Antibody to cardiolipin as a predictor of fetal distress or death in pregnant patients with systemic lupus erythematosus

During a prospective study of pregnancies in women with systemic lupus erythematosus, we examined the relation between antibody to cardiolipin, measured by the enzyme-linked immunosorbent assay, and midpregnancy fetal distress, identified by abnormal results of antepartum fetal heart-rate testing or by fetal death. All of nine patients with lupus and this complication had abnormally high antibody levels (mean, 212.3 +/- 55.3 units), as compared with values in normal nonpregnant women (28.2 +/- 10.1 units). None of 12 pregnant patients with lupus but without this complication had antibody levels above 50 units (mean, 27.5 +/- 3.4 units; P less than 0.005 vs. women with lupus and fetal distress); 4 of 12 pregnant subjects without lupus had antibody levels above 50 units (mean, 42.5 +/- 11.0), and fetal death occurred in the subject with the highest level. The mean antibody level in 12 nonpregnant patients with lupus was 117.4 +/- 35.0 units. Two patients who had lupus anticoagulant but not clinical lupus, both with histories of prior fetal death, also had high antibody levels; fetal death occurred in one, and spontaneous fetal bradycardia in the other. Antibody to cardiolipin was loosely linked to a history, but not the simultaneous presence, of demonstrable lupus anticoagulant or thrombocytopenia, and could be detected as early in pregnancy as either anticoagulant or thrombocytopenia. We conclude that measurement of antibody to cardiolipin is the most sensitive assay to predict fetal distress or death in patients with systemic lupus erythematosus and may be of pathogenetic importance in this syndrome.

Antepartum fetal evaluation: development of a fetal biophysical profile

Five fetal biophysical variables, fetal breathing movements, fetal movements, fetal tone, qualitative amniotic fluid volume, and the nonstress test, were measured in the same observation period in 216 patients with high-risk pregnancies. All delivered within one week of the last observation. The relationship between individual biophysical variables and combinations of variables to the outcome of pregnancy as judged by five-minute Apgar score, fetal distress in labor, and perinatal mortality rate (PMN) was determined. For any single test, the false negative rate was low and was similar between tests, but the false positive rate was high (greater than 50%) and varied significantly between tests. Combining tests resulted in a significant change in both the false negative and false positive rates as compared to any single test. The most accurate differentiation of the normal from the compromised fetus was obtained when all five variables were studied. The PNM ranged from 0 when all variables were normal to 600 per 1,000 when all were abnormal. These data suggest that combined fetal biophysical testing is a more accurate method of antepartum fetal evaluation than any single method.

Induction of labor as compared with serial antenatal monitoring in post-term pregnancy. A randomized controlled trial. The Canadian Multicenter Post-term Pregnancy Trial Group

BACKGROUND

The rates of perinatal mortality and neonatal morbidity are higher for post-term pregnancies than for term pregnancies. It is not known, however, whether the induction of labor results in better outcomes than does serial fetal monitoring while awaiting spontaneous labor.

METHODS

We studied 3407 women with uncomplicated pregnancies of 41 or more weeks' duration. The women were randomly assigned to undergo induction of labor or to have serial antenatal monitoring and spontaneous labor unless there was evidence of fetal or maternal compromise, in which case labor was induced or cesarean section was performed. In the induction group, labor was induced by the intracervical application of prostaglandin E2. Serial antenatal monitoring consisted of counts of fetal kicks, nonstress tests, and assessments of amniotic-fluid volume. The outcomes we measured were the rates of perinatal mortality, neonatal morbidity, and delivery by cesarean section.

RESULTS

Among the 1701 women in the induction group, 360 (21.2 percent) underwent cesarean section, as compared with 418 (24.5 percent) of the 1706 women in the monitoring group (P = 0.03). This difference resulted from a lower rate of cesarean section performed because of fetal distress among the women in the induction group (5.7 percent vs. 8.3 percent, P = 0.003). When two infants with lethal congenital anomalies were excluded, there were no perinatal deaths in the induction group and two stillbirths in the monitoring group (P not significant). The frequency of neonatal morbidity was similar in the two groups.

