Contraction stress test versus ductus venosus Doppler evaluation for the prediction of adverse perinatal outcome in growth-restricted fetuses with non-reassuring non-stress test

Fetal Assessment in Pregnancy (Indication and Methodology for Fetal Monitoring in a low-risk Population). Guideline of the DGGG, DEGUM, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/089, February 2023)

PURPOSE

 The aim of this guideline was to find evidence on whether carrying out Doppler examinations and CTGs in low-risk cohorts of pregnant women improves outcomes.

METHODS

 First, a systematic search for guidelines was carried out. Identified guidelines were evaluated using the DELPHI instrument of the AWMF. Three guidelines were found to be suitable to evaluate CTG. Two DEGUM best practice guidelines were judged suitable to describe the methods. All studies on this issue were additionally analyzed using 8 PICO questions. A structured consensus of the participating professional societies was achieved using a nominal group process and a structured consensus conference moderated by an independent moderator.

RECOMMENDATIONS

 No antepartum Doppler sonography examinations should be carried out in low-risk cohorts in the context of antenatal care. No antepartum CTG should be carried out in low-risk cohorts. NOTE:  The guideline will be published simultaneously in the official journals of both professional societies (i. e., Geburtshilfe und Frauenheilkunde for the DGGG and Ultraschall in der Medizin/European Journal of Ultrasound for the DEGUM).

Fetal Assessment in Pregnancy (Indication and Methodology for Fetal Monitoring in a Low-risk Population). Guideline of the DGGG, DEGUM, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/089, February 2023)

Purpose The aim of this guideline was to find evidence on whether carrying out Doppler examinations and CTGs in low-risk cohorts of pregnant women improves outcomes. Methods First, a systematic search for guidelines was carried out. Identified guidelines were evaluated using the DELPHI instrument of the AWMF. Three guidelines were found to be suitable to evaluate CTG. Two DEGUM best practice guidelines were judged suitable to describe the methods. All studies on this issue were additionally analyzed using 8 PICO questions. A structured consensus of the participating professional societies was achieved using a nominal group process and a structured consensus conference moderated by an independent moderator. Recommendations No antepartum Doppler sonography examinations should be carried out in low-risk cohorts in the context of antenatal care. No antepartum CTG should be carried out in low-risk cohorts. Note The guideline will be published simultaneously in the official journals of both professional societies (i.e., Geburtshilfe und Frauenheilkunde for the DGGG and Ultraschall in der Medizin/European Journal of Ultrasound for the DEGUM).

Cerebroplacental Ratio Versus Nonstress Test in Predicting Adverse Perinatal Outcomes in Hypertensive Disorders of Pregnancy: A Prospective Observational Study

Introduction: In developing countries, nonstress test (NST) is the most widely used method for antenatal fetal surveillance.Lately, cerebroplacental ratio (CPR) has emerged as a predictor for adverse perinatal outcomes, especially in hypertensive disorders in pregnancy (HDP). Against this background, the present study was conducted with the primary objective of quantifying the diagnostic accuracy of cerebroplacental ratio (CPR) versus nonstress test (NST) in predicting adverse perinatal outcomes in women with HDP.

Methods: This was a prospective observational cohort study conducted in a tertiary care institute in eastern India. All consecutive women with hypertension in pregnancy at a gestational age of ≥32 weeks were recruited into the study. Both CPR and NST were performed at baseline and repeated weekly till delivery. The parameters obtained within one week of delivery were entered for analysis.

Results: Sixty-two of the 65 women completed the study. There were 22 women (35.5%) in group A (both CPR and NST normal), 17 (27.4%) in group B (CPR abnormal, NST normal), 14 (22.6%) in group C (CPR normal and NST abnormal), and nine (14.5%) in group D (both CPR and NST abnormal). CPR had greater sensitivity (93.33% versus 46.67%), with higher positive predictive value (53.85% versus 30.43%), specificity (74.47% versus 65.91%), and negative predictive value (97.22% versus 79.49%) than NST for predicting neonatal intensive care unit admission. CPR also had higher sensitivity (84.62% versus 61.54%) and specificity (91.34% versus 69.39%) than NST in predicting neonatal complications. The negative predictive value (NPV) of CPR was 100% for predicting requirement of bag and mask ventilation and continuous positive airway pressure.

