The relationship between intrapartum fetal heart rate disturbances, electrocardiographic changes and umbilical venous troponin-I (T-I)

OBJECTIVE: To analyse the relationship between intrapartum fetal heart rate disturbances and electrocardiographic changes and umbilical venous troponin-I (T-I), concentrations as well. MATERIAL AND METHODS: 14 fetuses were continuously surveyed by CTG and ECG recordings in the first and second stage of labor, using STAN S-21 analyser. After birth, umbilical venous blood samples were collected for determination of acid-base balance, base excess and troponin-I concentrations. RESULTS: From among monitored fetuses, in 8 cases the CTG and FECG patterns were correct. Vaginally delivered neonates were born in good clinical status, with normal acid-base balance, base excess and T-I < 0.3 ng/ml. In 3 cases abnormal CTG patterns were observed with early decelerations but FECG patterns were correct. Vaginally delivered neonates were born in good clinical status, with normal acid-base balance, base excess and T-I < 0.3 ng/ml. In 2 cases abnormal CTG patterns were observed with variable decelerations but FECG patterns were correct. Vaginally delivered neonates were born in good clinical status, with normal acid-base balance, base excess and T-I < 0.3 ng/ml. In one case abnormal CTG pattern were observed with late decelerations but FECG patterns was correct. The pregnancy was terminated by caesarean section because of fetal distress. The neonate was born in good clinical status with normal acid-base balance and base excess but T-I concentration was increased (1.5 ng/ml).     

STAN S21 fetal heart monitor for fetal surveillance during labor: an observational study in 637 patients.

OBJECTIVE: To assess the value of the STAN fetal heart monitor for intrapartum fetal monitoring using cardiotocography (CTG) and fetal electrocardiography (ECG). DESIGN: Prospective observational study. MATERIAL AND METHODS: Between August 2000 and November 2002, 637 high-risk labors were monitored using a STAN S21 fetal heart monitor, providing CTG plus automatic ST analysis of the fetal ECG. Guidelines with recommendations about when to intervene were available. During the study period labor-ward personnel were systematically instructed about the (patho)-physiology of asphyxia and CTG and ST changes during labor. RESULTS: Four hundred and forty-nine recordings were available for analysis of outcome in relation to ST changes. In 61 cases, ST changes requiring intervention occurred > 10 min before birth. In 35 (57%) of these cases, umbilical artery blood pH at delivery was < 7.15. Eighteen (4.0%) neonates were born with metabolic acidosis (umbilical artery pH < 7.05 and extracellular base deficit > 12 mmol/l). Significant ST changes (18-31 min before birth) were present in all five cases with pH < 7.00 and in six of the 13 cases with pH of 7.00-7.04 (false-negative rate 1.6%). Neonatal follow-up showed no adverse outcome. One hundred and ninety-two fetal blood samples (121 in the first stage and 71 in the second stage of labor) were taken from 142 women. Fetal scalp blood pH was < 7.15 in ten samples, 7.15-7.19 in 11 samples, 7.20-7.24 in 30 samples and > or =7.25 in 141 samples. ST changes occurred in eight (80%), six (55%), nine (30%) and 15 (11%) of these cases, respectively. In 188 (29.5%) women, outcome could not be analyzed in relation to ST changes because of inadequate recording (time between end of recording and delivery > 20 min or poor signal quality) or the absence of umbilical cord gases. In this group, four (2.1%) neonates with metabolic acidosis were born. In three of these cases the fetal ECG signal was of was poor quality and in one case the recording had ended 60 min before birth. CONCLUSION: ST changes were present in all five cases with severe metabolic acidosis (umbilical artery pH < 7.00). ST changes occurred in 46% of cases with mild metabolic acidosis. CTG plus ST analysis was more specific in detecting fetal acidemia than CTG alone.     

STAN® S21 fetal heart monitor for fetal surveillance during labor: an observational study in 637 patients

Objective: To assess the value of the STAN^® fetal heart monitor for intrapartum fetal monitoring using cardiotocography (CTG) and fetal electrocardiography (ECG).

Design: Prospective observational study.

