Absent End-diastolic Flow In Umbilical Artery Research Articles

Maternal Steroids on Fetal Doppler Indices, in Growth-Restricted Fetuses with Abnormal Umbilical Flow from Pregnancies Complicated with Early-Onset Severe Preeclampsia.

Corticoids are largely used for fetal interest in expected preterm deliveries. This study went further, evaluating the effect of maternal administration of dexamethasone (Dex) on the umbilical artery (UA), middle cerebral artery (MCA), and ductus venous (DV) spectrum, in growth-restricted fetuses, with the absent end-diastolic flow (AEDF) in UA, from singleton early-onset severe preeclamptic pregnancies. Supplementary, the impact on both uterine arteries (UTAs) flow was also evaluated. In 68.7% of cases, the EDF was transiently restored (trAEDF group), in the rest of 31.2% remained persistent absent (prAEDF group). UA-PI significantly decreased in the first day after Dex (day 1/0; p < 0.05), reaching its minimum during day 2 (day 2/1; p > 0.05), revealing a significant recovery to day 4 (day 4/2; p < 0.05), in both groups. The MCA-PI decreased from day 1 until day 3 in both groups, but significantly only in the trAEDF group (p = 0.030 vs. p = 0.227. The DV-PI's decrease (during day 1) and the CPR's increase (between days 0 and 2) were not significant in both groups. UTAs-PIs did not vary. The prAEDF group had a significantly increased rate of antenatal worsening Doppler and a poorer perinatal outcome compared with the trAEDF group. In conclusion, Dex transiently restored the AEDF in UA in the majority of cases, a "positive" effect being a useful marker for better perinatal prognosis. UA-PI significantly decreased in all cases. The improvement in umbilical circulation probably was responsible for the short but not significant DV-PI reduction. MCA-PI decreased only in sensitive cases, probably due to an already cerebral "full" vasodilation in the prAEDF group. Furthermore, the CPR's nonsignificant improvement was the result of a stronger effect of Dex on UA-PI than on MCA-PI. Finally, despite the same etiology, it was only a weak correlation between the severity of the umbilical and uterine abnormal spectrum.

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.

Umbilical artery Doppler changes in fetal growth restriction with intermittently absent umbilical artery end-diastolic flow

Absent or reversed end-diastolic flow (A/REDF) are umbilical artery Doppler (UAD) velocimetry abnormalities associated with increased risk of perinatal demise and neonatal morbidity in pregnancies with fetal growth restriction (FGR). However, the clinical implications of intermittent (iAEDF) versus persistent (pAEDF) absent end-diastolic flow are unclear. This study compared changes in UAD velocimetry and latency to delivery in FGR pregnancies with iAEDF versus pAEDF at diagnosis.

Maternal and fetal effects of COVID-19 virus on a complicated triplet pregnancy: a case report

BackgroundCoronavirus disease 2019 (COVID-19), the global pandemic that has spread throughout the world, is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Given the limited scientific evidence on the manifestations and potential impact of this virus on pregnancy, we decided to report this case.Case presentationThe patient was a 38 year-old Iranian woman with a triplet pregnancy and a history of primary infertility, as well as hypothyroidism and gestational diabetes. She was hospitalized at 29 weeks and 2 days gestational age due to elevated liver enzymes, and finally, based on a probable diagnosis of gestational cholestasis, she was treated with ursodeoxycholic acid. On the first day of hospitalization, sonography was performed, which showed that biophysical scores and amniotic fluid were normal in all three fetuses, with normal Doppler findings in two fetuses and increased umbilical artery resistance (pulsatility index [PI] > 95%) in one fetus. On day 4 of hospitalization, she developed fever, cough and myalgia, and her COVID-19 test was positive. Despite mild maternal symptoms, exacerbated placental insufficiency occurred in two of the fetuses leading to the rapid development of absent umbilical artery end-diastolic flow. Finally, 6 days later, the patient underwent cesarean section due to rapid exacerbation of placental insufficiency and declining biophysical score in two of the fetuses. Nasopharyngeal swab COVID-19 tests were negative for the first and third babies and positive for the second baby. The first and third babies died 3 and 13 days after birth, respectively, due to collapsed white lung and sepsis. The second baby was discharged in good general condition. The mother was discharged 3 days after cesarean section. She had no fever at the time of discharge and was also in good general condition.ConclusionsThis was a complicated triplet pregnancy, in which, after maternal infection with COVID-19, despite mild maternal symptoms, exacerbated placental insufficiency occurred in two of the fetuses, and the third fetus had a positive COVID-19 test after birth. Therefore, in cases of pregnancy with COVID-19 infection, in addition to managing the mother, it seems that physicians would be wise to also give special attention to the possibility of acute placental insufficiency and subsequent fetal hypoxia, and also the probability of vertical transmission.

