Doppler Flow Velocity Waveforms Research Articles

Fetal Aortic and Umbilical Doppler Flow Velocity Waveforms in Pregnancy: The Concept of Aortoumbilical Column.

Low impedance within the uteroplacental circulation is crucial for fetal development. Flow velocity waveforms (FVW) have been established for the aortic and umbilical arteries in low-risk pregnancies during the second half of pregnancy, but data regarding early gestation is limited. Both vascular territories exhibit higher impedance patterns in pregnancies complicated by fetal growth restriction (FGR), hypertensive disorders, fetal anemia, and chromosomal abnormalities. Early identification of these complications is critical in obstetric practice, to reduce perinatal morbidity and mortality through prevention and close antenatal surveillance. Available data suggest that aortic and umbilical impedances follow the same variation pattern as pregnancy progresses. This observation implies that both vessels may be considered as a single artery, referred to as the "aortoumbilical column". Our hypothesis posits that changes in the hemodynamic pattern of this column could identify high-risk pregnancies, particularly those complicated by preeclampsia, FGR, intrauterine fetal demise, fetal aneuploidies, and fetal anemia. Understanding vascular embryogenesis and the FVWs of the aortic and umbilical arteries enables comprehension of impedance changes throughout normal pregnancies. The continuous variation in impedance along a single vessel supports our concept of the aortoumbilical column. Deviations from the regular pattern could assist in identifying compromised fetuses during early pregnancy. Further research on normal aortoumbilical column FVW and the development of reference charts is necessary to consider this arterial column as a screening tool in clinical practice.

Comparative Study between Effect of Dexamethasone and Betamethasone used for Fetal Lung Maturity on Daily Fetal Movement Count and Doppler Flow Velocity Waveforms

Comparative Study between Effect of Dexamethasone and Betamethasone used for Fetal Lung Maturity on Daily Fetal Movement Count and Doppler Flow Velocity Waveforms

Associations between prenatal alcohol and tobacco exposure on Doppler flow velocity waveforms in pregnancy: a South African study

BackgroundThe negative impact of prenatal alcohol and tobacco exposure (PAE and PTE) on fetal development and birth outcomes are well described, yet pathophysiologic mechanisms are less clear. Our aim was to investigate (1) the associations between quantity, frequency and timing (QFT) of PAE and PTE with blood flow velocities in arteries of the fetal-placental-maternal circulation and (2) the extent to which combined effect of QFT of PAE and/or PTE and Doppler flow velocity waveforms (FWV) predict infant birth weight.MethodsThe Safe Passage Study is a cohort based in urban Cape Town, South Africa. Recruitment occurred between 2007 and 2015. Information on QFT of PAE and PTE was collected prospectively at up to 4 occasions during pregnancy using a modified Timeline Follow-Back approach. Ultrasound examinations consisted of Doppler flow velocity waveforms of the uterine, umbilical (UA) and fetal middle cerebral arteries for the pulsatility index (PI) at 20–24 and 34–38 weeks. Exclusion criteria included: twin pregnancies, stillbirths, participants exposed to other drugs. The sample was divided into three groups (controls, PAE and PTE) and included 1396 maternal-fetal-dyads assessed during the second trimester; 1398 assessed during the third trimester.ResultsPTE was associated with higher UA PI values in second and third trimesters (p < 0.001), compared to the PAE and control group. The total amount of cigarettes smoked during pregnancy was positively correlated with UA PI values (r = 0.087, p < 0.001). There was a positive correlation between cigarettes smoked per day in trimester one (r = 0.091, p < 0.01), and trimester two (r = 0.075, p < 0.01) and UA PI (in trimester two), as well as cigarettes smoked per day in trimester two (r = 0.058, p < 0.05) and trimester three (r = 0.069, p < 0.05) and the UA PI in trimester three. Generalized additive models indicated that PAE in trimester two, PTE in trimester one and Doppler FWV in trimester three were significant predictors of birth weight in this sample.ConclusionIn our study, PTE in trimesters two and three resulted in increased vascular resistance of the placenta. These findings highlight nuance in associations between PAE, PTE and blood flow velocities in arteries of the fetal-placental-maternal circulation and birth weight, suggesting that quantity and timing are important factors in these relationships.

Effects of Right Lateral Position on Changes of Fetal Hemodynamics in Late Pregnancy.

