Umbilical Artery Waveforms Research Articles

Fetal Growth Restriction: A Pragmatic Approach.

An accurate diagnosis of fetal growth restriction relies on a precise estimation of gestational age based on a carefully obtained history as well as early ultrasound, since a difference of just a few days can lead to a significant error. There is a continuum of risk for adverse outcome that depends on the certainty of dates and presence or absence of comorbidities, in addition to the estimated fetal weight percentile and the umbilical artery waveform. The results of several studies, most notably the TRUFFLE trial, demonstrate that optimal management of fetal growth restriction with an abnormal umbilical artery waveform requires daily electronic fetal heart rate monitoring, and this monitoring does not require computerized interpretation. The role of ductus venosus waveform, biophysical profile, and middle cerebral artery waveform is less clear, and the results of these three modalities should be interpreted with caution.

Umbilical artery half peak systolic velocity deceleration time: a novel Doppler parameter for prediction of neonatal outcomes in pregnant women with preeclampsia.

To assess the effectiveness of half peak systolic velocity deceleration time (hPSV-DT) in predicting neonatal outcomes in pregnant women with preeclampsia and to compare its usefulness with the conventional umbilical artery (UA) pulsatility index (PI) approach. A prospective cohort study was conducted among pregnant women with preeclampsia who were admitted to the Department of Perinatology, Ministry of Health Ankara City Hospital between 01 September 2022 and 01 January 2023 at 28-41weeks gestational age. 55 patients were divided into two groups: the study group with UA hPSV-DT value < 5th percentile (n = 22) and the control group with UA hPSV-DT value ≥ 5th percentile (n = 33). UA hPSV-DT calculates the time in milliseconds needed to halve the maximal velocity of the UA waveform using Doppler ultrasonography. Birth weight, gestational age at birth, 1st minute APGAR, 5th minute APGAR, and umbilical cord pH values were significantly lower in the anormal hPSV-DT group (p < 0.05). Additionally, the rates of admission to NICU, respiratory distress syndrome (RDS), delivery time < 34weeks, and birth weight < 2500g were significantly more frequent in the anormal hPSV-DT group compared to the normal hPSV-DT group (p < 0.05). UA-PI > 95th percentile was detected in only 2 (8%) of 23 patients whose newborns were admitted to the NICU (p = 0.149), while hPSV-DT < 5th percentile was detected in 16 (69%) of 23 patients (p < 0.001). According to ROC analysis, the area under the curve was 0.82 (95% CI 0.06-0.28) for admission to the NICU. The best balance of sensitivity/specificity in ROC curves was 221.5 (82.6% sensitivity, 69.1% specificity, p < 0.001). UA hPSV-DT was successful in predicting composite adverse perinatal outcomes in pregnant women with preeclampsia. It is a promising novel method that is accurate, quantitative, reproducible, and easily applicable. With further studies, this method may be a primary diagnostic tool in the management of high-risk pregnancies and in determining the optimal timing of delivery.

Clinical significance of intermittent absent end-diastolic flow of the umbilical artery in fetal growth restriction

Fetal growth restriction can result from a variety of maternal, fetal, and placental conditions. Umbilical artery Doppler assesses the impedance to blood flow along the fetal component of the placental unit. An abnormal umbilical artery waveform reflects the presence of placental insufficiency and can help differentiate a growth-restricted fetus from the constitutionally small, thus guiding further management. The presence of persistently absent end-diastolic flow and reversed end-diastolic flow is an indication for inpatient antenatal surveillance and preterm delivery. There is no consensus on the optimal management of intermittent absent end-diastolic flow owing to a lack of data to support the ideal delivery timing for growth-restricted fetuses with this finding. This study aimed to estimate the risks of adverse perinatal outcomes among growth-restricted pregnancies with persistently elevated, intermittently absent, and persistently absent end-diastolic flow. Fetal growth restriction is a common condition that is associated with an increased risk of fetal morbidity and mortality. Intermittently absent umbilical artery end-diastolic flow may be identified among pregnancies with fetal growth restriction. The fetal risks associated with persistently absent end-diastolic flow have been described. However, the risks associated with intermittent absent end-diastolic flow are not as well-known. We performed a retrospective cohort study including nonanomalous, singleton, growth-restricted pregnancies that received umbilical artery Doppler assessment at our institution from 2009 to 2020. Fetuses were classified into the following 3 categories: elevated umbilical artery Doppler, intermittent absent end-diastolic flow, and persistently absent end-diastolic flow. The Doppler categories were classified by the most severe in the pregnancy. The primary outcome was a composite of neonatal morbidity. Total 233 fetuses met the criteria. Of which 78 (33.0%) had elevated umbilical artery Doppler waveforms, 37 (16.0%) had intermittent absent end-diastolic flow, and 119 (51.0%) had absent end-diastolic flow. The composite outcome was statistically different between the groups, occurring in 16.9% with elevated umbilical artery Doppler waveforms (13/77), 35.1% (12/39) with intermittent absent end-diastolic flow, and 56.3% (65/127) with absent end-diastolic flow (P<.001).The odds ratio for the composite outcome was significantly increased in absent end-diastolic flow (odds ratio, 6.15; 95% confidence interval, 3.14-12.80) and was not significantly increased for intermittently absent end-diastolic flow (odds ratio, 2.46; 95% confidence interval, 0.98-6.19) when compared with elevated umbilical artery Doppler waveforms. When adjusted for gestational age at delivery and antenatal steroids, no difference was seen in the primary outcome for intermittent absent end-diastolic flow (adjusted odds ratio, 0.73; 95% confidence interval, 0.20-2.68) and absent end-diastolic flow (adjusted odds ratio, 1.44; 95% confidence interval, 0.51-4.07). Among growth-restricted pregnancies, intermittent absent end-diastolic flow is associated with a similar rate of composite neonatal morbidity as persistently elevated Doppler waveforms. In addition, there is no difference in composite neonatal morbidity between the 3 groups when corrected for gestational age at delivery and antenatal steroid administration. These similar outcomes should be considered when creating an antenatal surveillance plan and discussing the potential for outpatient management.

