The association between cord pH at birth and intellectual function in childhood

Correlation of cardiotocography with combined APGAR scores and diagnostic performance of umbilical cord parameters in predicting low combined APGAR scores - A prospective Cohort study

Objectives

Combined Apgar score includes utilization of interventions such as Continuous positive airway pressure, Oxygen, Mask and Bag ventilation, I ntubation and ventilation, Ne onatal chest compression, Drugs, and newborn assessment. It has been proposed as a substitute for conventional Apgar score which is the gold standard for evaluating newborns right after birth but is impacted by medical interventions and preterm. Combined Apgar scores were examined to check for correlation with CTG tracing and umbilical cord blood parameters which gives an objective assessment of fetal hypoxia, in response to the demand for a more accurate tool for evaluating the neonate and to be used for medico-legal purposes. The study's objectives were to (1) determine the association of combined Apgar scores with suspicious and pathological CTG (2) the association of umbilical cord parameters with low combined Apgar scores and the diagnostic performance of these parameters in predicting low combined Apgar scores.

Study design

A prospective observational cohort study was conducted in a tertiary care center in East India. 2350 consecutive laboring mothers who had completed 34 weeks of gestation underwent cardiotocography according to institutional protocol and those with suspicious and pathological CTG who delivered within 1 h of abnormal CTG were recruited. Arterial blood was analyzed and the newborn was evaluated immediately after delivery with a combined Apgar scoring system.

Results

Of the 2350 women, 50.7 % and 49.3 %, respectively, exhibited suspicious and abnormal CTG tracings. CTG was reported to have low diagnostic accuracy and specificity, with a sensitivity of 66.7 % and 88.9 %, respectively, in detecting combined Apgar at 1 and 5 min. The combined Apgar score at five minutes showed a strong association with acidosis. There was a statistically significant correlation between low combined Apgar and excess lactate and base at one and five minutes. With 100 % sensitivity and 95 % specificity, high lactate levels > 4.1 mM/L were found to predict newborn encephalopathy.

Conclusion

Umbilical cord blood parameters were found to be correlated with low combined Apgar scores. Combined Apgar scores may be a more useful tool for neonatal assessment and long-term morbidity of newborns. Additional research is required to determine whether it can take the role of conventional Apgar scores in clinical practice.

Umbilical cord pH, blood gases, and lactate at birth: normal values, interpretation, and clinical utility

