Prediction of perinatal outcome in fetuses suspected to have intrauterine growth restriction: Doppler US study of fetal cerebral, renal, and umbilical arteries

Role of Ultrasonography and Color Doppler in the Assessment of High-Risk Pregnancies and Their Accuracy in Predicting Fetal Outcome

Introduction Various methods are employed to evaluate the well-being of the fetus in high-risk pregnancies which consists of a biophysical profile (BPP), a non-stress test (NST), and daily fetal movements. Detection of aberrant blood flow in fetoplacental beds has been revolutionized by recent developments in ultrasound technology, such as color Doppler flow velocimetry. The cornerstone of maternal and fetal care is lowering maternal and perinatal mortality and morbidity is antepartum fetal surveillance. Doppler ultrasound is a non-invasive way of obtaining a qualitative and quantitative evaluation of maternal and fetal circulation and is utilized to investigate complications like fetal growth restriction (FGR) and fetal distress. Thus, it is useful in making distinctions between fetuses that are truly growth restricted and small for gestational age and healthy fetuses. The aim of the current study was to determine the role of Doppler indices in high-risk pregnancies and their accuracy in predicting fetal outcomes. Material and methods This prospective cohort study included 90 high-risk pregnancies in the III trimester (after 28 weeks of gestation) on whom ultrasonography and Doppler were performed. Ultrasonography was performed using PHILIPS EPIQ 5, a curvilinear probe of frequency 2-5MHz. Gestational age was determined with a biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femoral length (FL). Placental grading and position were noted. Estimated fetal weight and the amniotic fluid index were calculated. BPP scoring was done. Doppler study was conducted and the findings of Doppler indices that is pulsatility index (PI) and resistive index (RI) of the middle cerebral artery (MCA), umbilical artery (UA), and uterine artery (UTA), and cerebroplacental (CP) ratio in these high-risk pregnancies were documented and compared with standard. The flow patterns in MCA, UA, and UTA were also assessed. These findings were correlated with fetal outcomes.  Results Among 90 cases, the common high-risk factor in pregnancy was preeclampsia without severe features (30%). Growth lag was present in 43 (47.8%) participants. Among the study population, HC/AC ratio was increased in 19 (21.1%) participants which indicates asymmetrical intrauterine growth restriction. Adverse fetal outcomes were seen in 59 (65.6%) of the subjects. CP ratio and UA PI had better sensitivity (83.05% and 79.66%, respectively) and positive predictive value (PPV) (87.50% and 90.38%, respectively) in identifying the adverse fetal outcomes. Diagnostic accuracy of CP ratio and UA PI (Accuracy=81.11%) was highest in predicting adverse outcomes than all the other parameters. Conclusion CP ratio and UA PI had better sensitivity, PPV, and diagnostic accuracy in identifying adverse fetal outcomes than other parameters. The study's findings support that the use of color Doppler imaging in high-risk pregnancies will help in the early identification of adverse fetal outcomes and aid in early intervention. This study is non-invasive, simple, safe, and reproducible. This study can also be performed bedside in high risk and unstable patients. This study is required to accurately assess fetal well-being in all high-risk pregnancies in order to improve fetal outcomes and to incorporate this procedure as a part of the protocol for the assessment of fetal well-being in these patients.

Postnatal middle cerebral artery Dopplers in growth-restricted neonates

This prospective observational study compared the middle cerebral artery (MCA) Doppler characteristics of FGR neonates (N = 20) with abnormal antenatal Dopplers, with those of appropriately grown (AGA) neonates (N = 20), in the immediate postnatal period. MCA peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistive index (RI) were measured on day 1 and day 3. MCA PSV and EDV values were not significantly different between FGR (mean (SD) gestation: 31.4 (3.1) weeks, weight 1205 (463) grams) and AGA (31.1 (3.0) weeks; 1668 (490) grams) groups, on day 1 and day 3. Both FGR (30.85 (10.02) vs. 42.12 (9.16) cm/s, p = 0.007) and AGA groups (31.77 (9.32) vs. 42.0 (8.98) cm/s, p = 0.001) showed a significant increase in MCA PSV, but only the FGR group showed significant increase in EDV values (7.01 (4.23) vs. 11.78 (4.98), p = 0.002) from day 1 to day 3. This was associated with significant differences in RI (0.72 (0.10) vs. 0.79 (0.07), p = 0.01) and PI (1.36 (0.47) vs. 1.73 (0.4), p = 0.01) values between FGR and AGA groups on day 3.Conclusion: Significant differences in MCA resistive and pulsatility indices were noted in the first few days of life of FGR neonates with abnormal antenatal Doppler as compared with AGA neonates. This may suggest a delayed transition or persistence of cerebral redistribution in FGR neonates.What is Known:• FGR infants have increased risk of neonatal morbidity and mortality, and long-term neuro-disabilities.• Antenatal Doppler Ultrasound is the most common modality used to assess fetal growth restriction.What is New:• Antenatally detected abnormal cerebral Dopplers may persist during the neonatal period in growth-restricted neonates.• Early cerebral Doppler values may be a useful marker to identify "at risk" growth-restricted neonates..

Renal artery Doppler compared with the cerebral placental ratio to identify fetuses at risk for adverse neonatal outcome

Background: Current clinical practice incorporates an umbilical artery resistance index or a ratio of the middle cerebral artery (MCA PI) to the umbilical artery pulsatility index (UA PI) known as the cerebral placental ratio (CPR) to assess wellbeing in the small for gestational age fetus. Previous reports using the renal artery Doppler indices have not been consistent in regards to their design and clinical use. Our objective is to develop reference values for renal artery Doppler indices and validate their use compared with the UA PI or CPR to identify fetuses that will develop a composite neonatal outcome.Methods: We performed 9700 ultrasounds among 2852 women at 20-40 weeks of gestation at the University of Maryland between 1 June 2016 and 1 December 2016. Nomograms were first developed using one randomly selected scan from each of a subgroup of 860 women without any comorbidities. The nomograms were validated among a cohort of 550 women who subsequently delivered at the University of Maryland Medical Center. We compared the area under the receiver operating characteristic curve (AUROC) between the CPR and UA PI, and the renal artery Doppler parameters (renal artery pulsatility index (RA PI), systolic diastolic ratio (RA SDR), and peak systolic velocity (RA PSV)). The primary outcome was the development any one of the composite neonatal outcome components (death, intensive care unit admission, ventilator for more than 6 h, hypoxic ischemic encephalopathy or necrotizing enterocolitis) or admission to the neonatal intensive care unit (NICU) for any indication.Results: The renal artery Doppler indices did not improve identification of fetuses that would subsequently develop one of the components of the composite neonatal outcome (AUROC for CPR 0.54, 95% CI (0.49-0.59), versus the UA PI: 0.59 (0.54-0.64) p = .07, the RA PI: 0.51 (0.48-0.55) p = .41, RA SDR 0.54 (0.49-0.58) p = .99, or RA PSV 0.51 (0.47-0.55) p = .37). There was no difference when comparing AUROC to detect NICU admission (AUROC for CPR 0.53, 95% CI (0.49-0.58), versus the UA PI: 0.57 (0.52-0.62) p = .14, the RA PI: 0.50 (0.47-0.54) p = .44, RA SDR: 0.54 (0.50-0.59) p = .62 or RAPSV: 0.51 (0.47-0.55) p = .54).Conclusion: The renal artery indices do not improve detection of fetuses at risk for adverse neonatal outcomes compared with the CPR or the UA PI.