Conclusion: CPR had greater diagnostic accuracy in terms of both higher sensitivity and greater specificity than NST in predicting adverse perinatal outcomes in women with hypertensive disorders of pregnancy.

The Present Utility of the Oxytocin Challenge Test-A Single-Center Study

Introduction: The oxytocin challenge test (OCT) used to be one of the most important tools in assessing fetal well-being before ultrasonography became prevalent. We show that, after modifying the classification of the results and the intervention algorithm, OCT can still be a useful tool in present-day obstetrics. Material and methods: The study included 318 OCTs performed in patients admitted to our department from 2010 to 2012. A modified classification of test results was introduced, dividing the results in four groups: I-negative, II-positive, III-non-diagnostic and type IV (fetal tachycardia or increased variability). The purpose of the study was to evaluate the clinical significance of OCT in assessing intrauterinal fetal well-being and predicting the necessity for ending the pregnancy. Results: A significant difference (p < 0.001) in the delivery method and the indications for cesarean sections (CS) was found between negative and positive OCT results. CS indicated by an abnormal fetal heart rate (FHR) pattern had to be performed in 40% of cases with positive OCT results, having constituted 84.6% of all CSs in this group. After negative OCTs, 12.8% pregnancies were ended by CS from FHR indications (62.3% of all the indications). Conclusions: A positive OCT result can be a valuable predictor of an abnormal fetal heart rate pattern after the test and during the delivery, as well as a higher probability of a CS from cardiotocography (CTG) indications, with positive predictive value (PPV) 0.50 and negative predictive value (NPV) 0.85.

No. 197a-Fetal Health Surveillance: Antepartum Consensus Guideline

OBJECTIVE

This guideline provides new recommendations pertaining to the application and documentation of fetal surveillance in the antepartum period that will decrease the incidence of birth asphyxia while maintaining the lowest possible rate of obstetrical intervention. Pregnancies with and without risk factors for adverse perinatal outcomes are considered. This guideline presents an alternative classification system for antenatal fetal non-stress testing to what has been used previously. This guideline is intended for use by all health professionals who provide antepartum care in Canada.

OPTIONS

Consideration has been given to all methods of fetal surveillance currently available in Canada.

OUTCOMES

Short- and long-term outcomes that may indicate the presence of birth asphyxia were considered. The associated rates of operative and other labour interventions were also considered.

EVIDENCE

A comprehensive review of randomized controlled trials published between January 1996 and March 2007 was undertaken, and MEDLINE and the Cochrane Database were used to search the literature for all new studies on fetal surveillance antepartum. The level of evidence has been determined using the criteria and classifications of the Canadian Task Force on Preventive Health Care (Table 1).

SPONSOR

This consensus guideline was jointly developed by the Society of Obstetricians and Gynaecologists of Canada and the British Columbia Perinatal Health Program (formerly the British Columbia Reproductive Care Program or BCRCP) and was partly supported by an unrestricted educational grant from the British Columbia Perinatal Health Program. RECOMMENDATION 1: FETAL MOVEMENT COUNTING: RECOMMENDATION 2: NON-STRESS TEST: RECOMMENDATION 3: CONTRACTION STRESS TEST: RECOMMENDATION 4: BIOPHYSICAL PROFILE: RECOMMENDATION 5: UTERINE ARTERY DOPPLER: RECOMMENDATION 6: UMBILICAL ARTERY DOPPLER.

Hypercoiled cord can cause a reversible abnormal Doppler in ductus venosus in cases of fetal growth restriction

AIM

Although an absent or reversed a-wave in ductus venosus (DV-RAV) is reported to be the terminal finding of fetal growth restriction (FGR), we have seen DV-RAV that disappears within a short span of time in some FGR cases with a hypercoiled cord. The purpose of this study was to investigate the relationship between hypercoiled cord and reversible DV-RAV in FGR.

