Fetal Middle Cerebral Artery Blood Research Articles

Are fetuses that fail to achieve their growth potential at increased risk of intrapartum compromise?

The true growth potential of a fetus is difficult to predict but recently a new definition, independent of fetal weight, using cerebroplacental (cerebro-umbilical) ratio (CPR) < 0.6765 multiples of the median (MoM), was reported. We applied this definition to a cohort of low-risk pregnancies recruited prospectively to determine if fetuses with CPR < 0.6765 are at increased risk of developing signs of intrapartum fetal compromise. Recruitment to this prospective observational study took place between March 2011 and March 2014. All women with low-risk singleton pregnancies at term were eligible. Women with known or suspected placental dysfunction were excluded, as were women with fetuses with an estimated fetal weight < 10(th) centile. All participants underwent ultrasound examination prior to active labor (≤ 4 cm cervical dilatation), during which fetal biometry as well as umbilical artery and fetal middle cerebral artery blood flow were assessed. Following delivery, intrapartum and neonatal outcomes were compared between fetuses that had a CPR < 0.6765 MoM and those that had a CPR ≥ 0.6765 MoM. In total, 775 women were recruited. Fetuses with CPR < 0.6765 MoM were significantly more likely to require Cesarean delivery because of presumed fetal compromise (P < 0.001). These fetuses were also at increased risk of compromise at any time during labor and were less likely to be delivered vaginally, spontaneously or otherwise, than were those with CPR ≥ 0.6765 MoM. CPR < 0.6765 MoM gave a positive predictive value (PPV) for Cesarean delivery because of presumed fetal compromise of 36.7% and a negative predictive value of 88.7%, with a sensitivity of 18% and a specificity of 95.4%. Fetuses that failed to achieve their growth potential (defined as CPR < 0.6765 MoM) were at increased risk of intrapartum compromise and were less likely to be delivered vaginally. However, a low negative predictive value was observed for fetal compromise and further studies are required to support the translation of this technique into clinical practice.

Effects of maternal abdominal decompression on umbilical artery and fetal middle cerebral artery blood flow

Introduction: Maternal abdominal decompression during pregnancy could be used in an attempt to improve utero-placental blood flow. We utilized Doppler ultrasonography to investigate the effects of this procedure on blood flow in the umbilical artery and fetal middle cerebral artery.&#x0D; Methods: Women (n = 23) with singleton pregnancies attending antenatal abdominal decompression were enrolled in the study. Doppler velocity waveforms were obtained from umbilical artery and fetal middle cerebral artery before and after a 30-minute decompression session. Resistance indices were compared using the Student's t - test (p &lt; 0.05 significant).&#x0D; Results: 23 healthy pregnant women were included at an average gestational age of 36+1 weeks. The mean resistance index before decompression in the umbilical artery was 0.58 (s = 0.10) and after decompression 0.54 (s = 0.07, p = 0.06). In the middle cerebral artery the values were 0.72 (s = 0.11) and 0.77 (s = 0.08), respectively (p = 0.01).&#x0D; Discussion and conclusion: Significantly increased resistance index in the middle cerebral artery implies a higher fetal brain oxygenation after decompression. This is further corroborated by the trend towards a decrease in umbilical artery resistance index. The effects of decompression could be beneficial in pregnancies complicated by IUGR or hypertensive disorders of pregnancy.

Correlation of fetal middle cerebral artery Doppler indices in IUGR pregnancies

Background and objectives: Doppler velocimetry studies of placental and fetal circulation can provide an important information regarding fetal well being providing an opportunity to improve fetal outcome. The present study was undertaken to evaluate the role of fetal middle cerebral artery blood velocity waveforms, Systolic/Diastolic ratio (S/D), Pulsatility Index (PI), Resistance Index (RI) as predictor of perinatal outcome in intrauterine growth restriction (IUGR) pregnancies in IInd and IIIrd trimester. Methods: In the study group, 50 cases of IUGR were studied in IInd and IIIrd trimester. They were first subjected to ultrasonography biometry and then middle cerebral artery Doppler sonography. Results: In both control and study group the values of S/D ratio, PI and RI in middle cerebral artery decline during IInd to IIIrd trimester. The values were lower in the study group as compared to the control group. Thus the present study predicts that; a) Lower PI values were suggestive of fetal hypoxia. b) The lower values is due to vasodilatation due to hypoxia in order to supply more blood to the brain to protect it from the damaging effects of hypoxia. Thus the brain is spared from damage. Interpretation and conclusion: Doppler can be considered as one of the important non invasive technique to assess the fetomaternal and uteroplacental circulations. The middle cerebral artery indices were valuable for predicting the outcome of IUGR pregnancies.

