Relationship of fetal biophysical profile and blood gas values at cordocentesis in severely growth-retarded fetuses

The role of the fetal biophysical profile in the management of fetal growth restriction

Growth-restricted fetuses are at risk of hypoxemia, acidemia, and stillbirth because of progressive placental dysfunction. Current fetal well-being, neonatal risks following delivery, and the anticipated rate of fetal deterioration are the major management considerations in fetal growth restriction. Surveillance has to quantify the fetal risks accurately to determine the delivery threshold and identify the testing frequency most likely to capture future deterioration and prevent stillbirth. From the second trimester onward, the biophysical profile score correlates over 90% with the current fetal pH, and a normal score predicts a pH >7.25 with a 100% positive predictive value; an abnormal score on the other hand predicts current fetal acidemia with similar certainty. Between 30% and 70% of growth-restricted fetuses with a nonreactive heart rate require biophysical profile scoring to verify fetal well-being, and an abnormal score in 8% to 27% identifies the need for delivery, which is not suspected by Doppler findings. Future fetal well-being is not predicted by the biophysical profile score, which emphasizes the importance of umbilical artery Doppler and amniotic fluid volume to determine surveillance frequency. Studies with integrated surveillance strategies that combine frequent heart rate monitoring with biophysical profile scoring and Doppler report better outcomes and stillbirth rates of between 0% and 4%, compared with those between 8% and 11% with empirically determined surveillance frequency. The variations in clinical behavior and management challenges across gestational age are better addressed when biophysical profile scoring is integrated into the surveillance of fetal growth restriction. This review aims to provide guidance on biophysical profile scoring in the in- and outpatient management of fetal growth restriction.

Planning management and delivery of the growth-restricted fetus

A uniform approach to management of fetal growth restriction (FGR) improves outcome, prevents stillbirth, and allows appropriately timed delivery. An estimated fetal weight below the tenth percentile with coexisting abnormal umbilical artery (UA), middle cerebral artery (MCA), or cerebroplacental ratio Doppler index best identifies the small fetus requiring surveillance. Placental perfusion defects are more common earlier in gestation; accordingly, early-onset (≤32 weeks of gestation) and late-onset (>32 weeks) FGR differ in clinical phenotype. In early-onset FGR, progression of UA Doppler abnormality determines clinical acceleration, while abnormal ductus venosus (DV) Doppler precedes deterioration of biophysical variables and stillbirth. Accordingly, late DV Doppler changes, abnormal biophysical variables, or an abnormal cCTG require delivery. In late-onset FGR, MCA Doppler abnormalities precede deterioration and stillbirth. However, from 34 to 38 weeks, randomized evidence on optimal delivery timing is lacking. From 38 weeks onward, the balance of neonatal versus fetal risks favors delivery.

The effect of halogen light stimulation on duration of ultrasound parameters of biophysical profile: a randomized clinical trial

INTRODUCTION

The objective is to assess if fetal halogen light stimulation can reduce the time needed to obtain a normal biophysical profile (BPP).

METHODS

Patients scheduled for a BPP and who satisfied the inclusion criteria were prospectively randomized to halogen light stimulation and no stimulation groups. The study group was exposed to handheld halogen light for 10 s whenever fetal breathing, movement, or tone was absent through the first 5 min of BPP. The time required to achieve complete BPP score was recorded. In patients with complete BPP score who had delivery within 1 week after the test, perinatal morbidity was examined.

RESULTS

A total of 598 patients were randomized (light = 302, no light = 296). There was no difference between the two groups in terms of gestational age, maternal age, body mass index, and indication for BPP except for preterm labor (light: 9%, no light: 4%, p = 0.03). Among the patients who had a normal BPP score (n = 507), the mean (light: 7.1 ± 6 min, no light: 12.3 ± 8 min, p < 0.0001) and median (light: 4.3, no light: 8, p = 0.004) time needed to complete the BPP score was significantly less in the light stimulation group than the no stimulation group. Perinatal outcomes were not different between groups who had delivery during the first week after BPP.

CONCLUSION

Fetal halogen light stimulation can be utilized to reduce the time needed to complete a BPP. However, further studies should be conducted in order to determine the effect of this method on decreasing non-reassuring test results.

CLINICAL TRIAL REGISTRATION

The study was submitted to the Registry of Clinical Trials on 04/20/2017 (IRCT2017041633470N1). After IRCT registration on 06/07/2017, we recruited patients from 06/08/2017 till 10/15/2017.