CONCLUSIONS

In post-term pregnancy, the induction of labor results in a lower rate of cesarean section than serial antenatal monitoring; the rates of perinatal mortality and neonatal morbidity are similar with the two approaches to management.

Cerebral-umbilical Doppler ratio as a predictor of adverse perinatal outcome

Using a 3.5-MHz duplex Doppler system, 45 normal-growth and 45 growth-retarded fetuses were studied between 30-41 weeks' gestation. Velocity recordings were obtained from the middle cerebral artery and umbilical artery to calculate the ratio between the two pulsatility indexes. The cerebral-umbilical Doppler ratio is usually constant during the last 10 weeks of gestation. Therefore, a single cutoff value (1.08) was used, above which velocimetry was considered normal and below which it was considered abnormal. The cerebral-umbilical Doppler ratio provided a better predictor of small for gestational age newborns and adverse perinatal outcome than either the middle cerebral artery or umbilical artery alone. In fact, in predicting those newborns who were small for gestational age, the cerebral-umbilical ratio had a 70% diagnostic accuracy [(true positive + true negative)/total number of cases], compared with 54.4% for the middle cerebral artery and 65.5% for the umbilical artery. The results were more encouraging for prediction of adverse perinatal outcome; diagnostic accuracy for the cerebral-umbilical ratio was 90%, compared with 78.8% for the middle cerebral artery and 83.3% for the umbilical artery.

Cardiotocography only versus cardiotocography plus ST analysis of fetal electrocardiogram for intrapartum fetal monitoring: a Swedish randomised controlled trial

BACKGROUND

Previous studies indicate that analysis of the ST waveform of the fetal electrocardiogram provides information on the fetal response to hypoxia. We did a multicentre randomised controlled trial to test the hypothesis that intrapartum monitoring with cardiotocography combined with automatic ST-waveform analysis results in an improved perinatal outcome compared with cardiotocography alone.

METHODS

At three Swedish labour wards, 4966 women with term fetuses in the cephalic presentation entered the trial during labour after a clinical decision had been made to apply a fetal scalp electrode for internal cardiotocography. They were randomly assigned monitoring with cardiotocography plus ST analysis (CTG+ST group) or cardiotocography only (CTG group). The main outcome measure was rate of umbilical-artery metabolic acidosis (pH <7.05 and base deficit >12 mmol/L). Secondary outcomes included operative delivery for fetal distress. Results were first analysed according to intention to treat, and secondly after exclusion of cases with severe malformations or with inadequate monitoring.

FINDINGS

The CTG+ST group showed significantly lower rates of umbilical-artery metabolic acidosis than the cardiotocography group (15 of 2159 [0.7%] vs 31 of 2079 [2%], relative risk 0.47 [95% CI 0.25-0.86], p=0.02) and of operative delivery for fetal distress (193 of 2519 [8%] vs 227 of 2447 [9%], 0.83 [0.69-0.99], p=0.047) when all cases were included according to intention to treat. The differences were more pronounced after exclusion of 291 in the CTG+ST group and 283 in the CTG group with malformations or inadequate recording.

INTERPRETATION

Intrapartum monitoring with cardiotocography combined with automatic ST-waveform analysis increases the ability of obstetricians to identify fetal hypoxia and to intervene more appropriately, resulting in an improved perinatal outcome.

Nonstressed fetal heart rate monitoring in the antepartum period

The role of nonstressed monitoring of the fetal heart rate (HR) in determining fetal well-being during the antepartum period was assessed in 125 high-risk patients. Observations on HR, variability, and HR response to fetal movement (FM) and uterine contractions (UC) over a 30 minute period were made with an external microphone and tocotransducer. A total of 625 tests were performed; the earliest gestation tested was 28 weeks, and the latest was 46 weeks. A reactive pattern (variability greater than 6 b.p.m. and accelerations with FM) appears to be a reliable indicator of fetal well-being. All the 51 fetuses exhibiting this pattern survived. This group also had the lowest incidence of neonatal complications. On the other hand, of the babies who failed to show variability greater than 6 b.p.m. or accelerations with FM (nonreactive pattern), 40% died in the perinatal period. Thirty-five patients showed features of both a reactive and nonreactive pattern (combined pattern). Poor outcome in this group was confined to those in whom the majority of the pattern was nonreactive. An undulating HR pattern with virtually absent variability (sinusoidal pattern) was found in 20 Rh-sensitized fetuses, 50% of whom died in the perinatal period. Bradycardia and tachycardia were not found to be reliable signs of fetal distress antepartum. Of the 12 fetuses who died during observation, six showed late decelerations with spontaneous UC but all showed diminished variability. The close correlation between nonstressed patterns and neonatal outcome demonstrated by this preliminary study warrants further use of this technique for fetal evaluation.