Normal birth is a eustress reaction, a beneficial hedonic stress with extremely high catecholamines that protects us from intrauterine hypoxia and assists in the rapid shift to extrauterine life. Occasionally the cellular O2 requirement becomes critical and an O2 deficit in blood (hypoxemia) may evolve to a tissue deficit (hypoxia) and finally a risk of organ damage (asphyxia). An increase in H+ concentration is reflected in a decrease in pH, which together with increased base deficit is a proxy for the level of fetal O2 deficit. Base deficit (or its negative value, base excess) was introduced to reflect the metabolic component of a low pH and to distinguish from the respiratory cause of a low pH, which is a high CO2 concentration. Base deficit is a theoretical estimate and not a measured parameter, calculated by the blood gas analyzer from values of pH, the partial pressure of CO2, and hemoglobin. Different brands of analyzers use different calculation equations, and base deficit values can thus differ by multiples. This could influence the diagnosis of metabolic acidosis, which is commonly defined as a pH <7.00 combined with a base deficit ≥12.0 mmol/L in umbilical cord arterial blood. Base deficit can be calculated as base deficit in blood (or actual base deficit) or base deficit in extracellular fluid (or standard base deficit). The extracellular fluid compartment represents the blood volume diluted with the interstitial fluid. Base deficit in extracellular fluid is advocated for fetal blood because a high partial pressure of CO2 (hypercapnia) is common in newborns without concomitant hypoxia, and hypercapnia has a strong influence on the pH value, then termed respiratory acidosis. An increase in partial pressure of CO2 causes less increase in base deficit in extracellular fluid than in base deficit in blood, thus base deficit in extracellular fluid better represents the metabolic component of acidosis. The different types of base deficit for defining metabolic acidosis in cord blood have unfortunately not been noticed by many obstetrical experts and organizations. In addition to an increase in H+ concentration, the lactate production is accelerated during hypoxia and anaerobic metabolism. There is no global consensus on definitions of normal cord blood gases and lactate, and different cutoff values for abnormality are used. At a pH <7.20, 7% to 9% of newborns are deemed academic; at <7.10, 1% to 3%; and at <7.00, 0.26% to 1.3%. From numerous studies of different eras and sizes, it can firmly be concluded that in the cord artery, the statistically defined lower pH limit (mean -2 standard deviations) is 7.10. Given that the pH for optimal enzyme activity differs between different cell types and organs, it seems difficult to establish a general biologically critical pH limit. The blood gases and lactate in cord blood change with the progression of pregnancy toward a mixed metabolic and respiratory acidemia because of increased metabolism and CO2 production in the growing fetus. Gestational age-adjusted normal reference values have accordingly been published for pH and lactate, and they associate with Apgar score slightly better than stationary cutoffs, but they are not widely used in clinical practice. On the basis of good-quality data, it is reasonable to set a cord artery lactate cutoff (mean +2 standard deviations) at 10 mmol/L at 39 to 40 weeks' gestation. For base deficit, it is not possible to establish statistically defined reference values because base deficit is calculated with different equations, and there is no consensus on which to use. Arterial cord blood represents the fetus better than venous blood, and samples from both vessels are needed to validate the arterial origin. A venoarterial pH gradient of <0.02 is commonly used to differentiate arterial from venous samples. Reference values for pH in cord venous blood have been determined, but venous blood comes from the placenta after clearance of a surplus of arterial CO2, and base deficit in venous blood then overestimates the metabolic component of fetal acidosis. The ambition to increase neonatal hemoglobin and iron depots by delaying cord clamping after birth results in falsely acidic blood gas and lactate values if the blood sampling is also delayed. Within seconds after birth, sour metabolites accumulated in peripheral tissues and organs will flood into the central circulation and further to the cord arteries when the newborn starts to breathe, move, and cry. This influence of "hidden acidosis" can be avoided by needle puncture of unclamped cord vessels and blood collection immediately after birth. Because of a continuing anaerobic glycolysis in the collected blood, it should be analyzed within 5 minutes to not result in a falsely high lactate value. If the syringe is placed in ice slurry, the time limit is 20 minutes. For pH, it is reasonable to wait no longer than 15 minutes if not in ice. Routine analyses of cord blood gases enable perinatal audits to gain the wisdom of hindsight, to maintain quality assurance at a maternity unit over years by following the rate of neonatal acidosis, to compare results between hospitals on regional or national bases, and to obtain an objective outcome measure in clinical research. Given that the intrapartum cardiotocogram is an uncertain proxy for fetal hypoxia, and there is no strong correlation between pathologic cardiotocograms and fetal acidosis, a cord artery pH may help rather than hurt a staff person subjected to a malpractice suit based on undesirable cardiotocogram patterns. Contrary to common beliefs and assumptions, up to 90% of cases of cerebral palsy do not originate from intrapartum events. Future research will elucidate whether cell injury markers with point-of-care analysis will become valuable in improving the dating of perinatal injuries and differentiating hypoxic from nonhypoxic injuries.

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

BACKGROUND

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.

OBJECTIVE

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.

SEARCH STRATEGY

We searched six databases using the search strategy: umbilical cord AND outcomes.

SELECTION CRITERIA

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.

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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.

CONCLUSION

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.

[Impact of a service protocol on the practice of vaginal delivery of breech presentations at term]

OBJECTIVES

The delivery of breech presentations remains controversial. Our study analysed the impact of a service protocol on the proportion of planned vaginal delivery and its success. Immediate neonatal morbidity and factors that may influence the success of vaginal delivery were studied.

METHODS

Retrospective study, between 2009 and 2020 at the CHRU of Limoges, type 3 maternity hospital, on patients with a breech foetus at term. The proportion of planned vaginal delivery and the rate of effective vaginal delivery were compared before/after 2015. Neonatal morbidity was compared for planned vaginal delivery and planned cesarean delivery groups.