Fetal umbilical artery absent end-diastolic flow and decreased cerebral-placental ratio and pregnancy outcome and prognosis of survival children

Fetal umbilical artery absent end-diastolic flow and decreased cerebral-placental ratio and pregnancy outcome and prognosis of survival children

Abnormal umbilical artery Doppler velocimetry and placental histopathological correlation in fetal growth restriction

Background . Doppler velocimetry (DV) is widely used to assess the vascular formation of the placenta in fetal growth restriction (FGR) and to estimate the haemodynamic condition of the growth-restricted fetus. Umbilical artery (UA) flow is essentially placental, rather than fetal. Hence, DV provides information about the fetal side of the placenta and, alongside placental histopathology, it could possibly help to decipher aetiopathogenesis in FGR cases. Objective . To correlate UA DV findings occurring in FGR with placental findings. Methods. The study was prospective and conducted in a low-income setting. A total of 130 non-anomalous singleton FGR pregnancies (≥24 weeks) were included in the study. All pregnancies were confirmed to be small for gestational age (SGA) after the birth of the neonate. The placental lesions and neonatal outcomes were correlated with DV findings before delivery: 65 cases with normal DV results constituted group 1, and group 2 had 65 cases with abnormal DV results such as reduced flow, absent UA end diastolic flow or reversal of UA end diastolic flow. Results . Group 2 had significantly lower mean (standard deviation) birth weights of 1.59 (0.4) kg v. 1.87 (0.23) kg for group 1 ( p <0.001). Considerably higher NICU mortality was seen in group 2 (30.5%) compared with group 1 (6.7%) ( p <0.001). The group 2 placentas weighed less, had a higher number of maternal underperfusion (MUP) lesions, higher levels of calcification. Among lesions of MUP, 4 lesions i.e. villous infarction ( p <0.001), villous agglutination ( p <0.001), syncytial knots ( p =0.003) and intervillous fibrin deposition ( p =0.001) were present in significantly higher numbers in the abnormal Doppler group compared with the normal Doppler group. Abnormal Doppler had a sensitivity of 80% and specificity of 92.3% for abnormal placental pathology (placental lesions ≥3). Conclusions. There was a significantly higher number of MUP lesions and neonatal morbidity in SGA patients with abnormal DV findings

279: Midtrimester isolated oligohydramnios in monochorionic diamniotic multiple gestations

To describe outcomes in monochorionic diamniotic multiple gestations with midtrimester isolated oligohydramnios (iOligo). This is a retrospective study of iOligo patients initially referred for treatment of evolving twin-twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR) Type II (persistent absent or reversed umbilical artery end diastolic flow). iOligo was defined as a maximum vertical pocket of amniotic fluid of ≤ 2 cm in the iOligo twin’s sac and > 2 and < 8 cm in the co-twin’s sac. Patients who did not develop subsequent TTTS or sIUGR Type II were classified as Group I, and patients that did develop TTTS or sIUGR Type II were classified as Group II. Of 868 referred patients, 41 (4.7%) were initially diagnosed with iOligo. After initial consultation, 2 patients terminated and 1 was lost to follow-up, leaving 38 iOligo patients. Twelve (31.6%) were classified as Group I, and 26 (68.4%) were classified as Group II. In Group I, 11 of 12 were expectantly managed, which resulted in fetal demise of the iOligo twin in 2/11 (18.2%) with a median gestational age (GA) at delivery of 34.7 weeks (range 18.0 - 36.4), a 30-day perinatal survival of at-least-one twin of 90.9% (10/11), and dual 30-day survivors in 9/11 (81.8%). One of the 12 had an umbilical cord occlusion for sIUGR complicated by intermittent absent umbilical artery end-diastolic flow, fetal anomalies, and recurrent fetal heart rate decelerations. In Group II (N=26), 15 (57.7%) developed TTTS and 11 (42.3%) developed sIUGR Type II. Laser surgery was performed for 18 of the Group II patients, who subsequently reached a median GA at delivery of 33.9 weeks (range 26.4 - 37.1); fetal demise of the iOligo twin occurred in 9/18 (50.0%), and 30-day perinatal survival of at-least-one twin was 100% (18/18) and dual survivorship was 44.4% (8/18). The majority (68%) of monochorionic diamniotic multiple gestations that presented in the second trimester with iOligo subsequently progressed to TTTS or sIUGR Type II.