The evaluation of continuous fetal heart rate monitoring in high-risk pregnancy

Intrapartum electronic fetal heart rate monitoring of the high-risk obstetric patient is thought to improve the perinatal outcome. A prospective randomized study of 483 high-risk obstetric patients in labor was carried out comparing the effectiveness of electronic fetal monitoring with auscultation of fetal heart tones. The infant outcome was measured by neonatal death, Apgar scores, cord blood gases, and neonatal nursery morbidity. There were no differences in the infant outcomes in any measured category between the electronically monitored group and the auscultated group. The cesarean section rate was markedly increased in the monitored group (16.5 vs. 6.8 per cent in the auscultated patients). The presumptive benefits of electronic fetal monitoring for improving fetal outcome were not found in this study.

Pregnancy outcome at extremely advanced maternal age

OBJECTIVE

The purpose of this study was to evaluate pregnancy outcome in women at extremely advanced maternal age (≥ 45 years).

STUDY DESIGN

We compared the condition of women aged ≥ 45 years (n = 177) in a 10:1 ratio (20-29, 30-39, and 40-44 years.). Subgroup analysis compared the condition of women aged 45-49 years with those women aged ≥ 50 years.

RESULTS

The rates of gestational diabetes mellitus and hypertensive complications were higher for the study group, compared with the whole group (17.0% vs 5.6% and 19.7% vs 4.5%, respectively; P < .001), as was the rate of preterm delivery at <37 and <34 weeks of gestation (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.2-3.6 and OR, 3.5; 95% CI, 1.4-9.0, respectively). The rates of cesarean delivery (OR, 31.8; 95% CI, 18.0-56.1), placenta previa, postpartum hemorrhage, and adverse neonatal outcome were significantly higher among the study group. The risk for gestational diabetes mellitus, preeclampsia toxemia, preterm delivery, and neonatal intensive care unit admission was increased for women aged ≥ 50 years.

CONCLUSION

Pregnancy at extreme advanced maternal age is associated with increased maternal and fetal risk.

Fetal outcome in obstetric cholestasis

Obstetric cholestasis has been associated with a high incidence of stillbirth and perinatal complications. Between 1975 and 1984, 83 pregnancies were complicated by cholestasis. Meconium staining occurred in 45%, spontaneous preterm labour in 44%, and intrapartum fetal distress in 22%. Of 86 infants two were stillborn and one died soon after birth. Perinatal mortality fell from 107 in a previous series from this hospital (1965-1974) to 35/1000 in this series. Cardiotocography, estimations of oestriol, liver function tests and ultrasonic assessment of amniotic fluid volume failed to predict fetal compromise, whereas amniocentesis revealed meconium in 8 of 26 pregnancies. Early intervention was indicated in 49 pregnancies, 12 because of fetal compromise. This study suggests that intensive fetal surveillance, including amniocentesis for meconium, and induction of labour at term or with a mature lecithin/sphyngomyelin ratio, may reduce the stillbirth rate in this 'high-risk' condition.

