The relationship between Apgar score, umbilical artery pH and operative delivery for fetal distress in 2778 infants born at term

A total of 2778 infants born at term were studied to determine the relationship between Apgar scores after 1 min, umbilical artery pH values, mode of delivery, a diagnosis of fetal distress leading to operative delivery, and sex. Eighty-three percent of the population had normal Apgar scores (greater than or equal to 8) and normal pH values (greater than 7.15) in which 10% were operatively delivered for fetal distress (ODFD). Sixty-one percent of the children with low Apgar scores (less than or equal to 7) had normal pH values, and 74% of the infants with acidosis (pH less than or equal to 7.15) had normal Apgar score. Twenty-four percent of the infants with a low Apgar score and/or acidosis were ODFD (sensitivity). Ninety percent of the infants who had Apgar scores and pH values were not ODFD (specificity). The predictive value (a low Apgar score and/or acidosis) of ODFD was 33%, and the negative predictive value (normal Apgar score and a normal pH) of ODFD was 85%. A significantly higher incidence of ODFD and acidosis was found in boys.     

Status of infants at birth and risk for adverse neonatal events and long-term sequelae: a study in low birth weight infants

We evaluated the relationship of infant status at birth to neonatal morbidity and long-term development in 246 low birth weight infants (600 to 1750 gm). Nineteen percent of infants had 1-minute Apgar scores of less than or equal to 3, and 8% had an umbilical artery pH of less than or equal to 7.2. Acidosis was associated with an increased risk of grade 3 to 4 intracranial hemorrhage (odds ratio = 3.3). Low 1-minute Apgar score was associated with an increased risk of death (odds ratio = 4.8). Grade 3 to 4 intracranial hemorrhage was a strong risk factor for cerebral palsy among survivors (odds ratio = 16.1), as was low 1-minute Apgar score (odds ratio = 2.9). Only 15% of cases of cerebral palsy in this study were associated with acidosis at birth.     

Diagnosis of birth asphyxia on the basis of fetal pH, Apgar score, and newborn cerebral dysfunction

Imprecise diagnosis of birth asphyxia coupled with uncertainties about causal factors for neurologic abnormalities in the newborn have greatly fueled the current litigation crisis in obstetrics. Our goal was to more precisely define birth asphyxia based on fetal condition as measured by umbilical artery blood pH, Apgar scores, and neurologic condition of newborns. We selected for study 2738 patients with singleton pregnancies with cephalic presentations who were delivered of infants at term to avoid complications such as prematurity, which may affect infant outcome independent of birth condition. The basis for study of these particular patients were defined criteria for high risk and an indicated arterial cord pH value. A total of five infants demonstrated cerebral dysfunction as evidenced by seizures during the neonatal period. Infection was linked to seizures in three of these infants; one infant had neonatal asphyxia and only one infant's clinical course could be attributed solely to birth events (uterine rupture). Stratification of umbilical artery blood pH values, Apgar scores, and combinations of these dependent variables in relation to newborn clinical outcomes revealed that infants must be severely depressed at delivery before birth asphyxia can be reliably diagnosed. Such depression includes Apgar scores less than or equal to 3 at 1 and 5 minutes plus umbilical artery pH values less than 7.00.     

Correlation of neonatal acid-base status with Apgar scores and fetal heart rate tracings

In this study the immediate neonatal acid-base status, obtained via a double-clamped segment of umbilical cord, in 75 term, singleton vaginal deliveries was compared to electronic fetal heart rate recordings and Apgar scores. Of 75 neonates, 59 had 1-minute Apgar scores greater than or equal to 7 and 52 had an initial pH greater than 7.20. Six of the 16 neonates with a 1-minute Apgar score less than 7 demonstrated a low pH (less than 7.20). At 5 minutes only eight of 75 neonates had Apgar scores less than 7 with six of the eight having pH values less than 7.20. Of those neonates with Apgar scores greater than or equal to 7 and pH less than 7.20 (seven neonates at 1 minute, two at 5 minutes), none had metabolic acidosis. Eighteen fetal heart rate tracings were considered abnormal; acidosis was confirmed in eight (44%) by pH criteria, yet only three of the eight neonates had low Apgar scores. Our investigations suggest that the combination of fetal heart rate monitoring, cord blood pH, and Apgar assessment is better than any one parameter alone as an evaluation of fetal status just after delivery.     

