Uterine Blood Flow Velocity Research Articles

Коагуляційні характеристики пуповинної крові при затримці росту плода

Fetal growth restriction (FGR) is a common complication of pregnancy associated with severe perinatal consequences, a significant part of which is hemorrhagic and thrombotic disorders. Fetuses with FGR have thrombocytopenia, platelet dysfunction, and distortion of standard coagulation tests. There are few studies of the coagulation system in such newborns in vivo in the literature. Аim - to assess the relationship between the Doppler criteria of FGR and the kinetic manifestations of umbilical artery blood coagulation and fibrinolysis according to rotational thromboelastometry. Materials and methods. Prenatal Doppler parameters and postpartum kinetic parameters of blood coagulation and fibrinolysis in 118 newborns from singleton births were analyzed: the Group I - 67 newborns with FGR; the Group II - 51 full-term newborns from healthy mothers. Results. A significant decrease in the uterine and umbilical arteries resistance and blood flow velocity in FGR cases has been established. Thromboelastometric tests in the umbilical cord blood of the Group I newborns showed faster than in the Group II the blood clot formation, its greater firmness and delayed fibrinolysis. Comparison using rank correlation showed a relationship of average strength between the velocity of blood flow in the umbilical cord arteries and the blood clot firmness. Correlation between blood flow velocity in the midbrain and uterine arteries and coagulation indicators are weak. Conclusions. Reduced resistance index in the middle cerebral artery of fetuses with FGR indicates reduced resistance in these vessels, which should be regarded as signs of decentralization of fetal circulation. The blood of newborns with FGR is dominated by the processes of increased coagulation and slowing down of fibrinolysis, regardless of the date of birth. An increase in the pulsation index in the umbilical cord arteries during pregnancy can be considered a prognostically favorable hemodynamic characteristic in FGR. The study was carried out in accordance with the principles of the Helsinki Declaration. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. The authors declare that there is no conflict of interest.

Ovarian and uterine arteries blood flow velocities waveform, hormones and nitric oxide in relation to ovulation in cows superstimulated with equine chorionic gonadotropin and luteolysis induction 10 and 17 days after ovulation

To investigate the ovarian responses, ovarian and uterine hemodynamics, circulating ovarian hormones, and nitric oxide (NO) with their relations in superstimulated cows. Eight Holstein Friesian dry cows previously synchronized with CIDR underwent rectal Doppler ultrasound scanning and blood sampling after administrating eCG (1500 I.U) on day 10 of the second ovulation (day -5). Cows were treated with 12.5 mg prostaglandin F2α (PGF2α) on days 10 and 17 after ovulation. Estradiol, progesterone, and NO were measured. Results showed that from ≥ 13 follicles, five follicles ovulated from both ovaries. The ovulated follicles increased antrum colored area and colored area % till day -1. The developed corpora lutea (CLs) attained similar diameter, area, colored area, and colored area % from day 2 till day 15. The peak point of velocity (PSV) of uterine arteries decreased while that of ovarian arteries increased from day -4 to day 0. Both ovarian arteries diameter, resistance index (RI), PSV, end velocity (EDV) and systolic/diastolic ratio (S/D) positively correlated (P < 0.0001), but their pulsatility index (PI) negatively correlated (P < 0.0001). The uterine arteries PI, RI, PSV, EDV, time average velocity (TAMV) and S/D negatively correlated (P < 0.0001) but their diameters positively correlated. Estradiol increased but progesterone decreased from day -5 till day 0. After ovulation, P4 reached maximum values on day 9 and started to decrease till day 19.NO showed one peak on day -3 and another one from day 3 to day 9. Conclusions: Blood flow of ovarian arteries is different from uterine arteries and depended on pre- or post-ovulation.

EP16.07: Postpartum uterine arteries blood flow velocity as a predictor of retained products of conception

EP16.07: Postpartum uterine arteries blood flow velocity as a predictor of retained products of conception

Trophoblast-induced spiral artery remodelling and uteroplacental haemodynamics in pregnant rats with increased blood pressure induced by heme oxygenase inhibition

