Cord Blood Acid-base Research Articles

Umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes in children: a systematic review and meta-analysis.

Umbilical cord blood acid-base sampling is routinely performed at many hospitals. Recent studies have questioned this practice and the association of acidosis with cerebral palsy. To investigate the associations between the results of umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes and mortality in children. We searched six databases using the search strategy: umbilical cord AND outcomes. Randomised controlled trials, cohorts and case-control studies from high-income countries that investigated the association between umbilical cord blood analysis and neurodevelopmental outcomes and mortality from 1 year after birth in children born at term. We critically assessed the included studies, extracted data and conducted meta-analyses comparing adverse outcomes between children with and without acidosis, and the mean proportions of adverse outcomes. The certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach. We have very low confidence in the following findings: acidosis was associated with higher cognitive development scores compared with non-acidosis (mean difference 5.18, 95% CI 0.84-9.52; n = two studies). Children with acidosis also showed a tendency towards higher risk of death (relative risk [RR] 5.72, 95% CI 0.90-36.27; n = four studies) and CP (RR 3.40, 95% CI 0.86-13.39; n = four studies), although this was not statistically significant. The proportion of children with CP was 2.39/1000 across the studies, assessed as high certainty evidence. Due to low certainty of evidence, the associations between umbilical cord blood gas analysis at delivery and long-term neurodevelopmental outcomes in children remains unclear.

Umbilical Cord Blood Acid-Base Parameters and Lactate as Predictors of Subsequent Meconium Aspiration Syndrome in Neonates.

Meconium aspiration syndrome (MAS) in neonates born through meconium-stained amniotic fluid (MSAF) causes significant morbidity and mortality. Early recognition of at-risk neonates could help optimize treatment. The aim was to determine predictive characteristics of cord blood pH, base deficit and lactate with subsequent MAS. Receiver operating characteristic (ROC) curves with area under curve (AUC) were estimated. Among 231 MSAF complicated pregnancies, 25 (10.8%) had MAS. Mean cord pH was significantly lower in neonates with MAS compared to those without MAS (7.15 ± 0.11 vs. 7.26 ± 0.07; p < 0.001). Median lactate between the two groups [5.6 (7.5, 3.7) vs. 2.7 (4.5, 2.0)] and base deficit [-10.6 (-13.2, -4.2) vs. -3.7 (-6.3, -2.6)] also differed significantly (p = 0.01). ROC curve area for cord lactate, pH, and base deficit were 0.81, 0.79, and 0.75, respectively. The predictive cutoff values for pH, lactate, and base deficit were 7.20, 3.55mmol/L, and -5.3mmol/L, respectively.

Relationship between Apgar score and umbilical cord blood acid-base balance in full-term and late preterm newborns born in medium and severe conditions.

Application of Apgar scores (AS) and umbilical cord blood acid-base analysis is a base for the prediction of future neurological development in children. In clinical practice we often observe huge discrepancy between clinical and biochemical status of newborn. Because many obstetricians consider both assessments as substitute and measure of their proceeding's outcome, we decided to scientifically measure actual correlation between them among newborns born with Apgar less than 8 points. This was an observational retrospective study. The study included 141 newborns born in general medium and severe condition (Apgar < 8 points in first minute of life). Acid-base analysis of umbilical cord vein blood immediately after birth was performed. We correlated gasometer parameters with Apgar scores of newborns. The clinical condition of a newborn at 1, 5, and 10 minutes after birth correlates positively and significantly with pH values (0.25; 0.24; and 0.26; respectively) and bicarbonate levels (0.21; 0.27; 0.28; respectively) in the umbilical cord vein, however correlation was low. Subsequently we qualified newborns to four groups depending on the degree of invasiveness of respiratory support after delivery, and the groups were compared in terms of parameters of acid-based balance. No significant differences were observed between groups in terms of acid-base balance parameters. There is low, but significant correlation between clinical condition of a newborn after birth with most of acid-base parameters from umbilical vein blood. The assessment of the newborn's condition after birth using the Apgar score, (but not acid-base parameters) determines the degree of invasiveness of respiratory support activities for newborns after birth.

Взаимосвязь кислотно-основного состава пуповинной крови с развитием гипоксически-ишемической энцефалопатии у новорожденного

Взаимосвязь кислотно-основного состава пуповинной крови с развитием гипоксически-ишемической энцефалопатии у новорожденного

Effect of Chorionicity on Umbilical Cord Blood Acid-Base Analysis of the Second Twin.