Down-regulation of placental neuropilin-1 in fetal growth restriction

Fetal growth restriction (FGR) is associated with adverse outcomes extending from fetal to adult life, and thus, constitutes a major health care challenge. Fetuses with progressive growth restriction show increasing impedance in the umbilical artery flow, which may become absent during end-diastole. Absent end-diastolic flow (AEDF) is associated with adverse perinatal outcomes including stillbirths and perinatal asphyxia. Placentas from such pregnancies demonstrate deficient fetoplacental vascular branching. Current evidence, moreover, indicates an antiangiogenic state in maternal circulation in several pregnancy complications including preeclampsia, small-for-gestational-age births, fetal death, and preterm labor. The angiogenic mediators in maternal circulation are predominantly of placental origin. Information, however, on the role of specific proangiogenic and antiangiogenic mechanisms operating at the placental level remains limited. Elucidation of these placenta-specific angiogenic mechanisms will not only extend our understanding of the causal pathway for restricted fetal growth but may also lead to the development of biomarkers that may allow early recognition of FGR. We sought to test the hypothesis that fetoplacental angiogenic gene expression is altered in pregnancies complicated with FGR and umbilical artery Doppler AEDF. Placental samples were collected from FGR pregnancies complicated with umbilical artery Doppler AEDF (study group, n = 7), and from uncomplicated pregnancies (control group, n = 7), all delivered by cesarean during the last trimester of pregnancy. Angiogenic oligonucleotide microarray analysis was performed and was corroborated by quantitative real-time polymerase chain reaction, Western blot analysis, and immunohistochemistry. The Student t test with Bonferroni correction was used with P < .05 considered statistically significant. Independent groups t test was used to analyze the immunostain intensity scores with a P < .05 considered statistically significant. Our microarray results showed that among several differentially expressed angiogenic genes in the growth-restricted group, only the down-regulation of neuropilin (NRP)-1 was most significant (P < .0007). Quantitative real-time polymerase chain reaction confirmed a significantly lower NRP-1 gene expression in the FGR group than in the control group (mean ± SD (ˆ)cycle threshold: 0.624 ± 0.55 and 1.325 ± 0.84, respectively, P = .04). Western blot validated significantly lower NRP-1 protein expression in the FGR group than in the control group (mean ± SD NRP-1/β-actin ratio: 0.13 ± 0.04 and 0.34 ± 0.05, respectively, P < .001). Finally, immunohistochemistry of placental villi further corroborated a significantly decreased expression of NRP-1 in the FGR group (P = .006). The study demonstrated significant down-regulation of placental NRP-1 expression in FGR pregnancies complicated with AEDF in umbilical artery. As NRP-1 is known to promote sprouting angiogenesis, its down-regulation may be involved in the deficient vascular branching observed in FGR placentas suggesting the presence of an antiangiogenic state. Further studies may elucidate such a causal role and may lead to the development of novel diagnostic and therapeutic tools.

PL109. Corticosteroids in the management of severe preeclampsia: What evidence?

Introduction The fundamental premise that has governed the proposal relative to the use of corticosteroids for the purpose of disease modification in severe preeclampsia was that preeclampsia is a condition characterized by an inappropriate maternal systemic inflammatory response and possibly immune-mediated impairment in maternal-fetal communication, while corticosteroids have the capacity to exercise anti-inflammatory and immunosuppressive effects. Objective The presentation will review the evidence behind this proposal. The risks associated with such an approach, especially in fetuses manifesting growth restriction and umbilical artery absent end-diastolic flow, will also be discussed. Methods The literature published between 1990 and 2015 was searched for papers dealing with corticosteroids treatment for disease modification in preeclampsia and HELLP syndrome, using a combination of keywords including “HELLP syndrome”, “preeclampsia”, “corticosteroids” and “maternal and fetal outcomes”. The MEDLINE bibliographic database yielded studies heterogeneous as methodology including retrospective analyses, randomized trials, and meta-analyses. Published studies were assessed for quality according to Jadad’s quality assessment scale. Results On the basis of a critical interpretation of the available literature, we argue that corticosteroids administration, either antepartum or postpartum, does not improve the outcome of pregnancies affected by severe preeclampsia. Conclusion Until more convincing data become available, corticosteroids for disease modification in women with preeclampsia should not be used outside the setting of an approved investigational protocol. In antepartum HELLP syndrome, if a brief period (not to exceed 48 hours) of expectant management is elected to allow optimal exposure to corticosteroids strictly for fetal benefit, intensive surveillance of both mother and fetus is indicated.

