MMP1), an inflammation biomarker whose down-regulation was associated with pre-mature birth implications, showed significant negative correlation with industrial chemicals and pesticides. Interestingly, the detected urinary phthalate metabolites in pregnant women could not be linked with the two parent phthalates found in the tap water, suggesting that the two phthalates in tap water may not be the primary source of phthalate exposure to human body. Furthermore, hormones in tap water showed significant moderate-to-strong negative correlations with birth outcomes, raising specific health concerns for pregnant women in northern Puerto Rico. This is the first study to investigate the association among a wider spectrum of tap water micropollutants with pregnancy exposure and birth outcome in Puerto Rico and provide insights into water quality and associated human health impacts.

Experiences of multiple psychosocial stressors and associations with oxidative stress biomarkers during pregnancy

BACKGROUND

Oxidative stress is hypothesized to be one mechanism linking psychosocial stressor exposure to preterm birth and other adverse pregnancy outcomes. However, prior studies have focused solely on singular psychosocial stressors, which may not reflect real world exposures as pregnant women may experience multiple stressors simultaneously.

METHODS

Participants included a subset of the Chemicals in Our Bodies cohort, a prospective birth cohort in San Francisco, California (N = 227). Self -reported psychosocial stressors were assessed via questionnaires administered during the second trimester that addressed financial strain, food insecurity, job strain, neighborhood quality, caregiving, stressful life events, unplanned pregnancy, and perceived community status. Oxidative stress biomarkers were measured during the second trimester of pregnancy and included 15-F2t-IsoP, and its two major metabolites 2,3-dinor-5,6-dihydro-15-F2t-IsoP, and 2,3-dinor-15-F2t-IsoP, and PGF2α. Linear regression models were used to examine associations between individual and pairwise combinations of psychosocial stressors in relation to each oxidative stress biomarker.

RESULTS

15-F2t-IsoP, 2,3-dinor-15-F2t-IsoP, and 2,3-dinor-5,6-dihydro-15-F2t-IsoP were elevated among participants reporting experiences of low perceived community status, job strain, poor neighborhood quality, food insecurity, and stressful life events (e.g., β = 0.36, 95 % CI = 0.00, 0.72 for food insecurity in association with 15-F2t-IsoP). In models that included pairwise combinations of stressor exposures, nearly every combination was also associated with an increase in all oxidative stress biomarkers compared to those who experienced one or neither stressor. For example, stressful life events and poor neighborhood quality was associated with statistically significant increases in all biomarkers (e.g., β = 0.94, 95 % CI = 0.17, 1.71 for 2,3-dinor-5,6-dihydro-15-F2t-IsoP).

CONCLUSIONS

Urinary oxidative stress biomarkers were elevated among pregnant women exposed to psychosocial stressors, and exposure to multiple stressors resulted in the strongest associations. These findings support oxidative stress as one potential biological pathway linking prenatal psychosocial stress to preterm birth and other adverse pregnancy outcomes.

Assessment of per- and polyfluoroalkyl substances (PFAS) exposure and associations with oxidative stress biomarkers among pregnant women from the PROTECT cohort

INTRODUCTION

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals linked with adverse pregnancy outcomes, yet they remain understudied in Puerto Rico. Moreover, underlying biological mechanisms of PFAS are not fully understood, although oxidative stress and inflammation are suspected pathways.

OBJECTIVES

We aimed to characterize PFAS exposure among pregnant women in Puerto Rico and examine associations between early to mid-pregnancy PFAS concentrations and repeated measures of oxidative stress biomarkers.

METHODS

This study included 434 participants enrolled in the PROTECT birth cohort. We analyzed serum samples (∼18 weeks of gestation) for nine PFAS, while urinary oxidative stress biomarkers [8-isoprostaglandin F2α (8-IsoP), its metabolite (IsoP-M), and prostaglandin F₂α (PGF2α)] were measured up to three times during pregnancy. We examined associations between each PFAS and oxidative stress biomarker using linear mixed effects regression models and multivariable regression analyses, adjusting for maternal demographic, socioeconomic, and study-related factors.

RESULTS

PFOS, PFNA, PFHxS, and PFOA were detected in over 50 % of participants, with PFOS being the most dominant. The majority of participants had total PFAS levels above 2 ng/mL. In repeated measures analyses, an interquartile range increase in PFHxS was associated with a 5.35 % (95 % CI: 0.12, 10.86) rise in IsoP-M levels. In categorical analyses, moderate levels of PFOS and PFNA were positively associated with PGF2α, while higher PFDeA was suggestively linked to 8-IsoP and IsoP-M.

