Cord Blood Gas Parameters Research Articles

Comparison of Apgar scores and cord blood gas parameters in fetuses with isolated congenital heart disease and healthy controls.

This retrospective study aimed to investigate how congenital heart disease (CHD) affects early neonatal outcomes by comparing Apgar scores and umbilical cord blood gas parameters between fetuses with structural cardiac anomalies and healthy controls. Additionally, within the CHD group, the study explored the relationship between these parameters and mortality within six months. Data from 68 cases of prenatally diagnosed CHD were collected from electronic medical records, excluding cases with missing data or additional comorbidities. Only patients delivered by elective cesarean section, without any attempt at labor, were analyzed to avoid potential confounding factors. A control group of 147 healthy newborns was matched for delivery route, maternal age, and gestational week. Apgar scores at 1, 5, and 10 minutes, as well as umbilical cord blood pH, base deficit, and lactate levels, were recorded. Maternal age, gestational week at delivery, and birth weight were similar between the CHD and control groups. While Apgar score distribution was significantly lower at 1st, 5th, and 10th minutes in the CHD group, umbilical cord blood gas parameters did not show significant differences between groups. Within the CHD group, lower umbilical cord blood pH and larger base deficit were associated with mortality within six months. Newborns with CHD exhibit lower Apgar scores compared to healthy controls, suggesting potential early neonatal challenges. Furthermore, umbilical cord blood pH and base deficit may serve as predictors of mortality within six months in CHD cases. Prospective studies are warranted to validate these findings and integrate them into clinical practice, acknowledging the study's retrospective design and limitations.

Effect of maternal hyperoxygenation on neonatal outcomes among women in labour with pathological cardiotocography: an open-label randomized controlled trial

Hyperoxygenation has shown promise in improving suspicious fetal heart patterns in women in labor. However, the effect of hyperoxygenation on neonatal outcomes in women in labor with pathologic fetal heart rate tracing has not been studied. This study aimed to evaluate the effect of fractional inspiration of oxygen of 80% compared with fractional inspiration of oxygen of 40% on neonatal outcomes in women with pathologic fetal heart rate tracing. This randomized, open-label, parallel arm, outcome assessor-blinded clinical trial was conducted in a large tertiary care university hospital. Singleton parturients aged ≥18 years at term gestation in active labor (cervical dilatation of ≥6 cm) with pathologic fetal heart rate tracing were recruited in the study. Pathologic fetal heart rate tracing was defined according to the International Federation of Gynecology and Obstetrics 2015 guidelines. The International Federation of Gynecology and Obstetrics classifies fetal heart rate tracings into 3 categories (normal, suspicious, and pathologic) based on rate, variability, and deceleration. Women in the intervention arm received oxygen at 10 L/min via a nonrebreathing mask, and those in the usual care arm received oxygen at 6 L/min with a simple face mask. Oxygen supplementation was continued until cord clamping. The primary outcome measure was a 5-minute Apgar score. The secondary outcome measures were the proportion of neonatal intensive care unit admission, umbilical cord blood gas variables, level of methyl malondialdehyde in the cord blood, and mode of delivery. Overall, 148 women (74 women in the high fractional inspiration of oxygen arm and 74 in the low fractional inspiration of oxygen arm) with pathologic fetal heart rate tracing were analyzed. The demographic data, obstetrical profiles, and comorbidities were comparable. The median 5-minute Apgar scores were 9 (interquartile range, 8-10) in the hyperoxygenation arm and 9 (interquartile range, 8-10) in the usual care arm (P=.12). Furthermore, the rate of neonatal intensive care unit admission (9.5% vs 12.2%; P=.6) and the requirement of positive pressure ventilation (6.8% vs 8.1%; P=.75) were comparable. Concerning cord blood gas parameters, the hyperoxygenation arm had a significantly higher base deficit in the umbilical vein and lactate level in the umbilical artery. The cesarean delivery rate was significantly lower in women who received hyperoxygenation (4.1% [3/74]) than in women who received normal oxygen supplementation (25.7% [19/74]) (P=.00). In addition, umbilical vein malondialdehyde level in the umbilical vein was lower in the hyperoxygenation group (8.28±4.65 μmol/L) than in the normal oxygen supplementation group (13.44±8.34 μmol/L) (P=.00). Hyperoxygenation did not improve the neonatal Apgar score in women with pathologic fetal heart rate tracing. In addition, neonatal intensive care unit admission rate and blood gas parameters remained comparable. Therefore, the results of this trial suggest that a high fractional inspiration of oxygen supplementation confers no benefit on neonatal outcomes in women with pathologic fetal heart rate tracings and normal oxygen saturation.