Our objective was to determine whether chorionicity affects umbilical cord blood acid-base parameters of the second twin. This was a retrospective cohort of twin pregnancies delivered at ≥23 weeks of gestation at a tertiary hospital from 2010 to 2016. Patients were included if arterial and venous umbilical cord gas results were available for both newborns and chorionicity was confirmed histologically. Exclusion criteria included intrauterine fetal demise of either twin prior to labor, major fetal anomalies, monoamnionicity, uncertain chronicity and twin-to-twin transfusion syndrome. The primary outcome evaluated was the umbilical artery (UA) pH of the second twin. A total of 593 dichorionic (DC) and 86 monochorionic (MC) twin pregnancies were included. No difference in UA pH was observed between MC and DC twins. Among vaginal deliveries (n = 97), the UA pH of the first twin was higher than the second twin (7.26 vs. 7.24; p = .01). Twin-to-twin delivery interval (TTDI) ≥20 min was associated with a higher UA pH in the first twin compared to the second twin (7.25 vs. 7.16, respectively; p = .006). Multivariable logistic regression was used to predict arterial pH < 7.20 for the second twin; the most predictive factors were arterial pH < 7.20 for the first twin, chronic hypertension and prolonged TTDI. Chorionicity was not associated with any acid-base parameter of umbilical cord blood in either the first or second twin. No differences in neonatal outcomes were observed based on chorionicity or birth order. Populations with a lower cesarean delivery rate may yield different findings.

Кислотно-основное состояние и газовый состав пуповинной крови в зависимости от использования эпидуральной аналгезии в родах через естественные родовые пути

Кислотно-основное состояние и газовый состав пуповинной крови в зависимости от использования эпидуральной аналгезии в родах через естественные родовые пути

Arterio-venous blood gas Δvalues for validation of umbilical cord blood samples at birth are not only biased by sample mix ups but also affected by clinical factors.

Traditional validation of umbilical cord blood samples with positive veno-arterial ΔpH and arterio-venous ΔpCO2 values confirms the source of samples, whereas negative Δvalues represent mix-up of samples. To investigate whether this is true, the distributions of V-A ΔpO2 and A-V Δlactate were also explored and related to clinical characteristics. In addition, different cord blood sampling techniques were evaluated. Register study with cord blood acid-base and clinical data from 27233 newborns. Clinical characteristics were related to positive, zero and negative Δvalues. Blood samplings from unclamped and double-clamped cords were compared. A two-sided P<0.05 was considered significant. ΔpH and ΔpCO2 values distributed into positive, around zero, and negative sub-populations, with significant differences in pH and clinical characteristics between sub-populations. No such sub-populations were distinguished for ΔpO2 and Δlactate. The 2.5th and 5th ΔpH percentiles were 0.013 and 0.022, respectively, and for ΔpCO2 0.30 and 0.53kPa. Applying 5th percentile criteria resulted in 3.5% of "approved" cases showing a ΔpO2 ≤0. Puncture and sampling of the unclamped cord resulted in significantly better sample quality. Unphysiological negative ΔpO2 values occurred despite correct validation with traditional criteria. Δlactate cannot be used for validation because both positive and negative values are physiological. Positive/around zero/negative ΔpH and ΔpCO2 sub-populations were associated with significant differences in pH and clinical characteristics, indicating that defective sampling and sample handling are not the sole explanations for negative Δvalues. Prompt puncture and sampling of the unclamped cord resulted in best sample quality.

Определение кислотно-основного состояния пуповинной крови. Показания и техника

Определение кислотно-основного состояния пуповинной крови. Показания и техника

The Course of Parturition Affects Piglet Condition at Birth and Survival and Growth through the Nursery Phase.