CONCLUSIONS

Despite relatively modest levels compared to the U.S. NHANES, certain PFAS were positively linked with oxidative stress or inflammation, highlighting the need for broader investigations to examine PFAS-related alteration of inflammatory processes during pregnancy.

Placental Proteomics Reveals an Elevated Level of Aldo-Keto Reductase 1-B1, Highlighting Its Potential Role in Spontaneous Preterm Birth

Preterm birth (PTB) refers to the delivery of a baby before the completion of 37 weeks of gestation. It is a significant global health issue with implications for both mothers and neonates. The placenta is a transient organ crucial in the sustenance of pregnancy until parturition; its dysfunction is associated with different adverse pregnancy outcomes, including PTB. We conducted a nested case-control study of 40 placental tissue samples from preterm and term deliveries to study their comparative protein profiles. Label-free quantitation (LFQ) revealed 23 differentially expressed proteins (DEPs). Aldo-keto reductase-B1 (AKR1B1) protein expression profile exhibited a declining trajectory with an increasing period of gestation (POG). Immunoblotting and immunohistochemistry analyses of placental samples also revealed elevated protein levels in extreme preterm samples. AKR1B1 is a functional Prostaglandin F synthase responsible for the synthesis of Prostaglandin-F2α, a prostanoid that is elevated during parturition and involved in cervical ripening, membrane rupture, myometrial contraction, and inflammation. Hence, our finding supports the idea that elevated AKR1B1 levels play a significant role in the pathology of preterm birth by amplifying Prostaglandin-F2α synthesis in the placental milieu and can be further explored as a potential predictor of this condition. Data are available via ProteomeXchange with the identifier PXD043480.

Oxidative stress as a potential mechanism linking gestational phthalates exposure to cognitive development in infancy

BACKGROUND

Gestational exposure to phthalates, endocrine disrupting chemicals widely used in consumer products, has been associated with poor recognition memory in infancy. Oxidative stress may represent one pathway linking this association. Hence, we examined whether exposure to phthalates was associated with elevated oxidative stress during pregnancy, and whether oxidative stress mediates the relationship between phthalate exposure and recognition memory.

METHODS

Our analysis included a subset of mother-child pairs enrolled in the Illinois Kids Development Study (IKIDS, N = 225, recruitment years 2013-2018). Concentrations of 12 phthalate metabolites were quantified in 2nd trimester urine samples. Four oxidative stress biomarkers (8-isoprostane-PGF2α, 2,3-dinor-5,6-dihydro-8-isoPGF2α, 2,3-dinor-8-isoPGF2α, and prostaglandin-F2α) were measured in 2nd and 3rd trimester urine. Recognition memory was evaluated at 7.5 months, with looking times to familiar and novel stimuli recorded via infrared eye-tracking. Novelty preference (proportion of time looking at a novel stimulus when paired with a familiar one) was considered a measure of recognition memory. Linear mixed effect models were used to estimate associations between monoethyl phthalate (MEP), sum of di(2-ethylhexyl) phthalate metabolites (ΣDEHP), sum of di(isononyl) phthalate metabolites (ΣDINP), and sum of anti-androgenic phthalate metabolites (ΣAA) and oxidative stress biomarkers. Mediation analysis was performed to assess whether oxidative stress biomarkers mediated the effect of gestational phthalate exposure on novelty preference.

RESULTS

The average maternal age at delivery was 31 years and approximately 50 % of participants had a graduate degree. A natural log unit increase in ΣAA, ΣDINP, and ΣDEHP was associated with a statistically significant increase in 8-isoPGF2α, 2,3-dinor-5,6-dihydro-8-isoPGF2α, and 2,3-dinor-8-isoPGF2α. The association was greatest in magnitude for ΣAA and 2,3-dinor-5,6-dihydro-8-isoPGF2α (β = 0.45, 95 % confidence interval = 0.14, 0.76). The relationship between ΣAA, ΣDINP, ΣDEHP, and novelty preference was partially mediated by 2,3-dinor-8-isoPGF2α.