A successful program to lower cesarean-section rates

Despite the consensus that national cesarean-section rates are excessive, they continue to rise. Currently, approximately one of every four deliveries is by cesarean section. We developed an initiative to reduce the number of cesarean deliveries to a rate of 11 percent of all deliveries at our inner-city hospital. Participation by attending physicians was voluntary and not linked to any sanction. The program included a stringent requirement for a second opinion, objective criteria for the four most common indications for cesarean section, and a detailed review of all cesarean sections and of individual physicians' rates of performing them. During the first two years of the program, the cesarean-section rate fell from 17.5 percent of 1697 deliveries in 1985 to 11.5 percent of 2301 deliveries in 1987 (P less than 0.05). The proportion of infants with five-minute Apgar scores lower than 7 increased from 3 percent in 1985 to 4.9 percent in 1987 (P less than 0.05), but neither the fetal mortality rate (11.9 per 1000) nor the neonatal mortality rate (11.2 per 1000) in 1987 differed significantly from the rates in 1985. A single maternal death, unrelated to cesarean delivery, occurred during the study. Rates of both primary and repeat cesarean sections decreased, although only the decline in the rate of primary cesarean sections, from 12 to 6.8 percent, was statistically significant (P less than 0.05). During the same period, operative vaginal deliveries (i.e., forceps deliveries and midpelvic procedures) declined from 10.4 to 4.3 percent (P less than 0.05) of total deliveries. We conclude that an initiative within an obstetrics department can reduce cesarean-section rates substantially without adverse effects on the outcome for mother or infant.

Intrapartum electronic fetal heart rate monitoring versus intermittent auscultation: a meta-analysis

OBJECTIVE

To use a meta-analysis of all published randomized trials to determine whether the use of continuous electronic fetal heart rate monitoring (EFM) as the main method of intrapartum fetal surveillance is associated with improved pregnancy outcome compared to intermittent auscultation.

DATA SOURCES

We used the MEDLINE data base and reference lists of articles to identify all published randomized trials of EFM versus intermittent auscultation.

METHODS OF STUDY SELECTION

A total of nine randomized trials published in peer-review journals were identified. The selection criterion was the use of EFM or intermittent auscultation as the main intrapartum fetal surveillance technique.

DATA EXTRACTION AND SYNTHESIS

A total of 18,561 patients were included in the nine published randomized trials, 9398 in the EFM group and 9163 in the auscultation group. Measures of pregnancy outcome included cesarean delivery, cesarean for suspected fetal distress, overall use of forceps or vacuum, use of forceps or vacuum for suspected fetal distress, overall perinatal mortality, and perinatal mortality due to fetal hypoxia (intrapartum or early neonatal death) attributable to the method of intrapartum monitoring. The meta-analysis showed that the patients monitored electronically had a significantly higher overall cesarean rate (odds ratio [OR] 1.53, 95% confidence interval [CI] 1.17-2.01), higher cesarean rate for fetal distress (OR 2.55, 95% CI 1.81-3.53), overall increased use of forceps or vacuum (OR 1.23, 95% CI 1.02-1.49), increased use of forceps or vacuum for suspected fetal distress (OR 2.50, 95% CI 1.97-3.18), and decreased perinatal mortality due to fetal hypoxia (OR 0.41, 95% CI 0.17-0.98).

CONCLUSION

Electronic fetal monitoring is associated with increased rates of surgical intervention and decreased perinatal mortality due to fetal hypoxia.

Elimination of fetal scalp blood sampling on a large clinical service

OBJECTIVES

To describe the use of fetal scalp blood sampling on a large teaching service over 7 years and to assess any association between changes in use and the rates of cesarean delivery for fetal distress and of various indirect indicators of perinatal asphyxia in term infants.

METHODS

We reviewed computerized and tabular data bases for fetal scalp blood sampling, cesarean delivery for fetal distress, Apgar score, and the clinical diagnoses of asphyxia and meconium aspiration syndrome for the years 1986-1992.

RESULTS

Live births averaged 16,330 annually. The rate of fetal scalp blood sampling for the first 3 years of the study period was 1.76%, consistent with the rate of 1.5-2.0% noted for the preceding decade at our institution. An increase in sampling in 1987 was followed by a steady decline over the next 4 years, to a low of 0.03% in 1992. During the period of declining scalp pH usage, there was no increase in the cesarean rate for fetal distress, low Apgar score (less than 5 at 5 minutes) requiring neonatal intensive care unit admission, or the clinical diagnosis of perinatal asphyxia or meconium aspiration syndrome.

CONCLUSIONS

Fetal scalp blood sampling has been virtually eliminated without an increase in the cesarean rate for fetal distress or an increase in indicators of perinatal asphyxia. The role of fetal scalp blood sampling in clinical practice is questioned.