Impact of passive smoking on uterine, umbilical, and fetal middle cerebral artery blood flows

The aim of this study was to evaluate the influence of passive maternal smoking on blood flow velocities in arteries of the fetal-placental-maternal circulation. A total of 79 pregnant women in their third trimester, including 33 passive smokers, 23 active smokers, and 23 nonsmoking controls, were enrolled in the study. Fetal biophysical indices were evaluated with B-mode scanning, whereas blood flow waveforms of uterine, umbilical, and fetal middle cerebral (MCA) arteries were analyzed with Doppler ultrasonography. There were significant differences among active smokers vs. passive smokers vs. controls with regard to the presence of a uterine artery diastolic notch (39.1% vs. 18.2% vs. 4.3%; P = 0.012); ratio of peak systolic/end-diastolic velocity of fetal MCA [3.73 ± 1.27 vs. 4.26 ± 1.20 vs. 5.00 ± 2.15, analysis of variance (ANOVA) P = 0.026]; resistance index of fetal MCA (0.74 ± 0.08 vs. 0.75 ± 0.07 vs. 0.80 ± 0.09; ANOVA P = 0.014); ratio of fetal MCA/umbilical artery resistance index (1.27 ± 0.20 vs. 1.24 ± 0.14 vs. 1.39 ± 0.21; ANOVA P = 0.011); and ratio of fetal MCA/umbilical artery pulsatility index (1.56 ± 0.44 vs. 1.63 ± 0.43 vs. 1.97 ± 0.54; ANOVA P = 0.046). Effects of passive maternal smoking on the fetal-placental-maternal unit were comparable to those with active maternal smoking as determined by the means of increased resistance in the maternal vasculature and adaptive changes of cerebroplacental circulation for maintaining fetal cerebral circulation.

Maternal serum alpha-fetoprotein, fetal middle cerebral artery blood flow velocity and fetal haemoglobin in pregnancies at risk of fetal anaemia

To evaluate the relationships between maternal serum alpha-fetoprotein (MSAFP) levels and both middle cerebral artery (MCA) peak systolic velocity and fetal haemoglobin in women at risk of fetal anaemia. Forty-one measurements of MSAFP were carried out in 22 women at risk of fetal anaemia (16 alloimmunised patients and 6 cases of parvovirus infection) who were monitored by using MCA Doppler measurements. The relationships between MSAFP (MoM) and both MCA peak systolic velocity (z-scores) and fetal haemoglobin (MoM) were studied. There were significant correlations between MSAFP and both MCA Doppler measurements (r = 0.56, p = 0.00017) and fetal haemoglobin (n = 13, r = -0.71, p = 0.006). MSAFP was higher in cases with fetal anaemia (n = 10) than in those with normal haemoglobin levels (n = 3) (1.7 +/- 0.4 vs 0.8 +/- 0.1 MoM; p = 0.006). In cases of alloimmunised pregnancies with fetal anaemia, MSAFP elevations preceded the presence of increased MCA Doppler velocity by 2.7 weeks (range 0-9 weeks). MSAFP is significantly correlated with both MCA Doppler measurements and fetal haemoglobin. Elevations of MSAFP may appear earlier than MCA Doppler abnormalities in cases of fetal anaemia associated with red blood cell alloimmunisation.