Validity of umbilical artery Doppler waveform versus umbilical vein Doppler waveform in the prediction of neonatal outcome in intrauterine growth restriction cases

Abstract Objective To assess the neonatal outcome in relation to umbilical vein Doppler compared to umbilical artery Doppler in growth restricted fetuses. Methods A total of 72 pregnant women with singleton pregnancy between 28 and 38 weeks of gestation with risk of developing intrauterine growth restriction (IUGR) were recruited to the study. All women were subjected to full assessment via detailed history, clinical examination, obstetric assessment, routine laboratory assessment and ultrasonography examination for fetal assessment. Doppler examination of umbilical artery (UA) and umbilical vein (UV) was performed. Absent or reversed UA end diastolic flow (EDF) and pulsatile flow in the umbilical vein were examined for their efficacy to predict critical outcomes (still birth, neonatal death, IUGR). Results A total of 13 deaths (18%) were reported; 13.9% were neonatal deaths and 4.2% were stillbirths. Fetuses were grouped according to Doppler parameters: those with normal Doppler finding ( n = 35), those with resistance index (RI) ( n = 20), those with Absent UA EDF ( n = 10) and those with reversed UA EDF ( n = 7). Pulsatile UV waveform was reported among 9.7% of patients all of them had reversed UA EDF. Patients with absent/reversed EDF have significant association with critical neonatal outcomes as lower birth weight, perinatal deaths, and lower Apgar score. UV Doppler was abnormal in patients with more severe deterioration (patients with reversed UA EDF) while it was normal in all patients with increased RI and absent UA EDF. All cases with Pulsatile UV Doppler have shown higher incidence of critical neonatal outcomes. Conclusion UV Doppler assessment can aid in detection and prediction of critical perinatal outcomes however, it required further evaluation and assessment.

Changes in Central and Peripheral Circulation in Intrauterine Growth-Restricted Fetuses at Different Stages of Umbilical Artery Flow Deterioration: New Fetal Cardiac and Brain Parameters

Objective: To evaluate changes in central and peripheral circulation, including new and standard parameters of the fetal brain and heart in fetuses with intrauterine growth restriction (IUGR) in relation to progressive deterioration of the umbilical artery (UA). Methods: Seventy-two IUGR fetuses were studied longitudinally. IUGR was defined as an estimated fetal weight <10th centile for gestational age. Fetuses were classified according the UA pulsatility index (PI) as: group 1, normal UA-PI (<95th centile; <1.645 z-scores), group 2, UA-PI (≧95th centile and <99th centile; ≧1.645 and <3 z-scores), group 3, UA absent end-diastolic flow, and group 4, UA reversed end-diastolic flow. Middle cerebral artery (MCA), anterior cerebral artery segments 1 (ACA1) and 2 (ACA2), aortic isthmus blood flow index (IFI), modified myocardial performance index (Mod-MPI), ductus venosus (DV), renal artery (RA), femoral artery (FA) and amniotic fluid index (AFI) were weekly evaluated until delivery. Results: A total of 263 scans were performed (median, 3 (range: 1–23) per patient). There were 6 intrauterine and 2 neonatal deaths. Although all cerebral arteries showed a reduction in the PI, ACA1 showed the earliest vasodilatation. From group 2 onwards, all cerebral vessels had a similar pattern of vasodilatation. Mod-MPI became abnormal at group 1 with no further changes. IFI and DV became constantly abnormal starting from group 2. No changes in the RA-PI or FA-PI were documented. Conclusion: The process of hemodynamic deterioration in IUGR fetuses seems to be earlier represented by the ACA1 and the Mod-MPI. Signs of further deterioration were observed in the DV, IFI and MCA. The peripheral blood in the RA and FA did not show any change. AFI showed a late deterioration process.