IntroductionThe aim of the present study was to determine the contribution of the heme oxygenase (HO) system to the adaptation of the uteroplacental circulation to pregnancy in the rat, and its relationship with the maintenance of blood pressure during late gestation. MethodsThe HO inhibitor, stannous mesoporphyrin (SnMP), or vehicle were administered intraperitoneally to virgin and midpregnant rats. Mean arterial pressure (MAP) was measured before and after the treatment, in the conscious rats. Uterine and radial arteries blood flow velocities were obtained from pregnant rats at days 14 and 19 of gestation using high frequency ultrasonography. Trophoblast invasion and spiral arteries remodelling were analyzed in the mesometrial triangle of pregnant rats by immunohistochemistry. ResultsHO activity inhibition during late gestation induced a significantly increase in the MAP of pregnant rats (114 ± 1 mmHg vs 100 ± 2 mmHg, p < 0.05) but it did not affect this parameter in virgin rats (121 ± 2 mmHg vs 124 ± 3 mmHg). MAP elevation was associated with marked (p < 0.05) decreases in the systolic and diastolic flow velocities in uterine and radial arteries, as compared with pregnant control rats. Furthermore, spiral arteries of pregnant rats treated with SnMP showed lower (p < 0.001) proportion of lumen circumference covered by trophoblast (21 ± 3%) and a higher (p < 0.05) proportion of vascular smooth muscle (33 ± 5%) than control pregnant rats (59 ± 5% and 16 ± 5%, respectively) DiscussionThese data indicate that HO system play an important role in the adaptation of the uteroplacental circulation to pregnancy and in the blood pressure regulation during late gestation.

The Influence of Lipid and Proinflammatory Status on Maternal Uterine Blood Flow in Women With Late Onset Gestational Diabetes.

Gestational diabetes mellitus (GDM) is associated with increased proinflammatory cytokines and is also associated with adverse cardiovascular disease (CVD) outcomes later in life. We aim to evaluate the relationships between uterine arteries vascularization and endothelial dysfunction markers, proinflammatory cytokines, and glycemic and lipid profile in women with GDM. Fifty pregnant women were recruited at the third trimester of pregnancy for a prospective cohort study. They were classified into 2 groups: control and GDM. Comparisons of maternal plasma concentrations of endothelial dysfunction markers (vascular cell adhesion molecule 1, intercellular adhesion molecule 1, and plasminogen activator inhibitor 1), proinflammatory cytokines and mediators (interleukin 6 [IL-6], tumor necrosis factor α, vascular endothelial growth factor, placental growth factor, leptin, leukocyte count, and C-reactive protein), lipid profile, glucose, and glycosylated hemoglobin levels were performed. Mean uterine arteries Doppler pulsatility index (PI) was calculated and the relationships between the variables and PI were also analyzed. Women with GDM showed higher proinflammatory cytokines, however, endothelial dysfunction markers were similar in both groups. In the diabetic group, significant correlations were found between the mean uterine arteries PI and maternal IL-6 ( r = .56, P = .01), triglycerides ( r = .49; P = .03), total cholesterol/high-density lipoprotein cholesterol (HDL-c) ratio ( r = .61; P = .006), glucose (r = .62, P = .005), and glycosylated hemoglobin ( r = .48; P = .03). A negative significant correlation between mean uterine arteries PI and HDLc ( r = -.58; P = .02) was also found. The proinflammatory status, hyperlipidemia, and metabolic control correlate with uterine blood flow velocity waveforms in women with gestational diabetes.

Relaxin mediates uterine artery compliance during pregnancy and increases uterine blood flow

Normal pregnancy involves dramatic remodeling of the uterine vasculature, with abnormal vascular adaptations contributing to pregnancy diseases such as preeclampsia. The peptide hormone relaxin is important for the renal and systemic hemodynamic adaptations to pregnancy, and has been shown to increase arterial compliance and outward hypertrophic remodeling. Therefore, we investigated the possibility that relaxin acts on its receptor, RXFP1, to mediate uterine artery compliance in late pregnancy and increase uterine blood flow velocity in rats. RXFP1 was predominantly localized to the tunica media vascular smooth muscle cells in the uterine artery, although receptors were also detected in endothelial cells. Highest expression of Rxfp1 in the uterine artery occurred in estrus and early pregnancy. Isolated uterine arteries from late pregnant rats treated with a monoclonal antibody against circulating relaxin (MCA1) had significantly increased vessel wall stiffness compared with controls, with no reduction in wall thickness. Chronic infusion of relaxin (4 μg/h, osmotic minipump) for 5 d in nonpregnant rats significantly increased uterine artery blood flow velocity. Overall, these data demonstrate a functional role for relaxin in mediating uterine artery compliance in pregnant rats, which may be necessary to maintain adequate uterine blood flow to the uterus and placenta.