Doppler evaluation of umbilical artery during normal gestation in sheep

Throughout gestation, changes in foetal umbilical cord Doppler parameters in ewes were detected. Doppler ultrasonography of the umbilical artery was performed weekly starting at 18 weeks before parturition until birth. In the foetal umbilical artery (UA), systolic peak velocity (SPV), end diastolic velocity (EDV), increased (p for within-subjects effect <0.001) while pulsatility index (PI) resistance index (RI) decreased (p for within-subjects effect <0.001) with the progress of pregnancy. A linear trend was found on all patterns (p < 0.001). In particular, the EDV values increased significantly (p < 0.05) with respect to previous weeks, at weeks 16, 11, 10, 7, and 1 before parturition. The SPV values increased significantly (p < 0.05), with respect to previous observations, at weeks 11, 10, and 7 before parturition. Finally, the PI and RI decreased significantly (p < 0.05) only at week 7 before parturition. The increased velocities and reduced resistance index suggest a progressive increment in blood flow to the foetus towards the end of pregnancy. Foetal and utero-placental vascular parameters can be reliably evaluated using high-frequency ultrasound.

Role of Color Doppler Flowmetry in Prediction of Intrauterine Growth Retardation in High-Risk Pregnancy

Objective: To evaluate the usefulness of Color Doppler flowmetry in the prediction of intrauterine growth restriction (IUGR) in high-risk pregnancies.

Materials and method: A total of 62 high-risk pregnant women underwent Color Doppler flowmetric umbilical artery pulsatility index (PI), resistive index (RI) and systolic/diastolic (S/D) ratio, middle cerebral artery PI, RI and S/D ratio, Ductus venosus S-wave/isovolumetric A-wave index (SIA) and vertebral artery RI at 23-27 weeks, 28-32 weeks and 32-36 weeks of their pregnancy. Cerebral-umbilical C/U PI, RI and S/D were evaluated at the third visit. All the pregnancies were followed up till delivery. Ponderal index <10 was considered to be indicative of IUGR. Data were analyzed using IBM Statistical Package for Social Sciences (SPSS) 21.0.

Results: Thirty-nine (62.9%) deliveries were IUGR. On all the three visits, umbilical artery, mean PI, RI and SD values were significantly higher while MCA PI, RI and SD values were significantly lower in IUGR as compared to non-IUGR cases. Third visit C/U PI, RI and SD ratio values were also significantly lower in IUGR as compared to non-IUGR cases. Ductus venosus SIA values did not show a significant difference between IUGR and non-IUGR groups. The vertebral artery resistive index was significantly higher in non-IUGR as compared to IUGR on all the visits. Umbilical artery PI was the most sensitive and specific for the prediction of IUGR at all the three visits, with the maximum sensitivity and specificity at the third visit (82.1% and 87%). Third visit C/U PI was most sensitive (82.1%) and specific (96.7%) for the prediction of IUGR.

Conclusion: This showed that Doppler flowmetry is a useful method for the prediction of IUGR in high-risk pregnancies.

Evaluation of feline uterine and umbilical arteries blood flow in a pharmacologically induced abnormal gestation model

The aim of this study was to describe resistance index (RI) and systolic/diastolic ratio (S/D ratio) of uterine and umbilical arteries in an experimental model of abnormal pregnancy in felids. On days 30 to 35 (32 ± 2.9) after mating, 20 domestic short-hair pregnant queens were randomly assigned to one of the following treatment groups: a treated group (TG; n = 8), which received 10 mg/kg of aglepristone subcutaneously twice, 24 hours apart, and a control nontreated group (CG; n = 12). M-mode and Doppler ultrasonographic evaluations were performed at the initiation of the treatment (Day 0) and then every other day during 8 days. In both groups, uterine and umbilical arteries were evaluated by Doppler ultrasound, whereas fetal heart rate was assessed by M-mode ultrasound. Resistance index of uterine artery augmented in TG from Day 2 onward, conversely it decreased in CG (P < 0.01). On Day 8, RI values were 0.64 ± 0.05 vs 0.37 ± 0.01 for TG and CG, respectively. Additionally, S/D ratio of the same artery presented an increase in TG, whereas this ratio diminished in CG (P < 0.01). On Day 8, this parameter showed values of 2.98 ± 0.4 vs 1.62 ± 0.06 for TG and CG, respectively. Resistance index of umbilical artery remained almost unchanged in TG from Day 6 onward, whereas it progressively decreased in CG throughout the course of the study (P < 0.05). On Day 8, RI were 0.89 ± 0.04 and 0.82 ± 0.01, for TG and CG, respectively. Furthermore, on Day 8, S/D ratio of umbilical artery progressively diminished in CG but not in TG (P < 0.01), being 14.7 ± 9.1 vs 5.9 ± 0.3 for TG and CG, respectively. Fetal heart rate was higher in TG than in CG (P < 0.05). Group differences in Doppler parameters appeared on Day 2, when the other clinical or ultrasonographic signs were still absent. It is concluded that blood flow of the uterine and umbilical arteries differed between these normal and abnormal gestations predicting an adverse obstetric outcome.

The association between fetal Doppler and admission to neonatal unit at term

OBJECTIVE

Fetal cerebroplacental ratio is emerging as a better proxy than birthweight for placental insufficiency and as a marker of fetal compromise at term. The extent to which these fetal Doppler changes are related to neonatal outcomes has not been systematically assessed. The main aim of this study was to evaluate the association between estimated fetal weight percentile, cerebroplacental ratio recorded at 34(+0)-35(+6) weeks' gestation, and neonatal unit admission at term.

STUDY DESIGN

This was a retrospective cohort study in a tertiary referral center over an 11 year period from 2002 to 2012. The umbilical artery pulsatility index (PI), middle cerebral artery PI, and cerebroplacental ratio were recorded at 34(+0)-35(+6) weeks. Weight values were converted into percentiles and Doppler parameters into multiples of the median (MoM), adjusting for gestational age. Logistic regression analysis was performed to identify, and adjust for, potential confounders.

RESULTS

We identified 2518 pregnancies in which a scan was performed at 34(+0)-35(+6) weeks and delivery occurred at or beyond 37 weeks. In the 2485 pregnancies included in the analysis, the umbilical artery PI MoM was significantly higher, and the middle cerebral artery PI and cerebroplacental ratio MoM significantly lower in the babies requiring neonatal unit admission (P < .05). However, the estimated fetal weight percentile was not significantly different between those who required neonatal unit admission and those who did not (P = .087). According to multivariate logistic regression, cerebroplacental ratio MoM (odds ratio, 0.39; 95% confidence interval, 0.19-0.79; P = .008) and gestational age at delivery (odds ratio, 0.70; 95% confidence interval, 0.61-0.80; P < .001) were significantly associated with the risk of neonatal unit admission, whereas maternal age and birthweight percentile were not (P = .183 and P = .460, respectively). Irrespective of birthweight or estimated fetal weight percentile, the fetal cerebroplacental ratio appears to be a better predictor of the need for neonatal unit admission (P < .001).