Material and methods: Between August 2000 and November 2002, 637 high-risk labors were monitored using a STAN^® S21 fetal heart monitor, providing CTG plus automatic ST analysis of the fetal ECG. Guidelines with recommendations about when to intervene were available. During the study period labor-ward personnel were systematically instructed about the (patho)-physiology of asphyxia and CTG and ST changes during labor.

Results: Four hundred and forty-nine recordings were available for analysis of outcome in relation to ST changes. In 61 cases, ST changes requiring intervention occurred >?10?min before birth. In 35 (57%) of these cases, umbilical artery blood pH at delivery was <?7.15. Eighteen (4.0%) neonates were born with metabolic acidosis (umbilical artery pH <?7.05 and extracellular base deficit >?12?mmol/l). Significant ST changes (18–31?min before birth) were present in all five cases with pH <?7.00 and in six of the 13 cases with pH of 7.00–7.04 (false-negative rate 1.6%). Neonatal follow-up showed no adverse outcome. One hundred and ninety-two fetal blood samples (121 in the first stage and 71 in the second stage of labor) were taken from 142 women. Fetal scalp blood pH was <?7.15 in ten samples, 7.15–7.19 in 11 samples, 7.20–7.24 in 30 samples and ??7.25 in 141 samples. ST changes occurred in eight (80%), six (55%), nine (30%) and 15 (11%) of these cases, respectively. In 188 (29.5%) women, outcome could not be analyzed in relation to ST changes because of inadequate recording (time between end of recording and delivery >?20?min or poor signal quality) or the absence of umbilical cord gases. In this group, four (2.1%) neonates with metabolic acidosis were born. In three of these cases the fetal ECG signal was of was poor quality and in one case the recording had ended 60?min before birth.

Conclusion: ST changes were present in all five cases with severe metabolic acidosis (umbilical artery pH <?7.00). ST changes occurred in 46% of cases with mild metabolic acidosis. CTG plus ST analysis was more specific in detecting fetal acidemia than CTG alone.     

ST analysis of the fetal electrocardiogram during labor: Nordic observational multicenter study

Objective: To assess the diagnostic power of cardiotocography (CTG) plus the ST interval of the electrocardiogram (ECG) clinical guidelines with combined fetal heart rate and ST waveform analysis of the fetal ECG recorded during labor, to identify an adverse labor outcome (neonatal neurological symptoms and/or metabolic acidosis). Study design: An observational, multicenter study was undertaken in 12 Nordic labor wards. A total of 573 women in labor were monitored using a prototype of the STAN® S 21 recorder with fetal ECG data and computerized ST analysis. Results: Fifteen cases of intrapartum fetal hypoxia identified from neurological neonatal symptoms and/or cord artery pH < 7.05 with base deficit in extracellular fluid > 12.0 mmol/l were recorded. All these cases were identified by CTG + ST clinical guidelines. Five developed neonatal symptoms and had ECG abnormalities during the first stage of labor and, of the remaining ten, eight showed ST changes during active pushing in the second stage. Another eight cases had acidemia only and normal neonatal outcome. Seven of these displayed CTG + ST abnormalities. The high sensitivity of CTG + ST to predict fetal acidosis was associated with a marked increase in positive predictive values compared with conventional CTG. Conclusion: The STAN clinical guidelines identify fetuses at risk of intrapartum asphyxia.     

Microprocessor based waveform analysis of the fetal electrocardiogram during labor

An increase in T wave amplitude of the fetal ECG (FECG) has experimentally been correlated to elevated catecholamine levels and myocardial glycogenolysis. The FECG changes have also been described during human delivery. The present aim was to investigate whether these ECG changes could be reproduced in an easily handled real time microprocessor system, and to correlate them to biochemical and clinical data. During 40 deliveries the FECG signal was transferred to a microcomputer system for real time averaging of the FECG. There was a high capacity of the system to reproduce the ST waveform changes though the averaging procedure reduced the QRS magnitude by 10%. With a normal umbilical artery pH (greater than or equal to 7.25) the highest T/QRS ratios recorded during each delivery was 0.26 +/- 0.19 (mean +/- S.D.). With lowered pH (less than 7.25) the T/QRS increased to 0.33 +/- 0.10 (P less than 0.02). A similar difference between the two groups was seen when the T/QRS ratios from the last hour before birth were compared; 0.13 +/- 0.08 and 0.18 +/- 0.05, respectively (P less than 0.01). Changes in the ST waveform with T/QRS greater than or equal to 0.30, ST segment alterations, or negative T waves appeared during 40% of the deliveries, however, 30% were short standing changes (less than 30 min). Intermediate CTG changes during at least 30 min occurred in 41% and the pattern was classified as abnormal in 18%. Using the scalp electrode as signal source, the ECG analysis could add further information to the routine CTG recording on the fetal condition during delivery.     

