Fetal assessment based on fetal biophysical profile scoring: experience in 19,221 referred high-risk pregnancies. II. An analysis of false-negative fetal deaths

Duration of biophysical profile in periviable and very preterm low-risk pregnancies

BACKGROUND

In recent years, perinatal viability has shifted from 24 to 22 weeks of gestation at many institutions after improvements in survival in neonates delivered at the limit of viability. Monitoring these fetuses is essential because antenatal interventions with resuscitation efforts are available for patients at risk of delivery at the limit of viability. However, fetal monitoring using biophysical profiles has not been extensively studied in very preterm pregnancies, particularly in the periviable period (20 weeks 0 days to 23 weeks 6 days).

OBJECTIVE

This study aimed to (1) investigate whether the completion of biophysical profiles within 30 minutes is feasible in very preterm pregnancies, and (2) determine the average observation time required to achieve a score of 8 out of 8 in very preterm pregnancies from 20 weeks 0 days to 31 weeks 6 days.

STUDY DESIGN

This study prospectively evaluated biophysical scores in singleton pregnancies undergoing routine ultrasonography at or near viability from 20 weeks 0 days to 23 weeks 6 days (periviable or group I), 24 weeks 0 days to 27 weeks 6 days (group II), and 28 weeks 0 days to 31 weeks 6 days (group III). The results and duration of biophysical profiles were compared with those of a control group (32 weeks 0 days to 35 weeks 6 days) undergoing indicated fetal surveillance. Biophysical profiles were performed for all studied pregnancies until a score of 8 out of 8 was obtained. When >1 biophysical profile was obtained during pregnancy, each was analyzed individually. Pregnancies with fetal anomalies or obstetrical/medical indications for fetal well-being surveillance were excluded. Analysis of variance and post hoc Tukey tests were used for comparisons.

RESULTS

Data were collected for 123 participants, yielding 79, 75, and 72 studies for groups I, II, and III, respectively. The control group included 42 patients, yielding 140 studies. At 30 minutes, 80% (63/79) of the studies in the periviable group had a score of 8 out of 8, as opposed to 100% (140/140) in the control group (P<.001). The mean±standard deviation time in minutes to achieve a biophysical score of 8 out of 8 was 23.3±10.1 in the periviable group, as opposed to 9.4±6.5 in controls (P<.001). Extending the study to +2 standard deviations (43.6 minutes) in the periviable group resulted in 97% (77/79) of the scans scoring 8 out of 8 in the absence of adverse outcomes. In the other groups, a biophysical score of 8 out of 8 within 30 minutes was obtained in 97% (73/75) and 100% (72/72) in groups II and III, respectively; the mean±standard deviation times were 17.1±8.4 minutes (group II) and 13.1±7.3 minutes (group III). No adverse outcomes developed during the study participation in groups I to III.

CONCLUSION

Biophysical scores of 8 out of 8 can be successfully achieved in low-risk periviable pregnancies (20 weeks 0 days to 23 weeks 6 days) within an observation time longer than the standard 30-minute duration. The time required to reach a score of 8 out of 8 decreases as gestation progresses. We suggest adjusting the observation time for biophysical profile completion according to the gestational age.

The amniotic fluid index and oligohydramnios: a deeper dive into the shallow end

Second- and third-trimester obstetrical ultrasound examinations include an amniotic fluid volume assessment. Professional organizations' clinical guidance recommends using semiquantitative techniques, such as the single deepest vertical pocket or amniotic fluid index, for this purpose. The single deepest vertical pocket is described as the preferred method of assessing amniotic fluid volume based on fewer oligohydramnios diagnoses and labor inductions with no demonstrable difference in pregnancy outcomes compared with the amniotic fluid index. We offer an alternative interpretation of the evidence for this advice, drawn from 6 randomized clinical trials and 2 meta-analyses comparing the single deepest vertical pocket to the amniotic fluid index. Individually and collectively, these reports are underpowered to detect significant differences in maternal and perinatal outcomes by study group. Moreover, randomized clinical trials comparing maternal and perinatal outcomes resulting from a policy of labor induction at or beyond 37 weeks of gestation vs expectant care consistently favor labor induction, the very intervention paradoxically cited as favoring the single deepest vertical pocket vs the amniotic fluid index. We conclude that the amniotic fluid index should be considered a reasonable method for third-trimester amniotic fluid assessment and diagnosing oligohydramnios.

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.

Factors Associated with Occurrence of Stillbirth before 32 Weeks of Gestation in a Contemporary Cohort

OBJECTIVE

We sought to quantify the distribution of stillbirths by gestational age (GA) in a contemporary cohort and to determine identifiable risk factors associated with stillbirth prior to 32 weeks of gestation.

STUDY DESIGN

Population-based case-control study of all stillbirths in the United States during the year 2014, utilizing vital statistics data, obtained from the National Center for Health Statistics. Distribution of stillbirths were stratified by 20 to 44 weeks of GA, in women diagnosed with stillbirth in the antepartum period. Pregnancy characteristics were compared between those diagnosed with stillbirth <32 versus ≥32 weeks of gestation. Multivariate logistic regression estimated the relative influence of various factors on the outcome of stillbirth prior to 32 weeks of gestation.