First trimester ultrasound screening for fetal aneuploidy and middle cerebral artery Doppler assessment for fetal alloimmunization

Traditional methods of fetal evaluation require invasive procedures (e.g. amniocentesis) with an inherent, albeit low, risk of complications and pregnancy loss. As medical knowledge and ultrasound technology have advanced, noninvasive modes of fetal evaluation have become increasingly used. Two disorders in which this has been most applied are fetal aneuploidy and alloimmunization to red blood cell antigens. First-trimester screening protocols for fetal aneuploidy combine ultrasound measurement of the fetal nuchal translucency with the measurement of two maternal serum hormones, free beta-human chorionic gonadotropin and pregnancy-associated plasma protein-A. This combination detects approximately 85% of women pregnant with fetuses with trisomy 21. An increase in the velocity of fetal middle cerebral artery blood flow occurs in the setting of moderate to severe fetal anemia and can be measured with Doppler ultrasound. Middle cerebral artery evaluation is equally sensitive in the prediction of anemia as amniocentesis for bilirubin breakdown products and has less associated risk. It has an additional benefit because it can also be applied to causes of anemia other than hemolysis. Noninvasive methods of fetal assessment are becoming increasingly commonplace. There has been a dramatic decrease in the use of prenatal diagnostic services as screening strategies have become available. Doppler assessment of the velocity of blood flow through the fetal middle cerebral artery will allow for more judicious application of invasive procedures to pregnancies at significant risk for anemia.

Increased Systolic Peak Velocity in Fetal Middle Cerebral Artery Blood Flow Shown by Doppler Sonography in Acute Fetomaternal Hemorrhage

Doppler measurement of peak systolic velocity of fetal middle cerebral artery (MCA) blood flow provides a noninvasive method to assess the degree of anemia in fetuses with chronic anemia secondary to Rh alloimmunization or parvovirus infection. 1 - 8 There are 2 prior case reports of increased MCA peak systolic velocity in acute fetal anemia. 9 , 1 0 This report adds to that literature and stresses the importance of checking the MCA peak systolic velocity when acute fetal anemia is of concern to appropriately care for the anemic neonate at birth. In this case of a large fetomaternal hemorrhage, neonatal transfusion was set up at the time of the cesarean delivery because of the information gleaned from the MCA Doppler study.

The Resistance Index in the Fetal Middle Cerebral Artery by Gestational Age and Ventricle Size in a Normal Population

In Brief OBJECTIVE To study the association between fetal middle cerebral artery flow and the lateral cerebral ventricular width throughout gestation. METHODS The study is a prospective cohort evaluation of 430 singleton male and female fetuses between 20 and 40 weeks' normal gestation. Abdominal ultrasonography and Doppler measurements were performed to measure the fetal atrial ventricular size and resistance index (RI) of the middle cerebral artery. RESULTS The mean (± standard deviation) ventricular width was 6.2 ± 1.2 mm. The modification in the RI of the middle cerebral artery throughout gestation showed a biphasic mode, increasing gradually to a peak at 30 weeks' gestation and decreasing progressively thereafter. No significant correlation was found between the middle cerebral artery flow and the lateral cerebral ventricular width (r = .11). In addition to the 430 cases studied, three cases of mild ventriculomegaly and three cases of hydrocephalus were evaluated. The RI of the middle cerebral artery was within the normal range in all six of these cases. CONCLUSION Fetal middle cerebral artery blood flow is not affected by the width of the lateral ventricles, even in enlarged ventricles. Prenatal ultrasonographic measurements of cerebral ventricular width and middle cerebral artery flow in 430 fetuses identified no significant association between middle cerebral artery flow and increased ventricular diameter.

The resistance index in the fetal middle cerebral artery by gestational age and ventricle size in a normal population

Objective To study the association between fetal middle cerebral artery flow and the lateral cerebral ventricular width throughout gestation. Methods The study is a prospective cohort evaluation of 430 singleton male and female fetuses between 20 and 40 weeks’ normal gestation. Abdominal ultrasonography and Doppler measurements were performed to measure the fetal atrial ventricular size and resistance index (RI) of the middle cerebral artery. Results The mean (± standard deviation) ventricular width was 6.2 ± 1.2 mm. The modification in the RI of the middle cerebral artery throughout gestation showed a biphasic mode, increasing gradually to a peak at 30 weeks’ gestation and decreasing progressively thereafter. No significant correlation was found between the middle cerebral artery flow and the lateral cerebral ventricular width ( r = .11). In addition to the 430 cases studied, three cases of mild ventriculomegaly and three cases of hydrocephalus were evaluated. The RI of the middle cerebral artery was within the normal range in all six of these cases. Conclusion Fetal middle cerebral artery blood flow is not affected by the width of the lateral ventricles, even in enlarged ventricles.