Fetal cardiac troponin I in relation to intrapartum events and umbilical artery pH

The objective of this study was to measure fetal cardiac troponin I in umbilical artery blood in relation to intrapartum events and umbilical artery pH. Umbilical artery blood samples were obtained after delivery from 110 infants and cardiac troponin I was measured. The onset of labor, mode of delivery, presence of meconium, and umbilical artery pH were examined in relation to cardiac troponin I. The median cardiac troponin I level was 0.03 ng/mL (range, 0.03 to 0.881 ng/mL). Neonates with a cardiac troponin I level above the normal range had a lower umbilical artery pH when compared with those neonates with a normal cardiac troponin I level (p = 0.005). No relationship between the following parameters and cardiac troponin I was observed: gestational age, parity, presence of labor, meconium staining, mode of delivery, birth weight, and Apgar scores. Fetal cardiac troponin I shows little variation at birth. Increased levels of cardiac troponin I are associated with a lower umbilical artery pH.     

Acidemia at birth in the vigorous infant as a trigger incident to assess intrapartum care with regard to CTG patterns

Abstract

Objective: To evaluate if acidemia in vigorous infants is a useful variable in the assessement of intrapartm care with regard to cardiotocographic (CTG) patterns during the second stage.

Methods: Cases (n?=?241) were infants with an umbilical artery pH?<?7.05, controls (n?=?482) were infants with pH?≥?7.05. Apgar score was?≥7 at 5?min in both groups. CTGs during the last two hours of labor were assessed and neonatal outcomes compared. A sub-analysis of cases with metabolic acidemia: pH?<?7.00 and base deficit ≥12?mmol/L and acidemia: 7.00?<?pH?<?7.05 was performed.

Results: 63% of cases had a pathological CTG versus 26% of controls (p?<?0.001). Patterns with severe variable decelerations had a significantly longer duration in cases. Metabolic acidemia was significantly associated with severe variable decelerations and decreased variability. Infants to cases were admitted to neonatal care in 19% versus 2% of controls (p?<?0.001). With metabolic acidemia, 32% were admitted.

Conclusion: An umbilical artery pH?<?7.05 at birth of vigorous infants may be a useful variable for quality control of intrapartum management with regard to the assessment of second-stage CTGs. Differences in duration of pathological patterns indicate passiveness in acidemic cases.     

Fetal pulse oximetry and wavelet analysis of the fetal heart rate in the evaluation of abnormal cardiotocography tracings

AIM: Previous studies indicate that the addition of wavelet analysis of the fetal pulse oximetry tracings (FSPO2) and fetal heart rate (FHR) variability to cardiotocography (CTG), for intrapartum fetal monitoring, provides useful information on the fetal response to hypoxia. We applied the new procedure in non-reassuring CTG patterns, in which cesarean section was performed, and tested its accuracy in the diagnosis of the intrapartum fetal compromise. METHODS: At the 'Aretaieion' University Hospital labor ward, 318 women with term fetuses in the cephalic presentation entered the trial during labor. They all were monitored with external CTG and fetal pulse oximetry. In the cases that cesarean section was applied, because of abnormal CTG tracings, we applied a method based on the multiresolution wavelet analysis and a self-organized map neural network on the first and second stage of labor. The main outcome parameter was the rate of cord metabolic acidosis at birth (pH < 7.05). Secondary outcomes included Apgar scores at 5 min, fetal transmission to neonatal intensive care unit (NICU) and neonatal encephalopathy. RESULTS: Fifty out of 318 cases delivered operatively because of abnormal CTG patterns (rate 15.72%). In 30 cases, cord pH was >7.05, while in 11 Apgar scores at 5 min were <7, while none of those neonates were transferred to NICU. In the rest 20 cases cord pH was <7.05; in all of these cases Apgar scores at 5 min were <7, while four neonates were transferred to NICU. In one of them, neonatal encephalopathy was diagnosed. After the offline application of wavelet analysis and neural networks to the pulse oximetry and FHR variability readings of the 50 cases, statistics calculated that the system showed a sensitivity of 85% and a specificity of 93%, while false negative and false positive rates were 15% and 7%, respectively. CONCLUSION: Computerized FHR and FSPO2 monitoring shows an excellent efficacy and reliability in interpreting non-reassuring FHR recordings.     