CONCLUSION

Lower cerebroplacental ratio and gestational age at delivery, but not fetal size, were independently associated with the need for admission to the neonatal unit at term in a high-risk patient group. The extent to which fetal hemodynamic assessment could be used to predict perinatal morbidity and optimize the timing of delivery merits further investigation.

Is fetal cerebroplacental ratio an independent predictor of intrapartum fetal compromise and neonatal unit admission?

OBJECTIVE

We sought to evaluate the association between fetal cerebroplacental ratio (CPR) and intrapartum fetal compromise and admission to the neonatal unit (NNU) in term pregnancies.

STUDY DESIGN

This was a retrospective cohort study in a single tertiary referral center over a 14-year period from 2000 through 2013. The umbilical artery pulsatility index, middle cerebral artery pulsatility index, and CPR were recorded within 2 weeks of delivery. The birthweight (BW) values were converted into centiles and Doppler parameters converted into multiples of median (MoM), adjusting for gestational age using reference ranges. Logistic regression analysis was performed to identify, and adjust for, potential confounders.

RESULTS

The study cohort included 9772 singleton pregnancies. The rates of operative delivery for presumed fetal compromise and neonatal admission were 17.2% and 3.9%, respectively. Doppler CPR MoM was significantly lower in pregnancies requiring operative delivery or admission to NNU for presumed fetal compromise (P < .01). On multivariate logistic regression, both CPR MoM and BW centile were independently associated with the risk of operative delivery for presumed fetal compromise (adjusted odds ratio [OR], 0.67; 95% confidence interval [CI], 0.52-0.87; P = .003 and adjusted OR, 0.994; 95% CI, 0.992-0.997; P < .001, respectively). The latter associations persisted even after exclusion of small-for-gestational-age cases from the cohort. Multivariate logistic regression also demonstrated that CPR MoM was an independent predictor for NNU admission at term (adjusted OR, 0.55; 95% CI, 0.33-0.92; P = .021), while BW centile was not (adjusted OR, 1.00; 95% CI, 0.99-1.00; P = .794). The rates of operative delivery for presumed fetal compromise were significantly higher for appropriate-for-gestational-age fetuses with low CPR MoM (22.3%) compared to small-for-gestational-age fetuses with normal CPR MoM (17.3%).

CONCLUSION

Lower fetal CPR, regardless of the fetal size, was independently associated with the need for operative delivery for presumed fetal compromise and with NNU admission at term. The extent to which fetal hemodynamic status could be used to predict perinatal morbidity and optimize the mode of delivery merits further investigation.

Risk-adjusted operative delivery rates and maternal-neonatal outcomes as measures of quality assessment in obstetric care: a multicenter prospective study

BACKGROUND

Although the evaluation of caesarean delivery rates has been suggested as one of the most important indicators of quality in obstetrics, it has been criticized because of its controversial ability to capture maternal and neonatal outcomes. In an "ideal" process of labor and delivery auditing, both caesarean (CD) and assisted vaginal delivery (AVD) rates should be considered because both of them may be associated with an increased risk of complications. The aim of our study was to evaluate maternal and neonatal outcomes according to the outlier status for case-mix adjusted CD and AVD rates in the same obstetric population.

METHODS

Standardized data on 15,189 deliveries from 11 centers were prospectively collected. Multiple logistic regression was used to estimate the risk-adjusted probability of a woman in each center having an AVD or a CD. Centers were classified as "above", "below", or "within" the expected rates by considering the observed-to-expected rates and the 95% confidence interval around the ratio. Adjusted maternal and neonatal outcomes were compared among the three groupings.

RESULTS

Centers classified as "above" or "below" the expected CD rates had, in both cases, higher adjusted incidence of composite maternal (2.97%, 4.69%, 3.90% for "within", "above" and "below", respectively; p = 0.000) and neonatal complications (3.85%, 9.66%, 6.29% for "within", "above" and "below", respectively; p = 0.000) than centers "within" CD expected rates. Centers with AVD rates above and below the expected showed poorer and better composite maternal (3.96%, 4.61%, 2.97% for "within", "above" and "below", respectively; p = 0.000) and neonatal (6.52%, 9.77%, 3.52% for "within", "above" and "below", respectively; p = 0.000) outcomes respectively than centers with "within" AVD rates.

CONCLUSIONS

Both risk-adjusted CD and AVD delivery rates should be considered to assess the level of obstetric care. In this context, both higher and lower-than-expected rates of CD and "above" AVD rates are significantly associated with increased risk of complications, whereas the "below" status for AVD showed a "protective" effect on maternal and neonatal outcomes.

The history of imaging in obstetrics

During the past century, imaging of the pregnant patient has been performed with radiography, scintigraphy, computed tomography, magnetic resonance imaging, and ultrasonography (US). US imaging has emerged as the primary imaging modality, because it provides real-time images at relatively low cost without the use of ionizing radiation. This review begins with a discussion of the history and current status of imaging modalities other than US for the pregnant patient. The discussion then turns to an in-depth description of how US technology advanced to become such a valuable diagnostic tool in the obstetric patient. Finally, the broad range of diagnostic uses of US in these patients is presented, including its uses for distinguishing an intrauterine pregnancy from a failed or ectopic pregnancy in the first trimester; assigning gestational age and assessing fetal weight; evaluating the fetus for anomalies and aneuploidy; examining the uterus, cervix, placenta, and amniotic fluid; and guiding obstetric interventional procedures.

Measurement of middle cerebral artery diameter as a method for assessment of brain sparing in intra-uterine growth-restricted discordant twins

OBJECTIVES

Blood vessel resistance is assessed by flow velocity indexes. However, the actual resistance should be more strongly correlated with vessel diameter rather than variations in flow velocity. We aimed to determine the utility of middle cerebral artery (MCA) diameter measurement as a tool for evaluating brain sparing effect in intrauterine growth-restricted (IUGR) discordant twins.

METHODS

Ten dichorionic-diamniotic twin pairs with weight discordance were included in the study. Fetal assessment included estimated fetal weight, umbilical artery flow, MCA flow and MCA diameter. Paired statistical analysis was used to compare MCA diameter and MCA pulsatility index (PI) between the discordant twins.

RESULTS

MCA diameter was significantly larger in the smaller twin (mean diameter 3.55 ± 0.26 vs 2.71 ± 0.22, P = 0.018, mean ratio 1.39 ± 0.14). There was no significant difference in MCA PI values within the twin pairs (mean PI 1.51 ± 0.13 vs 1.57 ± 0.07, P = 0.878, mean ratio 0.99 ± 0.11).

CONCLUSIONS

Measurement of MCA diameter can potentially be used as a tool for assessing vessel resistance. Further studies are needed to assess the feasibility and sensitivity of this method as well as the clinical significance of MCA dilatation in the presence of normal Doppler flow indexes.