Longitudinal changes of cardiotocographic parameters throughout pregnancy: a prospective cohort study comparing small-for-gestational-age and normal fetuses from 24 to 40 weeks

OBJECTIVE

To compare longitudinal trends of cardiotocographic (CTG) parameters between small-for-gestational-age (SGA) and normal fetuses, from 24 to 41 weeks of pregnancy.

METHODS

A prospective cohort study was carried out in singleton pregnancies without fetal malformations. At least one CTG was performed in each of the following intervals: 24-26 weeks+6 days, 27-29 weeks+6 days, 30-32 weeks+6 days, 33-35 weeks+6 days, 36-38 weeks+6 days and ≥39 weeks. Tracings were analyzed using the Omniview-SisPorto® 3.6 system. Cases with a normal pregnancy outcome, including a birthweight ≥10th percentile for gestational age, were compared with two groups of SGA fetuses: with birthweight <10th percentile (SGA<p10) and <3rd percentile (SGA<p3; a subgroup of the latter). Generalized linear mixed-effects models were used for analysis.

RESULTS

A total of 176 fetuses (31 SGA) and 1256 tracings (207 from SGA fetuses) were evaluated. All CTG parameters changed significantly throughout pregnancy in the three groups, with a decreasing baseline and probability of decelerations, and an increasing average long-term variability (LTV), average short-term variability (STV) and accelerations. Baseline showed a more pronounced decrease (steeper slope) in SGA fetuses, being higher in these cases at earlier gestational ages and lower later in pregnancy. Average LTV was significantly lower in SGA<p3 fetuses, but a parallel increase occurred in all groups. There was a considerable inter-fetal variability within each group.

CONCLUSION

A unique characterization of CTG trends throughout gestation in SGA fetuses was provided. A steeper descent of the baseline was reported for the first time. The findings raise the possibility of clinical application of computerized CTG analysis in screening and management of fetal growth restriction.

Cardiotocographic parameters in small-for-gestational-age fetuses: How do they vary from normal at different gestational ages? A study of 11687 fetuses from 25 to 40 weeks of pregnancy

AIM

The aim of this study was to assess how cardiotocographic (CTG) parameters differ between small-for-gestational-age (SGA) and normal fetuses at different gestational ages.

METHODS

This was a retrospective cross-sectional study using the first antepartum tracing of singleton pregnancies with no malformations. Fetuses with birthweight ≥10th percentile for gestational age and other normal pregnancy outcome criteria (term birth, normal umbilical artery pH and Apgar scores, no intensive care unit admission) were compared with fetuses with birthweight <10th and <3rd percentiles for gestational age (SGA < p10 and SGA < p3, a subgroup of the latter). Each CTG parameter was compared, by gestational age, using both statistical tests and percentile curves derived from normal outcome cases. Tracings were analyzed with the OmniviewSisPorto® 3.7 system.

RESULTS

A total of 11 687 tracings (from the same number of fetuses) were analyzed: 9701 normal, 1986 SGA < p10, and 543 SGA < p3. SGA fetuses had lower long- and short-term variability, and number of accelerations, with more pronounced differences between around 28 and 35 weeks. In contrast, baseline was lower in SGA fetuses from 34 weeks onwards. All differences were more pronounced for SGA < p3 fetuses. Similar trends throughout gestation occurred in all groups: decrease in baseline, and increase in long- and short-term variability, and accelerations.

CONCLUSIONS

This study represents an important step for accurate CTG interpretation in SGA fetuses and, consequently, management of fetal growth restriction (FGR), as it contributes to differentiate between maturational CTG changes that occur physiologically throughout pregnancy, and possible signs of fetal compromise in FGR.

The uses and limitations of the fetal biophysical profile

In the second half of the twentieth century, true antepartum fetal assessment became possible, mainly due to the advent of real-time ultrasound. Initially, the most widely used form of antepartum fetal assessment was electronic fetal heart rate monitoring, through the nonstress test or the oxytocin-induced contraction stress test. It was soon realized, however, that these forms of monitoring had significant limitations. The biophysical profile allows a more thorough evaluation of fetal well-being and has the potential to significantly reduce the false-positive rate of the nonstress test/contraction stress test.

Fetal growth restriction and postnatal development

The interaction between genetic constitution and in utero environment determines fetal growth and development and influences the susceptibility to certain disorders in adulthood. Data from both animal and human studies indicate that prenatal and early postnatal malnutrition can program the hypothalamus-pituitary-adrenal axis (HPA axis), altering neuroendocrine response to stressors throughout lifetime. Impaired uteroplacental perfusion results in fetal growth restriction (FGR). In FGR there is evidence of chronic hypoxemia and alterations in metabolic, endocrine, and hematological parameters, compatible with starvation. Furthermore, FGR is associated with increased perinatal mortality and in the survivors there is increased susceptibility to diabetes and cardiovascular disease in adulthood. There is evidence that early postnatal growth acceleration, which would normally be considered desirable, may exacerbate metabolic dysfunction in later life.