Fetal acidaemia, the cardiotocograph and the T/QRS ratio of the fetal ECG in labour.

OBJECTIVE: To relate the T/QRS ratio of the fetal electrocardiogram (ECG) to the cardiotocogram (CTG) and fetal pH during labour. DESIGN: Prospective data collection from selected monitored labours. SETTING: A postgraduate teaching hospital delivery suite. SUBJECTS: 113 women in labour at term. MAIN OUTCOME MEASURES: Correlation of fetal T/QRS ratio values with pH values at the time of fetal blood sampling and at birth (umbilical artery blood). Comparison of the predictive values of raised T/QRS ratio and a pathological CTG for fetal acidemia. RESULTS: Complete data sufficient for analysis was available for 51 fetal scalp blood samples and 93 umbilical artery pH samples. The median (range) of T/QRS ratio values before birth of 88 babies not requiring admission to the neonatal unit was 0.13 (0.00-0.32) with a 97.5th centile value of 0.28. T/QRS ratios did not correlate with fetal scalp pH values. Fetal scalp acidaemia (pH less than 7.20) was detected with rates of 50 and 13% respectively by a pathological CTG and by a T/QRS ratio above 0.28, the positive predictive values being 40% and 50%, respectively. There was a significant correlation between increasing T/QRS ratio and falling pH. Detection rates (sensitivities) for umbilical artery acidaemia (pH less than 7.12) were 76% and 29% whereas positive predictive values were 38% and 71% respectively for a pathological CTG and a T/QRS ratio above 0.28. CONCLUSION: A raised T/QRS ratio (greater than 0.28) had a considerably lower detection rate for fetal acidaemia during labour than a pathological CTG.     

Usefulness of the examination of fetal blood oxygen saturation (FSpO2) and fetal heart rate (FHR) as a prognostic factor of the newborn outcome

OBJECTIVES: Cardiotocography has become the standard for fetal monitoring in labor. False-positive findings during electronic fetal heart rate monitoring may were not associated with neonatal acidemia. Because of the poor specificity of fetal heart rate monitoring in predicting fetal distress, new methods are being investigated as a way to improve the accuracy of assessing the infant's condition during labor. DESIGN: The aim of this study was to determinate the efficiency of fetal blood oxygen saturation (FSpO2) and computer analysis of the fetal heart rate (Co-CTG) in the late 1-st stage of labor as a prognostic factor of newborn acidemia. MATERIALS AND METHODS: Total 62 subjects were studied. During labors and deliveries fetal oxygen saturation was continuously recorded, with use of Nellecor N-400 fetal pulse oximeter and continous CTG were performed by Hewlett Packard 50A. Transdermal fetal oxygen saturation measurements and CTG results obtained during the labors was analyzed using MONAKO system (ITAM Zabrze). The results were compared with the values of pH and base deficit in the umbilical artery measured just after delivery. RESULTS: The sensitivity, specificity, negative, positive predictive values and Youden factor based on FHR and FSpO2, for prognosis of neonatal acidosis were: 65%, 80%, 16%, 97.5% 60% and 0.135 respectively FHR; and 100%, 60%, 100%, 96.8% and 0.968 respectively FSpO2. CONCLUSIONS: 1. The examination of fetal blood oxygen saturation in the labor is a useful prognostic factor of the newborn outcome. 2. The best predictive value for intrapartum fetal asphyxia with metabolic acidosis was found when fetal pulse oximetry is added to cardiotocography.     