We aim to evaluate the effect of right lateral position on fetal hemodynamics (including umbilical artery [UA] and middle cerebral artery (MCA) blood flow-velocity waveform). In total, 150 low-risk singleton full-term pregnant women were included in the study from November 2021 to January 2022. Doppler flow velocity waveforms of the fetal UA and MCA tested by ultrasound were collected in gestation of 37-40 weeks. Computational analysis was performed using the one-way ANOVA test. Compared with the maternal left lateral position, there was a significant increase in Doppler indices of UA-RI (P = .033), UA-S/D (P = .019) and MCA-PSV (P = .021) and a significant decrease in MCA-RI (P = .030) in the supine position group. There was no statistical significance in all Doppler indices between the left and right lateral position (P > .05). Among the Doppler indices of three different maternal positions, there was no significance in both UA-PI and MCA-PI (P > .05). There were no significant differences on changes of the fetal hemodynamics between left and right lateral positions. Pregnant women could adopt to lie in the left or right lateral position alternately to relieve the discomfort in late pregnancy.

The Reproducibility of 3D power Doppler in Intrauterine Growth Restriction

Objective: it is to examine the reproducibility of 3D power Doppler in the management of intrauterine growth restriction compared with the conventional 2d Doppler. Patients and Methods: This study was performed between Jan 2021 and Feb 2022 and included 100 pregnant women recruited from outpatient clinic at Elgalaa Teaching Hospital, 3D power Doppler US was done for assessment of IUGR and compare the findings with 2D Doppler. Results: it is found that 3D Power Doppler parameters were significant in prediction of poor neonatal outcome regarding development of respiratory complications, neurological complications and IUFD as complications to IUGR comparing to 2D colour Doppler parameters which were non-significant in these cases. Our results also showed that the only parameter of 2D Colour Doppler that showed significance and positive correlation to birth weight among these cases was Middle Cerebral Artery Pulpability Index. Conclusion: 2D Doppler flow-velocity waveforms are of limited value in the prediction of poor neonatal outcome in IUGR except for MCAPI. 3D power Doppler was superior in the diagnosis and prediction of neonatal outcome.

Classification of intrauterine growth restriction at 34-38 weeks gestation with machine learning models.

Objective:Intrauterine growth restriction (IUGR) is one of the most common causes of stillbirths. The objective of this study is to develop a machine learning model that will be able to accurately and consistently predict whether the estimated fetal weight (EFW) will be below the 10th percentile at 34+0–37 + 6 week’s gestation stage, by using data collected at 20 + 0 to 23 + 6 weeks gestation.Methods:Recruitment for the prospective Safe Passage Study (SPS) was done over 7.5 years (2007–2015). An essential part of the fetal assessment was the non-invasive transabdominal recording of the maternal and fetal electrocardiograms as well as the performance of an ultrasound examination for Doppler flow velocity waveforms and fetal biometry at 20 + 0 to 23 + 6 and 34 + 0 to 37 + 6 week’s gestation. Several predictive models were constructed, using supervised learning techniques, and evaluated using the Stochastic Gradient Descent, k-Nearest Neighbours, Logistic Regression and Random Forest methods.Results:The final model performed exceptionally well across all evaluation metrics, particularly so for the Stochastic Gradient Descent method: achieving a 93% average for Classification Accuracy, Recall, Precision and F1-Score when random sampling is used and 91% for cross-validation (both methods using a 95% confidence interval). Furthermore, the model identifies the Umbilical Artery Pulsality Index to be the strongest identifier for the prediction of IUGR – matching the literature. Three of the four evaluation methods used achieved above 90% for both True Negative and True Positive results. The ROC Analysis showed a very strong True Positive rate (y-axis) for both target attribute outcomes – AUC value of 0.771.Conclusions:The model performs exceptionally well in all evaluation metrics, showing robustness and flexibility as a predictive model for the binary target attribute of IUGR. This accuracy is likely due to the value added by the pre-processed features regarding the fetal gained beats and accelerations, something otherwise absent from previous multi-disciplinary studies. The success of the proposed predictive model allows the pursuit of further birth-related anomalies, providing a foundation for more complex models and lesser-researched subject matter. The data available for this model was a vital part of its success but might also become a limiting factor for further analyses. Further development of similar models could result in better classification performance even with little data available.