METHODS

This was a retrospective study of 499 FGR cases, including 14 with DV-RAV. Transabdominal amnioinfusion (AI) was performed when oligohydramnios was severe (maximum vertical pocket <2 cm) and/or variable deceleration was detected. DV-RAV that disappeared quickly was defined as 'temporary DV-RAV'. DV-RAV that continued until delivery or fetal death (FD) was defined as 'persistent DV-RAV'. A hypercoiled cord was defined as one with an umbilical coiling index >0.6 antenatally or >0.3 postnatally. Clinical characteristics and clinical courses of the two types of DV-RAV were compared.

RESULTS

DV-RAV disappeared after AI in all five cases in which temporary DV-RAV was identified. The incidence of a hypercoiled cord was significantly higher among temporary DV-RAV cases (100%) than among persistent DV-RAV cases (14.3%; P = 0.015). The time from detection of DV-RAV to delivery or FD was significantly longer among temporary DV-RAV cases (4.5 weeks) than among persistent DV-RAV cases (0.7 weeks; P = 0.027).

CONCLUSION

Temporary DV-RAV is suspected to be related to the combination of a hypercoiled cord and oligohydramnios. DV-RAV may not be always be a terminal finding in FGR with a hypercoiled cord.

Admission Test and Pregnancy Outcome

BACKGROUND

The admission test (AT) has been carried out for many years, but there are still debates about the prognostic value of the test. Therefore, we aimed to examine the value of the AT in predicting the adverse outcome in neonates.

METHODS

In this cross-sectional study, 425 pregnant women with normal vaginal delivery were studied between2009 and 2014at Vali-e-Asr Hospital. Based on the results, the women were divided into 2groups of normal and abnormal ATs. All the patients were followed up until the birth of their baby, when the status of mother and neonate was determined. The main outcomes of the study were cesarean rate, neonatal intensive care unit (NICU) admission, fetus demise, neonatal acidosis, and Apgar score. The independent t-test, chi-square test, Fisher exact test, and logistic regression were used for statistical analysis. The data were analyzed using SPSS (version 17).

RESULTS

Of 425 pregnant women studied, 142 (33.4%) had abnormal ATs with a mean age of 29 (±4.5) years. Multivariate analysis showed that an abnormal AT was able to predict the incidence of cesarean section, intrauterine growth restriction, turned cord, and Apgar<7, but it could not predict neonatal death and hypoxia.

CONCLUSION

The AT was shown to be a useful screening test with risk factors such as oligohydramnios, bloody amniotic fluid, meconium amniotic fluid, intrauterine growth restriction, and turned cord. Additionally, the test was also able to predict NICU admission and the need for cesarean section, but it could not predict the occurrence of neonatal death.

Survey on the current trends in managing intrauterine growth restriction

OBJECTIVE

To provide a snapshot of the current trends in managing intrauterine growth restriction (IUGR) and to assess the agreement on the gestational age and the way of delivery in different clinical scenarios.

METHODS

A PubMed search was performed to identify all original articles on IUGR in the last 6 years. The most active 20 authors were selected as experts and were invited to respond to a survey on their preferred gestational age for elective delivery in several IUGR cases depending on Doppler measurements (including umbilical artery (UA), middle cerebral artery, cerebroplacental ratio, uterine artery and ductus venosus), biophysical profile and cardiotocography.

RESULTS

15 of the 20 selected experts agreed to participate in the survey, of which 3 failed to meet the deadline to complete the survey. Management of IUGR was relatively uniform for abnormal UA, uterine artery or cerebroplacental ratio. Although average gestational age at delivery reflected a clear progression with accepted markers of severity, discrepancies of up to 4 weeks were found for abnormal middle cerebral artery Doppler and absent end-diastolic velocity in the UA, and of up to 8 weeks for reverse end-diastolic velocity in the UA and abnormalities in the ductus venosus Doppler.

CONCLUSIONS

Management of IUGR is still far from being uniform among centers, with most controversy surrounding the management of early-onset IUGR. There is a need of prospective studies to address this issue.