Cordocentesis and evaluation of fetal wellbeing in a very high-risk population (a very reliable index)]

In a population of 57 very high-risk pregnant women (severe clinical history and/or compromised fetus). A total of 240 tests for antepartum fetal evaluation were performed: baseline cardiotocography (CTG), biophysical profile scoring (BPS), doppler-velocimetry of umbilical artery and determination of blood gas analysis in venous umbilical cord blood obtained by cordocentesis. The results of the CTG, BPS, and umbilical artery doppler velocimetry showed a significant relation with those of pH and pO2. The sensitivity, specificity, false-abnormal value, and false-normal value of the CTG, PBS, and doppler velocimetry, used for the diagnosis of fetal acidosis, hypoxia, and asphyxia were comparable. The rate of fetal (asphyxia) was high if present severe/terminal CTG (85.0%), abnormal (4) BPS (82.0%), or absent-end diastole in umbilical artery doppler velocimetry (74.0%). The immediate complication rate due to cordocentesis procedure was minimal.     

The prediction and prevention of intrapartum fetal asphyxia in term pregnancies

OBJECTIVE: This study was undertaken to examine the roles of clinical risk scoring, electronic fetal heart rate monitoring, and fetal blood gas and acid-base assessment in the prediction and prevention of intrapartum fetal asphyxia in term pregnancies. STUDY DESIGN: The outcomes of 166 term pregnancies with biochemically confirmed fetal asphyxia (umbilical artery base deficit at delivery, >12 mmol/L) were examined. This population included 83 pregnancies delivered abdominally matched with 83 pregnancies delivered vaginally. Antepartum and intrapartum clinical risk factors and neonatal complications were documented. Fetal assessments included fetal heart rate patterns in the fetal heart rate record and fetal capillary blood gas and acid-base assessments. Fetal asphyxia was classified as mild, moderate, or severe on the basis of umbilical artery base deficit (cutoff >12 mmol/L) and neonatal encephalopathy and other organ system complications. RESULTS: Fetal asphyxial exposures were as follows: mild, 140; moderate, 22; and severe, 4. Intervention and delivery during the first or second stage of labor occurred in 98 of the 166 pregnancies. Predictive fetal heart rate patterns were the primary indication leading to intervention and delivery during the first or second stage of labor. Clinical risk factors when present were secondary indications in the clinical decision to intervene. Fetal blood gas and acid-base assessment was a useful supplementary test in 41 pregnancies. Intervention and delivery may have prevented the progression of mild asphyxia in 78 pregnancies and may have modified the degree of moderate or severe asphyxia in 20 pregnancies. CONCLUSION: Although fetal heart rate patterns will not discriminate all asphyxial exposures, continuous fetal heart rate monitoring supplemented by fetal blood gas and acid-base assessment can be a useful fetal assessment paradigm for intrapartum fetal asphyxia. Such an assessment paradigm will not prevent all cases of moderate or severe fetal asphyxia. However, prediction and diagnosis with intervention and delivery during the first or second stage of labor could prevent the progression of mild asphyxia to moderate or severe asphyxia in some cases.     

A comparison of intrapartum automated fetal electrocardiography and conventional cardiotocography--a randomised controlled study

Objective  To examine whether intrapartum monitoring by means of automatic ST analysis (STAN) of fetal electrocardiography could reduce the rate of neonatal acidemia and the rate of operative intervention during labour, compared with monitoring by means of cardiotocography (CTG).
Design  Randomised controlled trial.
Setting  Labour ward in tertiary-level university hospital.
Sample  A total of 1483 women in active labour with singleton term fetus in cephalic presentation.
Methods  Women were randomly assigned to be monitored either by STAN or by CTG. Fetal blood sampling (FBS) was optional in both groups.
Main outcome measures  Neonatal acidemia (umbilical artery pH <7.10), neonatal metabolic acidosis (umbilical artery pH <7.05 and base excess <−12 mmol/l) and operative interventions: caesarean section rate, vacuum outlet (VO) rate and FBS rate.
Results  There were no statistically significant differences between the STAN group and CTG group in the incidence of neonatal acidemia (5.8 versus 4.7%) or metabolic acidosis (1.7 versus 0.7%). The caesarean section rate (6.4 versus 4.7%) and the VO rate (9.5 versus 10.7%) were also similar in the STAN and CTG groups. The incidence of FBS was lower ( P < 0.001) in the STAN group (7.0%) than in the CTG group (15.6%).
Conclusions  Intrapartum fetal monitoring by means of automatic STAN did not improve the neonatal outcome or decrease the caesarean section rate. However, the need for FBS during labour was lower in the STAN group.     