Assessment of Maternal-Fetal outcomes by Doppler Flow Velocity Waveforms in Preterm Labor Patients Undergoing Magnesium Sulfate Tocolysis

Background: Preterm labor is frequency uterine contractions, pro- gressive effacement and dilation of the cervix prior to term gestation. Prevention and treatment of preterm labor is important because it is one of the most important causes of perinatal morbidity and mortali- ty. The etiology of preterm labor is poorly understood. Aim of the Work: to evaluate the influence of antenatally admin- istrated magnesium sulfate (MgSO4) given to women at risk of preterm birth on the cerebral blood flow and systemic hemodynamic in preterm infants. Patients and Methods: This was a prospective observational in- terventional study conducted from October 2016 to February 2017 on (40) patients undergoing preterm labor at AL Zahraa hospital Al Azhar university and New Cairo Hospital, after informed a written consent was taken from every patient after counseling them the pro- cedure of the study. Results: In our study we found that the best blood level of magne- sium sulfate at which contractions stopped (cut off) is (>4.18) mg/dl which equal (6.82) gm of administrated magnesium sulfate with sen- sitivity (94.74%) and specificity (100%), positive predictive value (PPV) was (100%) and negative predictive value (NPV) was (50%). Conclusion: Maternal magnesium sulphate (Mgso4) decreases the cerebral perfusion pressure and blood flow, and this likely protects the germinal matrix against the development of circulatory stress in the early post natal period. Magnesium sulphate achived the primary outcome (prevention of delivery for 48 hours, with uterine quies- cence) at cut-off value of (≥4.18) mg/dl which equal (6.82) gm with sensitivity (94.74%), specificity (100%), positive predictive value (100%) negative predictive value (50%).

Ductus venosus Doppler and the postnatal outcomes of growth restricted fetuses with absent end-diastolic blood flow in the umbilical arteries

ObjectiveWe aimed to evaluate the outcomes of growth-restricted fetuses with absent end-diastolic velocity in the umbilical arteries (UA-AEDV), and investigate the relationship between Doppler flow velocity waveforms in the ductus venosus (DV) and the clinical features. Materials and methodsThis was a retrospective study of growth-restricted fetuses diagnosed with UA-AEDV delivered at our institution between 2013 and 2015. The time from diagnosis of UA-AEDV to delivery, postnatal survival, and developmental prognoses were the primary outcomes. The time lag between the occurrence of UA-AEDV and an abnormal increase in the DV pulsatility index (DV-PI) were investigated. We also examined the correlation between the DV-PI values immediately before birth and umbilical cord arterial pH at birth. ResultsThe median gestational age at birth among the 18 subjects was 28+2 (24+0–34+6) weeks, and the observation period between the first detection of UA-AEDV and delivery ranged from 0 to 35 days with a median of 8 days. Among the 18 infants, 15 (83%) survived, among whom 2 were diagnosed with a developmental disability. Gestational age at delivery was significantly lower in the poor outcome group. A positive correlation (correlation coefficient, 0.68) was observed between the umbilical artery pH and the last measured DV-PI. ConclusionThe time interval from initial detection of UA-AEDV to delivery is highly variable, and it is reasonable to manage these growth-restricted fetuses with UA-AEDV expectantly with careful surveillance for fetal well-being. Specifically, Doppler DV analysis is clinically valuable for their evaluation.

The early postnatal blood flow characteristics in the superior mesenteric and coeliac arteries in late preterm neonates

Objectives: The objective of this study is to evaluate intestinal blood flow changes within the first 72 h in the late preterm infants in comparison with the healthy term neonates. Methods: In this prospective study, we analyzed Doppler flow velocity waveforms of superior mesenteric artery (SMA) and coeliac trunc (TC) in 20 late preterm and 20 term infants at the age of 2, 24, and 72 h. Results: Significant end-diastolic velocity (end-diastolic velocity (EDV)SMA) rise up to 24 h was documented in all patients (late preterm: −9.32 ± 9.48 to 17.01 ± 6.94; p < .05; term: −8 ± 5.74 to 12.39 ± 3.33; p < .001), associated with a conversion from negative values to positive ones. Reversed blood flow was documented in SMA at 2 h in 75% late preterm neonates. Preterm infants showed significantly higher mean peak systolic velocities (peak systolic velocity (PSV)SMA), end-diastolic velocities (EDVSMA) at 24 h and PSVTC at 72 h than term infants (p < .05). The resistance and pulsatility indices (PI) decreased within 24 h in both groups and inversely reflected the postnatal changes in EDVSMA. Mean PIAMS at 2 h was significantly higher in term neonates. Conclusion: Late preterm neonates show similar progressive postnatal increase in blood flow velocities accompanied with a decrease in vascular resistance in SMA and TC then term neonates.

