Oxidative stress in the fetal circulation does not depend on mode of delivery

Oxidative Stress in Pregnancy

Recent years have seen an increased interest in the role of oxidative stress (OS) in pregnancy. Pregnancy inherently heightens susceptibility to OS, a condition fueled by a systemic inflammatory response that culminates in an elevated presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the circulatory system. The amplified OS in pregnancy can trigger a series of detrimental outcomes such as underdevelopment, abnormal placental function, and a host of pregnancy complications, including pre-eclampsia, embryonic resorption, recurrent pregnancy loss, fetal developmental anomalies, intrauterine growth restriction, and, in extreme instances, fetal death. The body's response to mitigate the uncontrolled increase in RNS/ROS levels requires trace elements that take part in non-enzymatic and enzymatic defense processes, namely, copper (Cu), zinc (Zn), manganese (Mn), and selenium (Se). Determination of ROS concentrations poses a challenge due to their short half-lives, prompting the use of marker proteins, including malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), catalase (CAT), and glutathione (GSH). These markers, indicative of oxidative stress intensity, can offer indirect assessments of pregnancy complications. Given the limitations of conducting experimental studies on pregnant women, animal models serve as valuable substitutes for in-depth research. This review of such models delves into the mechanism of OS in pregnancy and underscores the pivotal role of OS markers in their evaluation.

Both spontaneous vaginal delivery and elective caesarean section influence neonatal redox status in dogs

BACKGROUND

The influence of birth mode on redox balance is unknown in dogs. We aimed to compare antioxidant activity and oxidative stress of puppies born by elective c-section or vaginal delivery.

METHODS

Twenty-one bitches were elected for spontaneous vaginal delivery (n = 10) and elective cesarean section (n = 11) groups, considering only the first and last puppies born. Neonatal oxygen saturation, lactatemia, superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and total antioxidant capacity; marker of oxidative stress (thiobarbituric acid reactive substances [TBARS]) and protein oxidation were analysed at birth, 1 h, 12 h, 24 h and 72 h.

RESULTS

C-section newborns had lower oximetry at birth and 1 h. Lactatemia was higher in the last vaginal delivery puppies and higher at birth, and 1 h. Regardless of birth mode, last puppies had hyperlactatemia at birth. Vaginal delivery puppies had higher TBARS, while protein oxidation was higher in c-section, mostly in last puppies. C-section puppies had higher GPx activity, whereas GSH concentration decreased overtime. Surgically born puppies had lowering SOD between 12 h and 72 h.

CONCLUSIONS

Vaginal delivery enhances lipid peroxidation, counteracted mostly by GPx. Conversely, c-section triggers protein oxidation, acutely scavenged by SOD and GSH, thus puppies are less exposed to the negative consequences of oxidative stress.

The effects of water immersion and epidural analgesia on cellular immune response, neuroendocrine, and oxidative markers

Background/aim

Water immersion and epidural analgesia are the most preferred pain relief methods during the labor process. Adverse effects related to these methods, impact on the labor, and perception of pain is well studied in the literature. We aimed to investigate the cord blood level of copeptin, total serum oxidant (TOS), antioxidant (TAS), interleukin (IL)-1, IL-6, and oxytocin after the labor with water immersion, epidural analgesia, and vaginal birth without pain relief.

Materials and methods

The study was conducted with 102 healthy pregnant women admitted to the obstetric delivery unit for noncomplicated term birth. Copeptin, oxytocin, TAS, TOS, IL-1, and IL-6 levels of cord blood and obstetric and neonatal results after vaginal birth were compared.

Results

The study included a total of 102 patients (group 1 = 30, group 2 = 30, and group 3 = 42). We found no significant difference between the three groups in terms of BMI, age, gravidity, parity, birth week, birth weight, interventional birth, perineal trauma, breastfeeding, duration of labor, oxytocin, IL-1 and IL-6 levels (p > 0.05). Neonatal intensive care unit (NICU) need, TAS, TOS, and copeptin levels were higher. Apgar scores were lower in the epidural group (p = 0.011, p = 0.036, p = 0.027, p < 0.001, and p < 0.001 respectively).

Conclusion

Epidural analgesia has deteriorated oxidative stress status and lower neonatal Apgar scores with higher NICU administration compared with water birth and vaginal birth without pain relief.

Oxidative stress and peripartum outcomes (Review)

Pregnancy, labor and childbirth are accompanied by excessive oxidative aggression. The excessive formation of free radicals [reactive oxygen species (ROS), reactive nitrogen species (RNS), chlorine reactive species (CRS)] causes cellular oxidative damage, which can be scavenged by enzymatic or non-enzymatic antioxidants in normal healthy pregnancy, physiological labor and delivery without any complications. An imbalance between the pro-oxidant and antioxidant factors may lead to oxidative stress, which contributes to the development of many diseases. This oxidative aggression can be a precursor for pathologies in the pregnant woman including eclampsia, miscarriage, preterm labor, and intrauterine growth retardation; in the offspring it may lead to bronchopulmonary dysplasia/chronic lung disease, necrotizing enterocolitis, retinopathy of prematurity, and periventricular leukomalacia. This review summarizes the studies conducted to identify the mechanisms of oxidative stress and the effect of cell membrane oxidation, the mechanisms that are behind oxidative stress-related diseases, and also those studies which have demonstrated the effect of antioxidants in preventing diseases or diminishing the effects of oxidative stress in the body, in obstetrics and neonatology.

Is placental blood a reliable source for the evaluation of neonatal hemostasis at birth?

BACKGROUND

Phlebotomy is among the main determinants of anemia of prematurity. Blood sparing policies endorsed umbilical cord blood (here called placental) as an alternative source for laboratory testing. Little is known on the suitability of placental blood to evaluate neonatal hemostasis of newborn infants. We aimed to compare the hemostatic profile of paired placental and infant venous blood, by means of prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, antithrombin, protein C, thromboelastography (TEG) and thrombin generation assay (TGA).

STUDY DESIGN

This was an observational single-center study.

METHODS

We collected at birth venous citrated blood from both placental and infant venous source and performed PT, APTT, fibrinogen, antithrombin, protein C, TEG (reaction time-R; kinetics-K alpha angle-α, maximum amplitude-MA and lysis at 30 minutes-LY30), and TGA (endogenous thrombin potential-ETP).