Melatonin levels in maternal plasma before and during delivery, and in fetal and neonatal plasma

In the present study, in order to clarify the diurnal changes in pregnant women, fetuses and neonates, pineal hormone (melatonin) was analyzed with a RIA Kit. Results: 1. The venous melatonin concentration at night was higher than during the day in healthy women and full term pregnant women without labor. 2. Melatonin concentrations in maternal venous blood (MV) (67.44 pg/ml) were significantly higher than in umbilical venous blood (UV) (37.78 pg/ml). 3. A distinct midnight peak of melatonin was observed in MV, and UV at delivery. 4. Significant correlations were observed between MV, UV or umbilical arterial blood (UA), but those were non linear. 5. In neonates on the first to fourth day after birth, no midnight peak was able to be clearly observed, but fluctuations were observed. These result indicate that there is a diurnal change in melatonin in full term pregnant women without labor and women in labor. And we suggest that the pineal gland of early neonates secretes melatonin, but no diurnal change in melatonin is established up to 4th day after birth.     

Predicting pH at birth in absent or reversed end-diastolic velocity in the umbilical arteries

OBJECTIVE: To investigate arterial and venous blood flow in fetuses with absent or reversed end-diastolic flow in the umbilical arteries and to correlate the Doppler results with umbilical artery blood pH at birth to predict the probability of acidosis at birth. METHODS: Ninety-one fetuses from singleton pregnancies without fetal malformations with a diagnosis of absent or reversed end-diastolic flow in the umbilical arteries were prospectively studied. On the day of delivery, Doppler velocimetry of the umbilical arteries, middle cerebral artery, and ductus venosus was performed and the results were correlated with umbilical artery pH at birth at the following cutoff levels: pH < 7.20, < 7.15, < 7.10, and < 7.05. The association between fetal arterial and venous Doppler velocimetry and acidosis was then individually analyzed by the chi(2) and Fisher exact tests. The ability of these tests to predict the probability of acidosis at birth was estimated using a logistic regression model. RESULTS: There was a negative correlation between pH at birth and umbilical artery pulsatility index (r = -0.39; P < .001) and pulsatility index for veins in the ductus venosus (r = -0.63; P < .001). Assessment of the fetal arterial circulation (middle cerebral artery) showed no statistical correlation with pH at birth. Using logistic regression analysis, probability curves were constructed for pH values less than 7.20 (odds ratio [OR] 8.03), less than 7.15 (OR 11.92), less than 7.10 (OR 12.16), and less than 7.05 (OR 8.20). CONCLUSION: The pulsatility index for veins of the ductus venosus was related to pH at birth, demonstrating that the higher the ductus venosus pulsatility index for veins, the lower the pH at birth. Once the pulsatility index for veins in the ductus venosus is known, the probability of acidosis at birth can be estimated.     

Percentiles for gas values in human umbilical cord blood

The distribution of gas values of umbilical cord blood was studied in an university clinic population during a period of 3 yr. All patients in labor were guided by obstetrical personnel and continuous electronic fetal monitoring (CTG). Microblood analyses were performed on indication of the CTG. The tenth percentile for the total population for umbilical artery blood pH was 7.14 and base excess was -12.7 mmol/l. The tenth percentile for pH in umbilical venous blood was 7.23 and base excess was -10.2 mmol/l. Increase of acidemia was seen in the following order: optimal pregnancy and labor, spontaneous vertex delivery, multiparity, primiparity, instrumental and breech delivery. Percentiles of umbilical cord blood gases could serve as an index for the standard of obstetrical care in addition to perinatal mortality and other measures of perinatal morbidity.     