[Biochemical profile of fetal blood sampled by cordocentesis in 35 pregnancies complicated by growth retardation]

AIM OF THE STUDY

Intra-uterine growth retardation (IUGR) is a frequent pathology in obstetrics characterized by high heterogeneity. Fetal smallness is sometimes constitutional, but can also be accompanied by fetal distress and vital risks for the infant. In 35 pregnancies complicated by IUGR of different etiologies, we measured on fetal blood obtained by cordocentesis, biochemical variables characteristic of the fetuses' respiratory and metabolic status. The aim of the study was to identify the discriminative biological alterations, related to growth retardation and fetal distress.

PATIENTS AND METHODS

The studied population includes 27 cases of severe IUGR, of gestational age 30,2+/-4,6 weeks of gestation (WG) (divided into 20 cases of isolated IUGR and 7 cases of IUGR associated with malformative syndrome), as well as 8 cases of moderate IUGR, of gestational age 26+/-4,5 WG; all fetuses had normal karyotypes. A group of 73 normal fetuses, of gestational age 26,3+/-5,7 WG, constituted a reference population. PH, pCO(2), bicarbonate concentration, pO(2) and SaO(2), as well as glucose, pyruvate, lactate, free fatty acids, aceto-acetate, beta-hydroxybutyrate and cholesterol concentrations were measured on umbilical venous blood (UVB).

RESULTS

In case of severe but isolated growth retardation, UVB analysis showed the frequency of acid-base and gasometric disturbances: acidemia and hypoxemia (65% of cases), hypercapnia (60% of cases). Metabolic abnormalities were shown: decrease in glycemia (35% of cases), increase in pyruvatemia and lactatemia (40% of cases), increased free fatty acids serum concentration; a diminution of umbilical venous cholesterol level, the most frequent abnormality, can be seen in 70% of fetuses. In case of severe IUGR associated with malformative syndrome, UVB acid-base and metabolic changes were rarely seen; however, UVB cholesterol level is low in some cases. In case of growth retardation classified as moderate, modifications are relatively not frequent and essentially gasometric.

CONCLUSION

In about 60% of cases of severe and isolated IUGR, there is a risk of fetal distress, related to an alteration of the transplacental transfer of respiratory gases and nutritional substrates; chronic fetal malnutrition can be involved, with an impact on the growth of the fetus. In case of IUGR associated with malformative syndrome, fetal smallness is probably a result of intrinsic fetal damage, without nutritional origin.

Doppler and biophysical assessment in growth restricted fetuses: distribution of test results

OBJECTIVE

Multi-vessel Doppler ultrasonography and biophysical profile scoring (BPS) are used in the surveillance of growth restricted fetuses (IUGR). The interpretation of both tests performed concurrently may be complex. This study examines the relationship between Doppler ultrasonography and biophysical test results in IUGR fetuses.

METHODS

Three hundred and twenty-eight IUGR fetuses (abdominal circumference < 5th percentile, elevated umbilical artery (UA) pulsatility index (PI)) had concurrent surveillance with UA, middle cerebral artery (MCA) and ductus venosus (DV) Doppler ultrasonography and BPS (fetal tone, movement, breathing, maximal amniotic fluid pocket and fetal heart rate). Patients were stratified into three groups according to their Doppler examination: (1) abnormal UA alone; (2) brain sparing (MCA-PI > 2 SD below mean for gestational age); and (3) abnormal DV (PI > 2 SD above the mean for gestational age) and BPS groups: (1) normal (> 6/10); (2) equivocal (6/10); and (3) abnormal (< 6/10). Predictions of short-term perinatal outcomes by both modalities were compared for stratification. The distribution and concordance of Doppler and BPS test results were examined for the whole patient group and based on delivery prior to 32 weeks' gestation.