Color Doppler sonography in obstetrics and gynecology

This review aims to provide the reader with an overview of the present and future clinical applications in color Doppler sonography for the evaluation of vascularity and blood flow within the uterus (both gravid and nongravid), ovaries, fetus and placenta. The clinical use of color Doppler sonography has been demonstrated within many organ systems. Color Doppler sonography has become an integral part of cardiovascular imaging. Significant improvements have recently occurred, improving the visualization and evaluation of intra-organ vascularity, resulting from enhancements in delineation of tissue detail through electronic compounding and harmonics, as well as enhancements in signal processing of frequency- and/or amplitude-based color Doppler sonography. Spatial representation of vascularity can be improved by utilizing 3D and 4D (live 3D) processing. Greater sensitivity of color Doppler sonography to macro- and microvascular flow has provided improved anatomic and physiologic assessment throughout pregnancy and for pelvic organs. The potential use of contrast enhancement is also mentioned as a means to further differentiate benign from malignant ovarian lesions. The rapid development of these new sonographic techniques will continue to enlarge the scope of clinical applications in a variety of obstetric and gynecologic disorders.

Comparison of diagnostic efficacy of umbilical artery and middle cerebral artery waveform with color Doppler study for detection of intrauterine growth restriction

BACKGROUND AND OBJECTIVES

Intrauterine growth restriction is associated with increased perinatal mortality and morbidity, possibly extending also in adult life, as compared to fetuses and newborns presenting characteristics of normal growth. The present study had been planned to measure the pulsatility index (PI) and resistive index of the middle cerebral artery with pulsatility and resistive index of the umbilical artery in predicting fetal growth restriction.

MATERIALS AND METHODS

A total of 60 pregnant women with a clinical history and grayscale-screened patients were taken for Doppler analysis, and a final comparison of accuracy of Doppler indices was done with perinatal outcome.

STATISTICAL ANALYSIS

The statistical analysis was done using the Statistical Package for Social Sciences version 15.0 statistical analysis software. The values were represented in number (%) and mean ± SD.

OBSERVATION AND RESULTS

The umbilical artery PI had maximum sensitivity at the third visit (32-37 weeks) and maximum specificity also at the third visit (32-37 weeks). The umbilical artery resistive index had maximum sensitivity at the second visit (28-32 weeks) and maximum specificity at the third visit (32-37 weeks). The MCA PI had an overall diagnostic accuracy of 52.8 %.

CONCLUSION

The PI of the umbilical artery was more sensitive than the PI of the middle cerebral artery. Umbilical artery PI has the maximum overall diagnostic accuracy of 75 %.

Imaging and assessment of placental function

The placenta is the vital support organ for the developing fetus. This article reviews current ultrasound (US) methods of assessing placental function. The ability of ultrasound to detect placental pathology is discussed. Doppler technology to investigate the fetal, placental, and maternal circulations in both high-risk and uncomplicated pregnancies is discussed and the current literature on the value of three-dimensional power Doppler studies to assess placental volume and vascularization is also evaluated. The article highlights the need for further research into three-dimensional ultrasound and alternative methods of placental evaluation if progress is to be made in optimizing placental function assessment.

Doppler ultrasonographic assessment of maternal and fetal blood flow in abnormal canine pregnancy

The aim of this study was to describe the changes of uterine artery, umbilical artery and fetal abdominal aorta, renal and internal carotid arteries blood flow in abnormal canine pregnancy. Twenty-two, Brucella-negative pregnant bitches were retrospectively classified into abnormal (which had either interrupted their pregnancy between days 52 and 60 or had perinatal death >60% of the litter; n=11) and normal (which had delivered healthy puppies at term; n=11). In all the animals, color and pulsed-wave Doppler examinations of uterine artery were conducted every 10 days from Day 20 to 50 from estimated luteinizing hormone peak. Doppler ultrasonography was also conducted in the fetuses to assess umbilical artery, abdominal aorta, renal and internal carotid arteries from Day 40 to 60 of gestation. Throughout the study, resistance index (RI) of uterine, umbilical and fetal renal arteries decreased up to -15% compared to -36% (P<0.01), -11% compared to -23% (P<0.05) and 2% compared to -13% (P<0.05), respectively in the abnormal and normal bitches. Fetal abdominal aorta and internal carotid did not differ between groups (P>0.05). It is concluded that in dogs, uterine artery, umbilical artery and fetal renal artery RI differ between normal and abnormal gestation being useful for the prediction of adverse obstetric outcome.

Predictors of outcome at 2 years of age after early intrauterine growth restriction

OBJECTIVE

To examine the relative importance of antenatal and perinatal variables on short- and long-term outcome of preterm growth restricted fetuses with umbilical artery (UA) Doppler abnormalities.

METHODS

This was a cohort study of 180 neonates with birth weight < 10(th) percentile, gestational age at delivery < 34 weeks and abnormal Doppler ultrasound examination of the UA. Various antenatal and perinatal variables were studied in relation to short- and long-term outcome.

RESULTS

Neonatal and overall mortality (up to 2 years of age) were predicted by low gestational age at delivery. Neonatal mortality was additionally predicted by absent or reversed UA end-diastolic flow, while the presence of severe neonatal complications and placental villitis were additional predictors of both infant (between 28 days and 1 year of postnatal life) and overall mortality. Placental villitis was found to be the only predictor of necrotizing enterocolitis. Low gestational age at delivery, male sex, abnormal cardiotocography, absent or reversed UA end-diastolic flow and the HELLP syndrome predicted respiratory distress syndrome. Abnormal neurodevelopmental outcome at 2 years was predicted by low birth weight (< 2.3(rd) percentile), fetal acidosis (UA pH < 7.00), and placental villitis.

CONCLUSION

Less advanced gestation at delivery remains an important predictor of short-term outcome in growth-restricted fetuses. In addition, the presence of placental villitis may aid neonatologists in the early identification of infants at increased risk of necrotizing enterocolitis, death and abnormal neurodevelopment at 2 years of age. Abnormal neurodevelopment was related to low weight and acidosis at birth, indicating that the severity of malnutrition and fetal acidosis affect long-term outcome.

Can adverse neonatal outcome be predicted in late preterm or term fetal growth restriction?

OBJECTIVE

To identify independent predictors of adverse neonatal outcome in cases of fetal growth restriction (FGR) at > or = 34 weeks.

METHODS

From a cohort of 481 FGR cases delivered at > or = 34 weeks, demographic and obstetric variables, fetal biometry and Doppler indices of the uterine, umbilical and fetal middle cerebral arteries available within 2 weeks of delivery, were related to adverse neonatal outcome, defined as admission to the neonatal intensive care unit for indications other than low birth weight alone.

RESULTS

Logistic regression analysis showed that gestational age (GA) at delivery (odds ratio (OR) = 0.59; 95% CI, 0.50-0.70), abdominal circumference (AC) centile (OR = 0.69; 95% CI, 0.59-0.81) and umbilical artery (UA) pulsatility index (PI) centile (OR = 1.02; 95% CI, 1.01-1.04) significantly correlated with adverse neonatal outcome. From this model we calculated a score of adverse neonatal outcome expressed by the formula: (UA-PI centile/3) - (10 x AC centile) + (10 x (40 - GA at delivery in weeks)). Receiver-operating characteristics curve analysis demonstrated that a score of > or = 25 optimally predicted adverse neonatal outcome (sensitivity of 75%, false-positive rate of 18%). Beyond 37.5 weeks, gestational age no longer had an independent impact on outcome.