RESULTS

We included 923 patients. The rate of planned vaginal delivery was significantly higher after 2015 from 5.2% to 19% (P<0.001), with a success rate increasing from 60% to 82.1% (P=0.06). The rate of vaginal breech deliveries significantly increased from 3.8% to 17% (P<0.001). We found significantly more newborns with moderate acidosis when a vaginal delivery was attempted (P<0.001). The success of vaginal delivery was correlated to the Magnin index (P=0.044), to gestational age (P=0.037), and to multiparity (OR 3.78 95% CI [1.42-10.03] P=0.006).

CONCLUSION

Our study demonstrates the benefits of setting up a service protocol for the practice of breech vaginal delivery.

Neurodevelopmental outcome at 24 months of healthy infants at birth with an umbilical artery blood pH ≤ 7 and/or hyperlactacidemia ≥ 7 mmol/L

OBJECTIVE

The incidence of acidosis in term and healthy newborns and the consequences for their neurodevelopment are poorly understood. The aim of our study was to assess neurodevelopmental outcomes at 24 months of age via a parental questionnaire (ASQ, Ages and Stages Questionnaires) for a sample of infants born at term with an umbilical arterial blood pH ≤ 7 or/and hyperlactacidemia ≥ 7 mmol/L. In addition, we compared these groups' neurodevelopmental outcomes with a control group.

METHODS

During the 29 months of the study, we retrospectively included all children who had an umbilical artery (UA) cord blood pH ≤ 7 and/or lactates ≥ 7 mmol/L with good clinical adaptation. We also included a control group of term newborns with normal gases at birth. Ages and Stages questionnaires were sent to parents at 24 months of age.

RESULTS

Among the 9016 births during the study, 7.1% of babies had a UA pH ≤ 7 and/or lactates ≥ 7 mmol/L. The ASQ was considered non-optimal for 32.2% and 36.3% of respondents in the acidosis and control group, respectively, without any significant difference (P = 0.382). After matching for gestational age and sex, there was also no significant difference in the rate of non-optimal ASQ. The percentage of abnormal communication was significantly higher in the control group (19.7% vs 11.4%, P = 0.015).

CONCLUSIONS

Isolated biochemical umbilical cord blood abnormalities in term or near-term newborns with good adaptation do not appear to have a long-term impact on development. These results are rather reassuring, and the absence of specific follow-up for these children seems reasonable.

Umbilical artery pH and base excess at birth are poor predictors of neurodevelopmental morbidity in early childhood

AIM

We sought to evaluate the associations between umbilical artery pH and base excess and neurodevelopmental outcome at four years of age.

METHODS

This study comprised 84 588 singleton children born alive at term in 2005-2011 in the hospital district of Helsinki and Uusimaa in Finland. Data from the maternity hospital information system were linked to the data from the Medical Birth Register and the Hospital Discharge Register. Neurodevelopmental morbidity included cerebral palsy, epilepsy, intellectual or sensorineural impairment.

RESULTS

After adjustment for maternal and perinatal factors, a combination of pH <7.00 and base excess <-16.00 was associated with infant death (adjusted odds ratio 19.97; 95% confidence interval 5.38-74.17). Values of pH 7.00-7.10 were associated with cerebral palsy (adjusted odds ratio 2.40; 95% confidence interval 1.05-5.47). A combination of low five-minute Apgar score and umbilical artery base excess <-16.00 showed the highest positive predictive value (9.1%) for neurodevelopmental impairments. When umbilical artery pH <7.00 was included, a positive predictive value of 25.0% was observed for infant mortality.

CONCLUSION

Low umbilical artery pH and base excess at birth were the poor predictors of long-term neurodevelopmental morbidity in an unselected population. However, these parameters might be useful in assessing the risk of infant mortality.

Gestational age-related reference values for Apgar score and umbilical cord arterial and venous pH in preterm and term newborns

INTRODUCTION

Despite much literature on reference values of acid-base status in umbilical cord blood at birth, there are as yet no studies performed to determine gestational age-dependent references in cord venous blood and no studies on preterm acid-base standards. Similarly, the normal reference range of Apgar scores for term and preterm infants has not yet been determined.