The effect of methyldopa treatment on uterine, umblical and fetal middle cerebral artery blood flows in preeclamptic patients.

The purpose of this study was to evaluate the efficacy of methyldopa in the treatment of preeclamptic patients. This study was performed on 24 preeclamptic women who were in between 25-36 weeks of gestational age. 24 healthy pregnant women were taken as control group. Before starting treatment, 24 preeclamptic patients were examined with Doppler ultrasound. Pulsatility index, resistance index, systolic/diastolic ratio of uterine, umblical and fetal middle cerebral arteries were measured. Preeclamptic patients were treated with totally 1 g methyldopa per day. After 7 d, patients were reexamined with Doppler ultrasound. The effect of methyldopa on uterine, umblical and fetal middle cerebral artery blood flows were detected. Only one control with Doppler ultrasound was done to the healthy pregnant women. Before methyldopa treatment to the preeclamptic women, pulsatility index (PI), resistance index (RI) and systolic/diastolic ratio (S/D) on uterine and umblical arteries were significantly higher than the control group. However, fetal middle cerebral artery (MCA) values were significantly lower than the control group. When Doppler results of preeclamptic patients before and after the methyldopa treatment were compared, no significant differences in terms of Pulsatility Index, Resistance IndexI and S/D ratio of umblical and fetal middle cerebral arteries were found. However, the results of uterine artery were significantly lower after the treatment in preeclamptic patients. Treatment with methyldopa lowered the uterine artery resistance in preeclamptic patients but did not effect the resistance of umblical and fetal middle cerebral artery.

Fetal middle cerebral artery blood flow in patients with different stages of pacental insufficiency

Fetal middle cerebral artery blood flow in patients with different stages of pacental insufficiency

Fetal Middle Cerebral Artery Blood Flow Velocities in Pregnancies Complicated by Intrauterine Growth Restriction and Extreme Abnormality in Umbilical Artery Doppler Velocity

If they are not delivered in a timely fashion, pregnancies complicated by severe intrauterine growth restriction (IUGR) can lead to fetal loss. Conventional fetal well-being tests, including ultrasound measurement of fetal growth rate, biophysical profile, nonstress test, and contraction stress test are used to manage these pregnancies. Some fetuses delivered based on abnormal fetal well-being tests show long-term sequelae. A better understanding of the malfunction of the placenta and its effect on the fetus is desperately required for better management of these cases. We are reporting our experience of 6 such pregnancies followed by fetal middle cerebral artery (MCA) blood flow velocity measurements. There was significant decrease in MCA flow velocities in all of these fetuses compared to normal population (p < 0.05). Reverting to normal values occurred prior to the appearance of abnormal conventional tests, on average 4 days earlier. In other words, normalization of MCA flow velocities was a harbinger of fetal jeopardy. Although our observation includes a small number of patients, there is a potential for use of MCA blood flow velocity measurement to aid us in understanding and managing fetuses with IUGR. This needs to be evaluated in a larger study.

Fetal middle cerebral artery blood flow during normal active labour and in labour with variable decelerations.

To assess the distribution of fetal blood flow impedance of the umbilical and middle cerebral artery in active uncomplicated labour and in labour complicated by variable decelerations. Blood flow impedance of the umbilical and fetal middle cerebral arteries was assessed by means of pulsed Doppler ultrasonography and measured by the resistance index (RI) and the systolic/diastolic ratio. 35 women at 38-40 weeks gestation admitted to, or monitored in the intrapartum unit. One group of 25 women had a normal active labour, the second group of 10 women were in active labour with moderate variable decelerations. A control group of 25 women--healthy pregnant women at term but not in active labour. All three groups were comparable for maternal age and parity. Hospital department of obstetrics and gynaecology, Israel. A prospective descriptive study. There was a 40% reduction in middle cerebral artery blood flow impedance in the two groups of women in active labour compared with the control group. Umbilical blood flow did not differ significantly between the three groups. Fetal middle cerebral blood flow impedance in labour was not significantly different in uncomplicated labours and those complicated by fetal heart rate decelerations. During active labour, mechanisms that may be unrelated to low fetal blood oxygen content reduce fetal brain blood vessel impedance.