RESULTS

We enrolled 60 neonates with a median gestational age (range) of 37 weeks (28⁺¹ -41) and birth-weight 2417 g (950-4170). Based on TEG and TGA, placental blood showed a procoagulant imbalance as indicated by lower median R (4.0 vs. 6.1 min; p < 0.001) and K (1.3 vs. 2.2 min; p < 0.001); higher α-angle (69.7 vs. 57.4°; p < 0.001) and ETP (1260 vs. 1078; p = 0.002) than those observed for infant venous blood. PT and APTT did not differ significantly between the two groups.

CONCLUSIONS

While placental and neonatal blood samples are equally suitable to measure the standard coagulation tests PT and APTT, placental blood leads to a procoagulant imbalance when testing is performed with TEG or TGA. These effects should be considered when interpreting results stemming from investigation of neonatal hemostasis.

Effects of mode of delivery on pro-oxidant/antioxidant balance in fetal circulation

Objective: This study was undertaken to assess the influence of mode of delivery on the balance between pro-oxidant/antioxidant systems in fetal circulation. Materials and methods: Both umbilical arterial and venous blood samples were obtained from 37 pregnant women who delivered by spontaneous vaginal delivery (VD group) and from 29 pregnant women who delivered by elective cesarean section (CS group). Oxidative stress and antioxidant activity were evaluated by reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP), respectively. Results: The d-ROMs values of the VD group were higher than that of the CS group in both umbilical arterial and venous blood and these differences were found to be statistically significant (p < .01 and p < .01, respectively). The BAP values of only the umbilical arterial blood were found to be statistically significant (p < .01), with values from the VD group being higher than those of the CS group. In all measurements, the d-ROMs values averaged below 120 CARR U and BAP values averaged above 2200 µmol/L. The ratio of BAP/d-ROMs difference was found to be statistically significant (p < .01) only in the umbilical venous blood, with ratios in the VD group being lower than those in the CS group. Conclusions: Our statistical analyses suggest that vaginal delivery has an effect on increasing oxidative stress as a result of the stress of labor and that an elective cesarean section does not impair the mother's oxidative stress status. Furthermore, the high BAP values in all the measurements suggest that neonates just after birth have the ability to cope with oxidative stress. Rationale   In many studies, the diversity of views on the influence of mode of delivery on the redox status of neonates is likely to be caused by the use of different biomarkers to measure either the oxidative stress, the antioxidant activity, or both. Furthermore, incomplete explanation for sampling cord blood in these studies, either arterial, venous blood or both, complicates matters. To solve the above, this study was designed to assess the effects of mode of delivery on both pro-oxidants, via d-ROMs, and antioxidants, via BAP, in both umbilical arterial and venous blood samples obtained just after birth. There are no existing studies of BAP in both umbilical arterial and venous blood to which we can refer. In conclusion, our study suggests that the pro-oxidant/antioxidant balance in neonates just after birth is better than may be expected when compared to the potentials of adults (including pregnant mothers) according to interpretations of BAP/d-ROMs. This can be understood that neonates may have already been endowed with the ability to cope with oxidative stress, as informed by high BAP values in both umbilical arterial and venous blood. Vaginal delivery may have an effect on increasing oxidative stress as a result of the stress of labors (as measured by d-ROMs), and an elective cesarean section, which has better BAP/d-ROMs in umbilical venous blood than that of vaginal delivery, may not impair the mother's oxidative stress status.

Factors relating caesarean section to persistent pulmonary hypertension of the newborn

BACKGROUND

Several studies have clearly demonstrated a significantly higher incidence of persistent pulmonary hypertension of the newborn (PPHN) in neonates delivered by caesarean section (CS) compared to those delivered vaginally. The pathophysiological factors underlying the link between CS and PPHN are still poorly understood. In this review, we describe the mechanisms that could explain the association between CS delivery and subsequent PPHN, as well as potential preventive measures.

DATA SOURCES

A literature search was conducted by electronic scanning of databases such as PubMed and Web of Science using the key words "persistent pulmonary hypertension of the newborn", "caesarean section", "iatrogenic prematurity", "oxidative stress", "late preterm", "labor" and "vasoactive agents".

RESULTS

Iatrogenic prematurity, higher rates of late preterm delivery and lack of physiological changes of labor play an important role in the association between CS and PPHN. CS delivery also results in limited endogenous pulmonary vasodilator synthesis and lower levels of protective anti-oxidants in the neonates. In addition, CS delivery exposes infants to a higher risk of respiratory distress syndrome and its concomitant increase in endothelin-1 levels, which might indirectly lead to a higher risk of developing PPHN. We believe that neonates delivered by CS are exposed to a combination of these pathophysiological events, culminating in an endpoint of respiratory distress, hypoxia, acidosis, and delayed transition and thereby increased risks of PPHN. The use of antenatal corticosteroids prior to elective CS in late preterm deliveries, promoting accurate informedconsent process, delaying elective CS to 39 weeks of gestation or beyond and antenatal maternal anti-oxidant supplementation could potentially mitigate the effects of CS delivery and minimize CS-related PPHN.

CONCLUSIONS

The link between CS delivery and PPHN is complex. In view of the rising rates of CS worldwide, there is an urgent need to further explore the mechanisms linking CS to PPHN and experimentally test therapeutic options in order to allow effective targeted interventions.

An examination of the factors affecting intestinal wall integrity in newborns at birth

BACKGROUND

An understanding of the factors that influence intestinal wall integrity during the transition from fetal to neonatal life is important to elucidate and minimize potential contributions to the development of intestinal pathologies in vulnerable newborns.

OBJECTIVE

To assess the factors affecting intestinal wall integrity of late preterm and term newborns at birth.

METHODS

The concentrations of serum intestinal fatty acid-binding protein (I-FABP) as biomarker of intestinal wall injury, superoxide dismutase (SOD), and glutathione peroxidase (Gpx) as parameters of oxidative stress, and blood gas analyses were measured in the arterial cord blood of 80 newborns, delivered by spontaneous vaginal delivery (labor group) or elective cesarean delivery (non-labor group).

RESULTS

Compared with the non-labor group, I-FABP, SOD, and Gpx levels were significantly higher in the labor group. I-FABP concentration was inversely correlated with pH and BE and positively correlated with SOD and Gpx concentrations, second stage of labor duration, and active pushing time.