RESULTS

There were 15,998 nonlaboring women diagnosed with stillbirth during 2014 in the United States between 20 and 44 weeks. Of them, 60.1% (n = 9,618) occurred before antenatal fetal surveillance (ANFS) is typically initiated (<32 weeks) and 39.9% (n = 6,380) were diagnosed at ≥32 weeks. Women with stillbirth prior to 32 weeks were more likely to be of non-Hispanic Black race (29.0 vs. 23.9%, p < 0.001), nulliparous (53.8 vs. 50.6%, p = 0.001), have chronic hypertension (CHTN; 6.0 vs. 4.3%, p < 0.001), and fetal growth restriction as evidenced by small for GA (SGA < 10th%) birth weight (44.8 vs. 42.1%, p < 0.001) as opposed to women with stillbirth after 32 weeks. After adjustment, SGA birth weight (adjusted odds ratio [aOR] = 1.2, 95% confidence interval [CI]: 1.1-1.3), Black race (aOR = 1.2, 95% CI: 1.1-1.3), and CHTN (aOR = 1.3, 95% CI: 1.1-1.5) were associated with stillbirth prior to 32 weeks of gestation as opposed to stillbirth after 32 weeks.

CONCLUSION

More than 6 out of 10 stillbirths in this study occurred <32 weeks of gestation, before ANFS is typically initiated under American College of Obstetricians and Gynecologists recommendations. Among identifiable risk factors, CHTN, Black race, and fetal growth restriction were associated with higher risk of stillbirth before 32 weeks of gestation. Earlier ANFS may be warranted at in certain "at risk" women.

KEY POINTS

· Six out of 10 stillbirths occur before 32 weeks of gestation.. · We evaluated factors associated with stillbirth <32 weeks.. · Hypertension and fetal growth restriction were associated with early stillbirth..

Antepartum Fetal Surveillance: ACOG Practice Bulletin, Number 229

The goal of antepartum fetal surveillance is to reduce the risk of stillbirth. Antepartum fetal surveillance techniques based on assessment of fetal heart rate (FHR) patterns have been in clinical use for almost four decades and are used along with real-time ultrasonography and umbilical artery Doppler velocimetry to evaluate fetal well-being. Antepartum fetal surveillance techniques are routinely used to assess the risk of fetal death in pregnancies complicated by preexisting maternal conditions (eg, diabetes mellitus) as well as those in which complications have developed (eg, fetal growth restriction). The purpose of this document is to provide a review of the current indications for and techniques of antepartum fetal surveillance and outline management guidelines for antepartum fetal surveillance that are consistent with the best scientific evidence.

Stillbirth: Evaluation and Follow-up

A systematic, effective stillbirth evaluation is important for identification of potential causes of fetal death. Knowledge of potential causes of fetal death facilitates emotional closure for patients and informs recurrence risk as well as future pregnancy management. The highest-yield components of a stillbirth evaluation for finding a cause of fetal death are fetal autopsy, placental pathology, and genetic testing. All patients should be offered these tests following a stillbirth. A clear plan for postpartum follow-up should be made with the patient in order to ensure ongoing support through the grief and recovery process.

Interventions to prevent stillbirth

Stillbirth is one of the most distressing complications of pregnancy and still occurs far too frequently. The rate of stillbirth has been decreasing worldwide but room for improvement remains even in high-income countries. Risk factors for stillbirth have been identified in an effort to detect those women at increased risk. However, risk factors are non-specific and do not identify most stillbirths. Strategies employed to screen the general population such as assessment of fetal activity, fetal growth screening and biomarkers have also been used to identify increased risk for stillbirth. As with clinical risk factors, these methods are non-specific. Interventions to prevent stillbirth include antenatal testing of high-risk women, ultrasonographic assessments of fetal growth and Doppler velocimetry as well as iatrogenic preterm or term delivery. Additional research into the role of these interventions and better identification of those at high risk for stillbirth will help to achieve further stillbirth reduction.

Progesterone and ultrasonographic changes during aglepristone or cloprosternol treatment in queens at 21 to 22 or 35 to 38 days of pregnancy