CONCLUSIONS

Gestational exposure to some phthalates is positively associated with oxidative stress biomarkers, highlighting one mechanistic pathway through which these chemicals may impair early cognitive development.

Asking Why Is Necessary to Address Health Disparities: A Critical Approach for Solution-Oriented Environmental Epidemiological Research

BACKGROUND

In environmental epidemiology, we use an array of tools from various, related disciplines to answer key questions about environmental exposures in relation to health outcomes. Typically, we ask questions related to what, who, where, when, and how. We value these questions because they contribute to novel scientific discovery and our understanding of disease etiology linked to environmental exposures. In addition, these questions help us better understand who might be at highest risk of exposure and subsequent risk of disease. Although necessary for the goals of environmental epidemiology, these questions are insufficient for addressing environmental health disparities. Specifically, these questions may be able to help us describe exposure-health outcome associations but are limited in their ability to move beyond identification to intervening on observed disparities to achieve environmental health equity.

OBJECTIVES

We sought to emphasize the need to value and routinely add the key question of "Why?" in environmental epidemiological studies. In asking this additional critical question, we can identify and incorporate the structural determinants and drivers of environmental exposure disparities and determine whether these factors are linked to existing and historically recalcitrant health disparities. Further, we can design effective studies that build on existing frameworks to address the fundamental causes of environmental health disparities.

DISCUSSION

This commentary underscores the need to routinely incorporate "why" questions in the practice of environmental epidemiology. By asking and addressing "Why?" we can employ better, more solution-oriented study designs, improve data collection, and enhance our ability to collaborate with diverse study populations through trust-building and community-engaged research. Incorporating these approaches will move environmental epidemiology forward from mostly documenting to actively addressing environmental health disparities. https://doi.org/10.1289/EHP14513.

Association of per- and polyfluoroalkyl substances with the antioxidant bilirubin across pregnancy

BACKGROUND

In mechanistic and preliminary human studies, prenatal exposure to per- and polyfluoroalkyl substances (PFAS) is associated with oxidative stress, a potential contributor to maternal liver disease. Bilirubin is an endogenous antioxidant abundant in the liver that may serve as a physiological modulator of oxidative stress in pregnant people. Hence, our objective was to estimate the association between repeated measures of PFAS and bilirubin during pregnancy.

METHODS

The study population included 332 participants in the Atlanta African American Maternal-Child Cohort between 2014 and 2020. Serum samples were collected up to two times (early pregnancy: 6-18 gestational weeks; late pregnancy: 21-36 gestational weeks) for the measurement of perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and total bilirubin. We analyzed single PFAS with linear mixed effect regression and a mixture of the four PFAS with quantile g-computation. Models were repeated with a multiplicative interaction term to explore effect modification by study visit.

RESULTS

Overall, PFHxS was positively associated with bilirubin (β = 0.08, 95 % CI = 0.01, 0.15). We also found during late pregnancy, there was a positive association of PFHxS and the PFAS mixture with bilirubin (β = 0.12, 95 % CI = 0.02, 0.22; ψ = 0.19, 95 % CI = 0.03, 0.34, respectively). Finally, study visit modified the PFOA-bilirubin association (interaction p-value = 0.09), which was greater during early pregnancy (β = 0.08, 95 % CI = 0.01, 0.15).

CONCLUSION

In a prospective cohort of pregnant African Americans, an increase in PFOA, PFHxS, and the PFAS mixture was associated with an increase in bilirubin. Our results suggest that, depending on pregnancy stage, prenatal PFAS exposure disrupts the maternal liver antioxidant capacity.

Temporal Dynamics of Oxidative Stress and Inflammation in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is the most common lung complication of prematurity. Despite extensive research, our understanding of its pathophysiology remains limited, as reflected by the stable prevalence of BPD. Prematurity is the primary risk factor for BPD, with oxidative stress (OS) and inflammation playing significant roles and being closely linked to premature birth. Understanding the interplay and temporal relationship between OS and inflammation is crucial for developing new treatments for BPD. Animal studies suggest that OS and inflammation can exacerbate each other. Clinical trials focusing solely on antioxidants or anti-inflammatory therapies have been unsuccessful. In contrast, vitamin A and caffeine, with antioxidant and anti-inflammatory properties, have shown some efficacy, reducing BPD by about 10%. However, more than one-third of very preterm infants still suffer from BPD. New therapeutic agents are needed. A novel tripeptide, N-acetyl-lysyltyrosylcysteine amide (KYC), is a reversible myeloperoxidase inhibitor and a systems pharmacology agent. It reduces BPD severity by inhibiting MPO, enhancing antioxidative proteins, and alleviating endoplasmic reticulum stress and cellular senescence in a hyperoxia rat model. KYC represents a promising new approach to BPD treatment.