The effect of maternal hyperoxygenation on fetal circulatory system in normal growth and IUGR fetuses. What we can learn from this impact

Purpose: The objectives of study were to assess and compare the effects of maternal hyperoxygenation on fetal circulation, in fetuses with intrauterine growth retardation and normal fetal growth.Methods: Twelve singleton pregnant women with normal fetal growth and 12 singleton pregnant women with intrauterine growth restriction were recruited. Mean gestational age of 35.2 ± 3.5 and 34.7 ± 3.9 weeks, respectively. Doppler blood flow velocity waveforms were obtained from the middle cerebral artery, umbilical, main and proximal right pulmonary arteries. Pulsatility indices were calculated for all the vessels. Peak systolic velocity was determined for the middle cerebral artery. Following baseline measurements; each woman received 70% humidified oxygen for 10 min. Doppler measurements were then repeated.Results: The pulsatility index in the middle cerebral artery increased significantly from 1.5 ± 0.27 to 1.88 ± 0.48, respectively (p = .006) in the high-risk group. However, it did not change significantly in the low-risk group. Hyperoxygenation caused a significant decrease in pulsatility indices in the pulmonary arteries for both groups.Conclusions: Hyperoxygenation interrupts the relative brain-sparing effect in the intrauterine growth retardation group, but it did not significantly change the pulsatility index of the middle cerebral artery in fetuses with adequate weight. The pulsatility index in the pulmonary arteries decreased significantly following hyperoxygenation.

DOPPLER VELOCIMETRY OF THE FETAL MIDDLE CEREBRAL ARTERY, UMBILICAL AND UTERINE ARTERES IN THE PREDICTION OF PROLONGED PREGNANCY AND THEIR EFFECT ON NEONATAL OUTCOME

Background: Although the increased fetal morbidity and mortality associated with post-term pregnancy has long been appreciated, most authors have studied gestational age as the alone contributing factor. The influence of other factors such as maternal age, parity, maternal smoking, fetal genders, birth weight and past history of post-term has not been adequately evaluated, Additionally, the accuracy of earlier studies is limited by the fact that they predate the widespread use of both ultrasonography for accurate gestational dating and intensive fetal testing to establish fetal wellbeing. Objective: the present study was conducted to evaluate the effects of prolonged exceeding 287 days of menstrual age on the Doppler flow velocity waveforms in the umbilical, middle cerebral and uterine arteries, and its impact on neonatal outcome to determine the best predictor of adverse outcome in post-term. Patients and Methods: The present study included 50 pregnant ladies All patients were submitted to ultrasound for detection of fetal genders, fetal weight and amniotic fluid index (AFI) Also, they were submitted to color Doppler velocimetery of fetoplacental and fetal vessels including middle cerebral pulsitility index MCA PI), umbilical artery pulsitility index UA PI), middle cerebral resistance index MCA RI), umbilical artery resistance index UA RI), uterine artery pulsitility index UtA PI),and uterine artery pulsitility index UtA RI). Results: In the present study, there was no statistical signification with gestational age, fetal heart rate and parity. The primary gravida had the highest incidence. There was higher rate of CS which was significant with prolongation of pregnancy, but with no statistically significant difference between adverse and normal outcome Also, the incidence of males was more than females in our population with no significant relation between fetal gender and neonatal outcome. Adverse outcome was associated with lower MCA PI, MCA RI, AFI, Apgar score, and higher UA RI compared to normal outcome with statistically significant difference between them, but there was no statistically significant difference as regard UA PI, UtA PI, UtA RI. Conclusion: The perinatal morbidity and mortality may be increase in post-term pregnancies. However, the all screening tests and Doppler indices may be normal due to mode of delivery, time of delivery, and type of anesthesia during labor. So, during labor, rapid interference should be taken to decrease incidence of adverse neonatal outcome. In post-term pregnancies with adverse outcomes, impedance to flow in umbilical arteries may be increased, while impedance to flow in the fetal middle cerebral arteries may be decreased, but impedance to flow in uterine arteries may be normal