CONCLUSIONS

In late preterm or term FGR, GA at delivery is the most important predictor of adverse neonatal outcome. At > 37.5 weeks, delivery may be the best option to minimize adverse outcome in all FGR cases. At 34-37 weeks, a score based on GA at delivery, UA-PI centile and AC centile optimally predicts adverse neonatal outcome.

Defining normal and abnormal fetal growth: promises and challenges

Normal fetal growth is a critical component of a healthy pregnancy and influences the long-term health of the offspring. However, defining normal and abnormal fetal growth has been a long-standing challenge in clinical practice and research. We review various references and standards that are used widely to evaluate fetal growth and discuss common pitfalls of current definitions of abnormal fetal growth. Pros and cons of different approaches to customize fetal growth standards are described. We further discuss recent advances toward an integrated definition for fetal growth restriction. Such a definition may incorporate fetal size with the status of placental health that is measured by maternal and fetal Doppler velocimetry and biomarkers, biophysical findings, and genetics. Although the concept of an integrated definition appears promising, further development and testing are required. An improved definition of abnormal fetal growth should benefit both research and clinical practice.

Antenatal umbilical Doppler abnormalities: an independent risk factor for early onset neonatal necrotizing enterocolitis in premature infants

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency seen in neonatal units. Many factors have been considered as potentially important aetiologically, including gut ischaemia, sepsis and feeding. However, evidence remains equivocal.

OBJECTIVE

This study investigated whether preterm babies born to mothers with abnormal antenatal umbilical Dopplers (absent or reversed end diastolic flow--AREDF), that is exposed to antenatal gut ischaemia, are at an identical risk of developing NEC early in life, compared to babies born to mothers with normal Dopplers.

METHODS

All preterm (<or=32+6 week gestation) babies with no congenital anomaly, born to mothers resident in the county of Leicestershire in United Kingdom in 2001 and 2002 were identified using the Trent Neonatal Survey (TNS). Clinical data including the presence and severity of any NEC were extracted from the notes.

RESULTS

Two hundred forty-three preterm babies who met the criteria were identified during the period. Babies in whom umbilical Dopplers were not available and babies that died in the first 48 h were excluded. Complete data was thus available for 206 of these babies. A strong relation between AREDF and subsequent development of NEC was noted in these babies (OR: 5.88, 95% CI: 2.41 to 14.34, p<0.0001). This association still held after adjustment for gestational age at birth (OR: 7.64, 95% CI: 2.96 to 19.70, p<0.0001) and after adjustment for birthweight for gestational age z-score (OR: 6.72, 95% CI: 2.23 to 20.25, p=0.0007).

CONCLUSIONS

This study, based on a neonatal cohort, indicates that AREDF is an important independent risk factor for the production of NEC.

The posterior part of the human cerebral arterial circle (CAC): arterial caliber from gestational weeks 13 to 24

Numerous studies have reported that all components of the cerebral arterial circle in the 4-month-old human fetus are more slender than adult vessels, and of equal caliber. After that period, a degree of caliber differentiation is present, especially at the level of the posterior communicating arteries. The aim of this study was to determine arterial diameters in the posterior part of the fetal cerebral arterial circle from the 4th month (IV) to the 6th (VI). One hundred and seventy-two fetal cerebral arterial circles were examined by means of a surgical microscope. It was determined that average diameters of the left (right) pre-communicating parts of the posterior cerebral artery ranged from 0.30 +/- 0.03 (0.29 +/- 0.02) mm in month IV, to 0.36 +/- 0.04 (0.36 +/- 0.03) mm during month V and up to 0.55 +/- 0.22 (0.50 +/- 0.18) mm in month VI. The average diameters of the left (right) posterior communicating artery ranged from 0.24 +/- 0.02 mm (0.25 +/- 0.02) in month IV, to 0.30 +/- 0.03 mm (0.29 +/- 0.05) during month V and up to 0.38 +/- 0.08 (0.44 +/- 0.10) in month VI. Gender differences between posterior cerebral artery and posterior communicating artery diameters were not significant. Average posterior cerebral artery diameters were significantly larger than posterior communicating artery diameters in months IV and V, but not in month VI. It was established that caliber differentiation in the posterior part of the cerebral arterial circle began from gestational month IV, and that gender differences in arterial diameters were not significant until month VI of gestation.

Disproportionate Intrauterine Growth Intervention Trial At Term: DIGITAT

Background

Around 80% of intrauterine growth restricted (IUGR) infants are born at term. They have an increase in perinatal mortality and morbidity including behavioral problems, minor developmental delay and spastic cerebral palsy. Management is controversial, in particular the decision whether to induce labour or await spontaneous delivery with strict fetal and maternal surveillance. We propose a randomised trial to compare effectiveness, costs and maternal quality of life for induction of labour versus expectant management in women with a suspected IUGR fetus at term.

Methods/design

The proposed trial is a multi-centre randomised study in pregnant women who are suspected on clinical grounds of having an IUGR child at a gestational age between 36+0 and 41+0 weeks. After informed consent women will be randomly allocated to either induction of labour or expectant management with maternal and fetal monitoring. Randomisation will be web-based. The primary outcome measure will be a composite neonatal morbidity and mortality. Secondary outcomes will be severe maternal morbidity, maternal quality of life and costs. Moreover, we aim to assess neurodevelopmental and neurobehavioral outcome at two years as assessed by a postal enquiry (Child Behavioral Check List-CBCL and Ages and Stages Questionnaire-ASQ). Analysis will be by intention to treat. Quality of life analysis and a preference study will also be performed in the same study population. Health technology assessment with an economic analysis is part of this so called Digitat trial (Disproportionate Intrauterine Growth Intervention Trial At Term). The study aims to include 325 patients per arm.

Discussion

This trial will provide evidence for which strategy is superior in terms of neonatal and maternal morbidity and mortality, costs and maternal quality of life aspects. This will be the first randomised trial for IUGR at term.

Trial registration

Dutch Trial Register and ISRCTN-Register: ISRCTN10363217.

Application of the magnitude-squared coherence function between uterine and umbilical flow velocity waveforms for predicting placental dysfunction: a preliminary study

To examine whether the magnitude-squared coherence between uterine and umbilical blood flow velocity waveforms can, in conjunction with estimated fetal weight, uterine and umbilical pulsatility indices, fetal and maternal heart rates, diastolic notching and the amniotic fluid index, create a sensitive and specific model for the prediction of placental dysfunction. Binary logistic prediction models are created for preeclampsia, pregnancy induced hypertension and intrauterine growth restriction in a study group of 284 unselected midtrimester pregnancies. In each study group, the median value of derived parameters were compared with the uncomplicated pregnancy control group. The magnitude-squared coherence function between the uterine and umbilical flow velocity waveforms was found to be a statistically significant predictor of preeclampsia during the midtrimester of pregnancy. The magnitude-squared coherence did not improve the prediction of intrauterine growth restriction or pregnancy induced hypertension. The inclusion of magnitude-squared coherence as one of the prediction parameters may improve the early identification of pregnancies subsequently complicated by preeclampsia.