Placental insufficiency in relation to postterm pregnancy and fetal postmaturity. Evaluation of fetoplacental function; management of the postterm gravida

As pregnancy extends post term, incidence of placental insufficiency, fetal postmaturity (dysmaturity), and fetal perinatal death increases rapidly as a consequence of reduced respiratory and nutritive placental function. Despite a compensatory fetoplacental respiratory reserve capacity, fetal distress is observed in about one third of postterm pregnancies. On a biochemical level, placental pathophysiology in postterm-postmaturity pregnancies is not well understood. Postmaturity is correlated with increased incidence of placental lesions, fetal hypoxia-asphyxia, intrauterine growth retardation, increased perinatal death, and neonatal morbidity. Early diagnosis of fetal postmaturity is difficult because currently applied test methods allow recognition only when placental insufficiency is far progressed. Therefore, in postterm gravidas with a favorable cervix, induction of labor should be considered; in older primigravidas, in whom fetal losses may be sevenfold increased, or in multiparas with a history of obstetric complications, pregnancy may require termination by cesarean section. Pregnancy may be allowed to continue under close supervision in cases of uncertainty of duration of gestation, in gravidas carrying small babies, in young primigravidas, and in multigravidas in whom placentofetal function tests are normal. As long as fetal scalp blood sampling during labor does not show fetal acidosis, despite abnormal fetal heart rate pattern and meconium release, vaginal delivery may be attempted when deemed possible within a few hours. In parturients attention must be paid to the extent of uterine activity and type of medication; lateral positioning of the gravida and maternal oxygen breathing, facilitating fetal oxygen supply, are important features. Because during bearing-down efforts placentofetal respiratory reserves of postterm gravidas may become further compromised, immediate delivery by forceps or vacuum extraction may be considered. After delivery the umbilical cord should not be clamped immediately in order to allow increased fetal blood supply and to counteract fetal hypovolemia. Dysmature newborn infants require special care by the neonatologist.

Umbilical artery flow velocity waveforms in high-risk pregnancy. Randomised controlled trial

300 patients at high fetal risk (mean gestational age 34 wk) were randomised to a group for antenatal doppler umbilical artery waveform studies and a control group. The timing of delivery was similar in the control and doppler-report-available groups overall. However, in the report group obstetricians allowed the pregnancies of those not selected for elective delivery to continue longer. There was no difference in the rates for elective delivery (induction of labour or caesarean section) in the two groups, whereas among those who went into labour (induced or spontaneous) emergency caesarean section was more frequent in the control group (23%) than in the report group (13%). Fetal distress in labour was also more common in the control group. Babies from the control group spent longer in neonatal intensive care (level 3) and needed more respiratory support than did those in the report group. The findings indicate that the availability of doppler studies leads to better obstetrical decision making.

Maternal serum bile acid levels and fetal distress in cholestasis of pregnancy

Cardiotocography (CTG) and serum total bile acid level were used in the perinatal surveillance of 117 pregnancies with intrahepatic cholestasis. Signs of fetal distress occurred more commonly in cholestasis pregnancies with high maternal bile acid levels. Despite careful monitoring one intrauterine fetal loss occurred without any warning signs in CTG. In this case the serum bile acid level was only moderately elevated. CTG seems to be suitable for detection of fetal distress in cholestasis pregnancies. Those with high maternal bile acid level should be subjected to a more intensive follow-up. Some fetal risk, however, seems to remain despite of the use of these methods.

Intrapartum fetal surveillance: the role of fetal scalp blood sampling

Continuous electronic fetal heart rate monitoring and fetal scalp blood sampling have traditionally played a complementary role in intrapartum fetal surveillance. Nevertheless, biochemical assessment of fetal blood pH, with the use of scalp or umbilical cord blood, is often viewed as the "gold standard" against which biophysical indicators of fetal distress must be judged. In actual clinical practice, however, fetal scalp blood sampling is only rarely used. In addition, there is a growing body of evidence to suggest that, when properly interpreted, fetal heart rate assessment may be equal or superior to measurement of fetal blood pH in the prediction of both good and bad fetal outcomes. Under certain circumstances, fetal scalp blood sampling remains a valuable clinical tool; however, we recommend a deemphasis of fetal scalp blood sampling in general clinical practice. Both theoretical and practical considerations suggest that the properly trained clinician may pursue an approach for the detection of fetal distress that does not include scalp blood sampling without either compromising his ability to detect fetal distress or significantly increasing the cesarean section rate.