P08.09: Reference resistance indexes of the umbilical and middle cerebral artery and cerebroplacental ratio at 3,400 meters above sea level

To construct new reference ranges for Doppler flow velocity waveform resistance indices (RI) for the umbilical and middle cerebral artery and cerebroplacental (CPR) ratio in singletons fetuses of women pregnant without risks at 3400 m above sea level in the Peruvian Andes. This was a cross-sectional study of 500 women residents at 3400 m above sea level for more than two generations, with normal singleton pregnancies, from January 2013 to December 2014 at Research Centre for Maternal-Fetal Medicine of Altitude (CENIMFA) in Cusco, Peru. All of participants signed an informed written consent to participate in this trial. A total of 500 pregnant women met the inclusion criteria and satisfactory waveforms. Measurements were obtained in all cases. The umbilical artery RI decreased with gestation (regression coefficient (r2) = 0.581; P < 0.001). The middle cerebral artery RI increased with gestation, reaching a peak at 24–34 weeks and then decreased towards term (r2 = 0.035; P < 0.001). The CPR increased throughout to pregnancy, but was not constant and then decreased slightly towards term (r2 = 0.304; P < 0.001). 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.

Stable fetal hemodynamics measured by Doppler flow after initiation of anti-hypertensive treatment with methyldopa in pregnant women with diabetes

Aim: To evaluate whether initiation of anti-hypertensive treatment with methyldopa affects fetal hemodynamics in women with pregestational diabetes. Methods: Prospective study of unselected singleton pregnant women with diabetes (seven type 1 and two type 2 diabetes), normal blood pressure and kidney function at pregnancy booking. Methyldopa treatment was initiated at blood pressure >135/85 mmHg and/or urinary albumin excretion (UAE) >300 mg/g creatinine. Pulsatility indices (PI) of the uterine, umbilical, middle cerebral arteries before and 1 week after initiation of methyldopa treatment (250 mg three times daily) was performed and the cerebro-placental ratio (CPR) was calculated. Results: Methyldopa treatment was initiated at median 249 (range 192–260) gestational days, mainly due to gestational hypertension (n = 7). Blood pressure declined from 142 (112–156)/92 (76–103) mmHg before to 129 (108–144)/82 (75–90) mmHg after initiation of methyldopa treatment (p = 0.11 and 0.04 for systolic and diastolic blood pressure, respectively). There were no significant changes in the umbilical artery PI (0.82 (0.72–1.40) versus 0.87 (0.64–0.95), p = 0.62) or CPR (1.94 (0.96–2.33) versus 1.78 (1.44–2.76), (p = 0.73). Gestational age was 265 (240–270) d. Apgar scores were normal. Conclusions: Stable Doppler flow velocity waveforms were documented after initiation of methyldopa treatment for pregnancy-induced hypertensive disorders in this cohort of pregnant women with pregestational diabetes.

Doppler abnormalities in monochorionic diamniotic twin pregnancies with discordant growth.

We studied whether abnormal umbilical artery (UA) Doppler flow velocity waveforms occur with higher frequency in monochorionic diamniotic (MCDA) twin gestations with discordant fetal growth and whether this impacted neonatal outcome. We performed a retrospective study of MCDA twin pairs. We collected data from an electronic medical record. We classified pregnancies as discordant if there was at least 20% birth weight discordance. Abnormal UA Doppler velocity waveforms included absent or reversed end diastolic flow. We analyzed the data with chi square, Student's t-test and analysis of variance as appropriate. Seventy-three twin pairs met criteria for inclusion, including 16 with discordant growth. The discordant group was significantly more affected with twin-to-twin transfusion syndrome (TTTS) (P=0.02). The smaller fetuses in discordant pairs were more likely to display abnormal UA Doppler flow velocity waveforms (P<0.01). These neonates also had lower Apgar scores (P=0.03) and were more likely to require care in a neonatal intensive care unit. Our findings persisted after excluding pregnancies with TTTS. In MCDA twin gestations complicated by discordant growth, there is an increased frequency of abnormal UA Doppler flow velocity waveforms in small fetuses, and these neonates face clinical challenges after birth.