RESULTS

Abnormal UA Doppler results alone were observed in 109 fetuses (33.2%), brain sparing in 87 (26.5%) and an abnormal DV in 132 (40.2%). The BPS was normal in 158 (48.2%), equivocal in 68 (20.7%) and abnormal in 102 (31.1%). Both testing modalities stratified patients into groups with comparable acid-base disturbance and perinatal outcome. Of the nine possible test combinations the largest subgroups were: abnormal UA alone/normal BPS (n = 69; 21%) and abnormal DV Doppler/abnormal BPS (n = 62; 18.9%). Assessment of compromise by both testing modalities was concordant in 146 (44.5%) cases. In 182 fetuses with discordant results the BPS grade was better in 115 (63.2%, P < 0.0001). Marked disagreement of test abnormality was present in 57 (17.4%) fetuses. Of these, abnormal venous Doppler in the presence of a normal BPS constituted the largest group (Chi-square P < 0.002). Stratification was not significantly different in patients delivered prior to 32 weeks' gestation.

CONCLUSION

Doppler ultrasonography and BPS effectively stratify IUGR fetuses into risk categories, but Doppler and BPS results do not show a consistent relationship with each other. Since fetal deterioration appears to be independently reflected in these two testing modalities further research is warranted to investigate how they are best combined.

Pathophysiology of Fetal Growth Restriction: Implications for Diagnosis and Surveillance

Normal fetal growth depends on the genetically predetermined growth potential and is modulated by fetal, placental, maternal, and external factors. Fetuses with intrauterine growth restriction (IUGR) are at high risk for poor short- and long-term outcome. Although there are many underlying etiologies, IUGR resulting from placental insufficiency is most relevant clinically because outcome could be altered by appropriate diagnosis and timely delivery. A diagnostic approach that aims to separate IUGR resulting from placental disease from constitutionally small fetuses and those with other underlying etiologies (e.g., aneuploidy, viral infection, nonaneuploid syndromes) needs to integrate multiple imaging modalities. In placental-based IUGR, cardiovascular and behavioral responses are interrelated with the disease severity. Ultrasound assessment of fetal anatomy, amniotic fluid volume, and growth is complementary to the Doppler investigation of fetoplacental blood flow dynamics. A diagnostic approach to IUGR combining these modalities is presented in this review.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe the development of the placental interface, to outline the mechanisms of placental insufficiency, and to list the manifestations of placental insufficiency and the tests that can be used to diagnose fetal growth restriction.

Fetal growth restriction due to placental disease

Normal fetal growth depends on the genetically predetermined growth potential and its modulation by the health of the fetus, placenta and the mother. Fetuses that are small because of intrauterine growth restriction (IUGR) are at higher risk for poor perinatal and long-term outcome than those who are appropriately grown. Of the many potential underlying processes that may result in IUGR, placental disease is clinically the most relevant. Fetal cardiovascular and behavioral responses to placental insufficiency and the metabolic status are interrelated. The concurrent evaluation of fetal biometry, amniotic fluid volume, heart rate patterns, arterial and venous Doppler, and biophysical variables therefore allow the most comprehensive fetal evaluation in IUGR. In the absence of successful intrauterine therapy, the timing of delivery is perhaps the most critical aspect of the antenatal management. A discussion of the fetal responses to placental insufficiency and a management protocol that accounts for multiple Doppler and biophysical parameters as well as gestational age is provided in this review.

Fetal biophysical profile

This article begins with an outline of the theoretic basis of the fetal biophysical profile, the method for the biophysical profile score (BPS), and the timing and frequency of testing. The article further discusses the clinical management based on test scores; modified methods of the BPS; and clinical application, predictive accuracy, and impact on outcome of BPS. The authors specifically examine the relationship between BPS and cerebral palsy. They conclude with a discussion of adult sequelae and fetal adaptation to asphyxia.

Comparison of the modified biophysical profile to a "new" biophysical profile incorporating the middle cerebral artery to umbilical artery velocity flow systolic/diastolic ratio

OBJECTIVES

The objective of this study was to determine whether the addition of the middle cerebral to umbilical artery systolic/diastolic velocity waveform ratio to the modified biophysical profile would improve perinatal outcome in patients at high risk.

STUDY DESIGN

A prospective, randomized outcome study of patients referred to the perinatal laboratory for antenatal surveillance was undertaken. Six hundred sixty-five patients were randomized to two antenatal surveillance protocols: group 1, modified biophysical profile; and group 2, modified biophysical profile plus evaluation of the middle cerebral artery to umbilical artery systolic/diastolic ratio. Patients were followed up serially and neonatal outcome data including gestational age at delivery, birth weight, incidence of cesarean section delivery for fetal distress, admission to the neonatal intensive care unit, days in the neonatal intensive care unit, and the presence of significant neonatal morbidity were tabulated.

RESULTS

The total population showed no statistical difference in outcome parameters between groups 1 and 2. However, a subgroup of patients evaluated for suspected uteroplacental insufficiency did show a significant reduction in caesarean section for fetal distress in group 2 patients.