Fetal Wellbeing Monitoring: A Review Article.

While assessing maternal health is relatively easy, assessing fetal well-being has always been tricky. This has led to tremendous technological development in fetal well-being assessment, thus bridging the gap between biotechnology and antenatal medicine. It is broadly divided into early pregnancy, late pregnancy, and during labour assessment. While the early assessment involves genetic check-ups and malformations, the late pregnancy check-ups aim at delivering a healthy fetus at term by normal vaginal delivery. The early tests can be invasive or non-invasive. Non-invasive include cell-free fetal DNA assessment and fetal cell-based assessment. Invasive tests include amniocentesis and chorionic villous sampling. These are followed by chromosomal microarray and next-generation sequencing. Under this procedure, exome sequencing is done, which is either clinical or whole. Sequencing of the whole genome can also be done. A recent advancement is pre-implantation genetic testing. These are mainly useful in identifying monogenic disorders for which the locus causing disease is identified beyond any doubt. In late pregnancy, the most commonly used test is biophysical. It works on the principle that an increase in the fetal heart rate occurs in conjugation with fetal movements. The next widely employed technology is Doppler, which is used to know fetal heart rates, valve timing intervals, and umbilical artery waveforms. Cardiotocography is also widely used both during pregnancy and during labour. It measures the fetal heart rate while correlating it with uterine contractions. Wireless fetal and maternal heart monitoring and telemonitoring are recent upcoming fields.

Comparative Study of the Umbilical Artery Doppler Indices of Healthy and Growth-Restricted Foetuses in Lagos.

Aim of the Study:This study compared the umbilical artery Doppler indices (UADI) in normal and foetal growth-restricted (FGR) foetuses to determine the relationship between the UADI and pregnancy outcomes.Materials and Methods:This was a case-control study that recruited one hundred and eighty pregnant women comprising 90 with FGR pregnancies and 90 with normal pregnancies. Foetal biometric parameters and UADI were measured in all the participants. The UADI and clinical outcomes (preterm delivery, birth weight, perinatal death, etc.) of the normal and FGR foetuses were compared.Results:The mean estimated foetal weights of the FGR pregnancies (subjects) and normal pregnancies (controls) were 2.76 ± 0.66 kg and 3.62 ± 0.37 kg, respectively (P < 0.0001). The mean APGAR score at 5 min was 6.93 ± 1.72 for subjects and 8.03 ± 0.94 for controls (P < 0.0001). Abnormal umbilical artery Doppler waveforms were detected: decreased end-diastolic flow in 25 (27.8%), absent end-diastolic in 7 (7.8%) and reversed end-diastolic flow in 4 (4.4%) of the FGR pregnancies. There were 74 (82.2%) preterm deliveries among the subjects, while only 7 (7.8%) of the controls had preterm deliveries. Six deaths (two perinatal and four neonatal deaths) were recorded among the subjects, while no death occurred among the controls.Conclusion:Foetuses with FGR showed significantly higher quantitative Doppler indices (increased RI, PI, SD ratio), and a higher prevalence of abnormal umbilical artery waveform pattern (qualitative) than the healthy foetuses (controls).