Comparison of umbilical artery pH and 5-minute Apgar score in the low-birth-weight and very-low-birth-weight infant

The division between "normal" and low Apgar scores is based largely on data obtained from term newborns and may not apply to the premature infant. Umbilical artery pH has been suggested as a better indicator of intrapartum asphyxia. We examined the charts of 558 infants with birth weights less than or equal to 2500 gm with respect to umbilical artery pH, 5-minute Apgar scores, and birth weight percentiles. A positive correlation between birth weight and 5-minute Apgar score was noted. No such relationship existed between birth weight and umbilical artery pH. Within birth weight groups, small-for-gestational-age infants have higher Apgar scores and lower umbilical artery pH values than their appropriate-for-gestational age counterparts.     

The Northwestern University triplet study. IV. Biochemical parameters

Umbilical arterial and venous blood gas indices of 11 triplet pregnancies were reviewed. Ten sets of triplets were delivered by cesarean section and one set was delivered vaginally. Mean 1-minute Apgar scores were significantly lower in the group of infants delivered third than in either of the other birth order groups. There were no statistically significant differences when the mean umbilical arterial or venous pH, PCO2, and base deficit were compared among any one triplet and the other two. Similarly, no significant differences were found when these parameters were compared by birth order in relation to mean 5-minute Apgar scores, mean birth weights, and mean gestational ages at delivery. Birth order did not appear to significantly influence acid-base status, although it may become significant with an increasing time in utero after delivery of the firstborn infant. Further study is necessary to investigate whether there is a critical interval of delivery whereby the infants remaining in utero become acidotic.     

Umbilical cord pH and base excess values in relation to adverse outcome events for infants delivering at term

OBJECTIVE: This study was undertaken to determine the relationship of umbilical cord pH and base excess (BE) values to adverse neonatal outcomes for a large tertiary hospital population delivering at term.Study design The perinatal/neonatal database of St. Joseph's Health Care, London, Canada, was used to obtain the umbilical cord pH and BE values, incidence of adverse neonatal outcomes, and patient demographics for all term (>/=37 weeks' gestation), singleton, liveborn infants with no major anomalies delivering between November 1995 and March 2002 (n=20,456). Statistical analyses included chi(2) analysis, logistic regression models to develop odds ratios and creation of receiver operating characteristic (ROC) curves with area under curve (AUC) calculations. RESULTS: Umbilical vein and artery pH and BE values for this tertiary care population averaged 7.33 +/- 0.06 and 7.24 +/- 0.07, and -4.5 +/- 2.4 and -5.6 +/- 3.0 mmol/L, respectively. Apgar less than 7 at 5 minutes, neonatal intensive care unit (NICU) admission, and assisted neonatal ventilation had significant inverse relationships with both umbilical artery and umbilical vein pH and BE (all P < .0001), with marginal increases in the incidences of these outcomes beginning with cord blood values close to the mean, and more substantial increases with cord values less than 1 or 2 SD below the mean, depending on the outcome studied. The ROC AUC for all these relationships were significant (P < .001) ranging from 0.76 to 0.79 when predicting Apgar less than 7 at 5 minutes to 0.68 to 0.70 when predicting NICU admission, and with cutoff cord blood values at which sensitivity and specificity were maximized again close to mean values. For each of these neonatal outcomes, the relation to cord blood values was similar with little difference in the data analysis whether using pH or BE values, and whether from the umbilical artery or vein. CONCLUSION: There is a progression of risk in term infants for Apgar less than 7 at 5 minutes, NICU admission, and need for assisted ventilation with worsening acidosis at birth, which begins with cord blood values close to mean values indicating a higher threshold for associated acidemia with these outcomes than is seen for more severe neonatal outcomes.     

Hyaline membrane disease and acidosis at birth in twins.