CONCLUSIONS

In a subgroup of patients at risk for uteroplacental insufficiency, the addition of the middle cerebral/umbilical artery ratio to an antenatal surveillance protocol should be expected to improve perinatal outcome.

Asphyxia

The prevention of fetal asphyxia or hypoxia starts with prepregnancy counseling and continues with careful antenatal care and intrapartum fetal surveillance. Further progress in eliminating antepartum and intrapartum deaths will only be made when it is accepted that, even with intense investigation by detailed autopsy, the cause of many deaths remains unknown. Many of these deaths may be ascribed to hypoxia. In the future, with more detailed non-invasive probing with CAT scanning and magnetic resonance imaging, other causes may be determined. The mother at risk of hypoxia requires specialized attention. Such mothers will include those with severe cardiac, pulmonary or circulatory problems. Others will be those with endocrine problems, such as diabetes or thyroid dysfunction. At present, failure of fetal growth is generally ascribed to hypoxia, but undoubtedly, in solution to such problems of possible hypoxia is elective delivery at the appropriate time. What Hensleig said in 1986 (Hensleig et al, 1986) is equally true today: 'Preventative programmes will remain unsuccessful until the causation of cerebral palsy is more understood. What we are presently lacking is an understanding of the underlying conditions responsible for brain injury when asphyxia occurs despite our best efforts. While we have learned much about the causation and prevention of perinatal mortality very little has been established about the causation and prevention of cerebral palsy'. Finally, Hall (1989), in a review of birth asphyxia and cerebral palsy, concludes the following five points. 1. The incidence of cerebral palsy is not falling despite improved obstetrics. 2. The cause of more than 90% of cases of cerebral palsy remains unknown. 3. Asphyxia is hard to define and measure and is rarely the cause of cerebral palsy. 4. Hypoxic ischaemic encephalopathy is the most reliable indicator of asphyxia. 5. Neither traditional clinical signs nor electronic monitoring allow reliable recognition of asphyxia.

Fetal oxygenation at cordocentesis, maternal smoking and childhood neuro-development

OBJECTIVE

To assess the relationship between subsequent neuro-development and measurements in small for gestational age (SGA) fetuses, including oxygenation at cordocentesis.

DESIGN

A longitudinal study of a cohort of SGA fetuses using those with normal oxygenation as controls.

SUBJECTS

65 chromosomally normal children aged 12-66 months who, as fetuses, had been small for gestational age, had undergone cordocentesis and had been delivered after 32 weeks' gestation.

RESULTS

Griffiths' developmental quotient (DQ) was significantly associated with fetal blood pH (r = 0.41, P = 0.0008), PO2 (r = 0.25, P = 0.047) and PCO2 (r = -0.28, P = 0.027) at cordocentesis but not with the severity of growth retardation (r = 0.18, P = 0.17). However, the significant correlations between DQ and both PO2 and PCO2 were explained by their co-correlations with pH and neither remained significant after removing the effect of pH by analysis of variance. The association between DQ and pH was still significant after removing the effect of confounding variables. Maternal smoking during pregnancy was significantly associated with DQ (F to remove = 6.89, P = 0.011) even after allowing for the effects of possible confounding variables including fetal blood pH.

CONCLUSIONS

Both fetal pH at cordocentesis and maternal smoking correlate significantly with subsequent neuro-development. Further investigation into the causes of these associations is required.

Antenatal fetal magnetocardiography: a new method for fetal surveillance?

OBJECTIVE

To establish the reliability of fetal magnetocardiography as a method of measuring the time intervals of the fetal heart during the antenatal period.

DESIGN

A prospective study.

SETTING

Wellcome Biomagnetism Unit, Southern General Hospital.

SUBJECTS

One hundred and six low risk pregnant women at 20 to 42 weeks gestation.

MAIN OUTCOME MEASURES

Success in obtaining QRS complexes, P waves and T waves. Correlation of time intervals with fetal outcome.

RESULTS

The technique was acceptable to pregnant women. A QRS complex was successfully demonstrated in 68 (67%) of the unaveraged traces. Using off-line averaging techniques on these 68 cases, P waves were obtained in 75% and T waves in 72%. Although good quality traces were obtained throughout the range of gestational ages, in general it was more difficult below 28 weeks. QRS duration (R2 = 7%, P = 0.02) demonstrated a positive linear correlation with increasing gestation. Of the 35 (51%) cases with umbilical vein pH analysis available, only one result was less than 7.2. No significant relation was found between measurements of the fetal waveforms and the pH results.