M-Sign in Middle Cerebral Artery Doppler Waveforms: A Sign of Fetal Vasoconstriction Before and After Open Fetal Spina Bifida Repair.

Increased pulse wave reflection in the fetal arterial system, illustrated by a second systolic peak (M-sign) in middle cerebral artery (MCA) Doppler waveforms, allows interpretation of fetal systemic vasoconstriction. Little is known about fetal vascular regulation during fetal spina bifida (fSB) repair. Therefore, the aim of this study was to analyze MCA-Doppler waveform changes before, during, and after fSB repair. 31 pregnant women who underwent fSB repair were included. Fetal MCA-Doppler waveforms were prospectively analyzed before, during and after fSB repair, and categorized as follows: normal systolic downslope, systolic shoulder, second systolic peak (M-sign), and concave systolic downslope. These MCA waveforms were related to maternal and fetal characteristics, to anesthetic medication, and to umbilical artery (UA) waveforms. Before fSB repair, all fetuses repeatedly presented M-signs. After initiation of desflurane for general anesthesia, systolic shoulder and the M-sign vanished in 24/31 (78%) fetuses and 19/31 (61%) showed transient UA ARED flow. A significant association between these two Doppler findings was found (p=0.007). After fSB repair, signs of increased pulse wave reflection reappeared but resolved over time (23 days ± 20, SD) in all fetuses. Both fSB and intrauterine repair influence fetal vascular regulation. This phenomenon can be illustrated by MCA-Doppler waveforms. While anesthetic agents transiently eliminated M-signs and often provoked a UA ARED flow, fSB repair finally led to normalization of MCA-Doppler waveforms indicating return to normal fetal vascular regulation.

Association of Adverse Outcomes with Abnormal Umbilical Artery Waveform in Intrauterine Growth Restricted Pregnancies

Background: Intrauterine growth restriction refers to a fetus with a fetal weight in the 10th percentile on ultrasonography who has not reached its biologically set growth potential due to a pathologic condition. Aim: To determine the association of adverse outcome with abnormal umbilical artery waveform groups in intrauterine growth restricted pregnancies. Methods: This Cohort Study was conducted from February 2019 to 12 February 2020 at Gynae &amp; Obs Department, Imran Idrees Teaching Hospital Sialkot, Sialkot Medical College, Sialkot 120 pregnant females, attending Department of Gynae &amp; Obs were recruited into the study after 28 weeks of gestation. The women were divided into two groups depending on their Doppler findings. One group (exposed) comprised of women with intrauterine growth restriction, with absent or reversed diastolic flow in the umbilical artery. The control (unexposed) group included women with small-for-date fetuses, with normal umbilical artery Doppler flow. Results: The mean age of females was 27.40 ± 4.77 years. The mean gestational age was 30.69 ± 2.19 weeks. The mean birth weight of neonates was 2.37 ± 0.90 kg. The mean AGPAR score of neonates was 6.60 ± 1.70. It was observed that there was significant association between groups and low birth weight with p-value = 0.002. Admissions to NICU were significantly lower in normal Doppler wave form group having p-value = 0.001. Conclusion: The percentage of NICU admission was 46.7% and the percentage of low birth weight was 46.7% in intrauterine growth restriction. The mean birth weight was significantly lower in exposed group and the mean APGAR score was also significantly lower in exposed group. Keywords: Apgar score, neonatal intensive care unit, Intrauterine Growth Restriction, Doppler ultrasound,

“Early Screening Test for High Risk Pregnancies by Second Trimester Color Doppler Imaging Of the Feto-Placental Circulation”