MATERIAL AND METHODS

Data were obtained from the maternity units of Skåne University Hospital, Malmö and Lund, Sweden, from 2001 to 2010. Validated paired arterial and venous cord pH values were obtained from 27 175 newborns, of whom 18 584 had spontaneous, non-instrumental vaginal deliveries and a 5-minute Apgar score equal to or greater than the median value for the individual gestational week. Simple linear and polynomial regression analyses were performed. Values were reported as mean ± standard deviation and median with 2.5th and 97.5th percentiles.

RESULTS

Median 5-minute Apgar score was 7 for gestations shorter than 28 weeks, 8 for 28 weeks, 9 for 29-30 weeks, and 10 from 31 weeks onwards. A linear decline in pH for both cord arterial and venous blood was seen with advancing gestational age (P < 0.001).

CONCLUSIONS

Median 5-minute Apgar scores were <10 before 31 weeks of gestation. Both umbilical cord arterial and venous pH decreased linearly with increasing gestational age. Further studies are needed to show whether gestational age-related pH reference ranges might be preferred to fixed cut-offs in the estimation of umbilical cord acidemia at birth.

Dose-dependent relationship between acidosis at birth and likelihood of death or cerebral palsy

BACKGROUND

The acid-base status of infants around birth can provide information about their past, current and future condition. Although umbilical cord blood pH <7.0 or base deficit ≥12 mmol/L is associated with increased risk of adverse outcome, there is uncertainty about the prognostic value of degree of acidosis as previous studies have used different variables, thresholds, outcomes and populations.

METHODS

Retrospective review of routinely collected clinical data in all live-born inborn infants of 35 weeks gestation or more delivered between January 2005 and December 2013 at the Simpson Centre for Reproductive Health, Edinburgh, UK. Infants were included if their lowest recorded pH was <7 and/or highest base deficit ≥12 mmol/L on either umbilical cord blood and/or neonatal blood gas within 1 hour of birth. Neurodevelopmental outcome of the infants with encephalopathy was collected from the targeted follow-up database.

RESULTS

56 574 infants were eligible. 506 infants (0.9%) met inclusion criteria. Poor condition at birth and all adverse outcomes increased with worsening acidosis. Combined outcome of death or cerebral palsy was 3%, 10% and 40% at lowest pH of 6.9-6.99, 6.8-6.89 and <6.8, respectively, and 8%, 14% and 59% at a base deficit of 12-15.9, 16-19.9 and 20 mmol/L or more, respectively.

CONCLUSIONS

There is a dose-dependent relationship between the degree of acidosis within an hour of delivery, and the likelihood of adverse neonatal and later neurodevelopmental outcome in infants born at 35 weeks gestation or more.

Umbilical artery pH at birth and neurobehavioral outcome in early preterm infants: A cohort study

Objective:

The objective of the following study is to determine the effect of umbilical artery pH at birth on early neurobehavioral outcome of preterm infants as assessed by Neurobehavioral Assessment of Preterm Infants (NAPI) tool.

Materials and Methods:

Prospective cohort study conducted at the neonatal unit in a tertiary care center in North India. Preterm neonates < 34 weeks of gestation were enrolled at birth and divided into cases (umbilical artery pH < 7.2) and controls (umbilical artery pH > 7.2). At 34 weeks postconceptional age, the motor development and vigor (MDV) and alertness and orientation (AO) domains of neurobehavior were assessed by NAPI and compared among groups.

Results:

Hundred preterm neonates were enrolled in the study out of which 76 (30 cases and 46 controls) were finally analyzed. The groups were comparable in terms of gestational age, mode of delivery, birth weight and requirement of resuscitative measures at birth. There was no significant difference in incidence of meningitis, intraventricular hemorrhage, jaundice and hypoxic ischemic encephalopathy among the groups; however hypoglycemia was observed more commonly among cases. The MDV score (mean ± standard deviation [SD] [95% confidence interval]) was found to be significantly lower among cases compared to controls (37.0713 ± 13.616 [32.099-42.0431] vs. 47.506 ± 14.0692 [43.367-51.655]) (P = 0.002). Similarly, lower AO scores were observed among the cases.