Gestational urinary concentrations of glyphosate and aminomethylphosphonic acid in relation to preterm birth: the MIREC study

BACKGROUND

Few high-quality studies have evaluated associations between urinary glyphosate or its environmental degradate (aminomethylphosphonic acid (AMPA)] and preterm birth (PTB).

OBJECTIVES

To quantify associations between urinary glyphosate and AMPA and preterm birth in the pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study and determine if associations differ by fetal sex.

METHODS

We measured first trimester urinary glyphosate and AMPA concentrations in MIREC participants who were recruited between 2008-2011 from 10 Canadian cities. Of the 1880 participants whose first trimester urine samples were analyzed for glyphosate or AMPA, 1765 delivered a singleton, live birth. Our primary outcome was preterm birth (PTB) defined as births occurring between 20 and <37 weeks. Secondary outcomes were spontaneous preterm births (sPTB) and gestational age. We modelled the hazard of PTB and sPTB using discrete time survival analysis with multivariable logistic regression to calculate odds ratios (OR). We used multivariable linear regression models to quantify associations between analytes and gestational age. To assess effect modification by fetal sex, we stratified all models and calculated interaction terms. In the logistic regressions models we additionally calculated the relative excess risk due to interaction.

RESULTS

Six percent (n = 106) of the study population delivered preterm, and 4.7% (n = 83) had a spontaneous preterm birth. Median specific-gravity standardized concentrations of glyphosate and AMPA were 0.25 and 0.21 µg/L. Associations between both glyphosate or AMPA and PTB, sPTB, and gestational age centered around the null value. The adjusted ORs of PTB for each doubling of glyphosate and AMPA concentrations were 0.98 (95% CI: 0.94, 1.03) and 0.99 (95% CI: 0.92, 1.06) respectively. We observed no evidence of differences by fetal sex.

CONCLUSIONS

In this Canadian pregnancy cohort, neither glyphosate nor AMPA urinary concentrations was associated with PTB or reduced gestational length.

Cross-Sectional Associations between Prenatal Per- and Poly-Fluoroalkyl Substances and Bioactive Lipids in Three Environmental Influences on Child Health Outcomes (ECHO) Cohorts

Prenatal per- and poly-fluoroalkyl substances (PFAS) exposure may influence gestational outcomes through bioactive lipids─metabolic and inflammation pathway indicators. We estimated associations between prenatal PFAS exposure and bioactive lipids, measuring 12 serum PFAS and 50 plasma bioactive lipids in 414 pregnant women (median 17.4 weeks' gestation) from three Environmental influences on Child Health Outcomes Program cohorts. Pairwise association estimates across cohorts were obtained through linear mixed models and meta-analysis, adjusting the former for false discovery rates. Associations between the PFAS mixture and bioactive lipids were estimated using quantile g-computation. Pairwise analyses revealed bioactive lipid levels associated with PFDeA, PFNA, PFOA, and PFUdA (p < 0.05) across three enzymatic pathways (cyclooxygenase, cytochrome p450, lipoxygenase) in at least one combined cohort analysis, and PFOA and PFUdA (q < 0.2) in one linear mixed model. The strongest signature revealed doubling in PFOA corresponding with PGD2 (cyclooxygenase pathway; +24.3%, 95% CI: 7.3-43.9%) in the combined cohort. Mixture analysis revealed nine positive associations across all pathways with the PFAS mixture, the strongest signature indicating a quartile increase in the PFAS mixture associated with PGD2 (+34%, 95% CI: 8-66%), primarily driven by PFOS. Bioactive lipids emerged as prenatal PFAS exposure biomarkers, deepening insights into PFAS' influence on pregnancy outcomes.

Bridging Differences in Cohort Analyses of the Relationship between Secondhand Smoke Exposure during Pregnancy and Birth Weight: The Transportability Framework in the ECHO Program

BACKGROUND

Estimates for the effects of environmental exposures on health outcomes, including secondhand smoke (SHS) exposure, often present considerable variability across studies. Knowledge of the reasons behind these differences can aid our understanding of effects in specific populations as well as inform practices of combining data from multiple studies.