Longitudinal study of aortic isthmus Doppler in appropriately grown and small-for-gestational-age fetuses with normal and abnormal umbilical artery Doppler

OBJECTIVE

To establish reference ranges using longitudinal data for aortic isthmus (AoI) Doppler indices in appropriate-for-gestational-age (AGA) fetuses and to document the longitudinal trends in a cohort of small-for-gestational-age (SGA) fetuses with normal umbilical artery Doppler and in fetuses with intrauterine growth restriction (IUGR) and abnormal umbilical artery Doppler.

METHODS

AoI Doppler reference ranges were established from longitudinal data on 72 AGA singleton fetuses. Reliability of AoI Doppler flow measurements at two different sites and reproducibility between two operators was reviewed. A prospective longitudinal study of AoI Doppler indices in 48 SGA fetuses with normal umbilical artery Doppler and 10 IUGR fetuses was performed.

RESULTS

The AoI pulsatility index (PI) and peak systolic velocity (PSV) in AGA fetuses showed a significant increase with gestational age. Analysis of intra- and interoperator variability revealed no significant mean difference in measurements of AoI-PI or AoI-PSV. Observations of AoI-PI and AoI-PSV from SGA fetuses did not differ significantly from those of AGA or IUGR fetuses. Retrograde flow in the AoI did not predate changes in the ductus venosus in IUGR fetuses.

CONCLUSIONS

Reference ranges for fetal AoI Doppler parameters in AGA fetuses constructed using longitudinal data are consistent with those obtained from cross-sectional data. The AoI Doppler parameters in SGA fetuses did not differ from those in AGA fetuses. Preterm IUGR fetuses did not manifest alterations in AoI-PI or AoI-PSV prior to changes in biophysical profile or ductus venosus Doppler. Further large-scale prospective studies are needed to determine whether AoI Doppler parameters are of any value in timing delivery or reducing adverse neurodevelopmental outcome.

The importance of venous Doppler velocimetry for evaluation of intrauterine growth restriction

The management of growth-restricted fetuses requires accurate diagnosis to optimize the timing of delivery. Doppler velocimetry is the only noninvasive method for assessing the fetoplacental hemodynamic status. This review will give a critical overview of the current knowledge on fetal venous blood flow in pregnancies complicated by in-trauterine growth-restricted fetuses. Adaptation of the circulation in intrauterine growth-restricted fetuses is described. Normal and abnormal venous Doppler waveforms are presented. Correlations of abnormal waveforms with the presence of acidemia and perinatal outcomes are emphasized. Limitations of venous Doppler velocimetry for optimizing the time for delivery and the perinatal outcome are also presented.

Systematic review and meta-analysis of the test accuracy of ductus venosus Doppler to predict compromise of fetal/neonatal wellbeing in high risk pregnancies with placental insufficiency

OBJECTIVE

To evaluate the test accuracy of ductus venosus Doppler for prediction of compromise of fetal/neonatal wellbeing.

STUDY DESIGN

The search strategy employed searching of electronic databases (Medline, Embase, Cochrane library, Medion) from inception to May 2009, hand searching of journal and reference lists, contact with experts. Two reviewers independently selected articles in which the results of ductus venosus Doppler were associated with the occurrence of compromise of fetal/neonatal wellbeing. There were no language restrictions applied. Data were extracted on study characteristics, quality and results to construct 2 x 2 tables. Likelihood ratios for positive and negative test results, sensitivity, specificity and their 95% confidence intervals were generated for the different indices and thresholds.

RESULTS

Eighteen studies, testing 2267 fetuses met the selection criteria, all performed in a high risk population with placental insufficiency in second/third trimester. Meta-analysis showed moderate predictive accuracy. The best result was for the prediction of perinatal mortality, positive likelihood ratio 4.21 (95% CI 1.98-8.96) and negative likelihood ratio 0.43 (95% CI 0.30-0.61). For prediction of adverse perinatal outcome the results were positive likelihood ratio 3.15 (95% CI 2.19-4.54) and negative likelihood ratio 0.49 (95% CI 0.40-0.59).