Objective: To examine the diagnostic value of umbilical artery velocity waveforms for the early detection of pregnancy induced hypertension and fetal growth restriction. To determine the utility of color Doppler Sonography of the fetoplacetal circulation for early detection of high risk pregnancies. Methods: This prospective study was conducted in the Department of Obstetrics &amp; Gynecology, Sir Sallimullah Medical Collage &amp; Mitford Hospital Dhaka in collaboration with radiology and imaging department of Dhaka hospital in 1st July, 2006 to 30 June, 2008. 126 randomly selected patients from 17-35 years of ages whose umbilical artery Doppler sonography was done between 16-22 weeks of gestation. All the patient were taken umbilical artery Doppler ultrasonography. Informed consent was taken from all patients. Results: A total 126 subjects of 16 to 22 weeks of gestation were included in this series. On application of the student‘t’ test for S/D ratio between normal and abnormal waveforms of the umbilical artery was found significant difference (P&lt;.0001). Distribution of patient according to umbilical artery systolic / diastolic ratio (n=126). Normal UA waveform 76 (60%), abnormal UA waveform 50(40%), Age (Mean ±SD) in year, normal UA waveform 25.63 ± 4.47 and abnormal UA waveform 25.86±3.75. Para: Primiparous normal UA waveform 36 (60%) &amp; abnormal UA waveform 24 (40%), multiparous normal UA waveform 40 (60.6%) &amp; abnormal UA waveform 26 (39.4%). Gestation age at scan in weeks (Mean± SD), normal UA waveform 19.5 ±2.5, abnormal UA waveform 19±2.0. Gestation age at delivery in weeks (Mean± SD), normal UA waveform 39.03±1.61, abnormal UA waveform 35.78 ±1.53, P value 0.0001. Birth wt. in Kg. (Mean ±SD), normal UA waveform 3.10 ±0.38, abnormal UA waveform 2.42 ±0.53, P value 0.0001. S/D ratio (Mean ±SD), normal UA waveform 2.40 ±0.31, abnormal UA waveform 5.46±1.62, P value 0.0001. Cases with an abnormal outcome in relation to whether the umbilical artery waveform was classified as normal or abnormal (n=126). Abnormal outcome in PIH normal UA waveform (n=76) 4%, PIH abnormal UA waveform (n=50) 14%, P value 0.001. In PIH/FGR, normal UA waveform (n=76) 1% &amp; abnormal UA waveform (n=50) 5%, P value 0.024. FGR normal UA waveform (n=76) 5% &amp; abnormal UA waveform (n=50) 13%, P value 0.002. Asphyxia normal UA waveform (n=76) 0% &amp; abnormal UA waveform (n=50) 3%, P value 0.017. PIH /IUD normal UA waveform (n=76) 0% &amp; abnormal UA waveform (n=50) 1%. A significant association was found when the Chi Square (X 2) test was used to examine the relationship between umbilical artery blood flow and the outcome of patient (i.e FGR, PIH, fetal asphyxia). The screening test had a sensitivity of 78.26% &amp; specificity of 82.5% and accuracy 80.95%. The predictive value of a positive test was 72% and of a negative test 86.84%. Conclusion : A close linear relationship between diagnosis of high risk pregnancy &amp; umbilical artery Doppler velocity waveforms was observed .As umbilical artery Doppler is easy to perform and it is done in between 16 to 22 weeks of gestation can be done along with anomaly scan which is also done at 20-22 week of gestation. So, UA Doppler does not cause additional USG scan. Along with anomaly scan UA Doppler will help to screen out high risk pregnancy.

ROLE OF DOPPLER INDICES IN THE PREDICTION OF ADVERSE PERINATAL OUTCOME IN PREECLAMPSIA

Objective: To determine diagnostic accuracy of systolic/diastolic ratio and cerebro-placental index in predicting adverse perinatal outcome among patients in preeclampsia.&#x0D; Study Design: Cross-sectional validation study.&#x0D; Place and Duration of Study: Department of Obstetrics and Gynaecology, Pak Emirates Military Hospital, Rawalpindi, from Jun to Dec 2017.&#x0D; Methodology: A total of 191 patients with preeclampsia were included. Doppler ultrasound (including doppler wave forms obtained from free floating portion of umbilical artery and doppler waveform from middle cerebral artery at the level of circle of Willis) examination was done after gestational age 30 weeks and Doppler study repeated at 2-4 weeks interval depending on severity of preeclampsia and abnormalities of waveform. Cases were followed and results of last Doppler examination within 10 days of delivery were considered and perinatal outcome noted.&#x0D; Results: The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of systolic/diastolic ratio in predicting adverse perinatal outcome among patients in preeclampsia, keeping actual adverse perinatal outcome as reference standard was 82.35%, 86.52%, 87.50%, 81.05% and 84.29% respectively. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of cerebro-placental index in predicting adverse perinatal outcome among patients in preeclampsia, keeping actual adverse perinatal outcome as reference standard was 78.67%, 92.24%, 86.76%, 86.99% and 86.91% respectively.&#x0D; Conclusion: The diagnostic accuracy of systolic/diastolic ratio, cerebro-placental index in predicting adverse perinatal outcome among patients in preeclampsia is quite high.

Interpretation of Wave Reflections in the Umbilical Arterial Segment of the Feto-Placental Circulation: Computational Modeling of the Feto-Placental Arterial Tree.