Simple SummaryIn this study, data were collected on the condition in which piglets were born, and this was related to their position in the birth order, and to the progress of parturition. The objective of the study was to find out if these observations were related to performance in early life, up to 10 weeks. It appeared that the later the piglets were born in a litter, the higher the risk of being stillborn, and this was aggravated in sows that took a relatively long time to give birth to their litter. In the first few piglets in a litter, risk of stillbirth was only 2%, whereas this increased to 17% in piglets born 13th in the litter or later. Similarly, birth order affected the condition of the liveborn piglets, with blood values such as pH being evident of suboptimal oxygenation in piglets born later. These blood values were predictive of neonatal behaviour such as colostrum intake, but also for neonatal survival and growth during suckling and even to 10 weeks of life. These data are the first in piglets to emphasise the impact of condition at birth on survival and growth until the end of the nursery phase.The aim of this study was to relate the course of parturition to the condition of piglets at birth, based on umbilical cord blood acid-base values, and relate the condition at birth to neonatal survival and performance up to 10 weeks of life. Data were collected from 37 spontaneous unassisted parturitions, and neonatal performance was based on observations of 516 piglets. Stillbirth rate increased from 2% in the first piglets, to 17% in piglets born 13th in the litter or later. This was aggravated in sows with longer than average stage II of parturition. Umbilical cord blood values also reflected the effect of birth order, with pH decreasing and lactate increasing in the course of parturition. Interestingly, sows that had a long expulsion stage of parturition also took longer to give birth to the first four piglets (r = 0.74), suggesting that sows with complicated parturition were already experiencing problems at the start of expulsion of piglets. Piglets with signs of asphyxia, based on umbilical blood lactate higher than 4.46 mmol/L, were slower to start suckling, had a higher risk of neonatal mortality, and had a slower growth rate over the first 10 weeks of life.

Umbilical cord blood acid-base analysis and the development of significant hyperbilirubinemia in near-term and term newborns: a cohort study

BackgroundThe recognition, follow-up, and early treatment of neonatal jaundice has become more difficult, since the earlier discharge of newborns from hospitals has become common practice. Since intrapartum hypoxic stress has been pointed as predisposing factor for the occurrence of hyperbilirubinemia risk, we tested the association with the cord blood acid-base index tests.MethodsA cohort of healthy term and near-term newborns underwent umbilical cord hemogasanalysis at birth and capillary heel total serum bilirubin (TSB) pre-discharge, scheduled at 36 h of life, to define the risk of significant hyperbilirubinemia, defined as >9 mg/dL TSB level, ≥ 75th percentile on nomogram of Bhutani et al.ResultsIt was found that among 537 studied neonates, 133 (24.8%) had pre-discharge TSB levels of >9 mg/dL. When the cord blood gas analysis index tests were compared, their acidemia levels were significantly higher than those of neonates with normal TSB levels: HCO3− (20.71 ± 2.37 vs. 21.29 ± 2.25 mEq/L, p < 0.010), base deficit (−3.52 ± 3.188 vs. -2.68 ± 3.266 mEq/L, p < 0.010), and lactacidemia (3.84 ± 1.864 vs. 3.39 ± 1.737 mEq/L, p < 0.012), respectively. However, logistic regression analysis showed that base deficit was the strongest index of the pre-discharge hyperbilirubinemia risk (OR, 95% CI 0.593; 0.411–0.856), and the hyperbilirubinemia risk increased by 40% with the decrease of 1 mEq/L of base deficit.ConclusionsUmbilical cord blood acidemia and lactacidemia are significant indexes of adaptive mechanisms at birth. The base deficit provides the strongest association with future development of high bilirubin on an hour specific bilirubin nomogram generating risk stratification score in term and near-term neonates.

Assessment of fetal cord blood acid-base status following intrapartum maternal glucose infusion

Background and Aim: Supplementation of intravenous fluids is associated with with increased incidence of neonatal hypoglycemia. However, WHO guideline recommends no restriction of liquid or solid food to a parturient mother. Therefore, the aim of the study is to compare fetal acid-base status and neonatal blood glucose levels following intrapartum infusion of ringer lactate (RL) solution or dextrose normal saline (DNS) solution in active labor. Methods: It is a prospective, analytical study conducted on hundred women in active labor and they were randomly allocated into two groups. First group (Group A) received intravenous infusion of DNS, and the other group (Group B) was given RL infusion for at least 1 h before delivery. Results: There was no significant difference in fetal acid-base status between the two groups although neonatal blood glucose levels were higher in the DNS group (Group A). Conclusion: Intrapartum infusion of DNS can raise neonatal blood glucose level but does not cause fetal acidosis or any alteration in fetal acid-base status.

Umbilical cord blood acid-base status in pregnancy with congenital heart disease.