Cerebral Tissue Oxygen Saturation Measurements in Perinatal Asphyxia Cases Treated with Therapeutic Hypothermia.

Cerebral tissue oxygen saturation (CrSO2) measured with near-infrared spectroscopy (NIRS) technology has recently become the subject of several research studies. The aim of this study was to investigate the diagnostic value of CrSO2 measurements in perinatal asphyxia (PA) cases. The study included a patient group of 42 PA cases, who were to be applied with therapeutic hypothermia (TH), and a control group of 42 healthy term newborns. PA cases were determined as moderate or severe encephalopathy (Sarnat score stage II or III) in clinical evaluation. In both groups, left (CrSO2L) and right (CrSO2R) NIRS measurements were taken for 10 minutes on the scalp. The arithmetic mean value of measurements was calculated and compared. The mean measurements were CrSO2R 67.38 ± 9.39 and CrSO2L 66.73 ± 7.76 in the patient group, and CrSO2R 80.28 ± 8.04 and CrSO2L 79.14 ± 8.49 in the control group. The mean CrSO2R and CrSO2L measurements of the patient group were statistically significantly lower than those of the control group (p < 0.001). In the Pearson correlation analysis, a significant correlation was determined in the patient group between cord blood gas pH and CrSO2R (r: 0.539, p < 0.001) and CrSO2L (r: 0.54, p < 0.001). For a cutoff value of CrSO2L ≤ 72%, the positive predictive value was 80 and the negative predictive value was 84.6. For a cutoff value of CrSO2R ≤ 74%, the positive predictive value was 79.5 and the negative predictive value was 82.5. Low CrSO2 measurements obtained with the NIRS method in PA cases to be applied with TH together with cord blood gas parameters can be considered a helpful parameter in diagnosis.

Comparison of 2 anesthetic protocols and surgical timing during cesarean section on neonatal vitality and umbilical cord blood parameters

BackgroundThe objective of this study was to evaluate the relationship between the mode of anesthesia, the time form the induction to the extraction of a puppy and the immediate postnatal vitality and umbilical cord blood gases parameters in cesarean section derived-puppies. Two different anesthetic protocols were used: inhalation using isoflurane (ISO) and combined—inhalation and epidural (EPI) with propofol being the induction agent.ResultsSignificant differences were found in ISO group in pH values, pCO2 levels and Apgar scores between puppies at different extraction times (< 30 vs. ≥ 30 min). In ISO group puppies extracted later were more acidic (7.16 vs. 7.22), had higher levels of pCO2 (69 vs. 57 mmHg) and lower Apgar scores at birth (1.2 vs. 2.5). On the contrary, in EPI group no differences were observed between the delivery time, umbilical blood gas parameters and puppies’ vitality. Furthermore, the dams from the EPI group required lower concentrations of isoflurane (MAC 1.11 ± 0.19 vs.1.37 ± 0.16, p < 0.001).ConclusionsMultiple pregnancies frequent in dogs lead to significant differences in extraction times between the first and the last puppy during cesarean section. Obtained results showed that the mode of anesthesia and the surgical time would influence the neonatal outcome during cesarean section in dogs. The higher concentration of isoflurane with the longer time of exposure had a negative effect on the initial newborn vitality as well as the umbilical cord blood gas parameters. Therefore, when performing CS in giant dog breeds or expecting many puppies in the litter, it is worth considering epidural component that allow for lower concentrations of inhalant agents, which may contribute to a better clinical condition of newborns.

Evaluation of Umbilical Cord Blood Gas Parameters in the Prediction of Mortality in Extremely Premature Infants

Evaluation of Umbilical Cord Blood Gas Parameters in the Prediction of Mortality in Extremely Premature Infants

Association of umbilical cord blood gas values with mortality and severe neurologic injury in preterm neonates