Progesterone (P₄) is a requirement for pregnancy development. Previous reports observed a maximal value of serum P₄ concentration on 21 days after the first mating after which it slowly declines throughout the rest of pregnancy. Ultrasound examination should be performed to ensure that pregnancy interruption is complete. Limited information is available on the ultrasonic appearance of conceptuses during pregnancy termination in cats The objective was to study serum P₄ concentration and ultrasonographic changes during aglepristone (ALI) or cloprostenol (CLO) treatment and to evaluate the fertility after treatment. Two experiments (EXP) were carried out to accomplish this aim. Sixty queens, 12- to 36-month-old, were used. On Days 21 to 22 of pregnancy (EXP I) or 35 to 38 of pregnancy (EXP II), queens were divided into three groups (G). Queens in G1 received ALI (10 mg/kg, sc; EXP I, n = 10; EXP II, n = 10) for 2 consecutive days. Queens in G2 received CLO (5 μg/kg, sc; EXP I, n = 10; EXP II = 10) for 3 consecutive days. Queens in G3 received 1 mL of saline solution (PLA, sc; EXP I, n = 10; EXP II = 10). Blood samples were taken before treatment (Day 0) and every day during 10 days after the treatment to measure serum P₄ concentrations. Likewise, after treatment, queens were monitored daily by ultrasonography for 10 days and weekly until the end of gestation to obtain gestational sacs measurements (GS), fetal measurements, and fetal biophysical profile. Data were analyzed by ANOVA. Serum P₄ concentrations were significantly different on Day 6 (EXP I) and on Day 1 (EXP II) in ALI and CLO groups compared with PLA group (P < 0.05 and P < 0.01; respectively). The ultrasonographic monitoring during treatment allowed assessing changes in the GS and fetal measurements, embryo-fetal viability, and risk of pregnancy loss. In conclusion, the results from this study reported changes in serum P₄ concentration and in ultrasonography measurements during pregnancy interruption with ALI or CLO treatment. Also it was observed that ALI and CLO are safe drugs and can preserve posttreatment queen fertility. Therefore, the results obtained in our work will be applied in feline reproduction practice.

The clinical and diagnostic utility of S100B in preterm newborns

Preterm birth is still the most important cause of perinatal mortality and morbidity. Follow-up studies showed that the majority of neurological abnormalities during childhood are already present in the first week after birth. In this light, the knowledge of the timing of the insult and/or of the contributing factors is of utmost relevance in order to avoid adverse neurological outcome. Notwithstanding, the considerable advances in perinatal clinical care and monitoring, the early detection of cases at risk for brain damage is still a challenge because, when radiological pictures are still negative, brain damage may be already at a subclinical stage, with symptoms hidden by therapeutic strategies. Thus, it could be very relevant to measure quantitative parameters, such as neuroproteins, able to detect subclinical lesions at a stage when routine brain monitoring procedures are still silent. In the last decade, the assay of the brain-specific protein S100B in different biological fluids proved useful information on brain function and damage in the perinatal period. Therefore, the present study provides an overview of the most recent findings on S100B role as a reliable marker of brain development/damage in preterm high risk fetuses and newborns.

Antepartum evaluation of the fetus and fetal well being

Despite widespread use of many methods of antenatal testing, limited evidence exists to demonstrate effectiveness at improving perinatal outcomes. An exception is the use of Doppler ultrasound in monitoring high-risk pregnancies thought to be at risk of placental insufficiency. Otherwise, obstetricians should proceed with caution and approach the initiation of a testing protocol by obtaining an informed consent. When confronted with an abnormal test, clinicians should evaluate with a second antenatal test and consider administering betamethasone, performing amniocentesis to assess lung maturity, and/or repeating testing to minimize the chance of iatrogenic prematurity in case of a healthy fetus.

Identification, assessment and management of fetal compromise

The main goals of fetal surveillance are to avoid fetal death and to recognize the fetus that will benefit from early intervention with resuscitation or delivery. Surveillance can occur in the antepartum or intrapartum period. Continuous fetal heart rate monitoring is the most common form of surveillance in the intrapartum period. Several techniques are used in the antepartum period, including nonstress test, biophysical profile, and contraction stress test. Multiple techniques are used once distress is noted in the fetus, with the ultimate resuscitation effort being delivery.

Fetal assessment during pregnancy

Fetal monitoring during pregnancy is used to prevent fetal death. This article addresses the goals of fetal monitoring during pregnancy. Methods of fetal surveillance are reviewed, as well as the meaning of abnormal fetal testing and how these results relate to fetal and neonatal outcome. Overall, pediatricians who understand the goals, methods, and interpretation of fetal testing can communicate more effectively with the delivering obstetric team in anticipation of optimizing obstetric and pediatric outcomes.

Antenatal testing-a reevaluation: executive summary of a Eunice Kennedy Shriver National Institute of Child Health and Human Development workshop

In August 2007, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institutes of Health Office of Rare Diseases, the American College of Obstetricians and Gynecologists, and the American Academy of Pediatrics cosponsored a 2-day workshop to reassess the body of evidence supporting antepartum assessment of fetal well-being, identify key gaps in the evidence, and formulate recommendations for further research. Participants included experts in obstetrics and fetal physiology and representatives from relevant stakeholder groups and organizations. This article is a summary of the discussions at the workshop, including synopses of oral presentations on the epidemiology of stillbirth and fetal neurological injury, fetal physiology, techniques for antenatal monitoring, and maternal and fetal indications for monitoring. Finally, a synthesis of recommendations for further research compiled from three breakout workgroups is presented.

Nomograms of Iranian fetal middle cerebral artery Doppler waveforms and uniformity of their pattern with other populations' nomograms

BACKGROUND

Doppler flow velocity waveform analysis of fetal vessels is one of the main methods for evaluating fetus health before labor. Doppler waves of middle cerebral artery (MCA) can predict most of the at risk fetuses in high risk pregnancies. In this study, we tried to obtain normal values and their nomograms during pregnancy for Doppler flow velocity indices of MCA in 20-40 weeks of normal pregnancies in Iranian population and compare their pattern with other countries' nomograms.