CONCLUSIONS

This study demonstrates that oxidative stress at birth and prolonged second stage of labor may lead to the intestinal injury, which is reflected in increased serum concentration of I-FABP.

Peripartum events and molar-incisor hypomineralisation (MIH) amongst young patients in southwest France

AIM

This was to investigate the association of peripartum events with the occurrence of MIH.

METHODS

This study, carried out between 2010 and 2011, was based on objective information noted in child health booklets on putative risk factors for MIH during the Peripartum period, aged between 6 to 28 years. The target population consisted of patients with MIH and a control group. Among the 849 patients examined by two calibrated paediatric dentists, 75 patients with MIH were recorded. These patients attended for consultation either at the teaching dental hospital of Bordeaux (France) or at a private dental practice (Bordeaux, France). Pearson's Chi-squared test was used and Odds ratios (OR) with 95 % test-based confidence intervals (CI) were calculated.

RESULTS

Correlations were observed between hypoxia during delivery and occurrence of MIH (OR = 6.1; CI = 1.7-21.85), and also between birth by caesarean section and MIH (OR = 2.9; CI = 1.2-6.9). There was no association between prematurity and MIH.

CONCLUSIONS

Peripartum events such as hypoxia during birth or delivery by caesarean section are suggested to be risk factors for the occurrence of MIH in this population.

Assessment of fetal antioxidant and oxidant status during different anesthesia techniques for elective cesarean sections

Background:

We aimed to investigate the effects of general, spinal and epidural anesthesia on fetal total antioxidant status (TAS) and total oxidant status (TOS), and oxidative stress index (OSI) during elective cesarean section in this study.

Materials and Methods:

Forty-seven parturients scheduled for elective cesarean section were randomly allocated into three groups: Group spinal (n = 15), group epidural (n = 17), and group general (n = 15), This prospective randomized study was performed in Faculty of Medicine, Turgut Ozal University, Turkey. After the baby was delivered; TAS, TOS levels, and arterial blood gases parameters were analyzed in an umbilical arterial blood sample. OSI values are calculated by a ratio of TOS to the TAS.

Results:

The levels of TAS and TOS in umbilical arterial blood sample were not statistically different among three. However, OSI values were significantly different among the three groups (P = 0.042). Median OSI values is 24 (interquartile range [IQR], 2-37) in group spinal, 19 (IQR, 4-44) in group epidural, and 8 (IQR, 4-36) in group general. There was no significant difference in OSI values in the comparison of group spinal with group general and group epidural, but it was significantly lower in group general when compared with group epidural with Bonferroni correction (P = 0.017). Umbilical cord arterial blood gas values (pH, PaCO₂, PaO₂, SaO₂, HCO₃, and CtO₂), glucose, lactate, and hemoglobin levels were similar in three groups.

Conclusion:

General anesthesia may be more favorable than epidural in those undergoing cesarean section when fetal oxidative status gains importance.

A new approach to oxidative stress and inflammatory signaling during labour in healthy mothers and neonates

The objective of the current study was to investigate for the first time and simultaneously the oxidative stress and inflammatory signaling induced during the delivery in healthy mothers and their neonates. 56 mothers with normal gestational course and spontaneous delivery were selected. Blood samples were taken from mother (before and after delivery) both from vein and artery of umbilical cord. Lower antioxidant enzymes activities were observed in neonates compared with their mothers and lower oxidative stress in umbilical cord artery with respect to vein. There was an overexpression of inflammatory cytokines in the mother, such as IL-6 and TNF-α, and, in addition, PGE₂ was also increased. Neonates showed lower levels of IL-6 and TNF-α and higher values of sTNF-RII and PGE₂ in comparison with their mothers. Parturition increases oxidative damage in the mother, although the indicators of oxidative damage were lower in umbilical cord artery with respect to umbilical vein. The overexpression of inflammatory cytokines reveals that fetus suffers its own inflammatory process during parturition.

Antioxidative status and oxidative stress in the fetal circulation at birth: the effects of time of delivery and presence of labor

BACKGROUND

There are important physiological changes in the maternal, placental, and fetal compartments during pregnancy and labor. Increased oxidative stress has been demonstrated during labor. Melatonin has been reported to serve as an indirect antioxidant via the stimulation and induction of antioxidant enzymes as superoxide dismutase (SOD) and glutathione peroxidase (Gpx) in several tissues.

AIM

: To assess whether the melatonin status, presence of labor at the time of birth and the time of delivery influence the extracellular antioxidative enzymes and DNA oxidative stress in newborns.

METHODS

The extracellular antioxidative status and oxidative stress were analyzed by measuring the concentrations of the SOD3, Gpx3 and 8-hydroxydeoxyguanosine (8-OHdG) in the cord blood of 135 newborns. Newborns delivered during the day and at night and newborns delivered by spontaneous vaginal delivery (labor group) or elective caesarean section delivery (no labor group) were studied.

OUTCOME MEASURES

The concentration of melatonin, SOD3, Gpx3 and 8-OHdG.

RESULTS

Independent of the time of delivery, we found significantly higher melatonin, SOD3 and Gpx3 but lower 8-OHdG concentrations in the labor group than in the no labor group. We did not observe a correlation between the concentration of melatonin and SOD3, Gpx3 or 8-OHdG, or a day-night difference in SOD3, Gpx3 or 8-OHdG.

CONCLUSION

Our findings suggest that oxidative stress during labor leads to an elevation of melatonin, SOD3 and Gpx3 in the fetal circulation, protecting the newborn from serious impairment, which is reflected by lower 8-OHdG levels. The melatonin status at the time of birth does not influence the extracellular SOD3 or Gpx3 concentrations.

Lower nucleotide excision repair capacity in newborns compared to their mothers: a pilot study

Recognition of the potential vulnerability of children and newborns and protection of their health is essential, especially regarding to genotoxic compounds. Benzo(a)pyrene B(a)P a commonly found carcinogen, and its metabolite BPDE, are known to cross the placenta. To investigate how well newborns are able to cope with BPDE-induced DNA damage, a recent developed nucleotide excision repair cell phenotype assay was applied in a pilot study of 25 newborn daughters and their mothers, using the Alkaline Comet Assay and taking demographic data into account. Newborns seemed to be less able to repair BPDE-induced DNA damage since lower repair capacity levels were calculated compared to their mothers although statistical significance was not reached. Assessment of repair capacity in combination with genotypes will provide important information to support preventive strategies in neonatal care and to define science based exposure limits for pregnant women and children.