A population-based study of 518 very preterm neonates from high-risk pregnancies: Prognostic value of umbilical and cerebral artery Doppler velocimetry for mortality before discharge and severe neurological morbidity

OBJECTIVE

To evaluate in everyday practice the predictiveness of fetal umbilical artery and cerebral artery Doppler examination for mortality before discharge and for severe neurological morbidity among very preterm neonates from high-risk pregnancies.

METHODS

Data came from a population-based study (EPIPAGE) of all births before 33 weeks' gestation during 1 year in nine French regions. We examined the prognostic value of Doppler findings among the liveborn singletons delivered after pregnancies with maternal hypertension or antenatal suspicion of small-for-gestational-age status.

RESULTS

This study included 518 fetuses. Predischarge mortality for infants with abnormal umbilical artery Doppler findings was not significantly higher than for those with normal findings. Mortality for infants with abnormal cerebral artery Doppler findings was significantly higher in the bivariate analysis (crude OR: 3.5 (1.6-7.4)). After adjustment, the association between mortality and abnormal cerebral artery Doppler findings remained significant in the subgroup with an abnormal umbilical artery Doppler assessment (OR: 5.1 (1.1-23)). There was no significant association between neurological morbidity and Doppler findings.

CONCLUSION

The prognostic value of Doppler examinations appears lower in this study than in previous hospital series. This suggests the need for quality control and improvements in these examinations.

Outcome of 60 neonates who had ARED flow prenatally compared with a matched control group of appropriate-for-gestational age preterm neonates

OBJECTIVE

To describe the course and outcome of fetuses with absent or reversed end-diastolic (ARED) flow in the umbilical artery (UA) and to examine the influence of prematurity according to gestational age at delivery.

METHODS

Sixty pregnancies complicated by ARED flow in the UA were monitored by repeat Doppler measurements of arterial and venous vessels, non-stress tests (cardiotocogram (CTG)) and maternal investigations, and were delivered between 24 and 34 weeks. Fetal outcome was investigated and compared to a control group of appropriate-for-gestational age (AGA) preterm neonates, matched for gestational age. Mortality, birth weight, Apgar scores, postnatal cord arterial pH and need for ventilation were all recorded, as were cases of respiratory distress syndrome, bronchopulmonary dysplasia, persistent ductus arteriosus, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia, abnormal neurological findings and those requiring surgical intervention. Additionally, the group of fetuses with ARED flow was divided into three subgroups of different degrees of prematurity (delivery between 24 + 0 and 28 + 6 weeks, delivery between 29 + 0 and 31 + 6 weeks, and delivery after 32 weeks) and compared according to the above parameters.

RESULTS

Pre- or postnatal death occurred in 16 cases. Comparing the 44 (61%) that were born alive with the AGA neonates, significant differences were found in birth weight (P < 0.001), arterial pH value (P < 0.001), bronchopulmonary dysplasia (P = 0.002) and intestinal complications (P < 0.01). Prematurity-related complications were: need for ventilation (P = 0.001), respiratory distress syndrome (P < 0.0001), periventricular leukomalacia (P = 0.002) and pathological neurological testing (P = 0.005).

CONCLUSIONS

Neonates displaying ARED flow before birth are growth restricted, acidemic at delivery and are at high risk of developing bronchopulmonary dysplasia and intestinal complications. While perinatal mortality seems to be related to abnormal fetal Doppler velocimetry, age at delivery has a significant impact on short-term morbidity. After 32 weeks, morbidity is low and delivery should be considered. It could be speculated from our data that prolongation of pregnancy with Doppler velocimetry monitoring could help to reduce morbidity, although prolongation remains limited in most cases.

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.

Transient Bowel Ischaemia of the Fetus

OBJECTIVE

To discover the different underlying conditions in 2 fetuses suffering from temporary bowel ischaemia.

METHODS

Abnormal bowel findings were detected using antenatal sonography.

RESULTS

The abnormal bowel findings disappeared postnatally. Transient ischaemia of the fetal bowel due to different causes has been advocated antenatally to explain the abnormal findings. When a normal blood supply to the bowel has been restored, either in utero or after birth, the abnormal findings disappear.

CONCLUSIONS

Whenever gut dilatation is detected in a fetus at risk of bowel ischaemia the possibility of a transient functional finding must be considered.

Apport pronostique du Doppler de l’isthme aortique fœtal dans la prise en charge du retard de croissance intra-utérin

OBJECTIVE

Our purpose was to determine whether the use of aortic isthmus Doppler waveform analysis in growth restricted fetuses delivered at 28 to 38 weeks predicts perinatal outcomes.

MATERIAL AND METHODS

Prospective longitudinal study including singleton non-malformed euploid fetuses with accurate dating and diagnosed as growth restricted (abdominal circumference<10th percentile) and who were followed up at our institution and delivered<10 days after the last Doppler. Timing of delivery was collegial. Perinatal mortality and morbidity outcomes were compared in cases with anterograde blood flow versus retrograde net blood flow in aortic isthmus. Relative risk (RR) were calculated with 95% CI and P<0,05 was considered significant.

RESULTS

Thirty-two cases were considered for analysis: growth-restricted foetuses with anterograde blood flow (n=26) versus retrograde net blood (n=6). Maternal demographic characteristics in the two groups were similar and exceptions made of femur length average values for fetal biometrics were not significantly different. Doppler velocimetry results at the uterine, umbilical and cerebral arteries were similar in the two groups. Gestational age at delivery and birth weight were similar in both groups (respectively (239.65 20.1 vs. 247.3 16.4 (days) (p=0.349) and 1748.8 gr 468.7 vs. 1933.3 gr 468.7 (p=0.408)). There was a statistically significant increase in perinatal mortality in retrograde net blood flow group: 8.66 [IC 95% 2.03 - 36.84]. An interesting finding was that neonates with aortic isthmus retrograde net blood flow were more frequently born by cesarean delivery because of a suspected fetal compromise RR=3.22 CI 95% [1.29-8].

CONCLUSION

In our study Doppler identification of aortic isthmus retrograde net blood flow in growth-restricted fetuses was associated with an increase of perinatal death.

Diagnosis and management of intrauterine growth restriction

The growth-restricted fetus is a fetus who fails to reach his growth potential and is at risk for perinatal morbidity and mortality. When a fetus has an estimated weight below the 10th percentile, in the absence of congenital anomalies and in the presence of a normal amount of amniotic fluid, Doppler velocimetry gives the most important information to differentiate the truly growth-restricted fetus from the fetus that is constitutionally small but otherwise normal. One area of debate and research is whether Doppler velocimetry can help in timing the delivery of the growth-restricted fetus. Data appear to support the use of ductus venosus velocimetry in deciding when to deliver, but randomized data on this point are still lacking.

Blood flow parameters of the superior mesenteric artery as an early predictor of intestinal dysmotility in preterm infants

BACKGROUND

Blood flow parameters in the superior mesenteric artery (SMA) change with vasoconstriction or vasodilatation of the intestinal vascular bed. In cases of severe growth retardation as a result of haemodynamic disturbances, the blood flow changes persist into postnatal life.

OBJECTIVE

To assess early changes of Doppler sonographic blood flow parameters in the SMA for prediction of later intestinal motility disturbances in preterm infants and tolerance of enteral feeding during the first week of life.