Umbilical cord arterial and venous blood gas values reflect the acid-base balance status of a newborn at birth. Derangement in these values has been linked to poor neonatal outcomes in term and late preterm neonates; however, the utility of these values in preterm neonates of <29 weeks' gestation is unclear. This study aimed to determine the associations of umbilical cord arterial and venous blood gas values with neonatal mortality and severe neurologic injury in extremely preterm neonates and to identify the cutoff values associated with 2.5-fold increases or decreases in the posttest probabilities of outcomes. This was a retrospective cohort study of neonates who were born at 23+0 to 28+6 weeks' gestation between January 1, 2018 and December 31, 2019, and who were admitted to neonatal units in Canada. Various cut-offs of umbilical cord blood gas values and lactate values were studied. The main outcomes were mortality before discharge from the neonatal unit and severe neurologic injury defined as grade 3 or 4 periventricular or intraventricular hemorrhage or periventricular leukomalacia. The outcome rates were calculated for various cutoff values of umbilical cord blood gas parameters and were adjusted for birthweight, gestational age, sex, and multiple births. Likelihood ratios were calculated to derive posttest probabilities. A total of 1040 and 1217 neonates had analyzable umbilical cord arterial and venous blood gas values, respectively. In the cohort, the mean (standard deviation) gestational age was 26.5 (1.5) weeks, the mean birthweight was 936 (215) g, the prevalence of mortality was 10% (105/1040), and the prevalence of severe neurologic injury was 9% (92/1016). An umbilical cord arterial pH of ≤7.1 and base excess of ≤-12 mmol/L were associated with >2.5-fold higher posttest probability of mortality, and an umbilical cord arterial or venous lactate value of <3 was associated with a 2.5-fold lower posttest probability of mortality. An umbilical cord arterial lactate value of <3 was associated with a lower posttest probability of severe neurological injury. In preterm neonates of <29 weeks' gestation, low umbilical cord arterial pH and high umbilical cord arterial base excess values were associated with a clinically important increase in the posttest probability of mortality, whereas low umbilical cord arterial or venous lactate values were associated with a decrease in the posttest probability of mortality.

The role of cord blood gas parameters in prediction of significant hyperbilirubinemia among healthy term newborns

The role of cord blood gas parameters in prediction of significant hyperbilirubinemia among healthy term newborns

Umbilical Cord Blood Gas Parameters and Apgar Scoring in Assessment of New-Born Dogs Delivered by Cesarean Section.

Simple SummaryThe article presents the results of the clinical evaluation and umbilical cord blood analysis obtained from newborn pups delivered by the elective Caesarean section. In human medicine both the umbilical cord blood and Apgar score were proved to provide valuable information on neonatal status. In veterinary medicine very few reports concerning the relation between the clinical neonatal assessment (Apgar score) and umbilical cord blood parameters exist. All puppies show mild respiratory acidemia regardless the Apgar scores result. The lactates were not elevated whereas all the puppies with low Apgar sores had higher glucose and mortality rates. Only pups with low initial Apgar scores were at risk of death within first 24 h. Adaptation to the extra-uterine life is crucial and any practical improvement in neonatal diagnostics and care would be beneficial for newborn puppy survival.The article presents the results of the clinical evaluation (Apgar scores, AS) and umbilical cord blood gas analysis (UCBGA) obtained from clamped umbilical cords of newborn pups delivered by the elective Caesarean section. The study was planned as a controlled clinical study, the newborns were allocated into one of the groups, I—critical neonates (severe distress, AS ≤ 3), II—weak neonates (moderate distress, AS 4–6) and III—healthy neonates (no distress, AS ≥ 7). The following parameters were evaluated: pH (pH units), carbon dioxide partial pressure (pCO2; mmHg), oxygen partial pressure (pO2; mmHg), actual bicarbonate (cHCO3−; mmol/L), total carbon dioxide (cTCO2; mmol/L), base excess of extracellular fluid (BE(ecf); mmol/L), base excess of blood (BE(b); mmol/L), oxygen saturation (csO2; %), lactate (Lac; mg/dL), hematocrit (Hct; %PCV), hemoglobin (cHgb; g/dL), glucose (Glu; mg/dL), ions (Na, K, Ca, Cl). The majority of puppies had low AS at birth (AS 4–6 in 38.1% and AS ≤ 3 in 57.1% of the neonates), but most of them (85.7%) improved by the 20th min. reaching AS of 7 and more. Moreover, puppies with lower AS (≤ 3) were at higher risk of death within the first 24h (20.8% did not survive). The positive correlation was found between Apgar score measured at 0 min and pH (r = 0.46, p = 0.01), and between Apgar score (at 0 min) and base excess in whole blood measured [BE(b)] r = 0.36, p = 0.03). Whereas, a negative correlation was detected between Apgar score at 0 and 5th min and glycemia (r = −0.42, p = 0.05, r = −0.34, p = 0.02 respectively. Overall, the puppies with higher glucose levels had lower Apgar scores and were at higher risk of death. Furthermore, in our study, the newborn puppies had mild acidemia with elevated pCO2 levels and the HCO3 at the lower range of normal limits, suggesting the mixed component in the acidemic state. Adaptation to extra-uterine life is crucial and any practical improvement in neonatal diagnostics and care would be beneficial for newborn puppy survival.