Uterine artery Doppler flow velocity waveform analysis following uterine fibroid embolisation

The objective was to evaluate the relation of uterine artery Doppler flow pulsatility index (PI) with total uterine volume reduction following bilateral embolisation of uterine fibroids by injection of polyvinyl alcohol particles. Doppler flow velocity was examined before and within 8 days after embolisation (n = 13). Uterine size was assessed by magnetic resonance imaging (MRI) before, and at 3 and 6 months after, the procedure. Mean PI values (mean of right and left side) obtained before embolisation were negatively related to uterine size (r = −0.68, p = 0.010) but not to uterine volume reduction after the procedure. Mean PI values after the procedure were related to the percentage decrease in uterine volume both at 3 (r = 0.74, p = 0.004) and 6 months (p = 0.73, p = 0.005). Doppler ultrasound measures of the uterine arteries may be used to evaluate reduction of uterine size following fibroid embolisation.

Profiling left and right ventricular proportional output during fetal life with a novel systolic index in the aortic isthmus

Left ventricular ejection causes forward flow in the fetal aortic isthmus while the right ventricle has a retrograde influence. The aim of this study was to create reference values for an isthmic systolic index (ISI) reflecting the changing influence of right and left ventricular performance on Doppler flow velocity waveforms of the aortic isthmus throughout normal pregnancy. Doppler recordings of 260 normal fetuses with a gestational age of 18-37 weeks were reviewed. Peak systolic velocity (PSV) and end-systolic velocity (or systolic nadir; Ns) were measured on all aortic isthmus waveforms. An ISI was derived from the ratio Ns/PSV. Left and right ventricular outputs were also calculated. Up to 22-23 weeks' gestation, the mean ISI is stable at around 0.2. At about 28 weeks, a brief end-systolic deceleration wave is observed on the aortic isthmus waveforms, progressing steadily with gestation and causing a fall of ISI towards a mean value of zero between 30 and 31 weeks. This trend continues thereafter and a mean value of -0.4 was observed at the end of pregnancy. An inverse correlation was found between right ventricular output and Ns (r = -0.334, P = 0.001). Simultaneous recordings of the isthmus and the ductus arteriosus Doppler waveforms demonstrated that the primary cause of the end-systolic deceleration and ultimate reversal of flow at the isthmus is the increasingly dominant flow from the right ventricle. The transitional changes of the respective right and left ventricular outputs throughout pregnancy are well profiled by the ISI. This index highlights the physiological increase in fetal right ventricle flow preponderance as pregnancy progresses. Alteration of the ISI profile could be expected in clinical conditions associated with unbalanced alteration of the fetal ventricular outputs.

The effect of maternal supine position on umbilical and cerebral blood flow indices

ObjectiveThe brain sparing phenomenon in the fetus is a protective mechanism aimed at maintaining sufficient blood flow towards the brain during chronic or acute fetal stress, such as that caused by hypoxemia or utero-placental insufficiency. In this study we investigated whether the brain sparing effect can also be elicited by a physiological stress associated with maternal posture.Study design Twenty-three low-risk pregnant women participated in the study. Between 36 and 40 weeks’ gestation, Doppler flow velocity waveforms were obtained from the fetal middle cerebral and the umbilical artery in the supine and the left lateral decubitus positions. Pulsatility index, systolic/diastolic index, and peak systolic velocities were measured and comparison was made between the left lateral and supine positions. ResultsThe pulsatility index in the middle cerebral artery decreased from 1.78±0.27 in the left lateral decubitus position to 1.29±0.16 in supine position (p<0.0001). Peak systolic velocity decreased from 46.05±7.85cm/s to 39.43±7.95cm/s, respectively (p=0.001). The pulsatility index in the umbilical artery decreased from 0.89±0.13 in the left lateral position to 0.74±0.11 in the supine position (p<0.0001). ConclusionsThis study demonstrates that the supine position in late pregnancy, causing aortic and venacaval compression, leads to brain auto-regulation that activates the brain sparing effect in the fetus. This protective mechanism, shown here for the first time to be linked to a physiological stress, may provide the basis for a novel approach in the assessment of fetal wellbeing.