The risk of fetal and neonatal complications is higher in pregnant women with congenital heart disease (CHD). It remains unknown whether umbilical cord blood gas values are different between pregnant women with CHD and healthy women undergoing elective cesarean section during combined spinal-epidural anesthesia. The purpose of the present study was to compare umbilical cord blood acid-base status and gas values in pregnant women with CHD vs. healthy pregnant women undergoing elective cesarean section during combined spinal-epidural (CSE) anesthesia. Patients with singleton pregnancy undergoing elective cesarean delivery under CSE anesthesia were enrolled. Patients were divided into two groups: healthy pregnant women (group H) and pregnant with congenital heart disease (group CHD). Immediately after delivery, umbilical cord arterial blood sample and venous blood sample were collected and measured. The comparison between two groups was performed using grouped t-test. Forty-four women in group H and 33 women in group CHD were analyzed finally. Umbilical arterial blood pH, base excess (BE) and HCO3 (-) (pH 7.29 ± 0.05, BE -1.4 ± 1.9 mmol/L, HCO3 (-) 21.5 ± 1.4 mmol/L) were significantly lower in pregnant women with CHD than in healthy pregnant women (pH 7.33 ± 0.03, BE -0.1 ± 2.1 mmol/L, HCO3 (-) 22.5 ± 1.4 mmol/L). The lower values of umbilical arterial blood pH, BE and HCO3 (-) were observed in pregnant women with CHD than in healthy women undergoing elective cesarean section during CSE anesthesia.

Cord and jugular blood acid–base and electrolyte status and haematobiochemical profiles in goats with naturally occurring pregnancy toxaemia

This study was carried out to investigate umbilical cord and jugular blood acid–base and electrolyte status and haematobiochemical profiles in goats with normal parturition and in those with naturally occurring pregnancy toxaemia (PT). Fifty does, divided into two groups, were used. The first, control group, was comprised of 20 clinically healthy pregnant does. The second, diseased group consisted of 30 pregnant does suffering from PT. Jugular and umbilical vein blood samples were collected from each doe. In both samples, blood gas parameters including pH, partial pressure of carbon dioxide (PCO2), oxygen partial pressure (PO2), bicarbonate (HCO3), total carbon dioxide (TCO2), base excess (BE), oxygen saturation (SO2), sodium, potassium, chloride and lactate were determined immediately after collection. Compared to the jugular blood values in the controls, the blood pH, PO2, BE, HCO3, TCO2 and SO2 were lower in the goats with PT (P<0.01). However, the PCO2 and anion gap were higher (P<0.05). Compared to values in the cord blood of the controls, the blood pH, PO2, SO2, BE, HCO3 and TCO2 were lower in the goats with PT (P<0.01), although the PCO2, anion gap, potassium and lactate were significantly higher (P<0.05). The jugular and cord blood acid–base and electrolyte status and haematological and biochemical profiles in this study could be used as a reference for goats with normal birth and in goats with PT.

The value of epidural magnesium sulfate as an adjuvant to bupivacaine and fentanyl for labor analgesia

ObjectiveWe conducted this clinical study to assess the adjuvant effects of single dose magnesium sulfate (Mg) when administered epidurally during labor with fentanyl and bupivacaine.MethodsEighty healthy nulliparous women in labor requesting epidural analgesia were divided into two groups. Group 1 received bupivacaine 0.125% with magnesium sulfate 50 mg and fentanyl 50 μg as a loading dose; group 2, received bupivacaine 0.125% and fentanyl 50 μg only. Hemodynamic parameters, motor and sensory evaluation, cervical dilation at time of consenting, the progress of labor, the visual analog pain score (VAS), Apgar score, cord blood acid base status, side effects as nausea, vomiting, itching and respiratory depression were recorded. Fetal heart rate tracings were also documented.ResultsEpidural single dose magnesium sulfate added to bupivacaine and fentanyl in labor resulted in significantly faster onset and longer duration of epidural analgesia (169 ± 50 min) in comparison to those patients who received bupivacaine and fentanyl only (105 ± 41 min), also there was a significant reduction in the number of women requiring additional boluses of bupivacaine when Mg was added (P = 0.016). The two groups had no significant differences as regards maternal satisfaction score, maternal and neonatal adverse effects.ConclusionMagnesium sulfate added to bupivacaine and fentanyl for labor epidural analgesia resulted in faster onset, longer duration of action and reduced the break through pain.