Cord blood gas results of pregnancies complicated by preeclampsia and the relationship of these results with the amount of proteinuria.

To evaluate whether there is a statistically significant difference between the cord blood gas parameters of pregnancies complicated with preeclampsia and uncomplicated pregnancies and to show whether the amount of proteinuria affects fetal cord blood gas parameters in pregnancies complicated with preeclampsia. The study was designed retrospectively. Between 2016 and 2019, the neonatal results and cord blood gas results of 109 pregnant women who were diagnosed with preeclampsia and 75 nonpreeclamptic randomly selected pregnant women were compared. The preeclampsia group was divided into groups according to amount of proteinuria. SPSS 21.0 statistics program was used, and comparative analysis was carried out. The data of the 109 preeclampsia cases and 75 control groups included in the study were compared, and there was no statistical difference between the fetal cord blood gas parameters between the groups (p > 0.05). The median first and fifth minute Apgar scores were found significantly lower in the preeclampsia group compared to the control group (6, 8 and 8, 9, respectively; p < 0.001). Also, the amount of proteinuria does not alter cord blood gas parameters (p > 0.05). Preeclampsia poses a risk for the neonatal period as it reduces the neonatal Apgar scores due to the chronic hypoxic process it creates. However, it was observed that the amount of proteinuria, which is one of the diagnostic criteria, did not affect neonatal results on Apgar scores or fetal cord blood gas parameters.

The impact of nuchal cord on umbilical cord blood gas analysis and ischaemia-modified albumin levels in elective C-section

This study was designed to evaluate umbilical cord ischaemia-modified albumin (IMA) levels and the cord blood gas parameters of foetuses with or without nuchal cords, at the time of elective C-section. The cross-sectional study population consisted of the patients who were admitted to the Tertiary Care Center between February and June 2015. Women with uncomplicated single term gestations between 37 and 40 completed weeks and scheduled for elective C-sections were included in the study. Fifty cases with a nuchal cord and 50 cases without a nuchal cord were recruited. Nuchal cord blood gas analysis and the IMA levels were evaluated. The IMA levels in umbilical artery of foetuses both in the study and control groups were similar (0.714 ± 0.150 vs. 0.689 ± 0.107 ABSU, p = .340, respectively). The umbilical artery pH values of the study group were significantly lower than that in the control group (7.31 ± 0.04 vs. 7.32 ± 0.03, p = .042; respectively). The results of the current study indicate that the nuchal cord has an impact on the foetal cord blood gas parameters to some extent before the initiation of labour. Fortunately, this impact does not end up with foetal tissue ischaemia, as confirmed by the IMA levels.Impact statementWhat is already known on this subject? The impact of nuchal cord on perinatal outcomes has been the subject of research for many years. Although the accumulated data has pointed out some unfavourable perinatal effects, the heterogeneity of the study groups both including a vaginal delivery and C-section and the inability to adjust the interfering factors ended up with some controversies. This is why there is not much known about the effects of the nuchal cord in women who are not in the labour process.What do the results of this study add? The current study aimed to exclude the interfering effects such as the active stage of labour. In this study, elective caesarean sections were selected as the study population to evaluate the effects of the nuchal cord on cord blood gas parameters and the IMA values. pH analysis in cord blood is used to detect hypoxia and the IMA is a new ischaemia marker. The results revealed that the in utero nuchal cord is associated with a significantly higher pCO2 and lower pH values and similar IMA values.What are the implications of these findings for clinical practice and/or further research? The final outcome supports that the nuchal cord causes alterations in cord blood gas analysis but this does not reach critical levels. Therefore, the results show that there is no need to change clinical practice when the nuchal cord is detected by ultrasound in a term gestation.

A comprehensive analysis of continuous epidural analgesia's effect on labor and neonates in maternal hypertensive disorder patients.