Supplemental oxygen in elective cesarean section under spinal anesthesia: Handle the sword with care

BACKGROUND AND OBJECTIVES

We aimed to investigate the effect of 21% and 40% oxygen supplementation on maternal and neonatal oxidative stress in elective cesarean section (CS) under spinal anesthesia.

METHODS

Eighty term parturients undergoing elective CS under spinal anesthesia were enrolled in the study. We allocated patients randomly to breathe 21% (air group) or 40% (oxygen group) oxygen from the time of skin incision until the end of the operation. We collected maternal pre- and post-operative and umbilical artery (UA) blood samples. Total antioxidant capacity (TAC), total oxidant status (TOS) and the oxidative stress index (OSI) were measured.

RESULTS

Age, weight, height, parity, gestation week, spinal-skin incision time, skin incision-delivery time, delivery time, operation time, 1(st) and 5(th) minutes Apgar scores, and birth weight were similar between the groups (p > 0.05 for all comparisons). There were no differences in preoperative TAC, TOS, or OSI levels between the groups (p > 0.05 for all comparisons). Postoperative maternal TAC, TOS and OSI levels significantly increased in the oxygen group (p = 0.047, < 0.001 and 0.038, respectively); umbilical artery TAC levels significantly increased in the oxygen group (p = 0.003); and umbilical artery TOS and OSI levels significantly increased in the air group (p = 0.02 and < 0.001, respectively).

CONCLUSIONS

The difference in impact on maternal and fetal oxidative stress of supplemental 40% compared to 21% oxygen mandates further large-scale studies that investigate the role of oxygen supplementation during elective CS under spinal anesthesia.

Reference values of oxidative stress biomarkers in healthy newborns

BACKGROUND

Although oxidative stress-related diseases mostly affect neonates with extremely low birthweight, healthy preterm and term newborns may also be at risk of oxidative damage. There have been studies concerning factors that affect the level of oxidative stress biomarkers in term and preterm neonates, but there has not been a study of the reference values of oxidative stress biomarkers in healthy newborns having no risk factors. The aim of the present study was to clarify this issue.

METHODS

Serum total antioxidant capacity (TAC) and total oxidant status (TOS) were assessed by Erel's method. TAC and TOS values were measured in 100 term infants, 57 boys and 43 girls, with a mean gestational age of 39 weeks and a mean birthweight of 3174 g.

RESULTS

All blood samples for TAC and TOS were taken on the fifth day. The median TAC and TOS values for all male and female neonates were 1.92 mmol Trolox equivalent/L (min-max; 1.41-2.09) and 12.93 μmol H2O2/L (min-max: 3.01-53.94), respectively. TAC and TOS values were not statistically different in male and female newborns. TAC and TOS values were not statistically different in newborns who had been delivered via a vaginal route or by cesarean section.

CONCLUSION

This study can be used as a guide for the reference range of TAC and TOS values for healthy term newborns.

Oxidative stress in neonatology: a review

Free radicals are highly reactive oxidizing agents containing one or more unpaired electrons. Both in human and veterinary neonathology, it is generally accepted that oxidative stress functions as an important catalysator of neonatal disease. Soon after birth, many sudden physiological and environmental conditions make the newborn vulnerable for the negative effects of oxidative stress, which potentially can impair neonatal vitality. As a clinician, it is important to have in depth knowledge about factors affecting maternal/neonatal oxidative status and the cascades of events that enrol when the neonate is subjected to oxidative stress. This report aims at providing clinicians with an up-to-date review about oxidative stress in neonates across animal species. It will be emphasized which handlings and treatments that are applied during neonatal care or resuscitation can actually impose oxidative stress upon the neonate. Views and opinions about maternal and/or neonatal antioxydative therapy will be shared.

Effects of sevoflurane and desflurane on oxidative stress during general anesthesia for elective cesarean section

BACKGROUND

Anesthetic agents might considerably influence maternal-fetal oxidative stress and antioxidants during cesarean section (CS). The aim of this study was to investigate the effects of desflurane and sevoflurane on oxidative stress parameters both in mothers and newborns undergoing elective CS.

MATERIALS AND METHODS

Eighty ASA physical status I-II, term parturients undergoing elective CS under general anesthesia were randomized to desflurane (Group D) and sevoflurane (Group S) groups. Blood samples were collected from mothers before operation and postoperatively and umbilical artery samples were obtained at delivery. Total oxidant status (TOS), total antioxidant capacity (TAC) status, lipid hydroperoxide (LOOH), and free sulfhydryl (-SH) levels were measured and oxidative stress index was calculated. Secondary outcomes included maternal hemodynamics.

RESULTS

Preoperative LOOH, TOS, OSI, TAC, and -SH levels were similar among groups. Postoperative maternal serum LOOH, TOS, and OSI levels were significantly increased in Group D compared to Group S (p = 0.003, p = 0.005, p = 0.04; respectively). Postoperative umbilical artery LOOH, TOS, OSI levels were also significantly increased in Group D compared to Group S (p = 0.04, p = 0.02, p = 0.01; respectively). Postoperative TOS (p = 0.001, < 0.001 respectively) and OSI (p = 0.003, < 0.001 respectively) levels in both Group D and Group S were statistically significantly decreased compared to preoperative levels. Postoperative LOOH and -SH levels in Group S (p = 0.04, 0.029 respectively) were statistically significantly decreased compared to preoperative levels. There were no significant differences in TAC and -SH levels among groups (p = nonsignificant [n.s.]). Maternal perioperative mean blood pressure and heart rate were similar among groups (p = n.s.).

CONCLUSION

Oxidative stress indices might be modified with preferred anesthetic agent and sevoflurane showed more favorable effects than desflurane in view of oxidative stress.

Maternal and umbilical cord ischemia-modified albumin levels in nonreassuring fetal heart rate tracings regarding the mode of delivery

OBJECTIVE

To evaluate umbilical cord blood ischemia-modified albumin (IMA) levels in cases of fetal distress (FD) and to explore fetal blood IMA levels regarding the route of delivery.