METHODS

During present descriptive cross-sectional study, 1037 normal pregnant women with 20th-40th week gestational age were underwent MCA Doppler study. All cases were studied by gray scale ultrasonography initially and Doppler of MCA afterward. Resistive Index (RI), Pulsative Index (PI), Systolic/Diastolic ratio (S/D ratio), and Peak Systolic Velocity (PSV) values of MCA were determined for all of the subjects.

RESULTS

Results of present study showed that RI, PI, S/D ratio values of MCA decreased with parabolic pattern and PSV value increased with simple pattern, as gestational age progressed. These changes were statistically significant (P=0.000 for all of indices) and more characteristic during late weeks of pregnancy.

CONCLUSION

Values of RI, PI and S/D ratio indices reduced toward the end of pregnancy, but PSV increased. Despite the trivial difference, nomograms of various Doppler indices in present study have similar pattern with other studies.

Antenatal testing--benefits and costs

Antenatal testing is a common component of care for the high-risk pregnancy. The goals of antenatal testing include the prevention of stillbirth and the detection of the hypoxic fetus to allow intervention before acidosis and long-term damage. Data regarding the efficacy of antenatal testing are limited by a lack of randomized controlled trials. The majority of available data hinge on observational studies with the inherent potential for bias. There is also a paucity of data comparing the various testing modalities and addressing the issue of the optimal timing of initiation of testing. As well, data are limited regarding the various conditions most likely to benefit from testing and the frequency with which testing should be performed. The issue of cost relating to antenatal testing is an important one. Central to the issue of estimating cost is an understanding of the efficacy of the test. Given our current limitations, we have significant difficulty accurately estimating the cost of antenatal testing; however, rough estimates of cost are made.

Postdates and antenatal testing

The standard definition of a prolonged pregnancy is 42 completed weeks of gestation. The incidence of prolonged pregnancy varies depending on the criteria used to define gestational age at birth. It is estimated that 4 to 19% of pregnancies reach or exceed 42 weeks gestation. Several studies that have used very large computerized databases of well-dated pregnancies provided insights into the incidence and nature of adverse perinatal outcome such as an increased fetal and neonatal mortality as well as increased fetal and maternal morbidity in prolonged pregnancy. Fetal surveillance may be used in an attempt to observe the prolonged pregnancy while awaiting the onset of spontaneous labor. This article reviews the different methodologies and protocols for fetal surveillance in prolonged pregnancies. On the one hand, false-positive tests commonly lead to unnecessary interventions that are potentially hazardous to the gravida. On the other hand, to date, no program of fetal testing has been shown to completely eliminate the risk of stillbirth.

Fetal extremity kinetics quantified with Doppler ultrasonography

AIMS

To assess the responsive fetal extremity movement to vibro-acoustic stimulation test (VAST).

METHODS

The moving velocity of fetal femur was assessed after VAST by pulsed Doppler device. The ultrasonic beam was insonated at a right angle to the fetal femur. The following parameters were determined: limb retreat velocity in accelerative slope (Pk1); limb replenishment velocity in decelerative slope (Pk2); mean flexion to extension velocity; and the response time to VAST. Among 80 normal singleton pregnancies in 33-41 weeks, 68 were weekly evaluated and the others were assessed for two or more times during the study period, for a total of 680 studies of fetal kinetics.

RESULTS

The Pk1 declined from 9.6 to 6.26 cm/s; Pk2 decreased from 2.6 to 1.3 cm/s; mean velocity was reduced from 6.0 to 4.25 cm/s; whereas the response time increased from 0.1 to 0.3 s throughout the study period, i.e., fetal response reduces and the response time increases as maturation progresses.

CONCLUSION

The pulsed Doppler may assess fetal activity in any body structure. Reflex responses become slow and complex on both the velocity and response time as maturation increases with gestational age. Our observations have resulted in a novel and easy method for the quantitative assessment of fetal reflex reactivity to external stimuli.

Obstetric considerations in the management of pregnancy in kidney transplant recipients

Kidney transplant improves reproductive function; planning for pregnancy is crucial. Prenatal management must address potential fetal complications: preterm delivery, intrauterine growth restriction, low birth weight; as well as maternal: hypertension, preeclampsia, gestational diabetes, acute rejection or graft loss. The latter depends upon timing after transplant, prepregnancy kidney function, and continuation of immunosuppressive agents at appropriate levels. Graft function is not adversely affected if preconception kidney function was normal. Acute rejection, 9%-14%, must be immediately addressed, with kidney biopsy if necessary. Blood pressure should be meticulously managed; serious morbidity results from poor control. Blood pressures >130/80 mmHg require acceptable antihypertensives: beta-blockers, alpha-methyldopa, hydralazine, and calcium channel blockers. Preeclampsia requires seizure prophylaxis with magnesium sulfate, with expeditious delivery. Screening for urinary tract infections with aggressive treatment and for opportunistic infections that may affect the fetus is essential. Surveillance for fetal anomalies, growth, and antenatal testing is important. Steroids for fetal lung maturity are indicated for preterm delivery. Vaginal birth is preferred, reserving cesarean for obstetrical indications, with pain management similar to normal laboring patients. Surveillance for infection postpartum is warranted. Conflicting information exists regarding safety of breastfeeding with immunosuppressive drugs; immunosuppressive medication must be adjusted to prepregnancy levels and contraception counseling addressed.