Maternal hypertensive disorder is one of the most common and severe medical complications during pregnancy. Epidural analgesia administration is widely used during labor process. To evaluate the potential advantage or disadvantage of continuous epidural analgesia's on labor and neonates for maternal hypertensive disorder patients comprehensively. We have retrospectively analyzed 232 patients who diagnosed as maternal hypertensive disorder in our hospital since 2015. Among which, 126 patients including 28 cases of severe preeclampsia were administrated with continuous epidural analgesia (Analgesia group), the other 106 patients were untreated (Control group). We have compared the maternal age, body weight, gestational weeks, period for the first and second labor stage; the incidence of eclampsia, natural labor, cesarean section, forceps delivery and postpartum hemorrhage between these two groups respectively; furthermore, we recorded patients who received oxytocin and antihypertensive treatment during the delivery progress as well as evaluated the neonate body weight, Apgar score and performed umbilical cord blood gas analysis. Continuous epidural analgesia does not affect the first and second labor stage period (p=0.36), However, there is a significantly higher demand for oxytocin treatment (36.5% Vs 19.8%, p<0.01) and a significantly lower requirement for antihypertensive treatment (22.2% Vs 81.1%, p<0.001) in analgesia group compared to control group. We also notice that the natural delivery ratio in analgesia group is higher than control group and most importantly, continuous epidural analgesia can increase 1min Apgar score and has no other effect on neonates' body weight, umbilical cord blood gas parameters, 5min and 10min Apgar score. Our result based on a large cohort comprehensive analysis indicates that continuous epidural analgesia can benefit both maternal hypertensive disorder patients and neonates without any side effect.

The effect of maternal parameters on umbilical artery blood gas values and neonatal well-being in singleton pregnancies

Background. Umbilical cord blood analysis for assessment of the newborn’s acid-base status soon after birth is the most objective way of evaluating the fetal metabolic condition at delivery. We researched the effects of maternal age, multiple gestation, fetal heart rate, gestational age, parity, delivery mode and total duration of labor on fetal well-being as assessed by umbilical cord blood gas parameters. Methods. Prospective study conducted on 67 singleton pregnant women and their off-spring. Maternal age, multiple gestation, fetal heart rate (FHR), gestational age, parity, delivery mode and total duration of labor were recorded. Umbilical artery blood samples were collected at birth. A blood gas analysis was performed on each collected sample. The relationship between maternal parameters and umbilical cord arterial blood gas were investigated. Results. We found positive correlation between pH and gravida and parity ( p =0.026, p =0.049, respectively), whereas negative correlation between total duration of labor and O 2 saturation ( p =0.033). Base deficit was negatively correlated with gravida and parity ( p =0.025, p =0.011, respectively). In linear regression models, FHR and gravida were a significant predictor of pH value ( p =0.029 and p =0.040, respectively). Conclusions. We found no association between maternal age, gestational age, gravida, parity and duration of labor and neonatal acidemia. Thus, maternal age, gestational age, gravida, parity and duration of labor may not be at increased risk of perinatal morbidity. However, the elevation of FHR was related with an increased risk of neonatal morbidity.

Perinatal outcome in cases of isolated single umbilical artery and its effects on neonatal cord blood gas indices

We aimed to evaluate perinatal outcomes and blood gas indices of isolated single umbilical artery (SUA). In this retrospective study, 134 fetuses with SUA were evaluated. A total of 77 (57.4%) fetuses with isolated SUA (iSUA) were compared with maternal age-matched 95 fetuses with double umbilical arteries (DUA), with respect to pregnancy outcome and umbilical cord blood gas indices. The incidence of SUA in our cohort was 1.04%. Patients with iSUA had lower neonatal birth weight compared with the control group (2,635 ± 972 g vs 2,991 ± 669 g; p = 0.009). Small for gestational age (SGA) frequency was higher in the group of iSUA when compared with fetuses with DUA (17.4% vs 5.4%; p = 0.03). Regarding the umbilical cord blood gas, the parameters were comparable between the two groups. SUA has a favourable obstetric outcome as long as the accompanying malformations are ruled out. Furthermore, neonatal cord blood gas parameters in fetuses with iSUA do not differ from fetuses with DUA.