Predicting Perinatal Outcome Through Changes in Umbilical Artery Doppler Studies After Antenatal Corticosteroids in the Growth-restricted Fetus

OBJECTIVE: To investigate whether persistently absent umbilical artery end-diastolic flow in the intrauterine growth-restricted fetus after betamethasone administration is associated with altered perinatal outcomes. METHODS: This is a retrospective cohort study of 92 pregnancies complicated by intrauterine growth restriction (IUGR) and absent end-diastolic flow in which antenatal betamethasone was given. Predefined maternal outcomes (maternal age, gestational age at diagnosis of absent end-diastolic flow, gestational age at delivery, preexisting medical conditions) and neonatal outcomes (including birth weight; perinatal mortality; duration of neonatal intensive care unit admission; requirement for intubation, assisted ventilation, inotropic support; duration of supplemental oxygen, assisted ventilation; respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage) were analyzed. RESULTS: Betamethasone administration was associated with a transient return of end-diastolic umbilical artery flow in 58 pregnancies (63%) and persistent absent end-diastolic flow in 34 (37%). Persistent absent end-diastolic flow was seen more frequently in women with prepregnancy medical disorders (59% compared with 24%, P<.001). Neonates from the persistent absent end-diastolic flow subgroup were more likely to require assisted ventilation (93.1% compared with 73.5%, P=.03) and to have longer durations of assisted ventilation (median time 30 days compared with 4 days, P=.03) and supplemental oxygen (median time 45 days compared with 4 days, P=.04). CONCLUSION: Betamethasone administration is associated with a transient return of end-diastolic flow in two thirds of pregnancies complicated by IUGR and umbilical artery absent end-diastolic flow. Persistent absent end-diastolic flow in the umbilical artery after betamethasone administration may identify a subgroup of fetuses with IUGR at further heightened perinatal risk that, as neonates, are more likely to require assisted ventilation and a longer duration of ventilation and supplemental oxygen.

Predicting Perinatal Outcome Through Changes in Umbilical Artery Doppler Studies After Antenatal Corticosteroids in the Growth-Restricted Fetus

To investigate whether persistently absent umbilical artery end-diastolic flow in the intrauterine growth-restricted fetus after betamethasone administration is associated with altered perinatal outcomes. This is a retrospective cohort study of 92 pregnancies complicated by intrauterine growth restriction (IUGR) and absent end-diastolic flow in which antenatal betamethasone was given. Predefined maternal outcomes (maternal age, gestational age at diagnosis of absent end-diastolic flow, gestational age at delivery, preexisting medical conditions) and neonatal outcomes (including birth weight; perinatal mortality; duration of neonatal intensive care unit admission; requirement for intubation, assisted ventilation, inotropic support; duration of supplemental oxygen, assisted ventilation; respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage) were analyzed. Betamethasone administration was associated with a transient return of end-diastolic umbilical artery flow in 58 pregnancies (63%) and persistent absent end-diastolic flow in 34 (37%). Persistent absent end-diastolic flow was seen more frequently in women with prepregnancy medical disorders (59% compared with 24%, P<.001). Neonates from the persistent absent end-diastolic flow subgroup were more likely to require assisted ventilation (93.1% compared with 73.5%, P=.03) and to have longer durations of assisted ventilation (median time 30 days compared with 4 days, P=.03) and supplemental oxygen (median time 45 days compared with 4 days, P=.04). Betamethasone administration is associated with a transient return of end-diastolic flow in two thirds of pregnancies complicated by IUGR and umbilical artery absent end-diastolic flow. Persistent absent end-diastolic flow in the umbilical artery after betamethasone administration may identify a subgroup of fetuses with IUGR at further heightened perinatal risk that, as neonates, are more likely to require assisted ventilation and a longer duration of ventilation and supplemental oxygen.

Doppler changes in the main fetal brain arteries at different stages of hemodynamic adaptation in severe intrauterine growth restriction

To evaluate changes in the temporal evolution and regional distribution of arterial brain Doppler parameters in relation to different stages of hemodynamic adaptation in fetuses with severe intrauterine growth restriction (IUGR). Thirty-six fetuses with severe IUGR (<or= 32 weeks of gestation) and abnormal umbilical artery (UA) pulsatility index (PI) (mean > 2 SD) were evaluated longitudinally with pulsed Doppler ultrasound at four different hemodynamic stages: Stage 1 (n = 36), mean UA-PI > 2 SD or absent UA end-diastolic flow; Stage 2 (n = 34), abnormal middle cerebral artery (MCA) PI (mean < 2 SD); Stage 3 (n = 30), reversed UA end-diastolic flow; Stage 4 (n = 12), absent or reversed atrial flow in the ductus venosus. In addition, 36 normally grown fetuses were studied for comparison. PI and time-averaged maximum velocity (TAMXV) in the MCA and the anterior cerebral (ACA), pericallosal (PER) and posterior cerebral (PCA) arteries were measured. In IUGR fetuses, PI values from all arteries were significantly reduced at Stage 2. At Stages 3 and 4, ACA-PI and PCA-PI did not change further, whereas MCA-PI and PER-PI showed a slight increase. In the ACA, MCA and PER, TAMXV in Stage 2 increased significantly. In Stages 3 and 4, ACA and PER-TAMXV remained unchanged, whereas MCA-TAMXV showed a slight decrease, mirroring the PI values. PCA-TAMXV values were similar to controls at all stages. In IUGR fetuses, the brain arteries differ in the magnitude and time sequence of Doppler parameters in relation to systemic hemodynamic adaptation, suggesting the existence of regional brain redistribution processes.