Vibroacoustic stimulation in abnormal biophysical profile: verification of facilitation of fetal well-being

OBJECTIVES

To verify the effect of vibroacoustic stimulation on biophysical profile score, with a prospective randomised study.

STUDY DESIGN

All women with singleton pregnancy, gestational age >or=30 weeks, intact membranes and biophysical profile score <or=8/10 entered the study, after giving written consent, and were randomised to two groups. In group A, a 3-s stimulus with an artificial larynx was applied; if biophysical profile remained abnormal for 30 min, a second stimulus was applied and it was assessed again. In group B, the observation time was extended for 60 min to match the time periods of group A. Pregnancies were managed by final test score and patients delivering more than 24 h apart from last examination were disregarded from the study. Outcome criteria were intrauterine deaths, caesarean sections for fetal distress, Apgar score <7 at 5 min postpartum, meconium-stained amniotic fluid and neonatal intensive care unit admissions. Our null hypothesis was that application of vibroacoustic stimulation does not alter test's statistical parameters.

RESULTS

1349 patients were randomised in group A and 1484 in group B (2833 in total). When comparing group A to B, application of vibroacoustic stimulation significantly decreased the number of positive tests (4.74% vs. 6.67%, p<0.05) and increased the prevalence of outcome criteria in this subgroup (positive likelihood ratio: 24.1 95% CI: 11.12-52.46 vs. 7.52 95% CI: 4.93-11.46), without altering perinatal outcome. Furthermore, specificity, positive predictive value and test accuracy were significantly improved, as well as negative predictive value for intrauterine death.

CONCLUSION

Vibroacoustic stimulation improves the efficiency of biophysical profile score by decreasing false positive tests and improving test accuracy and should be considered as a means of a more thorough fetal evaluation when fetal compromise is suspected.

Management of Fetal Growth Restriction: An Evidence-Based Approach

This review provides an evidence-based approach to the management of fetal growth restriction (FGR). The management consists of the following components: appropriate fetal surveillance, timely intervention, and selective etiological management. Umbilical arterial (UA) Doppler sonography is the primary test. Supplementary tests include nonstress test (NST), amniotic fluid assessment, biophysical profile (BPP), and selective venous Doppler sonography. Ominous signs include UA absent or reverse end-diastolic flow, non-assuring NST, low BPP, and abnormal fetal venous flow patterns. An evidence-based clinical management guideline is included and individualization of care is recommended.

Use of umbilical-cerebral Doppler ratios in predicting fetal growth restriction in near-term fetuses

OBJECTIVE

To compare the sensitivity and specificity of different umbilical-cerebral ratios in the prediction and detection of fetal growth restriction in near-term fetuses when the umbilical arterial waveform is within normal.

METHODS

A prospective cross-sectional observational study was carried out recruiting consecutive singleton pregnancies with clinically suspected fetal growth restriction after 34 weeks gestation. The umbilical-cerebral ratios were then calculated from the S/D, RI and PI values and correlated with immediate perinatal outcome.

RESULTS

A total of 187 patients were recruited. Twelve cases had abnormal UA Doppler flow velocity waveform studies. Of the 175 with normal UA Doppler findings, 92 (53.1%) were confirmed to have fetal growth restriction (FGR) with birth weights below the tenth centile for gestation. The detection rate of FGR by ultrasound biometry was 96.7%. The mean umbilical artery S/D, RI and PI values were higher in the fetal growth restriction group, while the middle cerebral artery values were lower as compared to fetuses with no growth restriction. A small but significant difference was seen in the umbilical-cerebral ratios of the different indices between the two groups. Receiver operator characteristic curves showed that there was little difference between the performances of the S/D, RI or PI ratios and all had limited power in predicting fetal growth restriction.

CONCLUSION

In the presence of normal umbilical artery Doppler waveforms, umbilical-cerebral ratios have limited power to predict fetal growth restriction.

Comparison of fetal behavior in low- and high-risk pregnancies

Meta-analyses were conducted on archival data of human fetal behavior to identify differential behavior among high-risk fetuses in pregnancies complicated by threatened preterm delivery, maternal hypertension or diabetes compared with low-risk fetuses in uneventful pregnancies, delivering as healthy, full-term infants. Data for a total of 493 fetuses (260 high risk, 233 low risk) from 23 weeks' gestation to term who participated in a study using a standardized protocol including observations of spontaneous and auditory-induced behavior were retrieved from our laboratory database. There were no differences in spontaneous behaviors when scored using clinical criteria for the nonstress test and biophysical profile; however, there were differences in the magnitude of the behaviors measured in the tests. Developmental differences were observed between those threatening to deliver early and the fetuses of hypertensive and diabetic mothers. The latter two groups differed little from one another but differed from low-risk fetuses in their response to auditory stimulation. We concluded that differences in behavior among high-risk groups suggest that atypical fetal behaviors may represent adaptation to condition specific insult rather than a generalized response to insult per se. The finding that high-risk fetuses showed atypical responses to auditory stimuli indicates a need to examine the relation between fetal auditory function and later language acquisition.