CONCLUSION

The technique of fetal magnetocardiography provides a significant advance in the technological field for the demonstration of QRS complexes and the full PQRST waveforms in gestations from 20 weeks onwards. With further technical improvements the clinical impact of this technique can be assessed more fully.

Relationship between plasma adenosine concentration and breathing movements in growth-retarded fetuses

OBJECTIVE

The purpose of this study was to investigate the relationship between plasma adenosine concentration and breathing movements in growth-retarded fetuses.

STUDY DESIGN

We measured the incidence of fetal breathing movements and breathing rate immediately before cordocentesis in 26 growth-retarded fetuses at 31 to 38 weeks' gestation. Blood retrieved by cordocentesis was then analyzed for umbilical venous plasma adenosine concentration, blood gases, and pH.

RESULTS

In growth-retarded fetuses with hypoxia and acidosis plasma adenosine concentration was elevated and the incidence of fetal breathing movements was reduced. The change in plasma adenosine concentration correlated inversely and significantly with the incidence of fetal breathing movements.

CONCLUSION

Decreased breathing movements correlate with elevated plasma adenosine concentration in fetuses. We postulate that the enhanced adenosine formation in growth-retarded fetuses may modulate the inhibition of fetal breathing movements.

Relationship between the fetal biophysical profile score, umbilical artery Doppler velocimetry, and fetal blood acid-base status determined by cordocentesis

OBJECTIVE

Fetal hypoxia-acidosis is part of the terminal pathway leading to intrauterine fetal death. A central premise of antepartum surveillance is that identification and timely delivery of the hypoxic or acidotic fetus will prevent intrauterine death and decrease long-term neurologic damage. The optimal method to identify fetal hypoxia-acidosis has not been determined. We attempted to compare the performance of the biophysical profile score and umbilical artery Doppler velocimetry in the identification of fetal acidemia, hypoxemia, and hypercarbia as determined by pH and gas analysis of fetal blood obtained by cordocentesis.

STUDY DESIGN

Fetal biophysical profile and umbilical artery Doppler velocimetry studies were performed before cordocentesis in 24 patients (26 to 40 weeks). Umbilical vein pH and blood gas values were determined in all cases. The pulsatility index of the umbilical artery was obtained with pulsed Doppler equipment. Receiver-operator characteristic curve analysis and stepwise multiple logistic regression were performed to examine the relationship between biophysical profile score, umbilical artery Doppler velocimetry, and acid-base status.

RESULTS

The prevalence of fetal acidemia (pH 2 SD below the mean for gestational age) was 41.7% (10/24). There was a significant relationship between the change in umbilical artery pulsatility index and fetal acidemia (chi 2 = 26.6, p < 0.001) and hypercarbia (chi 2 = 22.9, p < 0.001), but not hypoxemia (chi 2 = 1.0, p > 0.1), and between the biophysical profile score and fetal acidemia (chi 2 = 11.1, p < 0.001) and hypercarbia (chi 2 = 9.0, p < 0.005), but not hypoxemia (chi 2 = 2.3, p > 0.1). Stepwise multiple logistic regression demonstrated that umbilical artery Doppler velocimetry was a better explanatory variable for acidemia and hypercarbia than the biophysical profile score.

CONCLUSION

A strong relationship between the degree of fetal acidemia and hypercarbia and the results of umbilical artery Doppler velocimetry and biophysical profile was found. However, umbilical artery Doppler velocimetry was a better explanatory variable for these outcome than the biophysical profile score.

Fetal biophysical profile score. VI. Correlation with antepartum umbilical venous fetal pH

OBJECTIVE

Our objective was to determine the relationship, if any, between the fetal biophysical profile score and antepartum umbilical venous pH.

STUDY DESIGN

This was a prospective observational study conducted concurrently in two centers and involving two discrete high-risk groups of fetuses. Fetal biophysical profile scores were compared with umbilical venous pH values measured in blood obtained by immediate cordocentesis. A total of 493 paired observations of biophysical profile score and pH were made; 104 observations were of fetuses with intrauterine growth retardation and 389 observations were of fetuses with alloimmune anemia.

RESULTS

In both data sets there was a highly significant linear correlation between biophysical profile score and umbilical venous pH. Poor biophysical profile score performance (a score of 0 of 10) was always associated with a pH < 7.20, whereas the pH was always > 7.20 when the biophysical profile score was 10 of 10. Sequenced sensitivity of short-term biophysical variables in the detection of acidemia was observed.

CONCLUSION

The fetal biophysical profile score accurately predicts antepartum umbilical venous pH.