CONCLUSION

Abnormal ductus venosus Doppler showed moderate predictive accuracy for compromise of fetal/neonatal wellbeing overall and perinatal mortality in high risk pregnancies with placental insufficiency.

Prediction of acidemia at birth by Doppler assessment of fetal cerebral transverse sinus in pregnancies with placental insufficiency

OBJECTIVES

To evaluate the prediction of acidemia at birth using cerebral transverse sinus (CTS) Doppler velocimetry and to determine the best parameter and cut-off values for its prediction in pregnancies complicated with placental insufficiency.

METHODS

This was a prospective cross-sectional study involving 69 pregnant women (26-40 weeks' gestation) with placental insufficiency managed in two Brazilian hospitals. Doppler assessment of the CTS was carried out in the last 24 h before delivery, and the peak ventricular systolic (S-wave) and diastolic (D-wave) velocities as well as the atrial systolic velocity (A-wave) were recorded and the pulsatility index for veins (PIV) was calculated. At birth, arterial and venous umbilical cord blood samples were collected to determine acid-base and pH status. A receiver-operating characteristics (ROC) curve was constructed for each Doppler parameter with birth acidemia as the dependent variable. Sensitivity, specificity, positive and negative predictive values, accuracy and false-positive and false-negative rates were calculated for the parameters considered to be good predictors of acidemia.

RESULTS

The S, D and A peak velocities and the S/A ratio were not good predictors of acidemia at birth. The PIV and the (S - A)/S ratio were good predictors of acidemia (area under the ROC curve = 0.698 (P = 0.009) and 0.654 (P = 0.009), respectively). The cut-off values were PIV = 0.855 and (S - A)/S = 0.703).

CONCLUSIONS

The PIV and the (S - A)/S ratio of the CTS were good predictors of acidemia at birth in this high-risk population with placental insufficiency.

Intrauterine restriction (IUGR)

Perinatal mortality and morbidity is markedly increased in intrauterine growth restricted (IUGR) fetuses. Prenatal identification of IUGR is the first step in clinical management. For that purpose a uniform definition and criteria are required. The etiology of IUGR is multifactorial and whenever possible it should be assessed. When the cause is of placental origin, it is possible to identify the affected fetuses. The major complication is chronic fetal hypoxemia. By monitoring the changes of fetal vital functions it is thus possible to improve both management and outcome. The timing of delivery is crucial but the optimal management scheme has not yet been identified. When IUGR is identified at very early gestational ages, serial assessments of the risk of continuing the in utero fetal life under adverse conditions versus the risks of the prematurity should be performed. Delivery of IUGR fetuses should take place in centers where appropriate neonatal assistance can be provided. Careful monitoring of the IUGR fetus during labor is crucial as the IUGR fetus can quickly decompensate once uterine contractions have started.

Doppler assessment of the aortic isthmus and perinatal outcome in preterm fetuses with severe intrauterine growth restriction

OBJECTIVES

To evaluate the characteristics and association with perinatal outcome of the aortic isthmus (AoI) circulation as assessed by Doppler imaging in preterm growth-restricted fetuses with placental insufficiency.

METHODS

This was a prospective cross-sectional study. Fifty-one fetuses with intrauterine growth restriction (IUGR) and either an umbilical artery (UA) pulsatility index (PI) > 95(th) centile or a cerebroplacental ratio < 5(th) centile were examined at 24-36 weeks' gestation. AoI impedance indices (PI and resistance index) and absolute velocities (peak systolic (PSV), end-diastolic and time-averaged maximum (TAMXV) velocities), were measured in all cases and compared with reference ranges by gestational age. Furthermore, fetuses were stratified into two groups according to the direction of the diastolic blood flow in the AoI: those with antegrade flow (n = 41) and those with retrograde flow (n = 10). Clinical surveillance was based on gestational age and Doppler assessment of the UA, middle cerebral artery and ductus venosus (DV). Adverse perinatal outcome was defined as stillbirth, neonatal death and severe morbidity (respiratory distress syndrome, bronchopulmonary dysplasia, Grade III/IV intraventricular hemorrhage, necrotizing enterocolitis and a neonatal intensive care unit stay > 14 days).