Diagnostic value of the unstressed antepartum cardiotocogram

The unstressed antepartum cardiotocogram (CTG) is principally judged by two aspects: baseline irregularity, and reaction to Braxton Hicks contractions and fetal movements. A classification into normal, sub-optimal, decelerative, and terminal CTG was devised. The ominous significance of the terminal CTG was confirmed in 26 patients; nine of the fetuses died in utero and the other 17 were delivered by elective Caesarean section; only one newborn was neither small-for-dates nor acidaemic. The significance of the other three categories was evaluated in 428 patients in whom labour was induced. All patients with repeated decelerative antepartum CTG showed signs of fetal distress during labour and most of them required Caesarean section; patients with a normal or sub-optimal CTG rarely showed signs of fetal distress during labour. The incidence of growth retardation was 41 per cent in the combined decelerative and sub-optimal groups against 9 per cent in the normal group. In comparing these results with studies of the oxytocin challenge test, it was concluded that, except in the case of a sub-optimal CTG, the oxytocin challenge test has no place in obstetrics.

Comparison of entropy-based regularity estimators: application to the fetal heart rate signal for the identification of fetal distress

This paper considers the multiscale entropy (MSE) approach for estimating the regularity of time series at different scales. Sample entropy (SampEn) and approximate entropy (ApEn) are evaluated in MSE analysis on simulated data to enhance the main features of both estimators. We applied the approximate entropy and the sample entropy estimators to fetal heart rate signals on both single and multiple scales for an early identification of fetal sufferance antepartum. Our results show that the ApEn index significantly distinguishes suffering from normal fetuses between the 30th and the 35th week of gestation. Furthermore, our data shows that the MSE entropy values are reliable indicators of the fetal distress associated with the presence of a pathological condition at birth.

Relation of private or clinic care to the cesarean birth rate

The rising rate of cesarean births in the United States has been the focus of academic attention as well as attention from the media during the past decade. Although there is a consensus about the indications for cesarean delivery that have led to the increased rate (dystocia, malpresentation, fetal distress, and previous cesarean delivery), the influence of other key factors, such as whether the patient received care from a private physician or through a hospital clinic, has not been established. In a review of 65,647 deliveries in four Brooklyn hospitals between 1977 and 1982, we found that private physicians performed significantly more cesarean sections than house officers and attending physicians. Private patients giving birth to their first child were significantly more likely than clinic patients to undergo cesarean delivery if dystocia, malpresentation, or fetal distress was diagnosed, and private patients with one or more previous deliveries were significantly more likely to undergo cesarean delivery if dystocia or malpresentation was diagnosed. Private patients had fewer perinatal deaths, which were concentrated among infants with birth weights under 2000 g, but the infants of private patients had a significantly higher rate of low Apgar scores and birth injuries than the infants of clinic patients.

Intrauterine growth retardation: prediction of perinatal distress by Doppler ultrasound

To investigate the ability of umbilical artery Doppler findings to identify true cases at risk of fetal distress among 51 pregnancies clinically judged to be compromised by intrauterine growth retardation (IUGR) Doppler data were related to pregnancy outcome, which was classified into three groups-group 1, healthy babies with normal placental function (16 fetuses), group 2, fetuses with definite signs of placental failure (30), and group 3, non-classifiable pregnancies (5). Group 2 was subdivided into 2A, placental failure with manifest perinatal distress (19), and 2B, placental failure without perinatal distress (11). All 19 compromised and distressed fetuses (group 2A) had extremely pathological Doppler findings, even several weeks before fetal distress became apparent by cardiotocography. The Doppler findings in the 11 small-for-dates fetuses without perinatal distress (group 2B) were inconsistently normal or slightly pathological. All 16 normal infants (group 1) had normal antenatal Doppler data. The Doppler technique thus allows accurate and early recognition of those fetuses who will become distressed perinatally. It also helps to identify which fetuses clinically suspected of IUGR have an adequate placental circulation.