Placental vascular abnormalities are associated with a host of pregnancy complications including placenta mediated fetal growth restriction (FGR). Umbilical arterial (UA) Doppler ultrasound velocity waveforms are widely used in the diagnosis of underlying placental vascular abnormalities in pregnancies with suspected FGR, which greatly helps to prevent stillbirth via ongoing fetal monitoring and timely delivery. However, the sensitivity of UA Doppler diagnosis diminishes late in gestation. Our goal was to present a generalized wave decomposition method to compute forward and reflected components from UA waveforms. A detailed anatomical based model was also developed to explain observed UA flow waveform and to explore how vascular properties affect the shape of flow wave components. Using data from a previous study of pregnant mice using high frequency ultrasound microscopy, we examined in utero Doppler and M-mode ultrasound measurements in 15 fetuses' UA. Following ultrasound, the placentas had been collected and perfused with contrast agent to obtain high-resolution 3D images of the feto-placental arteries. Model of these specimens indicates the significant role of terminal load impedance (capillary and/or veins) in creating positive or negative reflected flow waveforms. A negative flow reflected waveform is obtained when terminal impedance is elevated. This is consistent with the elongated and non-branching terminal villi that are proposed to cause the highly abnormal UA waveforms found in early-onset FGR. The significance of these findings for the diagnostic utility of UA Doppler in human pregnancy is that the identification and measurement of wave reflections may aid in discriminating between healthy and abnormal placental vasculature in pregnancies with suspected late-onset FGR.

Study of Maternal and Fetal Doppler Velocimetry, Histopathology of Placental Bed in Diabetic Pregnancy and Its Correlation to Fetal Outcome

Diabetes mellitus still represents an important medical problem during pregnancy, causing perinatal morbidity and mortality. Despite improved outcome reflected by a steep decline in perinatal mortality over the past few decades, controversy still exists regarding the care of the pregnant woman with both pre-existing and gestational Diabetes Mellitus. Doppler ultrasound is especially valuable during pregnancy because fetal maternal and placental circulations can be studied. The aim of this work was to study the vascular changes in the uteroplacental and fetoplacental circulations, and to correlate these findings with histopathology of the placenta and placental bed, which may occur in association with diabetic pregnancies. The study was carried out on 100 pregnant women of comparable age and parity. They were divided into 2 groups. The control group comprising 20 normal non-diabetic pregnant women and the normotensive diabetic group comprising 80 pregnant diabetic women. All were singleton pregnancies of 34 weeks or more and were delivered by C.S the control and the study cases were subjected to history taking and thorough physical examination. They were also subjected to ultrasonographic examination for fetal biometric parameters and for Doppler examination. Doppler examination included umbilical artery, uterine arteries fetal middle cerebral artery. At the time of C.S the placenta and placental bed biopsy was obtained. After delivery, the Apgar score of the newborn was assessed at 1 and 5 minutes, the body weight was measured, and the fetus was followed up for any complications. Result: There was a positive correlation between the umbilical artery PI and the mean blood glucose levels indicating that poor diabetic control is probably associated with increased umbilical artery PI. However, there was no significant difference between the mean value of the umbilical artery PI in the diabetic and control groups. The uterine arteries Doppler indices showed no significant findings between the diabetic and the control groups. Neither did the uterine arteries Doppler indices show a correlation with the mean blood glucose levels. There was no significant difference between the middle cerebral artery PI in the diabetic and control groups. This observation indicates that there was no redistribution in the fetal circulation in the fetuses of the diabetic group. There was also non correlation between the MCA Doppler indices and the glycemic control. Histopathologic studies of the placental bed showed marked difference between the diabetic group and the control group as regards lack of physiologic changes and arteriosclerotic changes, which emphasizes the effect of diabetes on the placental bed vasculature. Conclusion: Abnormal umbilical artery waveform analysis is one of significant predictors of fetal compromise in diabetic pregnancy, but fetal compromise can occur in association with normal Doppler waveform analysis. In maternal diabetes the classic redistribution seen in fetal hypoxemia due to uteroplacental insufficiency may not occur in diabetic patient even in severely compromised fetuses. In maternal diabetes mellitus, maternal glycemic control has no effect on impedance to flow in the uterine and middle cerebral arteries. No relationship was found between the uterine or umbilical arteries Doppler indices and the placental bed decidual vascular pathology in diabetic pregnancies. There was no correlation between placental findings and the Doppler waveform analysis of the umbilical and the uterine arteries.

Discrepancy in Doppler waveforms between two umbilical arteries in fetuses with absent or reversed end-diastolic flow: A prospective observational study.