Hidden acidosis: an explanation of acid–base and lactate changes occurring in umbilical cord blood after delayed sampling

To explore the 'hidden acidosis' phenomenon, in which there is a washout of acid metabolites from peripheral tissues in both vaginal and abdominal deliveries, by investigating temporal umbilical cord blood acid-base and lactate changes after delayed blood sampling. Prospective comparative study. University hospital. Umbilical cord blood from 124 newborns. Arterial and venous cord blood was sampled immediately after birth (T₀), and at 45 seconds (T₄₅), from unclamped cords with intact pulsations taken from 66 neonates born vaginally and 58 neonates born via planned caesarean section at 36-42 weeks of gestation. Non-parametric tests were used for statistical comparisons, with P < 0.05 considered significant. Temporal changes (T₀-T₄₅) in umbilical cord blood pH, the partial pressure of CO₂ (PCO₂) and O₂ (PO₂), and in the concentrations of lactate, haematocrit (Hct), and haemoglobin (Hb). In both groups all arterial parameters, except for PCO₂ in the group delivered by caesarean section, changed significantly (pH decreased and the other variables increased). There were corresponding changes in venous acid-base parameters. When temporal arterial changes were compared between the two groups, the decrease in pH and increase in PCO₂ were more pronounced in the group delivered vaginally. Neonates born vaginally had significantly lower pH and higher lactate, Hct, and Hb concentrations at T₀ and T₄₅ in both the artery and the vein. At T₄₅, arterial PCO₂ and PO₂ levels in the group delivered vaginally were also significantly higher. Delayed umbilical cord sampling affected the acid-base balance and haematological parameters after both vaginal and caesarean deliveries, although the effect was more marked in the group delivered vaginally. The hidden acidosis phenomenon explains this change towards acidaemia and lactaemia. Arterial haemoconcentration was not the explanation of the acid-base drift.

Intrapartum fetal asphyxia: study of umbilical cord blood lactate in relation to fetal heart rate patterns

To correlate between umbilical artery cord blood lactate and acid-base status with intrapartum fetal heart rate monitoring, and to measure the reliability of umbilical cord blood lactate for prediction of early neonatal outcome. Sixty-six participants with intrapartum abnormal fetal heart rate monitoring and 60 participants with normal intrapartum recordings were recruited. The abnormal recordings included late onset, atypical variable and simple variable decelerations. After delivery, the arterial cord blood lactate, pH, actual base excess (ABE), and Apgar score were measured in all participants. There was significant inverse correlation between cord lactate and pH and ABE in all participants (correlation coefficient = -0.7, p < 0.0001). The cord lactate was significantly higher in the late onset and atypical variable decelerations groups compared to control (p < 0.0001). There was no significant correlation between the Apgar score and blood lactate in all groups; however, the sensitivity and specificity of cord lactate to predict low score at 5 min were higher in comparison to cord pH. Umbilical cord blood lactate is a reliable marker for intrapartum fetal asphyxia compared to cord acid-base status with better prediction for newborns with low Apgar score.

SP6-28 Effect of umbilical cord blood acid-base status and gas values on the yield of mononuclear cells and cd34 cells

PurposeTo investigate the influence of umbilical cord blood (CB) acid-base status and gas values on the yield of mononuclear cells and CD34 cells, pH, pCO2, pO2, HCO3− and base excess...

Umbilical cord blood acid–base and gas analysis after early versus delayed cord clamping in neonates at term

To compare umbilical cord acid-base status and blood gas analysis between umbilical cords clamped within 10 s and at 2 min of delivery. A total of 158 healthy full-term mothers were randomly assigned to an early clamping (<10 s post-delivery, n = 79) or delayed clamping (2 min post-delivery, n = 79) group. After application of inclusion criteria, umbilical vein blood acid-base status and gases were analyzed in 65 early clamped and 51 delayed clamped cords. Fewer cases could be examined in the umbilical artery: 55 cords in the early clamping group and 44 in the delayed one. Acid-base and gas analysis results did not significantly differ between the groups in the umbilical vein or umbilical artery, with the exception of a higher (p < 0.001) mean umbilical artery pO(2) value in the delayed versus early clamping group. No significant differences in umbilical vein or artery pCO(2) or HCO(3) (-) values were observed between the early and delayed clamp groups. A delay of 2 min before umbilical cord clamping does not significantly change acid-base and gas analysis results, with the exception of a higher mean umbilical artery pO(2) value in the delayed clamping group.