A comparison of the nonstress test, oxytocin challenge test, Doppler velocimetry and biophysical profile in predicting umbilical vein pH in growth-retarded fetuses

OBJECTIVE

To examine and compare the value of the nonstress test (NST), oxytocin challenge test (OCT), Doppler velocimetry (S/D ratio), and biophysical profile (BPP) in predicting fetal acidosis.

METHOD

NST, OCT, S/D ratio and BPP were performed in 23 pregnancies with growth-retarded fetuses. The value of each parameter in predicting fetal acidosis (umbilical vein pH obtained by cordocentesis) was examined.

RESULT

The NST, OCT and BPP were found to have the same positive predictive value of 57.1% in predicting fetal acidosis. The S/D ratio was found to have a very low positive predictive value (14.3%). The only combination of two parameters that showed improved positive predictive value, was that of OCT and NST (66.7%).

CONCLUSION

(1) The best indirect method in assessing fetal well-being is the combination of NST and OCT. (2) Since the positive predictive value of the indirect methods is still low, direct assessment of the fetal metabolic status is recommended in premature growth-retarded fetuses with an abnormal test.

Evaluation of the fetal assessment score in pregnancies at risk for intrauterine hypoxia

OBJECTIVE

Our purpose was to define the diagnostic value of a new fetal assessment score that is based on each of the components of the Apgar score.

STUDY DESIGN

A fetal assessment score was established to study the main fetal vital functions: (1) cardiovascular (heart rate, color of the skin in the Apgar score), now based on fetal heart rate patterns and Doppler assessment of fetal blood flow redistribution, (2) fetal respiratory (quality of breathing in the Apgar score), now based on Doppler assessment of uteroplacental perfusion, and (3) neuromuscular function (tone and reflexes in the Apgar score), now based on fetal tone and response to external stimuli. The fetal assessment score was used in the study of 110 postdate pregnancies and 103 small-for-gestational-age infants and was compared with the traditional biophysical profile score in the prediction of perinatal outcome.

RESULTS

There were significant associations between both the fetal assessment score and the biophysical profile score with fetal distress that necessitated operative delivery, low Apgar scores, and low umbilical cord arterial blood pH. However, receiver-operator characteristic plots demonstrated that the fetal assessment score was superior to the biophysical profile score in predicting fetal distress and low Apgar values particularly in the small-for-gestational-age infants. The best single parameters in predicting fetal distress were the amniotic fluid volume in the biophysical profile score and fetal heart rate patterns and pulsed Doppler measurements in the new score.

CONCLUSION

A fetal Apgar score in which respiration is assessed by placental perfusion rather than chest movements and in which skin color is assessed by centralization of fetal blood flow may be better than the traditional biophysical profile score in predicting fetal hypoxic compromise.

Prediction of morbidity in small and normally grown fetuses by fetal heart rate variability, biophysical profile score and umbilical artery Doppler studies

OBJECTIVE

To assess the ability of noninvasive tests of fetal wellbeing to predict hypoxic morbidity independent of fetal size.

DESIGN

A prospectively planned, longitudinal, observational study.

SETTING

Fetal Surveillance Unit, King's College Hospital, London.

SUBJECTS

One hundred and ninety-one pregnant women with singleton pregnancies who were delivered after 32 weeks' gestation who were seen in the Fetal Surveillance Unit within seven days of delivery.

INTERVENTIONS

Fetal surveillance by fetal abdominal circumference, heart rate variability (mean range), biophysical profile score and umbilical artery pulsatility index measurements.

MAIN OUTCOME MEASURES

Birthweight was classified as > or < or = 2.5th centile (AGA or SGA) for gestational age and sex. Morbidity was defined as at least one of the following at birth: delivery by emergency caesarean section for fetal distress, umbilical venous blood pH less than 7.15, 5 min Apgar score less than 7 or admission to the Special Care Baby Unit (SCBU).

RESULTS

Fetal abdominal circumference was the best indicator of which fetuses (n = 30) would be SGA. Fourteen of the 30 (47%) SGA fetuses had morbidity at birth and abnormal umbilical Doppler studies significantly predicted this (chi 2 = 2.93, P = 0.003). By contrast, fetal heart rate variability and the biophysical profile score did not. Twenty-seven of the 161 (17%) AGA fetuses had morbidity at birth, but this was not significantly predicted by heart rate variability, biophysical profile score or umbilical Doppler studies.

CONCLUSIONS

None of the antenatal testing techniques studied predicted morbidity in normally grown fetuses but Doppler studies indicated whether a small fetus was 'sick small' or 'normal small'.