RESULTS

Adverse perinatal outcome was significantly associated with an increased AoI-PI (area under the curve 0.77; 95% CI, 0.63-0.92; P < 0.005). A significant correlation (P < 0.001) was found between retrograde blood flow in the AoI and adverse perinatal outcome, the overall perinatal mortality being higher in the retrograde group (70% vs. 4.8%, P < 0.001). In 4/5 (80%) fetuses the reversal of flow in the AoI preceded that in the DV by 24-48 h. AoI-PSV and AoI-TAMXV were < 5(th) centile in 40/51 (78%) and 48/51 (94%) cases, respectively, whereas AoI-PI was > 95(th) centile in 21/51 (41%) cases.

CONCLUSIONS

Retrograde flow in the AoI in growth-restricted fetuses correlates strongly with adverse perinatal outcome. Absolute velocities in the AoI are decreased in growth-restricted fetuses. The data suggest a potential role for Doppler imaging of the AoI in the clinical surveillance of fetuses with severe IUGR, which should be confirmed in larger prospective studies.

Ductus venosus Doppler measurement during labor

OBJECTIVES

To assess ductus venosus (DV) indices during the first stage of labor and the effect of ruptured membranes, meconium stained liquor and epidural analgesia (EDA).

METHODS

Prospective cross-sectional study. Eighty-one women with low-risk singleton term pregnancies participated, 51 had normal labor (Group 1), and 30 experienced ruptured membranes and/or stained liquor (Group 2). Of the latter group 14 received EDA. The effect of various interventions and application of EDA on the ductus venosus index (DVI) and pulsatility index for veins (DV PIV) were tested.

RESULTS

The feasibility rate was 94%. A significant increase of DV indices (DVI, DV PIV) was found in group 2 (P<0.001 and P<0.0005, respectively). The A-velocity was also significantly lower in group 2 (P<0.02). A markedly significant increase of DV indices (P<0.0001) among participants receiving EDA was observed in group 2. The mean+/-SD indices were: 0.53+/-0.10 for the DVI and 0.68+/-0.14 for the DV PIV in those women. There was a significant positive correlation of DV indices with the duration of amniorrhea in group 2 (PIV: r=0.66; P<0.002; DVI: r=0.68; P<0.001).

CONCLUSIONS

Long-term amniorrhea seems to affect the fetal venous circulation reflected in increased DV waveform indices.

Doppler Assessment of the Intrauterine Growth-Restricted Fetus

The evaluation of fetal well-being by Doppler velocimetry in cases of intrauterine growth restriction (IUGR) is of great importance as it is very useful in detecting those IUGR fetuses that are at high risk because of hypoxemia. Several Doppler studies initially on fetal arteries and recently on the fetal venous system provide valuable information for the clinicians concerning the optimal time to deliver. Doppler sonography in combination with the other biophysical methods such as cardiotocogram and biophysical profile score should be used in everyday practice for the monitoring and appropriate management of the growth-restricted fetuses. The purpose of this review is to describe the current approaches in Doppler assessment of IUGR fetal circulation.

Ductus venosus Doppler velocimetry in the prediction of acidemia at birth: which is the best parameter?

OBJECTIVES

To evaluate the prediction of acidemia at birth using ductus venosus Doppler velocimetry and to determine the best parameter and cut-off values for this prediction in pregnancies complicated with placental insufficiency.

METHODS

Prospective cross-sectional study. Forty-seven patients with placental insufficiency managed in two Brazilian hospitals were submitted to ductus venosus Doppler velocimetry in the last 24 h before delivery. All pregnancies were singleton, at least 26 weeks of age and without structural or chromosomal anomalies. A ROC curve was calculated for each ductus venosus parameter (independent variable) and acidemia (dependent variable). A cut-off value was established. The McNemar test was used to compare the various parameters.

RESULTS

The ductus venosus S, D and A peak velocities were not good predictors of acidemia at birth. Pulsatility Index for Veins (PIV) was a good predictor of acidemia (ROC curve area 0.79, p = 0.003), as well as S/A and (S - A)/S ratios (ROC curve area 0.818, p = 0.001). The cut-off values were PIV = 0.76, S/A = 2.67 and (S - A)/S = 0.63.