Effects of Varying Doses of Plain Bupivacaine with Fentanyl in Patients Undergoing Cesarean Section: Haemodinamics and Neonatal Outcome

Aim. The purpose of this study was to evaluate a three different regimes of spinal anaesthesia for caesarean delivery as well the incidence and severity of maternal hypotension and its influence over neonatal outcome. Material and Methods. Sixty (60) term healthy (ASA I) parturients scheduled for elective or non-elective caesarean delivery without fetal distress under spinal anaesthesia were randomly divided in three groups: group SA F10 (n = 20) received plain bupivacaine 12 mg plus 10 μg fentanyl, group SA F20 (n = 20) received 11 mg plus 20 μg fentanyl and SA LD group (low dose, n = 20 ) received 8 mg bupivacaine plus 20 μg fentanil. Ephedrine 5-10 mg i.v. bolus was given when systolic blood pressure (SBP) was < 95 mmHg. Maternal blood pressures, efedrin dosage, sensory level of anaesthesia, Apgar scores and neonatal umbilical cord blood acid-base (Ua) status were evaluated. Results. Spinal block provided surgical anaesthesia in all patients. Peak sensory level was higher in the greatest bupivacaine group (4.9 ± 1.33, 5.0 ±1.21 vs. 5.4 ±1.55). Parturient who received 12 mg bupivacaine (SA F10 group) develop significantly decrease of SBP - 97.9 ± 8.9 mmHg (23.8%), after spinal blockade compared with low dose group SA LD - 125.0 ± 12.9, (6.0 %, p< 0.05) and 115.1 mmHg (17.5%) in the SA F20 group. The total amount of ephedrine to treat hypotension was significantly lower in the low dose group (SA LD) compared with two other group (1.75 ± 1.0 mg vs. 13.75 ± 6.5 mg (SA F10) and 11.75 ± 6.2 (SA F20, p<0.5). Neonatal Ua pH was significantly lower with SA F10 group than low dose spinal group-SA LD (7.22 ± 0.07 vs. 7.27 ± 0.04, p < 0.05; 7.23 ± 0.04 SA F20 group). Conclusion. spinal anaesthesia for caesarean delivery with a low dose bupivacaine of 8 mg in conjunction with 20 μg fentanyl leads to less hypotension and ephedrine requirements with better neonatal outcome when compared with 12 and 11 mg bupivacaine – fentanyl spinal anaesthesia.

Delayed Umbilical Cord Clamping at Birth has Effects on Arterial and Venous Blood Gases and Lactate Concentrations

BJECTIVE: To estimate the influence of delayed umbilical cord clamping at birth on arterial and venous umbilical cord blood gases, bicarbonate (HCO3-), base excess (BE) and lactate in vigorous newborns. SETTING: University hospital. DESIGN: Prospective observational. SAMPLE: Vaginally delivered term newborns. MATERIAL AND METHODS: Umbilical cord arterial and venous blood was sampled repeatedly every 45 seconds (T(0)= time zero; T(45)= 45 seconds, T(90)= 90 seconds) until the cord pulsations spontaneously ceased in 66 vigorous singletons with cephalic vaginal delivery at 36-42 weeks. Longitudinal comparisons were performed with the Wilcoxon signed-ranks matched pairs test. Mixed effect models were used to describe the shape of the regression curves. MAIN OUTCOME MEASURES: Longitudinal changes of umbilical cord blood gases and lactate. RESULTS: In arterial cord blood, there were significant decreases of pH (7.24-7.21), HCO3- (18.9-18.1 mmol/l) and BE (-4.85 to -6.14 mmol/l), and significant increases of PaCO(2) (7.64-8.07 kPa), PO(2) (2.30-2.74 kPa) and lactate (5.3-5.9 mmol/l) from T(0) to T(90), with the most pronounced changes at T(0)-T(45). Similar changes occurred in venous blood pH (7.32-7.31), HCO3- (19.54-19.33 mmol/l), BE (-4.93 to -5.19 mmol/l), PaCO(2) (5.69-5.81 kPa) and lactate (5.0-5.3 mmol/l), although the changes were smaller and most pronounced at T(45)-T(90). No significant changes were observed in venous PO(2). CONCLUSION: Persistent cord pulsations and delayed cord clamping at birth result in significantly different measured values of cord blood acid-base parameters.