To test the hypothesis that the increased incidence of hyaline membrane disease in second-born twins is related to acidosis at birth, umbilical arterial [H+] was measured in 26 sets of premature twins. Although overall Twin B had a lower Apgar score than Twin A, there was no difference in their [H+]. If the delivery interval was prolonged over 8 minutes then Twin B infants were more acidemic and had lower Apgar scores. Infants with hyaline membrane disease had lower Apgar scores, but were not more acidemic than infants without respiratory distress. Our data suggest that acidosis at birth is not an important factor in the development of hyaline membrane disease.     

Correlation between neonatal Apgar scores and the results of maternal and umbilical cord blood gas analysis

The correlation between the Apgar scores of 162 neonatal 1 minute after birth and the result of maternal arterial and umbilical cord blood gas analysis was studied. The results were as follows: (1) With decreasing neonatal Apgar score, the value of the pH, PO2, HCO3, TCO2 and actual base excess (ABE) of the maternal arterial and umbilical cord blood also decreased markedly, while the PCO2, except that of the maternal arterial blood, increased obviously, and mixed acid base imbalance and hypoxemia also significantly increased (P less than 0.01). (2) Of the neonates with umbilical arterial blood pH less than or equal to 7.2, the proportion of neonates with Apgar score less than or equal to 3 amounted to 100%; that with on Apgar score of 4-7, was 77.7%; And that with on Apgar score of 8-10, was 56.31%. The difference was highly significant statistically (P less than 0.01).     

The Apgar score: is it enough?

One thousand thirty-two neonates were evaluated with umbilical venous and arterial blood samples drawn at delivery for assessment of pH, PO2, PCO2, and base deficit. These values were statistically correlated with Apgar scores in all of the neonates studied. Infants were divided into Apgar groupings (group A, greater than or equal to 7 at one and five minutes; group B, less than 7 at one minute, greater than or equal to 7 at five minutes; group C, less than or equal to 7 at both one and five minutes). Generally, umbilical artery and umbilical venous data were parallel. The differences in means for pH, PO2, PCO2, and base deficit was significant when group A was compared with group B in both umbilical artery and umbilical venous data. However, a severe degree of biochemical disturbance must take place before significant association with neonatal depression can be made. It appears that umbilical blood biochemical data are related to fetal metabolic status before birth but only modestly influence the one-minute Apgar score.     

Apgar score, meconium and acidaemia at birth in relation to neonatal neurological morbidity in term infants

Summary. The relation between Apgar score, meconium and acidaemia at birth and neonatal neurological morbidity was investigated in 805 vaginally born term infants whose birthweight was appropriate-for-dates (AFD). Presence or absence of meconium stained amniotic fluid was not related to the neonatal neurological condition. The 1-min and 3-min Apgar scores and the umbilical artery pH were related, but the variances explained in neonatal neurological optimality score were very low (0·9 and 0·5% respectively). Combination of Apgar score and pH slightly increased these percentages to 1·5. The highest frequency of neurologically deviant infants was, on the other hand, found in the group with a normal pH but low Apgar score. It is concluded that in AFD term infants nowadays the predictive value of a low Apgar score, acidaemia at birth and/or presence of meconium for the neonatal neurological morbidity is poor. Most neonatal neurological abnormalities must be due to other factors.     

Interrelationships among abnormal cardiotocograms in labor, meconium staining of the amniotic fluid, arterial cord blood pH, and Apgar scores

A prospective study of the relationships among fetal heart rate pattern, meconium staining of the amniotic fluid, umbilical cord artery pH, and Apgar score was carried out in 1219 consecutive births. Interpretable cardiotocogram patterns and cord arterial pH and blood gas analysis were obtained in 698 cases. The sensitivity of an abnormal cardiotocogram at any time for acidosis (more than 1 SD below the mean, pH less than 7.17) was 80%, and for severe acidosis (more than 2 SDs below the mean, pH less than 7.085) was 83%. However, the predictive value was low, and 32% of fetuses had an abnormal cardiotocogram but no acidosis. If only cardiotocogram abnormality in the first stage of labor was considered, sensitivity was still 47% for acidosis and 67% for severe acidosis, and the false-positive rate was reduced to only 14%. We attempted to improve the prediction of acidosis by including meconium staining of the amniotic fluid, but 65% of the variation in umbilical cord artery pH and 72 and 86% of the variation in 1- and 5-minute Apgar scores, respectively, remained unexplained. In light of these poor correlations, the current practice of considering cardiotocogram abnormality, meconium staining of the amniotic fluid, acidosis, and low Apgar scores as indicating one single disorder, "fetal distress," is not valid.     