Changes in fetoplacental vessel flow velocity waveforms following maternal administration of betamethasone.

To determine the timing of the onset of the umbilical artery flow velocity waveform changes following maternal administration of betamethasone in pregnancies complicated by umbilical artery absent end-diastolic flow, and to explore whether these changes are associated with flow velocity waveform changes in other fetoplacental vessels. This was a prospective study of 12 women with pregnancies complicated by umbilical artery absent end-diastolic flow. Flow velocity waveforms were recorded from the umbilical artery, fetal middle cerebral artery, renal artery, aorta and ductus venosus, before and after maternal betamethasone administration, using real-time pulsed wave Doppler. In all 12 pregnancies, the administration of maternal betamethasone was followed by the return of end-diastolic flow within 24 h. End-diastolic flow was first observed at 4 h and was present in all women studied at 8 h. In addition, there was a statistically significant decrease in the pulsatility index in the fetal aorta at 8 h and the middle cerebral artery at 24 h. No change was observed in the ductus venosus or the renal artery flow velocity waveforms. The findings suggest that, in pregnancies complicated by absent end-diastolic flow in the umbilical artery, maternally administered betamethasone induces a return in umbilical artery end-diastolic flow as early as 4 h, along with widespread vasodilatation throughout the fetoplacental vasculature.

Effect of antenatal betamethasone administration on placental vascular resistance

High placental vascular resistance is an important cause of fetal growth restriction and subsequent perinatal mortality. Identification of affected pregnancies allows appropriate fetal surveillance and delivery, but there are no known therapeutic strategies to decrease resistance and improve blood flow. However, placental corticotropin-releasing hormone (CRH) is thought to be a potent fetoplacental vasodilator, and exogenous corticosteroids can increase placental CRH secretion. Therefore, we examined whether corticosteroids could improve fetoplacental blood flow in pregnancies with increased vascular resistance. A retrospective review of umbilical-artery flow-velocity waveforms (FVWs) before and after betamethasone administration was undertaken in pregnancies with increased placental vascular resistance, as shown by umbilical-artery absent end-diastolic flow (AEDF). FVWs were obtained by pulsed-wave doppler ultrasonography. We studied all 28 pregnancies monitored at the maternal-fetal medicine unit of a university teaching hospital since 1995. The median duration of gestation at presentation with AEDF was 27 weeks (range 23-33). In 19 (68% [95% CI 49-86]) pregnancies, umbilical-artery diastolic flow returned within 24 h after betamethasone administration, consistent with decreased resistance. The median duration of this effect was 3 days (range 2-7). There were no differences in duration of gestation at diagnosis or delivery, or in birthweight between fetuses showing a return of flow after betamethasone and those not showing a return of flow. In pregnancies with umbilical-artery AEDF, betamethasone treatment is associated with decreased placental vascular resistance, possibly induced via increased placental CRH secretion. This study does not provide insights into whether this effect would be beneficial or harmful to the fetus.

Middle Cerebral Artery Velocity Waveforms in Fetuses with Absent Umbilical Artery End-Diastolic Flow

Middle cerebral artery (MCA) velocity waveforms were analyzed in 21 fetuses with absent umbilical artery end-diastolic flow (AEDF). Resistance index (RI) was measured from MCA velocity waveforms when AEDF was observed for the first time and at consecutive examinations. Fetal distress defined by fetal heart rate monitoring was found in 19 cases (90%). The difference between MCA RI values of first and last examinations was statistically significant (p < 0.01). There was a positive correlation between MCA RI values at the first examination and the time passing to delivery (r = 0.52; p < 0.05). There was no significant correlation between MCA RI values and the incidence of an adverse perinatal outcome. Pregnancies with AEDF are of high risk for the development of fetal distress. MCA resistance index values decrease gradually in fetuses with AEDF suggesting continuous reduction of cerebral vascular resistance during chronic fetal hypoxia.