OBJECTIVES

This study aimed to assess the presence of effect modification by measured sociodemographic characteristics on the effect of SHS exposure during pregnancy on birth weights that may drive differences observed across cohorts. We also aimed to quantify the extent to which differences in the cohort mean effects observed across cohorts in the Environmental influences on Child Health Outcomes (ECHO) consortium are due to differing distributions of these characteristics.

METHODS

We assessed the presence of effect modification and transportability of effect estimates across five ECHO cohorts in a total of 6,771 mother-offspring dyads. We assessed the presence of effect modification via gradient boosting of regression trees based on the H-statistic. We estimated individual cohort effects using linear models and targeted maximum likelihood estimation (TMLE). We then estimated transported effects from one cohort to each of the remaining cohorts using a robust nonparametric estimation approach relying on TMLE estimators and compared them to the original effect estimates for these cohorts.

RESULTS

Observed effect estimates varied across the five cohorts, ranging from significantly lower birth weight associated with exposure [- 167.3 g ; 95% confidence interval (CI): - 270.4 , - 64.1 ] to higher birth weight with wide CIs, including the null (42.4 g ; 95% CI: - 15.0 , 99.8). Transported effect estimates only minimally explained differences in the point estimates for two out of the four cohort pairs.

DISCUSSION

Our findings of weak to moderate evidence of effect modification and transportability indicate that unmeasured individual-level and contextual factors and sources of bias may be responsible for differences in the effect estimates observed across ECHO cohorts. https://doi.org/10.1289/EHP13961.

MicroRNA-322 overexpression reduces neural tube defects in diabetic pregnancies

BACKGROUND

Hyperglycemia from pregestational diabetes mellitus induces neural tube defects in the developing fetus. Folate supplementation is the only effective way to prevent neural tube defects; however, some cases of neural tube defects are resistant to folate. Excess folate has been linked to higher maternal cancer risk and infant allergy. Therefore, additional interventions are needed. Understanding the mechanisms underlying maternal diabetes mellitus-induced neural tube defects can identify potential targets for preventing such defects. Despite not yet being in clinical use, growing evidence suggests that microRNAs are important intermediates in embryonic development and can serve as both biomarkers and drug targets for disease intervention. Our previous studies showed that maternal diabetes mellitus in vivo activates the inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) in the developing embryo and that a high glucose condition in vitro reduces microRNA-322 (miR-322) levels. IRE1α is an RNA endonuclease; however, it is unknown whether IRE1α targets and degrades miR-322 specifically or whether miR-322 degradation leads to neural tube defects via apoptosis. We hypothesize that IRE1α can inhibit miR-322 in maternal diabetes mellitus-induced neural tube defects and that restoring miR-322 expression in developing neuroepithelium ameliorates neural tube defects.

OBJECTIVE

This study aimed to identify potential targets for preventing maternal diabetes mellitus-induced neural tube defects and to investigate the roles and relationship of a microRNA and an RNA endonuclease in mouse embryos exposed to maternal diabetes mellitus.

STUDY DESIGN

To determine whether miR-322 reduction is necessary for neural tube defect formation in pregnancies complicated by diabetes mellitus, male mice carrying a transgene expressing miR-322 were mated with nondiabetic or diabetic wide-type female mice to generate embryos with or without miR-322 overexpression. At embryonic day 8.5 when the neural tube is not yet closed, embryos were harvested for the assessment of 3 miR-322 transcripts (primary, precursor, and mature miR-322), tumor necrosis factor receptor-associated factor 3 (TRAF3), and neuroepithelium cell survival. Neural tube defect incidences were determined in embryonic day 10.5 embryos when the neural tube should be closed if there is no neural tube defect formation. To identify which miR-322 transcript is affected by maternal diabetes mellitus and high glucose conditions, 3 miR-322 transcripts were assessed in embryos from dams with or without diabetes mellitus and in C17.2 mouse neural stem cells treated with different concentrations of glucose and at different time points. To determine whether the endonuclease IRE1α targets miR-322, small interfering RNA knockdown of IRE1α or overexpression of inositol-requiring transmembrane kinase/endoribonuclease 1α by DNA plasmid transfection was used to determine the effect of IRE1α deficiency or overexpression on miR-322 expression. RNA immunoprecipitation was performed to reveal the direct targets of inositol-requiring transmembrane kinase/endoribonuclease 1α.