Fetal acidosis and the abnormal fetal heart rate tracing: the term breech fetus

The intrapartum fetal heart rate tracings of 27 terms fetuses in breech presentation were analyzed to evaluate their immediate neonatal outcome. The tracings were quantitatively evaluated for comparison with Apgar scores and umbilical cord gases at delivery. Of the 27 cases, 12 had monitoring strips that scored 4 or less before birth. The P50 for acidosis at delivery (an umbilical artery pH of 7.25 or less) was 55 minutes for an intrapartum tracing that scored 4 or less. Fetuses with intrapartum tracings scoring 8 or more throughout labor had normal Apgar scores and cord gases. In comparing the present data with those of a previous study of vertex presentations, the authors found that given similar tracings, the breech fetus deteriorates more rapidly than the vertex fetus. Cesarean section is recommended if delivery is not imminent in a laboring breech and the intrapartum tracing deteriorates to score 4 or less.     

Neonatal complications at term as related to the degree of umbilical artery acidemia

The degree of umbilical arterial acidemia associated with immediate newborn morbidity has not been determined. Therefore we compared 358 term infants with umbilical artery acidemia (pH less than 7.20) with 358 term, nonacidotic matched control infants, to evaluate immediate neonatal complications in both groups. Nonacidotic was defined as an umbilical artery pH greater than or equal to 7.20. Complications included seizures, persistent hypotonia, and/or signs of end-organ damage such as renal or cardiac dysfunction. None of the 693 newborns with an umbilical artery pH greater than or equal to 7.00 had such complications. Two of 23 infants with an umbilical artery pH less than 7.00 had sequelae related to intrapartum asphyxia. In these two infants the umbilical artery pH was less than 7.00, the 1-minute and 5-minute Apgar scores were less than or equal to 3 and the acidemia was metabolic in nature.     

Outcome after successful resuscitation of babies born with apgar scores of 0 at both 1 and 5 minutes

OBJECTIVE: Our purpose was to evaluate the outcome of infants who underwent successful resuscitation after initial Apgar scores of 0 at both 1 and 5 minutes.Study Design: Eligible infants were identified through the perinatal database at the University of Tennessee, Memphis. Hospital records and long-term outcomes, where available, of babies who met the above criteria occurring between January 1986 and February 1999 were reviewed. RESULTS: Thirty-three of 81,603 infants (0.4/1000 births) met our study criteria. Twenty-two (67%) babies died during hospitalization. Mortality decreased significantly from 100% for babies with a birth weight of <750 g to 38% for those weighing > or =2500 g at birth (P =.03). All 6 babies delivered before 26 weeks' gestation died. The incidence of 10-minute Apgar scores >0 was significantly higher among survivors than among those who subsequently died (82% vs 33%, P <.05). Nine survivors had hypoxic-ischemic encephalopathy diagnosed before discharge. Of the 7 infants with available follow-up, 4 had significant persisting morbidity. Two infants had normal neurologic examinations at follow-up. CONCLUSION: Survival in babies born with 1- and 5-minute Apgar scores of 0 is predicted by birth weight, gestational age, and 10-minute Apgar score. Long-term sequelae are common but not ensured.     

Outcome of fetuses with lactic acidemia

Umbilical arterial lactate, pH, PO2, PCO2, and base deficit were measured at delivery of 468 live-born infants. The correlation between the 1-minute Apgar score and lactate (r = -0.34) was comparable to that between the 1-minute Apgar score and pH (r = 0.30). The multiple correlation coefficient between the 1-minute Apgar score and all five parameters combined (lactate, pH, PO2, PCO2, and base deficit) was 0.36. This was not significantly higher than the simple correlation coefficient for pH alone (0.30). Similar correlation coefficients were noted for the 5-minute Apgar score. The dividing point between normal and pathologic lactate levels was 3.70 mmol/L. A pH less than 7.20 and a lactate level greater than or equal to 3.70 mmol/L had the same sensitivity, specificity, and positive and negative predictive values for low Apgar scores (less than 7). While pH and lactate are equally correlated with fetal outcome, their combination with each other and with other blood gas parameters does not predict outcome better than either pH or lactate alone.     