METHODS

Umbilical cord and maternal serum IMA concentrations were assessed in term 40 cases with cesarean section (CS) due to FD, 76 cases with elective repeat CS and 85 cases with noncomplicated vaginal delivery.

RESULTS

The maternal and umbilical cord IMA levels were significantly lower in vaginal deliveries when compared with CS cases either in FD or previous CS groups (p = 0.02). Although no statistically significant difference was found in IMA levels of CS groups (previous CS vs. FD), cord blood IMA levels tend to be higher in FD group. Neither demographic characteristics nor fetal outcome parameters were found to have any correlation with maternal IMA levels. However, umbilical cord IMA levels were found to be negatively correlated with 1th min Apgar scores (r = -0.143, p = 0.043).

CONCLUSIONS

IMA seems to be responsive to hypoxic FD showing the highest levels in cases with severe fetal hypoxia. Higher levels of IMA in cases with elective repeat CS might indicate acute transient hypoxia and possible myocardial ischemia in these cases.

Does mode of delivery affect neonate oxidative stress in parturition? Review of literature

PURPOSE

The production of reactive oxygen substances plays an important regulatory role in many physiologic reproductive processes. Excessive production may lead to oxidative stress (OS), and bring about pregnancy disorders. Growing evidence indicates that OS plays a major role in the pathophysiology of complications such as early pregnancy loss, placental insufficiency, preeclampsia, fetal growth restriction, and neonatal complications. Whether parturition induces oxidative stress is in dispute. In this review, we elaborate the influence of mode of delivery (vaginal delivery or cesarean delivery) on oxidative stress of neonates.

METHODS

A review of old and recent literature was done. The studies were divided according to the impact of mode of delivery on oxidative stress in the newborn.

RESULTS

There is a divergence in the oxidative stress production according to the mode of delivery.

CONCLUSIONS

In view of neonatal oxidative stress measures, no major difference was found between uncomplicated vaginal delivery and elective cesarean section.

Potential utility of melatonin as an antioxidant during pregnancy and in the perinatal period

Reactive oxygen species (ROS) play a critical role in the pathogenesis of various diseases during pregnancy and the perinatal period. Newborns are more prone to oxidative stress than individuals later in life. During pregnancy, increased oxygen demand augments the rate of production of ROS and women, even during normal pregnancies, experience elevated oxidative stress compared with non-pregnant women. ROS generation is also increased in the placenta during preeclampsia. Melatonin is a highly effective direct free-radical scavenger, indirect antioxidant, and cytoprotective agent in human pregnancy and it appears to be essential for successful pregnancy. This suggests a role for melatonin in human reproduction and in neonatal pathologies (asphyxia, respiratory distress syndrome, sepsis, etc.). This review summarizes current knowledge concerning the role for melatonin in human pregnancy and in the newborn. Numerous studies agree that short-term melatonin therapy is highly effective in reducing complications during pregnancy and in the neonatal period. No significant toxicity or treatment-related side effects with long-term melatonin therapy in children and adults have been reported. Treatment with melatonin might result in a wide range of health benefits, including improved quality of life and reduced healthcare costs.

Cord blood genomic analysis highlights the role of redox balance

Neonates are exposed to elevated levels of reactive oxygen species as they transition from a hypoxic intrauterine to a normoxic extrauterine environment at birth. This increased oxidative stress is associated with neonatal morbidity. Current antioxidant supplementation treatment strategies have yet to translate into improved neonatal outcomes. Our understanding of a newborn's intricate redox balance, particularly at the genomic level, remains limited. Here, we performed genomic microarray analyses (approximately 14,500 genes) on extracted mRNA from umbilical cord whole blood at term gestation (n=10). Bioinformatic analyses identified 282 genes (2.0%) that were consistently present within the highest quintile of expressed genes. These genes were highly associated with oxidant stress and included superoxide dismutase 1, catalase, peroxiredoxins, and uncoupling proteins. Pathway analyses identified statistically significantly overrepresented functional pathways including "oxidative stress," "oxidative stress response mediated by nuclear factor-erythroid 2-related factor," "hypoxia-inducible factor signaling," and "mitochondrial dysfunction" (p<0.05). These results suggest that neonates require high levels of antioxidants and an intricate cellular redox balance to ensure a successful transition to the extrauterine environment. Understanding the genes necessary to maintain this delicate redox balance may lead to the development of alternative treatment strategies.

On the relation of oxidative stress in delivery mode in pregnant women; a toxicological concern

The objective was to investigate the effect two modes of labor (vaginal delivery and elective cesarean section) on thiobarbituric reactive substances (TBARS) as markers of lipid peroxidation, total antioxidant power (ferric reducing ability, TAP), and total thiol molecules (TTM) in blood of mothers and their newborns. One hundred and twenty women with normal pregnancy and normal blood biochemical parameters were divided into groups of vaginal delivery (VD) and elective cesarean surgery (ECS). Blood samples were obtained firstly in the time 37-40 weeks of pregnancy and secondly during labor phase for VD or during ECS. Blood samples from umbilical cord arterial of newborns were also obtained at birth after separation of cord. Plasma levels of TBARS, TAP, and TTM were determined. There was no significant differences between VD and ECS mothers before labor in plasma levels of TBARS, TTM, and TAP. Mothers in the VD group showed a significant increase in TBARS (p < 0.05) after delivery. And TTM level showed a significant increase in ECS group (p < 0.05) as compared to pre-delivery levels. Comparing oxidative stress variables between VD and ECS groups after labor, plasma levels of TBARS, and TTM significantly increased (p < 0.05) in VD mothers. TAP was not significantly different between VD and ECS groups. Newborn of VD mothers showed a significant increase in TBARS (p < 0.05), and TAP (p < 0.05) as compared to newborn of ECS. TTM was not significantly different between two groups of newborns. The results indicate that mothers in VD and their newborns are in more oxidative stress than those who underwent ECS for delivery. Linking oxidative stress to severe neonatal diseases, it may be reasonable to assess whether antioxidant supplementation during pregnancy may reduce the frequency of neonatal diseases.

Effects of mode of delivery on maternal–neonatal plasma antioxidant status and on protein S100B serum concentrations

OBJECTIVE

To investigate the effect of the mode of labour and delivery on total antioxidant status (TAS) and on the protein S100B serum concentrations in mothers and their newborns.