Effects of intravaginally inserted controlled-release dinoprostone and oxytocin for labor induction on umbilical cord blood gas parameters

To compare the effects of oxytocin and dinoprostone used in labor induction on fetal blood gas parameters. This prospective randomized trial involved 108 women who completed 37 gestational weeks and who required labor induction prior to normal vaginal birth. Labor was induced in 57 women with an intravenous low dose oxytocin regimen and in 51 with intravaginal dinoprostone (PGE2). Following childbirth, umbilical artery blood gas was analyzed, with pH, pCO2, pO2, HCO3 and base excess (BE) compared in the two groups. Mean age and obstetrical data (gravidity, parity, gestational weeks and birthweight) were similar in the two groups (p>0.05). All infants had 1 and 5 minute APGAR scores ≥7. Umbilical artery blood pH was similar in the oxytocin and dinoprostone groups (7.31±0.07 vs. 7.31±0.05, p=0.780), as were the other blood gas parameters (pCO2, pO2, base excess and HCO3; p>0.05 each). Induction of labor with either oxytocin or dinoprostone in women with uncomplicated term pregnancies had no adverse effects on umbilical artery blood gas parameters.

Cord blood S100B levels in low-risk term pregnancies with meconium-stained amniotic fluid

Objective: The aim of this study was to compare cord blood S100B levels and cord blood gas parameters of term infants with meconium-stained amniotic fluid (MSAF) to those infants with clear amniotic fluid. Methods: Term pregnant women at an active phase of labor and having MSAF were defined as the study group (n = 35) and pregnant women with clear amniotic fluid, and matched for age, parity, and gestational age were defined as the control group (n = 35). Cord blood S100B levels and gas parameters were measured. Results: LogS100B values of study and control groups were 2.40 ± 0.21 and 2.43 ± 0.29 pg/ml, respectively. The difference was not statistically significant (p = 0.675). LogS100B levels slightly increased as meconium thickened. (2.32 ± 0.16, 2.41 ± 0.17, and 2.44 ± 0.28 pg/ml, respectively). However, no difference was found between groups (p = 0.438). Moreover, the study group had a statistically lower HCO3 level (21.80 vs 23.60 mmol/l) and a higher rate of base deficit (4.85 vs 3.25 mmol/l) than the control group. However, median HCO3 and base deficit values were within normal limits in both groups. Conclusion: The present study showed that cord blood S100B levels of infants born through MSAF were not different from those with clear amniotic fluid. This finding suggests that MSAF, regardless of its thickness, may not be related to brain damage in low risk term pregnancies.

Fetal Scalp Lactate Microsampling for Non-Reassuring Fetal Status during Labor: A Prospective Observational Study

Objective: The aim was to study the predictive value and feasibility of fetal scalp lactate microsampling in the management of non-reassuring fetal status during labor. Methods: A prospective observational study was conducted on cord blood gas samplings from 7,617 singleton and cephalic deliveries at ≧37 weeks of gestation. In this population, 450 fetal scalp blood samples (FBS) were performed for abnormal fetal heart rate (FHR) patterns. Microvolume scalp lactate measurements were compared to scalp pH, neonatal cord blood gas parameters (pH, lactate, base deficit) and the Apgar score. Results: Scalp lactate correlated significantly with scalp pH (r = –0.56, p = 0.001), umbilical artery pH (r = –0.39, p = 0.03), umbilical artery lactate (r = 0.48, p = 0.01) and umbilical artery base deficit (r = 0.51, p = 0.01), but not with Apgar scores. Using receiver operating characteristic curves, a scalp lactate cutoff value of 5 mmol/l was the most predictive for neonatal acidosis. Sampling failure with scalp lactate was inferior to scalp pH (1.3 vs. 14%, p < 0.001). Conclusion: Lactate microsampling in fetal scalp blood was found to be an attractive alternative to pH analysis and a useful 2nd-line tool for monitoring fetal asphyxia during labor.

Asphyxia at Birth as Determined by Cord Blood pH Measurements in Preterm and Term Gestations

Normal cord blood gas parameters were statistically defined, depending on the presence or absence of labor, in a group of 243 uncomplicated term and preterm infants. There were no differences in cord blood gas and acid-base measurements between preterm and term infants. However, patients delivered before the onset of labor had significantly higher cord blood pH values, in both artery and vein, as compared with those who underwent a spontaneous vaginal delivery and those delivered by cesarean section after the onset of labor. Subsequently, 442 patients were analyzed after taking into account the presence or absence of labor. It was found that acidemic infants had a significantly higher frequency of neonatal complications as compared to nonacidemic infants: neonatal death rate, 17% vs. 8%; intraventricular hemorrhage/seizures, 33% vs. 8%; severe respiratory distress syndrome, 46% vs. 11%; ventilatory support over a 1-week duration, 29% vs. 12%; mean days of ventilator, 7.6 vs. 3.9; 1-min Apgar scores < 6, 5...