Conclusion:

A low umbilical artery pH at birth is a predictor of poor early neurobehavioral outcome in preterm neonates.

Relationship between severe acidemia, verbal abilities, and behavior in a Spanish cohort of 5-year-old children born at term

AIM

To determine whether a relationship exists between the markers of severe acidemia (SA) and the developmental, verbal, and behavioral characteristics of children with SA born at term 5 years previously, without apparent neurological impairment.

METHODS

A cohort of 76 children-38 with SA (pH < 7, base deficit ≥12 mmol/L) and 38 non-SA (pH ≥ 7.20)-were evaluated using the Battelle Developmental Inventory, McCarthy's Verbal Scale, the Token Test for Children, and the Conners 3rd Edition-Parent. The relationships between markers of SA and verbal and behavioral scores were analyzed with parametric correlations. Multiple regression analysis was used to determine the possible effect of these markers on verbal abilities, verbal memory, and attention.

RESULTS

Although none of the scores were in the "impaired" range, the SA group scored lower in verbal index (p = .000) and verbal memory (p = .004) on the McCarthy's Scales and in verbal comprehension (p = .001) on the Token Test for Children-2, and higher on the inattention (p = .003) and hyperactivity-impulsivity domains of the Conners Scales (p = .009) compared with the control group. There were no differences between the groups in the motor, personal-social, or cognitive domains on the Battelle Developmental Inventory. The SA markers were found to be predictors, accounting for 61.6% of verbal variability.

CONCLUSIONS

SA markers reflect mild long-term consequences regarding verbal abilities and inattentiveness among children born at term without apparent neurological impairment on discharge but do not suggest severe impairment to the 5-year development of children. The authors recommend that these children should be monitored to determine whether they need or might benefit from an early intervention program.

Developmental outcome at 6.5 years after acidosis in term newborns: a population-based study

OBJECTIVES

Infants who develop encephalopathy after perinatal asphyxia have an increased risk of death and adverse neurologic outcome. Conflicting results exist concerning outcome in healthy infants with metabolic acidosis at birth. The aim of the current study was to evaluate whether metabolic acidosis at birth in term infants who appear healthy is associated with long-term developmental abnormalities.

METHODS

From a population-based cohort (14,687 deliveries), 78 infants were prospectively identified as having metabolic acidosis (umbilical artery pH < 7.05 and base deficit in the extracellular fluid >12.0 mmol/L). Two matched controls per case were selected. The child health and school health care records were scrutinized for developmental abnormalities.

RESULTS

Outcome measures at 6.5 years of age for 227 of 234 children (97%) were obtained. No differences were found concerning neurologic or behavioral problems in need of referral action or neurodevelopmental diagnosis in comparison of control children with acidotic children who had appeared healthy at birth, ie, had not required special neonatal care or had no signs of encephalopathy.

CONCLUSIONS

Infants born with cord metabolic acidosis and who appear well do not have an increased risk for neurologic or behavioral problems in need of referral actions or special teaching approaches at the age of 6.5 years.

Strength of association between umbilical cord pH and perinatal and long term outcomes: systematic review and meta-analysis

OBJECTIVE

To evaluate the association between umbilical cord pH at birth and long term outcomes.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline (1966-August 2008), Embase (1980-August 2008), the Cochrane Library (2008 issue 8), and Medion, without language restrictions; reference lists of selected articles; and contact with authors.

STUDY SELECTION

Studies in which cord pH at birth was compared with any neonatal or long term outcome. Cohort and case-control designs were included.

RESULTS

51 articles totalling 481 753 infants met the selection criteria. Studies varied in design, quality, outcome definition, and results. Meta-analysis carried out within predefined groups showed that low arterial cord pH was significantly associated with neonatal mortality (odds ratio 16.9, 95% confidence interval 9.7 to 29.5, I(2)=0%), hypoxic ischaemic encephalopathy (13.8, 6.6 to 28.9, I(2)=0%), intraventricular haemorrhage or periventricular leucomalacia (2.9, 2.1 to 4.1, I(2)=0%), and cerebral palsy (2.3, 1.3 to 4.2, I(2)=0%).