To asses the occurrence of discrepancies between the Doppler waveforms of the left and right umbilical arteries in their paravesical part in fetuses with absent or reversed end-diastolic flow in the free-floating umbilical cord. This prospective observational study included pregnant women with fetal growth restriction or twin-to-twin transfusion syndrome. Umbilical arterial Doppler waveforms were obtained from both umbilical arteries in their intra-abdominal paravesical part. Doppler findings were recorded as present end-diastolic flow (PEDF)/absent end-diastolic flow (AEDF); AEDF/AEDF; AEDF/reversed end-diastolic flow (REDF); or REDF/REDF pattern. There were 49 fetuses with AEDF or REDF at the free-floating umbilical cord. Of these, 20 (40.8%) had a discrepancy in Doppler waveforms between the two umbilical arteries, with 14 (28.6%) showing PEDF/AEDF, 17 (34.7%) AEDF/AEDF, 6 (12.2%) AEDF/REDF, and 12 (24.5%) REDF/REDF pattern. Doppler waveforms showed discrepancies between the two umbilical arteries in 40.8% of pregnant women with AEDF or REDF in the free-floating umbilical cord. The presence of end-diastolic flow in one umbilical artery cannot exclude the possibility of AEDF in the other.

Reflected hemodynamic waves influence the pattern of Doppler ultrasound waveforms along the umbilical arteries.

The pulsatile pattern of blood motion measured by Doppler ultrasound within the umbilical artery is known to contain useful diagnostic information and is widely used to monitor pregnancies at risk of fetal growth restriction or stillbirth. Animal studies have identified reflected pressure waves traveling counter to the direction of blood flow as an important factor in the shape of these waveforms. In the present study, we establish a method to measure reflected waves in the human umbilical artery and assess their influence on blood velocity pulsation. Ninety-five pregnant women were recruited from a general obstetrics clinic between 26 and 37 wk of gestation and examined by Doppler ultrasound. Blood velocity waveforms were recorded for each umbilical artery at three locations along the umbilical cord. With the use of a computational procedure, a pair of forward and reverse propagating waves was identified to explain the variation in observed Doppler ultrasound waveforms along the cord. Among the data sets that met data quality requirements, waveforms in 93 of the 130 arteries examined agreed with the wave reflection model to within 1.5% and showed reflections ranging in magnitude from 3 to 52% of the forward wave amplitude. Strong reflections were associated with large differences in pulsatility between the fetal and placental ends of the cord. As reflections arise from transitions in the biomechanical properties of blood vessels, these observations provide a plausible mechanism for the link between abnormal waveforms and clinically significant placental pathology and could lead to more precise screening methods for detecting pregnancies complicated by placental disease. NEW & NOTEWORTHY The pulsatile pattern of blood motion measured by Doppler ultrasound within the umbilical artery is known to contain useful diagnostic information and is widely used to monitor pregnancies at risk of fetal growth restriction. We demonstrate based on a study of 95 pregnant women that the shape of these umbilical artery waveforms is explained by the presence of a reflected pressure wave traveling counter to the direction of blood flow.

The Efficacy of Doppler Indices in Third Trimester of IUGR Pregnancies

Objective: To identify the usefulness of Doppler indices in the third trimester for intra-uterine growth- restricted pregnancies. Materials and Methods: It was an observational case-control study of singletons with intra-uterine growth restriction (fetal weight <10th percentile). Intra-uterine growth restricted fetuses (cases) and normal (controls) were examined for the umbilical artery. Time intervals between progressive Doppler abnormalities and configurations of worsening were related to umbilical artery Doppler status and gestational age. This study was conducted from August 2015 to January 2016 at Gilani Ultrasound Center Lahore Pakistan. A total of 60 pregnant females were studied with normal and abnormal umbilical artery Doppler ultrasound. Results: Doppler indices measurements of umbilical artery in intra-uterine growth restriction fetuses in the third trimester showed higher values as compared to normal fetuses. 30 females had normal umbilical artery Doppler indices and waveforms and 30 females showed (either thinning, absent or reversed Diastolic flow Doppler waveform) with higher indices. Conclusion: Fetal umbilical artery Doppler ultrasound is an effective tool in the detection of early intra-uterine growth restriction fetuses.