MATERIAL AND METHODS

Sixty women with normal pregnancies were divided into three groups: Group A (n = 20) with normal labour and vaginal delivery (VG), group B (n = 18) with prolonged labour+VG and group C (n = 22) with scheduled caesarean section (CS). Blood was obtained at the beginning of the labour process and immediately after delivery (pre- and post-delivery) as well as from the umbilical cord (CB). TAS and creatine kinase (CK) were measured using commercial kits. Serum S100B levels were evaluated with the electrochemiluminescence immunoassay "ECLIA" on the ROCHE ELECSYS 2010 immunoassay analyser.

RESULTS

Post-delivery, TAS levels were significantly decreased in group A and especially in group B. S100B levels were increased in group B (0.0712+/-0.02 microg/L) as compared with those of group A (0.0567+/-0.03 microg/L, p<0.01) and group C (0.038+/-0.03 microg/L, p<0.01), the levels in group C remaining practically unaltered (pre- versus post-delivery). In the newborns, S100B levels were almost 2-fold higher in group B (0.67+/-0.18 microg/L) than those in group A (0.40+/-0.05 microg/L p<0.001) and group C (0.31+/-0.04 microg/L p<0.001). A negative correlation was found between TAS and S100B protein (r = -0.61, p<0.001), the latter positively correlated to CK (r = 0.48, p<0.01).

CONCLUSIONS

The increased S100B serum levels in the mothers of group B, post-delivery, may have been due to the long-lasting, oxidative and/or psychogenic stress. The observed remarkably high levels of S100B in the group B newborns may have been due to compressive conditions on the foetus brain during this mode of delivery.

Labor augmentation with oxytocin decreases glutathione level

Objective. To compare oxidative stress following spontaneous vaginal delivery with that induced by Oxytocin augmented delivery. Methods. 98 women recruited prior to labor. 57 delivered spontaneously, while 41 received Oxytocin for augmentation of labor. Complicated deliveries and high-risk pregnancies were excluded. Informed consent was documented. Arterial cord blood gases, levels of Hematocrit, Hemoglobin, and Bilirubin were studied. Glutathione (GSH) concentration was measured by a spectroscopic method. Plasma and red blood cell (RBC) levels of Malondialdehyde indicated lipid peroxidation. RBC uptake of phenol red denoted cell penetrability. SPSS data analysis was used. Results. Cord blood GSH was significantly lower in the Oxytocin group (2.3 +/- 0.55 mM versus 2.55 +/- 0.55 mM, P = .01). No differences were found in plasma or RBC levels of MDA or in uptake of Phenol red between the groups. Conclusion. Lower GSH levels following Oxytocin augmentation indicate an oxidative stress, though selected measures of oxidative stress demonstrate no cell damage.

Oxidative stress of the newborn in the pre- and postnatal period and the clinical utility of melatonin

Newborns, and especially those delivered preterm, are probably more prone to oxidative stress than individuals later in life. Also during pregnancy, increased oxygen demand augments the rate of production of reactive oxygen species (ROS) and women, even with normal pregnancies, experience elevated oxidative stress and lipid peroxidation compared with nonpregnant women. Also, there appears to be an increase in ROS generation in the placenta of pre-eclamptic women. In comparison with healthy adults, newborn infants have lower levels of plasma antioxidants such as vitamin E, beta-carotene, and sulphydryl groups, lower levels of plasma metal binding proteins including ceruloplasmin and transferrin, and reduced activity of erythrocyte superoxide dismutase. This review summarizes conditions of newborns where there is elevated oxidative stress. Included in this group of conditions is asphyxia, respiratory distress syndrome and sepsis and the review also summarizes the literature related to clinical trials of antioxidant therapies and of melatonin, a highly effective antioxidant and free radical scavenger. The authors document there is general agreement that short-term melatonin therapy may be highly effective and that it has a remarkably benign safety profile, even when neonates are treated with pharmacological doses. Significant complications with long-term melatonin therapy in children and adults also have not been reported. None of the animal studies of maternal melatonin treatment or in postnatal life have shown any treatment-related side effects. The authors conclude that treatment with melatonin might result in a wide range of health benefits, improved quality of life and reduced healthcare costs and may help reduce complications in the neonatal period.

Oxidant and antioxidant status in mothers and their newborns according to birthweight

OBJECTIVE

The aim of this study is to determine the oxidant and antioxidant status in Algerian mothers and their newborns according to birth weight.

STUDY DESIGN

Subjects for the study were consecutively recruited from Tlemcen hospital. 139 pregnant women and their newborns were included. The plasma total antioxidant activity (ORAC), vitamins A, C, E, hydroperoxides, carbonyl proteins, and erythrocyte antioxidant enzyme activities (catalase, glutathione peroxidase, glutathione reductase and superoxide dismutase) were measured on mothers and their newborns. Lipid and lipoprotein parameters were also determined. The results were assessed in accordance with small for gestational age (SGA), appropriate (AGA) and large (LGA) birth weight of the newborn.

RESULTS

SGA newborns and their mothers had low ORAC, vitamin C and E values (P<0.01) and high plasma hydroperoxide and carbonyl protein levels (P<0.01) compared to AGA groups. The SGA group showed also altered erythrocyte antioxidant enzyme activities and several lipid and lipoprotein changes. In LGA compared to control newborns, hydroperoxide, carbonyl protein levels and SOD activity were enhanced while ORAC, vitamin A and E levels were reduced. However, oxidant and antioxidant status in their mothers was similar to that in control mothers.

CONCLUSION

Oxidative stress is present in both SGA and LGA newborns, with a concomitant alteration in maternal oxidant and antioxidant status only in intrauterine growth restriction.

Cord blood ischemia-modified albumin levels in normal and intrauterine growth restricted pregnancies

Ischemia-modified albumin (IMA) is a sensitive biomarker of cardiac ischemia. Intrauterine growth restriction (IUGR) may imply fetal hypoxia, resulting in blood flow centralization in favour of vital organs (brain, heart, adrenals—“brain sparing effect”). Based on the latter, we hypothesized that cord blood IMA levels should not differ between IUGR and appropriate-for-gestational-age (AGA) full-term pregnancies. IMA was measured in blood samples from doubly-clamped umbilical cords of 110 AGA and 57 asymmetric IUGR pregnancies. No significant differences in IMA levels were documented between AGA and IUGR groups. IMA levels were elevated in cases of elective cesarean section (P = .035), and offspring of multigravidas (P = .021). In conclusion, “brain sparing effect” is possibly responsible for the lack of differences in cord blood IMA levels at term, between IUGR and AGA groups. Furthermore, higher oxidative stress could account for the elevated IMA levels in cases of elective cesarean section, and offspring of multigravidas.