Uterine and fetal cerebral Doppler predict the outcome of third-trimester small-for-gestational age fetuses with normal umbilical artery Doppler

OBJECTIVE

To assess the value of different admission tests in predicting the outcome of small-for-gestational age (SGA) fetuses with normal Doppler waveforms in the umbilical artery.

METHODS

Criteria for admission into this retrospective study included: singleton pregnancy with a birth weight < 10th centile; absence of severe maternal complications; no evidence of fetal anomalies on the sonogram; normal umbilical artery Doppler; and availability of complete follow-up. At the first antenatal sonogram classifying the fetus as SGA, Doppler analysis of the uterine and middle cerebral arteries was performed and amniotic fluid volume was assessed. Outcome variables included adverse perinatal outcome (perinatal death, severe morbidity) and emergency Cesarean section for fetal distress.

RESULTS

Two hundred and thirty-one pregnancies were included in the study. The mean +/- standard deviation birth weight and gestational age at delivery were 2222 +/- 502 g and 37.3 +/- 2.9 weeks, respectively. In 37 cases (16%), an emergency Cesarean section was performed. There was one intrauterine death and three fetuses delivered by emergency Cesarean section developed severe morbidity. Logistic regression demonstrated that abnormal velocimetry of the uterine arteries and fetal middle cerebral artery were independently correlated with the occurrence of Cesarean section.

CONCLUSIONS

SGA fetuses with normal umbilical artery Doppler waveforms and abnormal uterine arteries and fetal middle cerebral artery waveforms have an increased risk of developing distress and being delivered by emergency Cesarean section. Particularly when both uterine and fetal cerebral waveforms are altered at the same time, the risk is exceedingly high (86%) and delivery as soon as fetal maturity is achieved seems advisable. On the other hand, when both vessels have normal waveforms, the chances of fetal distress are small (4%) and expectant management is the most reasonable choice.

Comparison study between induced and spontaneous term and preterm births of small-for-gestational-age neonates

OBJECTIVE

To compare perinatal and maternal outcome between induced and spontaneous small-for-gestational-age (SGA) neonates at term and preterm deliveries.

STUDY DESIGN

A cross-sectional study was designed and two groups were identified at each gestational age: study group - SGA neonates born after induction of labor, comparison group - SGA neonates born after spontaneous onset of labor. SGA was decoded as birth weight below 10th percentile. The population consisted of 367 consecutive SGA singleton preterm neonates (24-36 weeks' gestation) and 3921 term SGA neonates (37-42 weeks' gestation) delivered between 1990 and 1997. Patients with antepartum death and congenital anomalies were excluded from this study.

RESULTS

The prevalence of SGA neonates among preterm deliveries was significantly higher than among term deliveries (9.3 versus 6.1%, P<0.001). The rate of induction of labor among preterm SGA deliveries was significantly higher than term SGA deliveries (17.7 versus 13.4%, P=0.002). The rates hypertensive disorders, suspected IUGR, placental abruption, cesarean section, chorioamnionitis and endometritis were significantly higher among preterm SGA than in term SGA. A multiple logistic regression analysis demonstrated that suspected IUGR, severe PIH (but not mild PIH), chronic hypertension and placental abruption were independent risk factors for induction of labor among preterm SGA neonates. In addition to these factors, oligohydramnios was considered to be an independent risk factor only among term SGA. No significant differences were found in the mean birthweight and post-partum death rates between the induced and spontaneous preterm and term SGA. The incidence of Apgar score < 7 at 5 min was significantly lower only among induced term SGA.

CONCLUSIONS

Induction of labor in preterm SGA neonates is performed mainly due to maternal severe hypertension disorders. The indications for induction of labor among term SGA include maternal hypertensive disorders (mild or severe) as well as neonatal status, represented mainly by oligohydramnios. In addition, induction of labor in preterm or term SGA neonates does not change neonatal outcome. Moreover, since no evidence of improved neonatal outcome was demonstrated in either indicated group, preterm or term, the question of timing and indications for induction of labor should be discussed.

Effect of antenatal steroid administration on the fetal biophysical profile

PURPOSE

Our objective was to determine whether antenatal steroid administration affects the biophysical profile score in fetuses.

METHODS

A prospective study was conducted in 84 fetuses between 28 and 34 weeks' menstrual age at risk of preterm delivery. Two intramuscular injections of 12 mg of betamethasone were given to the mother 24 hours apart. All fetuses underwent biophysical profile testing prior to and between 24 and 48 hours after steroid administration. Biophysical profiles (including nonstress tests) were evaluated by two maternal-fetal medicine specialists blinded to the timing of steroid administration. Neonatal outcome, including Apgar score, menstrual age at delivery, admission to and length of stay in the neonatal intensive care unit, and mortality, was analyzed in all subjects.