Sex differences in umbilical artery Doppler indices: a longitudinal study

BackgroundSexual dimorphism in placental size and function has been described. Whether this influences the clinically important umbilical artery (UA) waveform remains controversial, although a few cross-sectional studies have shown sex differences in UA pulsatility index (PI). Therefore, we tested whether fetal sex influences the UA Doppler indices during the entire second half of pregnancy and aimed to establish sex-specific reference ranges for UA Doppler indices if needed.MethodsOur main objective was to investigate gestational age-associated changes in UA Doppler indices during the second half of pregnancy and compare the values between male and female fetuses. This was a prospective longitudinal study in women with singleton low-risk pregnancies during 19–40 weeks of gestation. UA Doppler indices were serially obtained at a 4-weekly interval from a free loop of the umbilical cord using color-directed pulsed-wave Doppler ultrasonography. Sex-specific reference intervals were calculated for the fetal heart rate (HR), UA PI, resistance index (RI), and systolic/diastolic ratio (S/D) using multilevel modeling.ResultsComplete data from 294 pregnancies (a total of 1261 observations from 152 male and 142 female fetuses) were available for statistical analysis, and sex-specific reference ranges for the UA Doppler indices and fetal HR were established for the last half of pregnancy. UA Doppler indices were significantly associated with gestational age (P < 0.0001) and fetal HR (P < 0.0001). Female fetuses had 2–8% higher values for UA Doppler indices than male fetuses during gestational weeks 20+0–36+6 (P < 0.05), but not later. Female fetuses had higher HR from gestational week 26+0 until term (P < 0.05).ConclusionsWe have determined gestational age-dependent sex differences in UA Doppler indices and fetal HR during the second half of pregnancy, and correspondingly established new sex-specific reference ranges intended for refining diagnostics and monitoring individual pregnancies.

Correlation between umbilical arterial pH values and fetal vertebral artery Doppler waveforms at the beginning of the second stage of labor: a pilot prospective study

Objective: The aim of this study was to evaluate the association between umbilical arterial pH and fetal vertebral artery Doppler velocimetry waveforms measured at the beginning of the second stage of labor in physiological term pregnancies.Methods: This was a prospective cohort study of 250 pregnancies. The resistance index, pulsatility index, and peak systolic velocity were measured. The relationship between the fetal Doppler and the umbilical arterial pH was evaluated. A simple linear regression and a general linear model were used to explore possible correlations of Doppler parameters with fetal and neonatal outcome adjusted for confundents.Results: Umbilical arterial pH values were directly associated with vertebral artery pulsatility index. Fetuses with lower pulsatility index values were at increased risk of a subsequent diagnosis of pathological fetal heart rate tracing patterns (presence of decelerations or reduced variability according to FIGO criteria during the second stage of labor). We estimated a decrease in pulsatility index of 10% in those fetuses destined to show a pathological fetal heart rate tracing.Conclusion: Vertebral artery Doppler waveforms correlates with umbilical pH in normal pregnancies and is also a function of fetal heart rate patterns. If this proportional association would be demonstrated also for abnormal pH values, vertebral artery pulsatility index might be useful to evaluate fetal wellbeing in those cases of suspected hypoxia/academia.

244: The effect of maternal hyperoxygenation on fetal pulmonary vasoreactivity and on blood flow patterns in the umbilical artery and middle cerebral artery in pregnancy

We sought to evaluate the changes in fetal pulmonary artery, umbilical artery and middle cerebral artery Doppler waveforms in response to maternal hyperoxygenation. Nineteen pregnant women with a singleton gestation in the third trimester were prospectively recruited to the study. The protocol for the investigation was approved by the National Ethics Committee and the Health Products Regulatory Authority (HPRA) in Ireland. Informed consent was signed by all participants. Blood flow velocity waveforms were recorded during periods of fetal quiescence. A comprehensive fetal echocardiogram was performed on all subjects. Pulsatility index (PI), acceleration time (AT), and ejection time (ET) were taken within the proximal portion of the fetal main pulmonary artery (PA). AT:ET was used to assess pulmonary vascular resistance (PVR). The sample volume gate was adjusted to 3 mm, and the angle of insonation was maintained at ≤ 15°. Umbilical artery (UAD) and middle cerebral artery (MCA) PIs were also obtained. Measurements were taken at baseline and repeated immediately following maternal hyperoxygenation with 60% FiO2 for a 10-minute duration. Values are presented as medians [Inter-quartile ranges] or means ±SD. The median gestational age was 36 [33 - 37] weeks. There was a decrease in fetal PA PI following maternal hyperoxygenation (from 2.47 [2.11 - 2.80] to 2.08 [1.75 - 2.49], p=0.02) with a mean decrease of 21% [9-36] from the baseline. There was an increase in PA AT (43 [40-47] to 57 [47 - 60] ms, p=0.005) leading to an increase in AT:ET (indicating a fall in PVR) following maternal hyperoxygenation (0.25 [0.24 - 0.28] to 0.32 [0.26 - 0.34], p=0.005). There were no changes in the PIs of the UAD or MCA following hyperoxygenation (0.93 to 0.99, p=0.92 and 1.54 to 1.72, p=0.20 respectively). This study demonstrates that maternal hyperoxygenation diminishes the relative vasoconstriction in the fetal pulmonary vasculature. There were no significant changes to the MCA or UAD PI indices following hyperoxygenation suggesting that this effect is unique to the fetal pulmonary vessels.