Linking Intrauterine Growth Restriction and Blood Pressure

Abnormal perfusion to the fetus can slow fetal growth and result in intrauterine growth restriction (IUGR).1 IUGR, or failure to reach one’s birth potential, is one of the most common complications during pregnancy and generally results from placental insufficiency.1 IUGR is generally not recognized before delivery, and treatment options for IUGR are limited, with early delivery being the most common.1 Preeclampsia is often a contributory cause of IUGR, and numerous studies indicate that individuals exposed to a preeclamptic pregnancy exhibit a higher body mass index and blood pressure during childhood and adult life.2 Individuals born with IUGR also demonstrate an increase in blood pressure later in life.3 This association forms the basis for the developmental origins of health and disease and indicates that adverse influences during fetal life that slow fetal growth program an individual for greater cardiovascular risk in later life.4,5 Article see p 2202 Experimental models of placental insufficiency provide proof of principle that IUGR induced by reduced uterine perfusion programs an increase in blood pressure and cardiovascular risk in later life.5 However, in this issue of Circulation , Gaillard et al6 provide a direct link between reduced uterine perfusion and IUGR with increased cardiovascular risk. Using a large, prospective, longitudinal cohort, Gaillard and colleagues report that an increase in third-trimester fetoplacental vascular resistance indicative of reduced perfusion was associated with a decrease in size at birth and a later increase in total fat mass and systolic blood pressure at 6 years of age.6 Thus, this study indicates that assessment of fetal growth characteristics via Doppler flow velocity waveforms in the umbilical artery not only may be indicative of IUGR but also may identify an individual at greater risk …

Thymic volume in healthy, small for gestational age and growth restricted fetuses

The aim of this study was to verify the hypothesis that a difference in thymic size exists between small for gestational age (SGA) fetuses, likely constitutional, and intrauterine growth restricted (IUGR) fetuses because of placental causes. We studied 27 SGA and 36 control fetuses. SGA was defined as fetal abdominal circumference (AC) and birthweight <10th percentile for gestational age. We defined as constitutional SGA those with normal uterine and umbilical artery Doppler flow velocity waveforms (FVW), and as IUGR those with abnormal uterine FVW. IUGR were further divided based on normal or abnormal umbilical FVW. Fetal thymic volume (TV) was acquired by three-dimensional ultrasound and reconstructed with virtual organ computer-aided analysis. To correct for the influence of fetal size on thymic dimension, TV/AC ratio was calculated. Controls presented a higher TV/AC compared with each group of SGA (p < 0.001). TV/AC was significantly lower in IUGR with abnormal umbilical FVW compared with both constitutional SGA (p = 0.01) and IUGR with normal umbilical FVW (p = 0.01). The differences in TV/AC between constitutional SGA and IUGR with abnormal umbilical FVW suggest that, in the latter, a specific 'trigger' might compromise trophoblastic invasion and thymic development; however, some kind of alteration of the immune system might occur in all SGA fetuses.

Homocysteine Exposure Affects Early Hemodynamic Parameters of Embryonic Chicken Heart Function

Maternal hyperhomocysteinemia has been associated with an increased risk of newborns with a congenital heart defect. This has been substantiated in the chicken embryo, as congenital heart defects have been induced after homocysteine treatment. Comparable heart defects are observed in venous clipping studies, a model of altered embryonic blood flow. Because of this overlap in heart defects, our aim was to test the hypothesis that homocysteine would cause alterations in embryonic heart function that precede the structural malformations previously described. Therefore, Doppler flow velocity waveforms were recorded in both primitive ventricles and the outflow tract of the embryonic heart of homocysteine treated and control chicken embryos at embryonic day 3.5. Homocysteine treatment consisted of 50 μL 0.05 M L-homocysteine thiolactone at 24, 48, and 72 hr. Homocysteine-treated embryos displayed significantly lower mean heart rates of 134 (SD 22) bpm, compared to 150 (14) bpm in control embryos. Homocysteine treatment caused an inhibiting effect on hemodynamic parameters, and altered heart function was presented by a shift in the proportions of the different wave times in percentage of total cycle time. Homocysteine induces changes in hemodynamic parameters of early embryonic chicken heart function. These changes may precede morphological changes and contribute to the development of CHD defects through alterations in shear stress and shear stress related genes, as seen before in venous clipping studies.