Changes of nitric oxide, carbon monoxide and oxidative stress in term infants at birth

The higher risk of respiratory problem in infants delivered by elective caesarean section in comparison with vaginally born infants may be favoured by lower level of nitric oxide (NO) and carbon monoxide (CO) and higher oxidative stress in infants born by caesarean section. We studied healthy term infants born by vaginal delivery or by elective caesarean section. Nitric oxide, CO, guanosine 3-5 cyclic monophosphate, total hydroperoxide and advanced oxidation protein products (AOPP) were measured at birth and 48-72 h of life. Nitric oxide, CO and cGMP were lower at birth and at 48-72 h of life in infants born by elective caesarean delivery. Total hydroperoxide and AOPP levels were similar in the two groups and increased from birth to 48-72 h of life. In conclusion, nitric oxide and CO concentrations were higher in term infants vaginally born than in infants born by elective caesarean section and decreased from birth to 48-72 h of life. The mode of delivery did not affect the oxidative stress which increases from birth to 48-72 h of life.

The effect of the mode of delivery on the maternal-neonatal erythrocyte membrane acetylcholinesterase activity

Free radical production and high catecholamine levels are implicated with the modulation of acetylcholinesterase (AChE) activity.

OBJECTIVE

To investigate the effect of the mode of delivery on maternal-neonatal erythrocyte membrane AChE activity.

SUBJECTS AND METHODS

Some women with normal pregnancy (N = 30) were divided into two groups: group A (N = 16) with normal labour and vaginal delivery and group B (N = 14) with scheduled Cesarean section, twenty non-pregnant women were the controls. Blood was obtained from controls and from mothers pre- vs post-delivery as well as from the umbilical cord (CB). Total antioxidant status (TAS), membrane AChE activities and catecholamine blood levels were measured with a commercial kit, spectrophotometrically and HPLC methods, respectively.

RESULTS

TAS and catecholamine levels as well as membrane AChE activities were similar in the two groups of mothers pre-delivery and in controls. TAS levels were reduced whereas AChE activities and catecholamine levels were increased post-delivery in mothers of group A and unaltered in group B at the same times of study. AChE activity was similarly lower in the CB of neonates than those of their mothers pre-delivery.

CONCLUSIONS

During a normal delivery process, the low TAS, the increased levels of catecholamines and the increased AChE activity, post-delivery, may be due to the increased stress due to the participation of uterus and skeletal muscles as during endurance exercise. The low AChE activity in newborns may be related to perinatal immaturity.

Evaluation of oxidative stress markers in neonates with intra-uterine growth retardation

Intra-uterine growth retardation (IUGR) is an abnormality of pregnancy. Neonates with IUGR weigh less than the 10th percentile for gestational age. The objective of the study was to identify the relationship between IUGR and the antioxidant status. Cord blood of 157 neonates with normal weight (control group) and 29 neonates with IUGR were included. The following parameters were determined and compared in the two groups: lipid peroxidation in the plasma, red blood cells and erythrocyte ghosts; protein and DNA damage; antioxidant enzyme activities (superoxide dismutase, catalase, glutathione peroxidase); the level of reduced glutathione; and the ferric reducing ability of the plasma. The level of lipid peroxidation was significantly higher in the IUGR group. The antioxidant enzyme activities and the levels of antioxidants were significantly lower in the IUGR group. Damage of proteins and DNA was slightly, but non-significantly, higher in the IUGR group. Neonates with IUGR seem to have significant deficiencies in antioxidant defence. IUGR is correlated with significant oxidative stress.

Plasma levels of 15-F(2t)-isoprostane in newborn infants are affected by mode of delivery

OBJECTIVE

To investigate how the mode of delivery affects the level oxidative stress in newborns.

DESIGN AND METHODS

15-F(2t)-isoprostane, as index of oxidative stress, was measured in umbilical cord plasma samples from 37 infants born after vaginal delivery or caesarian section, using specific immuno-affinity extraction and immunoassay.

RESULTS

15-F(2t)-isoprostane levels were higher in infants born after vaginal delivery (n=18) compared to those delivered by elective caesarian section (n=19).

CONCLUSIONS

15-F(2t)-isoprostane is a sensitive biomarker of fetal oxidative stress during labor.

Oxidative stress varies with the mode of delivery in intrauterine growth retardation: Association with Apgar score

OBJECTIVE

To assess if oxidative injury in intrauterine growth retarded and healthy newborns is affected by the mode of delivery and whether Apgar score as a marker of neonatal survival is dependent on lipid and protein oxidative injury assessed by measuring malondialdehyde and protein carbonylation.

METHODS

30 IUGR newborns, 15 born by normal vaginal delivery and 15 born by elective caesarean section, and 40 healthy control infants, 30 born by normal vaginal delivery and 10 born by elective caesarean section, were studied at birth. Cord blood was collected for determination of malondialdehyde and protein carbonylation.

RESULTS

IUGR newborns had significantly elevated MDA and protein carbonylation than the control group. Apgar scores, both at 1 and 5 min, were significantly lower in the IUGR group. These were assessed by independent sample t test. Using one-way ANOVA we found that MDA and protein carbonyls levels were not statistically different in healthy control group and in IUGR subgroup born by caesarean section however they were significantly different in other groups. Linear regression analysis revealed that Apgar scores both at 1 min and 5 min were dependent on MDA in IUGR newborns. Apgar score was however not dependent on protein carbonylation in the same group.

CONCLUSION

Apgar score in IUGR newborns is dependent on the extent of oxidative injury and elective caesarean section minimises the same.

Oxidative stress and antioxidant protection in the perinatal period

PURPOSE OF REVIEW

Oxidative stress is implicated in the pathophysiology of disorders during pregnancy, childbirth and the postnatal period, but open questions exist on the effects of antioxidants, the role of oxidative stress during resuscitation and the antioxidative protection of human milk.