CONCLUSIONS

Low arterial cord pH showed strong, consistent, and temporal associations with clinically important neonatal outcomes that are biologically plausible. These data can be used to inform clinical management and justify the use of arterial cord pH as an important outcome measure alongside neonatal morbidity and mortality in obstetric trials.

[Cerebral palsy and perinatal asphyxia (I--diagnosis)]

Cerebral palsy (CP) is a group of disorders of the development of movement and posture, causing activity limitations, that are attributed to nonprogressing disturbances that occurred in the developing fetal or infant brain. The motor abnormalies are often accompanied by disturbances of sensation, perception, cognition, behavior and/or by a seizure disorder. The prevalence of CP has not decreased in developed countries over the past 30 years, despite the widespread use of electronic fetal heart rate monitoring and a 5- to 6-fold increase in the cesarean delivery rate. In the term newborn, CP may be attributed to perinatal asphyxia in case of metabolic acidosis in the cord blood (pH<7,00 and base deficit>12 mmol/L), followed by a moderate or severe neonatal encephalopathy within 24 hours and a further neurological impairement characterized by spastic quadriplegia and dyskinesia/dystonia. Dating the time of fetal asphyxia during delivery is possible when there are acute catastrophic complications during labor and unexpected acute or progressive fetal heart rate anomalies after a normal admission test, when there is a need for intensive neonatal resuscitation, a multi-organ failure within 72 hours of birth and visualization of acute non focal cerebral abnormalities, mainly by early magnetic resonance imaging (MRI). MRI sequences show either a brain-damaged pattern of the central basal ganglia, thalami and posterior limbs of internal capsules with relative cortical sparing, in acute, near-total asphyxial insults manifested by a continuous bradycardia or a pattern of cortical injury in the watershed zones and relative sparing of the central grey matter, in prolonged partial asphyxia, manifested by late or atypical variable decelerations with progressive fetal tachycardia, loss of reactivity and absent fluctuation. Prolongation of either type of asphyxial insult results in more global brain damage. In order to differentiate a CP occurring after perinatal asphyxia from other neurological sequelae in relation with infection, hemorrhage, stroke, malformations, genetic or metabolic diseases, it is essential that a definitive information from the brain by MRI and an extensive histological examination of the placenta are at disposal.

Risk factors of neonatal respiratory distress following vaginal delivery and caesarean section in the German population

BACKGROUND

The incidence of caesarean section (CS) is steadily rising world-wide. In particular, CS on maternal demand is performed more frequently. In parts, this might be due to insufficient information of pregnant women about neonatal risks of CS. We sought to specify neonatal outcomes following different modes of delivery, i.e. vaginal delivery, primary CS and secondary CS and to define risk factors for respiratory morbidity and hospitalization.

METHODS

We analysed 2073 births (gestational age > 35 weeks) during a two-year period at a tertiary obstetric and neonatal centre in Germany. Statistical analyses were performed for single parameters by SPSS as well as by logistic regression to account for possible confounders. Furthermore, extensive model calculation was done.

RESULTS

Respiratory morbidity was increased following primary and secondary CS (p = 0.001). By multiple logistic regression, the strongest effect on respiratory symptoms was seen with gestational age, each week more in utero reducing the risk by an odds ratio (OR) of 0.69 (95% CI: [0.61; 0.79]; p = 1.9 x 10(-8)). Furthermore, a significant interaction between mode of delivery and gestational age was found for the risk of respiratory symptoms (p = 0.0035).

CONCLUSION

For every eight newborns delivered by primary CS one more than expected with vaginal delivery is hospitalized. It is highly relevant to recognize that each week of gestational age reduces the risk of respiratory symptoms, especially if primary CS is performed. The higher rate of respiratory morbidity and neonatal admission following CS should be clearly recognized in counselling of pregnant women.

Use of umbilical cord blood gas analysis in the assessment of the newborn

Analysis of paired arterial and venous specimens can give insights into the aetiology of acidosis in the newborn