P25.04: Stillbirth and fetal growth restriction from umbilical artery and ductus venosus diastolic waveform assessment: a systematic review and meta‐analysis

To assess the risks of stillbirth in early growth restricted fetuses with absent/reverse end-diastolic velocity in umbilical artery (UA) or ductus venosus (DV). We conducted a literature search to identify relevant studies that provided data on early growth restricted fetuses requiring delivery before 34 weeks, with information on stillbirth rate and the presence of absent/reverse end-diastolic velocity in the UA or DV. Both fixed and random effects models were applied. Between-study heterogeneity was assessed using the X2 (Cochrane Q), t2 and I2 statistics. Publication bias was evaluated and quantified by Egger method. A total of 35 studies were included in this analysis. The overall prevalence of stillbirth was 0.05%. Twenty-five studies reported a higher risk of stillbirth in UA waveform analysis. OR under random effects model was 7.32 (p<0.001) with no heterogeneity between them (t2=0.15). Publication bias through Egger k-coefficient was not significant (p=0.58). Fourteen studies showed an increased risk of stillbirth in DV analysis. OR under random effects model was 11.95 (p=0.001). Q statistic of 23.10 (p=0.03) and 46% I2, suggests the presence of heterogeneity throughout publications. Egger k-coefficient method of -1.18 (p=0.283) depicts absence of publication bias. Supporting information can be found in the online version of this abstract Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Human umbilical and fetal cerebral blood flow velocity waveforms following maternal glucose loading: a cross-sectional observational study.

Our aim was to study umbilical and fetal cerebral arterial blood flow velocity waveforms related to fetal biometric measures and maternal body mass index, glucose levels and parity following maternal oral glucose loading. The study had an experimental design in a cross-sectional observational study including 105 low-risk pregnancies (30-32weeks of gestation). Ultrasound Doppler measurements of umbilical and middle cerebral arterial (UA and MCA) velocity waveforms were performed before and at 2h after completed 75-g oral glucose tolerance tests (OGTT). We assessed changes in UA and MCA pulsatility indices (PI). MCA PI was significantly reduced following OGTT (p<0.001); these changes were not related to changes in fetal heart rate (r=-0.11, p=0.278). UA PI was also significantly reduced following OGTT (p=0.033); these changes were related to fetal heart rate (r=-0.47, p<0.001). This reduction was not significant (p=0.230) when the PI values were adjusted for fetal heart rate. The ratio MCA PI to UA PI was reduced (p=0.001). The effect of OGTT on MCA PI was not related to fetal abdominal circumference whereas the effect on the adjusted UA PI values was correlated to abdominal circumference (r=-0.20, p=0.045) but not to abdominal circumference Z-score (r=-0.16, p=0.115). The influence of OGTT on the Doppler parameters as well as heart rates was not related to prepregnant body mass index, glucose levels before or after OGTT, parity, fetal sex or gestational age. Maternal glucose loading seems to decrease fetal cerebral blood flow impedance independent of fetal size.

A study of role of Doppler ultrasound in Pregnancy induced hypertension (PIH) and perinatal outcome

Background: The main purpose of providing antenatal care is to identify women at risk of complications as a result of impaired uteroplacental circulation such as Pregnancy induced hypertension (PIH) and Preclampsia. Aim: To describe practical application of doppler ultrasound in obstetrics with analysis of blood flow velocity waveform in PIH and to examine perinatal outcome in pregnancies with altered Doppler indices. Material and Method: This is a prospective study of 41 pregnant women with pregnancy induced hypertension (PIH) evaluated sonographically with colour Doppler and to be followed subsequently for any adverse perinatal outcome. Result: Out of 41 cases 73.1% of cases were found in 20-29 yrs age group. 26 cases had abnormal uterine artery Doppler indices accounting for 63.46%, while 15 cases had a normal Doppler indices accounting for 36.53%. Out of 41 cases, 25 cases had abnormal Middle cerebral artery. In our study 14 cases had abnormal umbilical artery Doppler indices accounting for 34.2%, while 27 cases had a normal Doppler indices accounting for 65.8%., out of 41 cases in our study 6 cases had Reversal of a wave in Ductus Venosus waveform that is in 14.6%. In this study total 5 cases (35.7%) of perinatal mortality were seen. Conclusion: The knowledge of uterine and umbilical artery waveform may help to improve pregnancy management and any permit identification and assessment of pregnancy induced hypertension at earliest gestation age as compared to other antepartum test modalities.