RESULTS

In 31 (37%; 95 confidence interval, 26.6-47.2%) of 84 cases, the biophysical profile score decreased at least 2 points after steroid administration. The most commonly affected variables were fetal breathing and the nonstress test. There was no significant difference in the neonatal outcome between the fetuses whose biophysical profile decreased and those whose did not.

CONCLUSIONS

Biophysical profile scores were decreased in more than one third of fetuses within 48 hours of antenatal steroid administration, but neonatal outcome was not affected. Knowledge of this occurrence could avoid incorrect decision making regarding fetal well-being.

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.

Fetal death after normal biophysical profile score: An eighteen-year experience

OBJECTIVE

It was our goal to determine the false-negative rate of the biophysical profile, characterize an 18-year variation in the false-negative rate, examine the relationship between the last normal biophysical profile score and death, and compare the false-negative rate of 2 disparate populations.

STUDY DESIGN

Biophysical profile scores of 86,955 patients at 2 medical centers were collected and recorded prospectively. All perinatal deaths occurring within 1 week of a normal score were similarly recorded. The annual false-negative rate, the cumulative false-negative rate, and the ratio of false-negative results in cases of subsequent fetal death to the perinatal mortality rate were calculated.

RESULTS

There were 65 fetal deaths among 86,955 fetuses. Over an 18-year study period at one institution, the false-negative rate varied but not significantly. The cumulative false-negative rate was 0.708 per 1000 at one medical center studied and 2.289 per 1000 at the other center. The average interval between last normal score and fetal death was 3.62 days and did not vary significantly between the medical centers.

CONCLUSIONS

False-negative results in cases of subsequent fetal death reflect events that are subsequent to the last normal test result. Fetomaternal hemorrhage was the single most identifiable fetal cause of false-negative results in cases of subsequent fetal death. The ratio of the false-negative rate in cases of subsequent fetal death to the perinatal mortality rate should be used as a more objective approach to reporting this value, because the false-negative rate likely reflects the underlying perinatal mortality.

Maturation of body and breathing movements in 24-33 week-old fetuses threatening to deliver prematurely

Maturation of spontaneous fetal body and breathing movements of 24- to 33-week-old fetuses in 168 pregnancies threatening to deliver prematurely were examined on the basis of newborn outcome (premature compromised, premature healthy, term healthy). Maturation of fetuses in 60 low-risk pregnancies delivering as healthy full-term infants served as a normative comparison group. Each fetus was observed for 30 min; the amount of body and breathing movements were noted and an estimation of amniotic fluid volume was made. The pattern of behavioural maturation was similar for all outcome groups; with advancing gestation there was a decrease in body movements and an increase in breathing movements. Both reduced activity levels and advanced behaviours were observed in the high-risk outcome groups. The high-risk fetuses had reduced levels of body movements which increased with better outcome and, an earlier onset of increased amounts of breathing, occurring at 30 weeks in contrast to 33 weeks for the comparison group. In the presence of ruptured membranes, those high-risk fetuses who were born prematurely had less breathing compared to those who delivered at term. Similar maturation patterns among high- and low-risk outcome groups suggests normal/typical functional development in the high-risk fetal groups. The observed differential behaviours were associated with prematurity and most likely associated with events leading to premature labour.

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.

Antepartum fetal surveillance in patients with diabetes: when to start?

OBJECTIVE

Although antepartum fetal well-being testing is an accepted practice in the management of diabetic patients, there are few data suggesting when to start. Our goal was to examine when testing should be started in the pregnant diabetic woman.

STUDY DESIGN

Antepartum test results and patient histories were prospectively collected on all diabetic pregnancies from January 1981 through December 1991. The data were retrospectively analyzed for when fetal compromise became evident. Fetal compromise was defined as stillbirth, first positive contraction stress test, or intervention because of an abnormal antepartum fetal test result.

RESULTS

Six hundred fourteen patients were enrolled in the study. There were three stillbirths, 45 (7.4%) patients had at least one positive contraction stress test, and 71 (11.6%) patients were delivered because of an abnormal fetal test result. Those with early compromise (< or = 34 weeks' gestation) could not be identified solely by diabetic class. The majority of patients (73%) requiring early intervention because of an abnormal test were class R or F diabetic patients with a growth-retarded fetus or were patients who had a concomitant diagnosis of hypertension.

CONCLUSIONS

Class R or F diabetic patients or diabetic patients with a growth-retarded fetus or a concomitant diagnosis of hypertension may require testing to be started as early as 26 weeks' gestation. Otherwise, testing may be safely delayed until 32 weeks' gestation.

Electrocortical activity, electroocular activity, and breathing movements in fetal sheep with prolonged and graded hypoxemia

OBJECTIVE

Our objective was to determine the effect of a prolonged and graded reduction in fetal arterial oxygen saturation on electrocortical activity and associated biophysical variables.

STUDY DESIGN

Fourteen unanesthetized fetal sheep were studied between 126 and 135 days' gestation with continuous monitoring of electrocortical and electroocular activity and breathing movements, during a 24-hour control period, and subsequently during 4 days of prolonged and graded hypoxemia induced by progressively lowering the maternal inspired oxygen concentration.