RESULTS

Maternal diabetes mellitus suppressed miR-322 expression in the developing neuroepithelium. Restoring miR-322 expression in the neuroepithelium blocked maternal diabetes mellitus-induced caspase-3 and caspase-8 cleavage and cell apoptosis, leading to a neural tube defect reduction. Reversal of maternal diabetes mellitus-inhibited miR-322 via transgenic overexpression prevented TRAF3 up-regulation in embryos exposed to maternal diabetes mellitus. Activated IRE1α acted as an endonuclease and degraded precursor miR-322, resulting in mature miR-322 reduction.

CONCLUSION

This study supports the crucial role of the IRE1α-microRNA-TRAF3 circuit in the induction of neuroepithelial cell apoptosis and neural tube defect formation in pregnancies complicated by diabetes mellitus and identifies IRE1α and miR-322 as potential targets for preventing maternal diabetes mellitus-induced neural tube defects.

Association between Serum 8-Iso-Prostaglandin F2α as an Oxidative Stress Marker and Immunological Markers in a Cohort of Preeclampsia Patients

BACKGROUND

We aimed to analyze the presence and clinical use of serum 8-iso-prostaglandin F2-alpha (8-iso-PGF2α) as an oxidative stress marker and some inflammatory status biomarkers (tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), IL-10, high-sensitivity C-reactive protein (hs-CRP), and pentraxin-3 (PTX3)) for patients with preeclampsia (PE).

METHODS

Sixty pregnant women, including thirty diagnosed with PE and thirty who were healthy (NP), were included in this study. For the assessment of serum levels of biomarkers, we used the Enzyme-Linked Immunosorbent Assay (ELISA) technique.

RESULTS

Our preliminary study showed that the expression level of serum 8-iso-PGF2α in the PE group was higher than in the PE after delivery (PE-AD) group (742.00 vs. 324.00 pg/mL, p < 0.0001). Groups of preeclamptic patients (PE + PE-AD) expressed significantly elevated levels for all of the assessed inflammatory mediators as compared to NP. Significant strong positive correlations with 8-iso-PGF2α levels were found for systolic blood pressure (SBP), and TNF-α (Spearman's rho = 0.622, p-value = 0.020 and rho = 0.645, p-value = 0.002, respectively). Our study demonstrates that 8-iso-PGF2α and PTX3 have the greatest diagnostic value for pregnant women with PE.

CONCLUSIONS

8-iso-PGF2α and PTX3 can be used as independent predictor factors, along with already-known cytokines, that could represent a prophylactic way to help clinicians identify or predict which pregnant women will develop PE.

Status of Oxidative Stress during Low-Risk Labour: Preliminary Data

Pregnancy and childbirth are associated with the forming of reactive oxygen species that generate oxidative stress. Oxidative stress is a factor that may adversely affect the development of the fetus and the course of labour. Monitoring the parameters of oxidative stress can be used to assess the risk of health issues in the course of pregnancy and the condition of the newborn. Therefore, the analysis of oxidative stress in the physiological course of labour is the basis for understanding the role of oxidative stress in the pathogenesis of miscarriages and neonatal health circumstances. The study aimed to assess oxidative stress of mother-child pairs in the venous blood and umbilical cord blood at the time of physiological labour. One hundred and sixty-eight mother-child pairs were recruited to donate the mother’s venous blood in the first stage of labour and the venous umbilical cord blood after the newborn’s birth. Total antioxidant status (TAS), the activity of superoxide dismutase (SOD) with cofactors (Zn, Cu, Mn) and the activity of glutathione peroxidase (GPx) were analysed in venous blood plasma and umbilical cord blood. TAS value (p = 0.034), GPx activity (p < 0.001) and Zn concentration (p = 0.007) were significantly lower in maternal blood plasma as compared to neonatal umbilical cord blood. However, the activity of SOD (p = 0.013) and the concentration of Cu (p < 0.001) were significantly higher in the blood of mothers than of new-borns. The concentration of Mn in the plasma of the mother’s blood and the umbilical cord blood of the newborns was similar. Our research indicates higher levels of antioxidant enzyme (GPx) and total antioxidant potential (TAS) in umbilical cord blood compared to maternal blood, which may suggest depletion of redox reserves in women’s blood during labour.