CONCLUSIONS

In this high-risk population, angle-independent ductus venosus Doppler indexes were good predictors of birth acidemia. The S/A and (S - A)/S ratios and the ductus venosus PIV were statistically equivalent in this prediction.

Antenatal fetal surveillance

PURPOSE OF REVIEW

Antenatal fetal surveillance is a field of increasing importance in modern obstetrics, especially as results in perinatal care have recently made dramatic progress. It is an evolving field, and it is no longer acceptable just to wait and see when problems arise in pregnancy. During the past few decades many studies have shown that antenatal surveillance in unselected populations is of little value. However, high-risk patients benefit from antenatal fetal surveillance, especially women with pregnancy problems associated with intrauterine growth restriction.

RECENT FINDINGS

This review shows that modern antenatal fetal surveillance is based on fetal heart rate monitoring, ultrasound biometry and amniotic fluid assessment, Doppler blood flow studies of fetal and uteroplacental circulation, and an evaluation of biophysical fetal parameters.

SUMMARY

Used in combination these methods lead to improvements in fetal morbidity and mortality. The aim of future research should be to minimize the risks of fetal morbidity and mortality further by the optimal timing of delivery. Better organization of healthcare systems may improve our ability to identify at-risk patients during pregnancy. There is potential to improve the specificity of fetal surveillance tests, e.g. better methods of biometry and amniotic volume estimation with three-dimensional ultrasound and measurements of subcutaneous tissue. Improved knowledge of fetal physiology can be gained from research on fetal circulation with Doppler studies. Computer analysis of the fetal heart rate can increase the specificity of that test, and artificial neural networks may enhance the ability to evaluate the optimal use of integrated testing.

Doppler application in the delivery timing of the preterm growth-restricted fetus: another step in the right direction

This article provides an opinion on a study of relationships between umbilical artery (UA) Doppler, ductus venosus (DV) Doppler, fetal heart rate variation, and perinatal outcome in preterm, intrauterine growth-restricted (IUGR) fetuses published in the same issue of this journal by Bilardo and coworkers. Recent evidence on venous Doppler surveillance in preterm IUGR fetuses was also reviewed and discussed in the context of the study with a special emphasis on delivery timing. A search was conducted through MEDLINE and eight articles with similar inclusion criteria and reporting format of outcomes were identified. Numbers for perinatal mortality, intraventricular hemorrhage, respiratory distress syndrome, bronchopulmonary dysplasia and necrotizing enterocolitis (NEC) were extracted for cases where Doppler status was recorded in an identical format. Proportional distribution of outcomes was compared for fetuses with normal DV Doppler velocimetry, absent or reversed UA end-diastolic velocity (UA A/REDV), elevated DV Doppler index (abnormal DV) and absence or reversal of atrial velocity in the DV (DV-RAV). A total of 320 fetuses with normal and 202 with elevated DV Doppler indices were extracted. Of these fetuses, 101 with UA A/REDV only and 34 with DV-RAV were identified. Perinatal mortality was 5.6% (16/282) with normal DV, 11.9% (12/101) with UA A/REDV, 38.8% (64/165) with abnormal DV and 41.2% (7/17) with DV-RAV. With the exception of NEC, all complications were significantly more frequent with abnormal DV. With normal venous Doppler neonatal deaths account for most of the perinatal mortality, while with abnormal DV stillbirths and neonatal mortality are similar contributors to the significantly increased perinatal mortality. In conclusion, UA Doppler is a placental function test that provides important diagnostic and prognostic information in preterm IUGR. DV Doppler effectively identifies those preterm IUGR fetuses that are at high risk for adverse outcome (particularly stillbirth) at least 1 week before delivery, independent of the UA waveform. Relationships between perinatal outcome, arterial and venous Doppler status and gestational age require ongoing observational research effort. Randomized management trials are necessary to verify that delivery timing based on venous Doppler will impact on outcome in preterm IUGR.