Apgar score, meconium and acidaemia at birth in relation to neonatal neurological morbidity in term infants

The relation between Apgar score, meconium and acidaemia at birth and neonatal neurological morbidity was investigated in 805 vaginally born term infants whose birthweight was appropriate-for-dates (AFD). Presence or absence of meconium stained amniotic fluid was not related to the neonatal neurological condition. The 1-min and 3-min Apgar scores and the umbilical artery pH were related, but the variances explained in neonatal neurological optimality score were very low (0.9 and 0.5% respectively). Combination of Apgar score and pH slightly increased these percentages to 1.5. The highest frequency of neurologically deviant infants was, on the other hand, found in the group with a normal pH but low Apgar score. It is concluded that in AFD term infants nowadays the predictive value of a low Apgar score, acidaemia at birth and/or presence of meconium for the neonatal neurological morbidity is poor. Most neonatal neurological abnormalities must be due to other factors.     

产时不同类型胎儿酸血症与胎心监护图形的关系

目的研究产时脐动脉血显示的不同类型酸血症与产时胎心监护图形变化的关系及产后４年随诊的结果。方法采用回顾性病例对照研究方法,选择对象为１９９１年单胎、足月分娩的２９８１例新生儿,产程中定时胎心监护,分娩时测定脐动脉血气。生后４年进行儿童随诊。结果纯代谢性酸血症４７例（代酸组）,混合性酸血症６７例（混酸组）,该两组在第一产程末,胎心率评分＜６和６～７分者发生率显著高于对照组。减速图形特点显示晚期减速与纯代谢性酸血症有关,而异常可变减速与混合性酸血症有关。两组产后１分钟Ａｐｇａｒ评分＜７分者也明显高于对照组。儿童４岁时随诊其发育、运动和语言能力显示：代酸组及混酸组和对照组比较差异无显著性,只在混酸组语言表达迟钝的例数略多。结论晚期减速可能是纯代谢性酸血症的一个表现,而异常可变减速可能是混合性酸血症的一个表现。两者均与１分钟Ａｐｇａｒ评分低分的发生有密切关系。产时酸血症和以后的语言发育缺陷间关系需进一步估价     

The effect of preterm birth on umbilical cord blood gases.

Apgar scores are used routinely to assess early neonatal status, but are less accurate in the preterm neonate because of developmental immaturity. Attention has been directed to umbilical cord gases as a method of neonatal evaluation. Using a retrospective chart review of all viable preterm births (24-36 weeks' gestation) between January 1986 and December 1989, we tabulated the umbilical cord gas indices of these infants. Fetuses with lethal congenital anomalies and those with abnormal heart rate tracings on admission were excluded from the data base, leaving 1872 infants. Cord arterial blood gas values were available for analysis in 74.4% of cases and cord venous gas values in 81.8%. The mean (+/- standard deviation [SD]) arterial and venous umbilical cord blood gas values for the preterm infants, were, respectively: pH, 7.26 +/- 0.08 and 7.33 +/- 0.07; oxygen pressure, 19.0 +/- 7.9 and 29.2 +/- 9.7 mmHg; carbon dioxide pressure, 53.0 +/- 10.0 and 43.4 +/- 8.3 mmHg; bicarbonate, 24.0 +/- 2.3 and 22.8 +/- 2.1 mEq/L; and base excess, -3.2 +/- 2.9 and -2.6 +/- 2.5 mEq/L. Acidemia was defined statistically as 2 SDs or more below the population mean. The incidence of 5-minute Apgar scores below 7 in the preterm infants was 8.5% and within this group, 17.8% were acidemic (arterial pH 7.10 or lower). More than 82% of neonates with 5-minute Apgar scores less than 7 had normal umbilical cord blood gases. There was no significant difference in umbilical arterial blood gas values between preterm infants and 1924 term deliveries at our institution between 1986-1988.(ABSTRACT TRUNCATED AT 250 WORDS)