Antenatal screening for intrauterine growth retardation with umbilical artery Doppler ultrasonography

To assess the usefulness of continuous wave Doppler ultrasonography as an antenatal screening tool for the detection of intrauterine growth retardation and fetal compromise 2097 singleton pregnancies were studied. Umbilical artery velocity waveforms were obtained at 28, 34, and 38 weeks of gestation, from which the pulsatility index, A/B ratio, and resistance parameter were calculated. No abnormal features or indices of neonatal outcome were adequately predicted. The most sensitive index for being delivered of a growth retarded infant (less than 5th centile birth weight for gestation) was an A/B ratio at 34 weeks (sensitivity 40%, specificity 84%). Other measures that show poor neonatal nutritional state (ponderal index, skinfold thickness, and ratio of mid-arm circumference to head circumference) were even less well predicted. Acute and chronic hypoxia as determined by Apgar score, pH in blood from the cord artery, and packed cell volume correlated poorly with umbilical artery waveform indices, and there was no obvious difference between the indices of those who subsequently required operative or instrumental delivery for fetal distress and those requiring no intervention. There were three unexplained stillbirths in the series, in each of which the fetus had shown waveform patterns that suggested increased peripheral resistance, though the technique did not appear to be useful for predicting the time of subsequent death. Screening for small for dates babies in a three stage programme was of no value regardless of the threshold or index chosen. Obstetricians should resist the temptation to introduce screening with Doppler ultrasonography until its proper role has been determined.

A comparison of fetal heart rate monitoring and umbilical artery waveforms in the recognition of fetal compromise

Antenatal fetal heart rate monitoring was compared with the study of umbilical artery flow velocity waveforms for the recognition of fetal compromise in 170 patients considered at high fetal risk. In 53 patients the infant had a 5-min Apgar score of less than 7 and/or a birthweight less than 10th centile of weight for gestation. Fetal heart rate traces were classified as reactive or non-reactive and also assessed with a modified Fischer score. The systolic/diastolic A/B ratio was measured in the umbilical artery waveform. Fetal compromise was more efficiently recognized by study of the umbilical artery waveforms. The sensitivity of assessment by umbilical artery waveforms was 60% compared with 17% and 36% respectively, for the two methods of scoring fetal heart rate traces. This was not associated with an increase in false-positive results as the predictive value of both positive (64% compared with 69 and 58%) and negative (83% compared with 72 and 75%) results was similar when umbilical artery waveform analysis was compared with the two methods of scoring fetal heart rate traces. Specificity was also similar (85% compared with 97 and 88%).

Fetal distress and the condition of newborn infants

In a prospective audit of the obstetric management of 1210 consecutive deliveries the association was investigated between the need for operative delivery for fetal distress during labour and the condition of the newborn infant. Operative delivery was performed for only 11.5% of the newborn infants with severe acidosis at birth (umbilical artery pH less than 7.12, base deficit greater than 12 mmol (mEq)/1), 24.1% of those with an Apgar score less than 7 at one minute, and 15.8% of those with both severe acidosis and a one minute Apgar score less than 7. Most of the infants delivered operatively were in a vigorous condition at birth and did not have severe acidosis. Fetal blood sampling was done in 4.0% of labours. As none of the fetal blood values were less than 7.20 and only three of the infants sampled in utero suffered severe acidosis at birth, fetal blood sampling would have had to be performed much more often to provide a useful guide to metabolic state at birth. While the large majority of "at risk" fetuses had continuous fetal heart rate monitoring in labour, this had not been provided in 48.7% of the labours of infants with severe acidosis, 38.7% of infants with a one minute Apgar score less than 7, and 47.4% of infants with both severe acidosis and a one minute Apgar score less than 7. Continuous fetal heart rate monitoring was associated with a much higher incidence of operative delivery for fetal distress than was intermittent fetal heart rate auscultation. These results suggest an urgent need to review present methods for assessing the intrapartum condition of the fetus, making the diagnosis of fetal distress, and assessing the condition of the infant at birth.