Prediction of fetal acidaemia in intrauterine growth retardation: comparison of quantified fetal activity with biophysical profile score

OBJECTIVE

To study the relation between quantified fetal movements and fetal activity assessed by the biophysical profile score and the pH in umbilical arterial blood at elective caesarean section.

DESIGN

Fetal activity was assessed within 24 h prior to caesarean section for decelerative fetal heart rate patterns both by quantification (% of time spent moving) and by applying the biophysical profile score (BPS) criteria.

SETTING

Department of Obstetrics, University Hospital.

SUBJECTS

Nineteen growth retarded fetuses.

MAIN OUTCOME MEASURES

Fetal generalised movements (FGM%), fetal breathing movements (FBM%), total fetal activity (TFA% = FGM% + FBM%); FGM, FBM and tone as assessed according the biophysical profile score (BPS); umbilical arterial pH.

RESULTS

In all 11 acidaemic fetuses (pH < 7.20) TFA% was below the 10th centile for normal fetuses; nine had decreased FGM% and eight decreased FBM%. Absence of FGM or tone according to the biophysical profile score was only seen in two acidaemic fetuses.

CONCLUSION

TFA% < 11.7% was a better predictor of acidaemia at birth than either reduced FGM%, FBM%, or absence of FGM, FBM and tone as defined in the biophysical profile score. The two methods of assessing FBM were identical in predicting acidaemia, suggesting that in presence of acidaemia the decrease of FBM may be an all-or-none phenomenon. Furthermore, the data indicate that reduction in body movements may precede reduction in breathing movements.

Prediction of fetal acidaemia in pregnancies complicated by maternal diabetes mellitus by biophysical profile scoring and fetal heart rate monitoring

OBJECTIVE

To determine whether computer assisted fetal heart rate analysis or the biophysical profile score can provide noninvasive prediction of fetal acidaemia.

DESIGN

Cross sectional study.

SETTING

Harris Birthright Research Centre for Fetal Medicine, King's College Hospital School of Medicine, London.

SUBJECTS

Forty-one women with pregnancies complicated by diabetes mellitus.

INTERVENTIONS

Fetal heart rate (FHR) monitoring with computer assisted analysis, biophysical profile score (BPS) and cordocentesis for measurement of umbilical venous blood glucose concentration and blood gases, up to 24 h before delivery at 27 to 39 weeks gestation.

RESULTS

The mean umbilical venous blood pH was significantly lower than the normal mean for gestation, and was below the 5th centile in 18 pregnancies, including all six cases where the mother had nephropathy and hypertension. The mean pO2 was not significantly different from the normal mean for gestation. There were significant associations between fetal acidaemia and both the BPS (r = 0.46, P < 0.01) and FHR variation (r = 0.42, P < 0.01). However, of the 12 acidaemic fetuses of non-nephropathic mothers, nine had normal BPS and six had normal FHR variation.

CONCLUSIONS

In pregnancies complicated by maternal diabetes mellitus, BPS and FHR variation are of limited value in the prediction of fetal blood pH.

Changes with time in fetal heart rate variation, movement incidences and haemodynamics in intrauterine growth retarded fetuses: a longitudinal approach to the assessment of fetal well being

Fetal heart rate (FHR) variation, general movements (FGM), breathing movements (FBM) and haemodynamics were studied longitudinally in 19 intrauterine growth retarded fetuses, who eventually were delivered by caesarean section (CS) because of fetal distress, in order to determine changes occurring with time. The fetuses were studied for the last 10 days on average before delivery (range 2-14 days). During this period on average eight 1-h FHR records were made and three 1-h movement recordings. The FHR pattern was analyzed numerically; the incidence of FGM and FBM was quantified and expressed as percentage of time. Blood flow velocity waveforms were measured in the umbilical artery (n = 19) and in the internal carotid artery (n = 14). In 14 of 19 fetuses abnormal velocity wave forms were present from the beginning of the study onwards. FHR variation was initially just within or below the norm and fell further during the last 2 days before CS. FGM and FBM fell below the normal range later and in a lower rate of occurrence than FHR variation. FGM showed a more or less consistent fall in time, whereas FBM showed a wide range throughout the period of observation. The poorest outcome occurred in fetuses with reversed end-diastolic velocities and rapid fall in FHR variation. It is concluded that with progressive deterioration of the fetal condition abnormal velocity wave form patterns occur first; FHR variation is reduced subsequently and FGM and FBM are the last to become abnormal. Assessment of fetal activity may be of help in fetuses with a marginally reduced FHR variation, in which prolongation of pregnancy is considered desirable to allow further maturation in utero.