RESULTS

Graded reduction in fetal arterial oxygen saturation resulted in little change in arterial pH until close to 30% when metabolic acidemia was apparent. The incidence of low-voltage electrocortical activity, electroocular activity, and breathing movements were marginally decreased with hypoxemia alone; however, a significant decrease was not apparent until associated with the onset of fetal acidemia.

CONCLUSION

Hypoxemia of a chronic nature must approach the level at which acidemia becomes apparent before a marked change in fetal behavioral activity is noted.

Antepartum testing in the hypertensive patient: when to begin

Antepartum testing has been recommended for patients whose pregnancies are complicated by hypertension. Although this is considered accepted practice, there are little data available to help the clinician know when to start testing. To help answer this question in patients with chronic hypertension and nonproteinuric pregnancy-induced hypertension, we reviewed the results of all antepartum tests between 1976 and 1987 in patients with these diagnoses. The primary mode of surveillance in the majority of our patients was the contraction stress test. We determined when patients first had positive contraction stress test results and when intervention occurred because of an abnormal antepartum test result. There were a total of 917 patients tested with these diagnoses. Fifty-three (5.8%) of these patients had at least one positive contraction stress test result. Twenty-two patients were delivered of infants before 35 weeks' gestation because of abnormal antepartum test results. Those with early intervention (less than 35 weeks' gestation) could not be differentiated from those with later intervention (greater than or equal to 35 weeks' gestation) by maternal age, diastolic blood pressure, or systolic blood pressure at the time of testing. The majority of patients who were delivered of infants before 35 weeks' gestation had a concomitant diagnosis of systemic lupus erythematosus, intrauterine growth retardation, diabetes mellitus, or superimposed preeclampsia. On the basis of when compromise was evident, patients with these diagnoses may require testing to be started as early as the fetus is considered viable. However, in those without these diagnoses, the clinician may delay the beginning of testing until 33 weeks' gestation without significant risk of pregnancy loss before testing.

The value of cordocentesis in management of patients with severe preeclampsia

Severe preeclampsia affects placental function and causes fetal compromise. It is necessary to deliver the fetus at an appropriate time in order to minimize fetal mortality and morbidity. Cordocentesis was performed in 9 patients with severe preeclampsia (group 1) and 10 patients with other pregnancy complications (group 2). Intrauterine growth retardation occurred in 5 patients in group 1 and in only one patient in group 2. Blood gas parameters including pH, pO2 and O2 saturation were significantly lower for group 1, while pCO2 was significantly higher, as compared to group 2. For patients in group 1, non-invasive fetal surveillance successfully identified 5 patients with fetal compromise, who required immediate termination of pregnancy. All 5 of these patients had abnormal fetal blood gas analyses by cordocentesis. Fetal blood gas analysis was abnormal in 2 additional fetuses among the remaining 4 patients who exhibited normal findings by non-invasive methods of fetal surveillance. These results suggest that cordocentesis is useful in identifying fetal compromise (fetal hypoxia/acidosis) prior to the onset of labor in high-risk patients, such as preeclampsia associated with intrauterine growth retardation.

Fetal well-being: nonimaging assessment and the biophysical profile

All of the testing methods described above are very good at predicting continued fetal health when test results are reassuring. Each test also suffers from a very poor ability to predict compromise when results are abnormal. Thus, the primary value of antepartum fetal monitoring is in identifying those pregnancies that do not require immediate intervention and may be allowed to continue. Certainly, all pregnant women (regardless of risk status) should monitor fetal movement as part of their fetal surveillance. For patients at risk, a variety of testing schemes are available using combinations of the NST, CST and BPP. There are several reasons for using the NST as the primary testing method for those at risk. Even a small antenatal testing area can accommodate three or four FHR monitors, and a single antenatal testing nurse can perform several NSTs at a time. Because the BPP requires an ultrasound machine and a trained technician to perform, and because only one BPP can be done at a time, many obstetricians who do their own in-office fetal testing are unable to adopt BPP testing as their primary means of surveillance. Additionally, it is more economical to use the NST than the BPP for first-line testing. Assuming charges of $150 and $300 for the NST and BPP, respectively, and assuming that 20% of NSTs are nonreactive and require a BPP for second-line testing, the weekly cost of testing 100 patients is $21,000 for the NST and $37,500 for the BPP. This increase-in-testing cost must be balanced against the small improvement in perinatal mortality rates achieved with the use of the BPP. Because it must be performed in a hospital setting and takes an average of 90 minutes to complete, the CST is more expensive and time-consuming than either the NST or BPP and it is less frequently used as the primary method of fetal testing. In the past the CST was the most commonly used secondary test after a nonreactive NST, but use of the BPP in this situation has now become commonplace. Although the CST still has an important role in fetal testing, the BPP is better suited for use in this setting because of its technical ease and low incidence of abnormal results. Thus, many centers use the NST as the primary mode of testing for the fetus at risk, often with a sonographic assessment of AFV.(ABSTRACT TRUNCATED AT 400 WORDS)