MATERIALS AND METHODS

Doppler sonographic blood flow parameters in the SMA were measured on the first day of life and the following 5 days in 478 neonates with a birth weight below 1,500 g. According to the Doppler results, the neonates were divided into two groups-those with pathological parameters and those with normal blood flow parameters. Correlations between blood flow parameters, the development of intestinal dysmotility and the tolerated amount of enteral feeding were calculated.

RESULTS

Pathological blood flow parameters were observed in 148 neonates (group 1) and normal blood flow parameters in 330 neonates (group 2). Intestinal motility disturbance occurred in 125 neonates (83%) of group 1 and 47 neonates (15%) of group 2. Neonates in group 2 tolerated significantly more feed by the fifth day of life than neonates in group 1. Postnatal adaptation did not differ between the two groups, although the majority of neonates with intestinal dysmotility were small for gestational age. The predictive value of blood flow parameters for prediction of intestinal motility revealed high sensitivity and specificity by the first postnatal day, 2 or 3 days before development of clinical signs of intestinal dysmotility. There was a strong negative correlation between pathological pulsatility index on day 1 and the quantity of tolerated enteral feeding on day 5.

CONCLUSIONS

Pathological blood flow parameters in the SMA can predict problems of intestinal motility and tolerance of enteral feeding. With the early detection of these problems a prompt start of adequate therapy to avoid complications is possible.

Association between maternal-fetal Doppler velocimetry and fetal lung maturity

AIMS

To correlate maternal-fetal Doppler velocimetry parameters to indices of fetal lung maturity (FLM).

METHODS

Fifty-five consecutive third trimester pregnancies in which a pulsed-wave Doppler study, including uterine resistance index (Ut RI), umbilical artery pulsatility index (UA PI), middle cerebral artery pulsatility index (MCA PI) and the UA/MCA ratio was performed within 24 hours before amniocentesis and within a week from birth. FLM was determined by amniotic fluid lamellar bodies count (LBs).

RESULTS

A positive correlation between MCA PI and LBs (p < 0.007, r = 0.44) was found. MCA PI showed a trend to lower values in fetuses that developed RDS at birth (1.3 +/- 0.5 vs. 1.7 +/- 0.4, NS). LBs significantly decreased as Ut RI increased (O.R.: 0.98, C.I. 0.97-0.99, p < 0.05). A mean Ut RI > 0.64 was correlated to delayed FLM (LBs < 20,000/microl; sensitivity: 90.9%, specificity: 90.3%; positive predictive value: 76.9%, negative predictive value: 96.6%).

COMMENT

In third trimester pregnancies abnormal uterine artery waveforms may be associated to a delayed FLM, as expressed by decreased amniotic fluid LBs.

Doppler predictors of adverse neonatal outcome in the growth restricted fetus at 34 weeks' gestation or beyond

OBJECTIVE

The study was undertaken to assess whether prenatal Doppler variables can identify cases of fetal growth restriction (FGR) approaching term who are at risk for adverse neonatal outcome.

STUDY DESIGN

From a cohort of FGR cases delivered at >or=34 weeks, fetal biometry and pulsatility indices (PI) of fetal arteries obtained less than 2 weeks before delivery were related to adverse neonatal outcome, defined as admission to the neonatal intensive care unit (NICU) for indications other than low birth weight alone.

RESULTS

Stepwise regression analysis showed that after controlling for gestational age at delivery and fetal biometry, only the last umbilical artery (UA) PI percentile was significantly predictive of adverse neonatal outcome (odds ratio=1.02, 95% CI 1.01-1.03, P=.02). Receiver operating characteristic curve analysis identified a UA PI at the 65th percentile as optimal predictor of adverse neonatal outcome (sensitivity=60%, false-positive rate=30%).

CONCLUSION

In FGR cases delivered at >/=34 weeks' gestation, Doppler PI at the UA independently predicts the likelihood of admission to the NICU for reasons other than low birth weight alone.

Prospect for vaginal delivery of growth restricted fetuses with abnormal umbilical artery blood flow

BACKGROUND

The best mode of delivery in cases of intrauterine growth restriction (IUGR) with umbilical artery blood flow changes is not well elucidated.

OBJECTIVE

To evaluate outcome in IUGR with umbilical artery blood flow changes planned for vaginal delivery after a negative oxytocin challenge test (OCT).

METHODS

In 84 term singleton pregnancies with suspected IUGR and no unanimous indication for abdominal delivery, Doppler velocimetry and OCT were performed. Positive OCT cases were delivered by cesarean section, negative OCT cases planned for vaginal delivery.

RESULTS

Umbilical artery Doppler velocimetry was normal in 51 cases (normal group) and abnormal in 33 cases (increased pulsatility index with maintained forward diastolic flow). Gestational age at delivery was shorter (p = 0.008), positive OCT more common (33% vs. 16%; p = 0.06), and vaginal delivery less common (40% vs. 63%; p = 0.04) in the abnormal blood flow group compared with the normal flow group. When in labor, 68% in the abnormal flow group and 76% in the normal flow group delivered vaginally (p = 0.6). One baby had a lethal malformation and another suffered meconium aspiration and pneumothorax, but was discharged home healthy.

CONCLUSIONS

The vaginal delivery rate was significantly lower in the abnormal flow group compared with the normal flow group, but in cases finally destined for a trial of labor the vaginal delivery rates were similar. There was no indication that any fetus was exposed to detrimental hypoxia or distress.

Perinatal outcome following amniotic septostomy in chronic TTTS is independent of placental angioarchitecture

OBJECTIVES

To determine whether the vascular anatomy of monochorial placenta influences the success of amniotic septostomy for the treatment of chronic mid-trimester twin-twin transfusion syndrome, we report placental anastomoses and perinatal data of 13 pregnancies treated by amniotic septostomy in combination with amnioreduction (AR). The placental anastomoses were delineated postnatally by perfusion studies. Perinatal outcome was also evaluated in relation to umbilical artery Doppler waveform of the donor twin.

RESULTS

The median gestational age at septostomy was 21 weeks (range 18 to 25.5 weeks). Amniotic septostomy in combination with single AR procedure successfully resolved polyhydramnios in all cases. The median gestational age at delivery and the septostomy to delivery interval were 27 weeks (range 20 to 34 weeks) and 4 weeks (range 0.3 to 13.6 weeks), respectively. Of the 26 fetuses, 10 died in utero and four died within a week of life, with a combined survival rate of 46%. There was no relation between the clinical outcome and angioarchitecture of the placenta. However, pregnancy loss was higher in the donor twin with absent end-diastolic flow umbilical artery Doppler waveform than those with end-diastolic flow (85 vs 17%; p < 0.001).

CONCLUSION

This study suggests that although amniotic septostomy is a promising method for the correction of oligohydramnios and/or polyhydramnios, perinatal survival rate does not depend on angioarchitecture of the placenta. Instead, umbilical artery Doppler waveform of the donor twin may be a better marker for survival rate.

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

OBJECTIVES

(1) To investigate fetal intracranial circulation, relative to peripheral blood flow, during labor with abnormal cardiotocographic (CTG) patterns, using three non-invasive methods. (2) To determine the utility of monitoring middle cerebral artery (MCA) Doppler during labor.