Umbilical artery N-terminal peptide of proatrial natriuretic peptide in hypertensive pregnancies and fetal acidemia during labor

OBJECTIVE: To assess the activity of the human fetal atrial natriuretic peptide system in hypertensive pregnancies with and without signs of increased fetal systemic venous pressure and in pregnancies complicated by fetal acidemia during labor. METHODS: Umbilical artery plasma N-terminal peptide of proatrial natriuretic peptide concentrations were measured in neonates by radioimmunoassay. The control group consisted of 50 neonates with uncomplicated gestation and labor. In group 1, there were 22 newborns of hypertensive pregnancies. Doppler ultrasonography showed abnormal umbilical artery blood velocity waveform in five cases and normal nonpulsatile umbilical vein blood velocity profile in every case. Group 2 consisted of five newborns of pregnancies complicated by maternal hypertensive disorder. Atrial pulsations in the umbilical vein and retrograde diastolic blood velocity pattern in the umbilical artery were detected in every case. Group 3 was composed of 27 newborns of uncomplicated pregnancies with fetal acidemia (pH 7.10 or less) during labor. RESULTS: In groups 1-3, N-terminal peptide of proatrial natriuretic peptide concentrations were higher (P <.001) than in the control group. In group 1, neonates with abnormal umbilical artery blood velocity pattern had higher N-terminal peptide of proatrial natriuretic peptide concentrations than neonates with normal umbilical artery Doppler findings (P <.006). N-terminal peptide of proatrial natriuretic peptide concentrations were higher in group 2 (P <.002) than in groups 1 and 3. CONCLUSIONS Maternal hypertensive disorder and fetal acidemia during labor stimulate fetal atrial natriuretic peptide production, which was greatest in fetuses with severe placental insufficiency and signs of congestive heart failure.     

The clinical significance of Doppler findings in fetal middle cerebral artery during labor

OBJECTIVES: (1) To investigate fetal intracranial circulation, relative to peripheral blood flow, during labor with abnormal cardiotocographic (CTG) patterns, using three non-invasive methods. (2) To determine the utility of monitoring middle cerebral artery (MCA) Doppler during labor. INTERVENTIONS: Fetuses were assessed using simultaneous CTG, pulse oximetry, and Doppler ultrasonography of both the MCA and umbilical artery (UA) to measure the pulsatility index (PI), resistance index (RI), and flow velocity integral (FVI). STUDY DESIGN: During labor 20 term fetuses with abnormal CTG patterns and oxygen saturation values >30%, and 24 term fetuses with abnormal CTG patterns and oxygen saturation values <30% were studied, and peripartum outcomes were compared. The groups were comparable with regard to maternal age and parity. Results were evaluated using the Student's t-test and Fisher exact test. RESULTS: MCA Doppler showed significantly lower PI and RI, and higher FVI in the presence of reduced oxygen saturation. Differences in fetal outcomes between the two groups correlated with MCA Doppler findings. CONCLUSIONS: In experienced hands, Doppler screening of fetal middle cerebral artery waveforms during labor can be useful in the evaluation of intrapartum hypoxia in complicated pregnancies.     

Nucleated red blood cell counts in term neonates with umbilical artery pH < or = 7.00

The purpose of this study was to determine whether nucleated red blood cell (NRBC) counts are elevated in term neonates who have severe fetal acidemia at birth. The neonatal NRBC counts of term (gestational age > or = 37 weeks) neonates with pathological acidemia were compared with those from control neonates who met the following criteria: gestational age > or = 37 weeks, birth weight > or = 2800 g, umbilical artery pH > or = 7.25, and a 5-minute APGAR > 7. Pathological acidemia was defined as an umbilical artery pH < or = 7.0 and a base excess > -12 mEq/L. Twenty-six neonates met all inclusion criteria and were compared to 78 controls. The mean NRBC/100 WBC was 11.9 +/- 13.5 (range 0 to 45) for acidemic neonates compared to 3.9 +/- 2.9 NRBC/100 WBC (range 0 to 11) for control neonates [p <0.001]. Our findings suggest that the onset of hypoxia-ischemia in pregnancies complicated by severe fetal acidemia often begins prior to the intrapartum period.