RECENT FINDINGS

In a randomized controlled trial, fish oil supplementation to pregnant women did not enhance oxidative stress. Two randomized controlled trials supplementing high dosages of both vitamins C and E did not show any reduction in the incidence of preeclampsia. A systematic review and meta-analysis of studies comparing resuscitation of asphyxiated infants either with 100% oxygen or with room air demonstrated significantly lower neonatal mortality with use of room air. Antioxidative properties of human milk were greater in milk from mothers of term than of preterm infants.

SUMMARY

Increased levels of oxidative stress and reduced antioxidative capacities may contribute to the pathogenesis of disorders in the perinatal period. Based on the available evidence, supplementation of pregnant women with high dosages of both vitamin C and E cannot be recommended. Asphyxiated newborn infants should be resuscitated with room air rather than with 100% oxygen. Breastfeeding appears beneficial in providing antioxidative protection.

Oxidative stress as determined by glutathione (GSH) concentrations in venous cord blood in elective cesarean delivery versus uncomplicated vaginal delivery

OBJECTIVE

To determine whether neonates are subject to oxidative stress by the labor process and the mode of delivery by measuring glutathione (GSH) concentrations in umbilical cord venous blood.

STUDY DESIGN

Forty-eight women with singleton term pregnancies were prospectively recruited and classified as follows: 26 women had a spontaneous uncomplicated vaginal delivery (VD), and 22 women had an elective cesarean delivery (CD). GSH concentration in umbilical venous blood samples was determined by a spectroscopic method.

RESULTS

Umbilical cord venous blood GSH levels were significantly lower in the elective CD group than in the VD group (2.2 and 2.7 mM, respectively, P = 0.0003). There was a significantly negative correlation between cord blood pO(2) and GSH levels; however, the negative correlation was significantly higher in the elective CD group (P < 0.05).

CONCLUSION

Neonates delivered by CD were exposed to a higher oxidative stress as determined by GSH levels compared to those who had an uncomplicated VD.

Different degrees of fetal oxidative stress in elective and emergent cesarean section

BACKGROUND

Several studies have addressed the influence of labor and mode of delivery on oxidative stress. Still it is unclear whether oxidative stress is related to delivery itself or whether it reflects a pre-existing fetal oxidative status.

OBJECTIVE

To investigate whether the degree of fetal oxidative stress is different between distressed fetuses that were delivered by emergent cesarean section and non-distressed fetuses that were delivered by elective cesarean section.

METHODS

The protocol of this prospective study was approved by the Institutional Review Board Committee. Amniotic fluid and umbilical artery blood were prospectively collected from 21 parturients who were delivered by an emergent cesarean section for non-reassuring fetal heart rate pattern and from 21 parturients who were delivered by an elective cesarean section in a tertiary care center. Oxidative stress was evaluated in amniotic fluid, umbilical cord plasma and erythrocytes by determining malondialdehyde concentration and glutathione peroxidase (GPX) activity.

RESULTS

Malondialdehyde concentration was higher in amniotic fluid (mean +/- SEM) (2.2 +/- 0.7 nmol/l vs. 0.6 +/- 0.02 nmol/l, p < 0.05), in umbilical cord plasma (1.2 +/- 0.2 nmol/l vs. 0.7 +/- 0.3 nmol/l, p < 0.05) and in umbilical cord erythrocytes (159.6 +/- 48.6 nmol/g Hb vs. 85.8 +/- 5.2 nmol/g Hb, p < 0.05) in women delivering by emergent cesarean compared to those delivering by elective cesarean. GPX activity was enhanced in amniotic fluid (12.4 +/- 2.2 U/l vs. 5.1 +/- 0.6 U/l, p < 0.05) and GPX activity/hemoglobin ratio was higher in cord blood (22.0 +/- 0.8 U/g Hb vs. 18.7 +/- 0.9 U/g Hb, p < 0.05) in women delivering by emergent cesarean compared to those delivering by elective cesarean.

CONCLUSION

Distressed fetuses delivered by emergency cesarean exhibited increased malondialdehyde concentrations, an indicative parameter for oxidative damage, and enhanced GPX activity an antioxidant enzyme, in amniotic fluid and umbilical cord blood compared to non-distressed fetuses delivered by elective cesarean section. This is probably an indication of higher fetal oxidative stress.

Maternal–neonatal serum paraoxonase 1 activity in relation to the mode of delivery

AIM

To investigate the effect of the mode of labour and delivery on the total antioxidant status (TAS) and the paraoxonase 1 (PON 1) serum activity in mothers and their newborns.

SUBJECTS AND METHODS

One hundred six women with normal pregnancy were divided into 4 groups: group A (n = 28) with normal labour and vaginal delivery (VG), group B (n = 25) with scheduled caesarean section (CS), group C (n = 26) with "emergency" CS and group D (n = 27) with prolonged labour + VG. Blood was obtained from the mothers at the beginning of the labour process and immediately after delivery (pre- and post-delivery) as well as from the umbilical cord (CB). PON 1 activity and blood chemistry were determined using the Bayer Advia 1650 Clinical Chemistry System, whereas TAS levels were measured spectrophotometrically at 450 min in microtiter plates.

RESULTS

TAS levels were similar pre-delivery and low in CB in all the groups. In contrast, TAS levels were remarkably reduced in group C and in group D post-delivery whereas they were nearly unchanged in group B and just lowered in group A, at the same time of study. PON 1 activity was practically unaltered in group A and group B pre- vs. post-delivery. Interestingly, the enzyme activity was remarkably decreased in group C (222 +/- 16 vs. 153 +/- 14 U/min/mL) and group D (216 +/- 16 vs. 135 +/- 15 U/min/mL, p < 0.001) as compared with those of the other groups at the same time of study. Additionally, PON 1 activity was higher in the newborns of group A and group B than those in group C and group D. TAS and HDL positively correlated with PON 1 activity.

CONCLUSION

The low TAS levels and the decreased PON 1 activity, which were found in groups C and D post-delivery, may be due to the increased production of free radicals, during long-lasting labour + VG and obstructive labour + CS. PON 1 activity was low in CB irrespectively of the mode of delivery, probably due to the low lipid levels in the serum of the umbilical cord. Neonates born with normal delivery or scheduled CS are benefited with a higher antiatherogenic enzyme activity perinatally.