INTERVENTIONS

Fetuses were assessed using simultaneous CTG, pulse oximetry, and Doppler ultrasonography of both the MCA and umbilical artery (UA) to measure the pulsatility index (PI), resistance index (RI), and flow velocity integral (FVI).

STUDY DESIGN

During labor 20 term fetuses with abnormal CTG patterns and oxygen saturation values >30%, and 24 term fetuses with abnormal CTG patterns and oxygen saturation values <30% were studied, and peripartum outcomes were compared. The groups were comparable with regard to maternal age and parity. Results were evaluated using the Student's t-test and Fisher exact test.

RESULTS

MCA Doppler showed significantly lower PI and RI, and higher FVI in the presence of reduced oxygen saturation. Differences in fetal outcomes between the two groups correlated with MCA Doppler findings.

CONCLUSIONS

In experienced hands, Doppler screening of fetal middle cerebral artery waveforms during labor can be useful in the evaluation of intrapartum hypoxia in complicated pregnancies.

Noninvasive tests to predict fetal anemia: a study comparing Doppler and ultrasound parameters

OBJECTIVE

This study was undertaken to compare test characteristics of ultrasound and Doppler parameters in the prediction of fetal anemia in alloimmunized pregnancies.

STUDY DESIGN

In a prospective cohort study, 16 nonhydropic fetuses with red blood cell alloimmunization were evaluated with ultrasound and Doppler imaging. Middle cerebral artery (MCA) peak systolic velocity, intrahepatic umbilical venous (IHUV) maximum velocity, liver length, and spleen perimeter were measured. Results before first fetal blood sampling (FBS) or delivery were analyzed. Fetal anemia was defined as hemoglobin deficit 5 SD or greater. Sensitivity and specificity were calculated.

RESULTS

Six fetuses were anemic and required intrauterine transfusion, and 10 were not severely anemic at birth. MCA Doppler imaging was the best predictor of fetal anemia (100%), followed by IHUV (83%). Sensitivity was low for spleen perimeter (66%) and liver length (33%).

CONCLUSION

Doppler evaluation of MCA peak systolic velocity is better than IHUV maximum velocity, liver, or spleen size in the prediction of fetal anemia in red blood cell alloimmunization.

Correlation between biomagnetic and Doppler findings of umbilical artery in fetal growth restriction

OBJECTIVE

To assess the value of biomagnetic recordings of the umbilical artery over Doppler ultrasound screening in order to predict complications of impaired uteroplacental blood flow in fetuses with intrauterine growth restriction (IUGR).

METHODS

Our study population included 11 IUGR preeclamptic (34-37-weeks gestation; birth weight 1969 +/- 129 g) and 19 normal pregnancies (34-37-weeks gestation; birth weight 3195 +/- 229 g). Umbilical artery Doppler ultrasound waveform measurements were expressed in terms of pulsatility index (PI). Biomagnetic signals (waveforms) recorded from the IUGR umbilical artery were expressed in terms of magnetic power spectral amplitudes.

RESULTS

In all cases, the frequency band considered was 2 to 7 Hz. The spectral amplitudes were low (mean: 117+/-24 fT/ radical Hz) in most (90.9%) IUGR pregnancies and high (mean: 224+/-37 fT/ radical Hz) in most normal pregnancies (89.5%). There was a statistically significant difference between normal and IUGR pregnancies with respect to spectral amplitudes (p < 0.0001), Doppler PI (p < 0.0005), pH (p < 0.0005) and Apgar score (p < 0.0005). Multiple linear regression analysis revealed an influence of PI, pH and Apgar scores on the biomagnetic values (ANOVA: p < 0.0005).

CONCLUSION

Our data imply that biomagnetic values of the umbilical artery flow could prove to be a helpful method for the evaluation of fetal well being especially in pregnancies complicated with preeclampsia and growth restriction.

Decreased vascularization and cell proliferation in placentas of intrauterine growth-restricted fetuses with abnormal umbilical artery flow velocity waveforms

OBJECTIVE

The purpose of this study was to compare the morphologic features of placentas in severe intrauterine fetal growth restriction with abnormal umbilical artery blood flow velocity waveforms and normal gestation.

STUDY DESIGN

Immunohistochemical methods were used to evaluate cell proliferation, vascular density, and alpha-smooth muscle actin expression by stromal cells in a group of 9 age-matched intrauterine growth-restricted and control placentas at 25 to 41 weeks of gestation.

RESULTS

Fewer MIB1-positive nuclei were observed in both trophoblast and stromal cell populations in intrauterine growth restriction, which indicates fewer cells in cycle. Furthermore, a greatly reduced vascular density was observed, along with higher levels of alpha-smooth muscle actin expression in stromal cells.

CONCLUSION

Intrauterine growth-restricted placentas show reduced cell proliferation in both trophoblast and stromal cell compartments. Peripheral villous vascularization is highly reduced.

Temporal sequence of abnormal Doppler changes in the peripheral and central circulatory systems of the severely growth-restricted fetus

OBJECTIVE

To identify the temporal sequence of abnormal Doppler changes in the fetal circulation in a subset of early and severely growth-restricted fetuses.

METHODS

This was a prospective observational study in a tertiary care/teaching hospital. Twenty-six women who were diagnosed with growth-restricted fetuses by local standards before 32 weeks' gestation and who had abnormal uterine and umbilical artery Doppler velocimetry were enrolled onto the study. To compare Doppler changes as a function of time, pulsed-wave Doppler ultrasound was performed on five vessels in the fetal peripheral and central circulations. Doppler examinations were performed twice-weekly and on the day of delivery if the fetal heart rate tracing became abnormal. Doppler indices were scored as abnormal when their values were outside the local reference limits on two or more consecutive measurements. Biometry for assessment of fetal growth was performed every 2 weeks. Computerized fetal heart rates were obtained daily. Delivery was based on a non-reactive fetal heart rate tracing and not on Doppler information. Patients with a severely growth-restricted fetus who were delivered for maternal indications such as pre-eclampsia were excluded. Perinatal outcome endpoints included: intrauterine death, gestational age at delivery, newborn weight, central nervous system damage of grade 2 or greater, intraventricular hemorrhage and neonatal mortality.

RESULTS

Mean gestational age and newborn weight at delivery were 29 (standard deviation (SD), 2) weeks and 818 (SD, 150) g, respectively. The sequence of Doppler velocimetric changes was described by onset time cumulative curves that showed two time-related events. First, for each vessel there was a progressive increase in the percent of fetuses developing a Doppler abnormality. Second, severely growth-restricted fetuses followed a progressive sequence of acquiring Doppler abnormalities which were categorized into 'early' and 'late' Doppler changes. Early changes occurred in peripheral vessels (umbilical and middle cerebral arteries; 50% of patients affected 15-16 days prior to delivery). Late changes included umbilical artery reverse flow, and abnormal changes in the ductus venosus, aortic and pulmonary outflow tracts (50% of patients affected 4-5 days prior to delivery). The time interval between the occurrence of early and late changes was significantly different (P < 0.0001) and late changes were significantly associated with perinatal death (P < 0.01).

CONCLUSIONS

Doppler velocimetry abnormalities develop in different vessels of the severely growth-restricted fetus in a sequential fashion. Late changes in vascular adaptation by the severely growth-restricted fetus are the best predictor of perinatal death.