Reference Values for Blood Flow Velocity in the Uterine Artery in Normal Pregnancies from 18 Weeks to 42 Weeks of Gestation Calculated by Automatic Doppler Waveform Analysis

The goal of the present study was to establish new Doppler reference ranges for maternal heart rate, intensity-weighted mean blood flow velocities (Vmean) and impedance indices (PI, RI) for the uterine artery by automated waveform analysis. A cross-sectional prospective study of 921 low-risk pregnancies was performed at 18-42 weeks of gestation. Uterine blood flow velocities were derived with pulsed-wave color Doppler. Measurements were carried out 1 to 2cm above the crossing of the uterine and external iliac arteries. Reference ranges for the individual measuring parameters were constructed based on a growth function from a four-parameter class of monotonic continuous functions according to the smallest square principle. A significant increase in intensity-weighted mean uterine blood flow velocities was observed at 18-42 weeks of gestation (Vmean=43cm/s to 50cm/s (p<0.001)). Reference curves for the pulsatility and resistance indices (PI, RI) significantly decreased with progressing gestation (PI: 18 weeks: 0.89; 42 weeks: 0.65 and RI: 18 weeks: 0.45; 42 weeks: 0.35). No significant PI and RI differences were observed when different placental locations were compared. The maternal heart rate decreased from 88 bpm to 77 bpm. Normal ranges for blood flow velocities and impedance indices in the uterine artery were established by Doppler ultrasound antenatal examinations of a large population of low-risk pregnancies. The data are proposed as reference curves to allow the early diagnosis of maternal and fetal risks.

P41.02: Prediction of pre‐eclampsia and intrauterine growth restriction by uterine artery doppler blood flow velocity analysis

P41.02: Prediction of pre‐eclampsia and intrauterine growth restriction by uterine artery doppler blood flow velocity analysis

Application of the Magnitude-Squared Coherence Function Between Uterine and Umbilical Flow Velocity Waveforms for Predicting Placental Dysfunction: A Preliminary Study

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

Experimental validation of uterine artery volume blood flow measurement by Doppler ultrasonography in pregnant sheep

To test the hypothesis that Doppler-derived (calculated) uterine artery volume blood flow (cQ(UtA)) reflects accurately volume blood flow measured directly (mQ(UtA)) in an experimental setting. Five pregnant sheep were instrumented at 122-130 days of gestation under general anesthesia. After a 4-day recovery period, maternal hemodynamics were varied by administering to the sheep under general anesthesia noradrenaline, beta-blocker, low oxygen gas mixture, epidural bupivacaine and ephedrine, consecutively. The central venous pressure was obtained with the help of a thermodilution catheter. The mean arterial pressure and acid-base status were monitored using a 16-gauge polyurethane catheter inserted into the descending aorta via a femoral artery. A 6-mm transit-time ultrasonic perivascular flow probe was used to measure the mQ(UtA). Doppler ultrasonography of the uterine artery was performed and volume blood flow was obtained simultaneously by the transit-time ultrasonic perivascular flow probe during each phase of the experiment. A total of 31 observations were made. The mQ(UtA) varied between 90 and 800 (mean +/- SD, 419 +/- 206) mL/min during the experiments. The corresponding values for the cQ(UtA) were 110 and 900 (mean +/- SD, 459 +/- 211) mL/min. There was a significant correlation (R = 0.76; P < 0.0001) between mQ(UtA) and cQ(UtA). The mQ(UtA) correlated positively with Doppler-derived uterine artery absolute velocities, i.e. peak systolic (R = 0.50; P = 0.004), end-diastolic (R = 0.53; P = 0.002) and time-averaged maximum (R = 0.69; P < 0.0001) and time-averaged intensity weighted mean (R = 0.75; P < 0.0001) velocities. cQ(UtA) correlates well with volume blood flow measured directly. Doppler-derived uterine artery absolute blood flow velocities reflect uteroplacental volume blood flow in pregnant sheep. Published by John Wiley & Sons, Ltd.

Effect of the copper-intrauterine device (TCu 380A) on subendometrial microvascularization and uterine artery blood flow

During this cohort study, the copper-intrauterine device (IUD) did not modify subendometrial microvascularization. However, subendometrial blood flow increased in patients who experienced IUD-induced side effects.

The effects of continuous epidural analgesia on Doppler velocimetry of uterine arteries during different periods of labour analgesia

The transient effects of epidural bupivacaine 0.25-0.5% on the Doppler velocimetry of umbilical and uterine arteries had been reported, but the effects of continuous lower dose epidural bupivacaine (0.05-0.1%) infusion for labour analgesia have never been reported. In this study, we evaluated the effects of continuous epidural bupivacaine 0.075% on the Doppler velocimetry of uterine arteries. Twenty pregnant women for labour analgesia received continuous epidural bupivacaine 0.075% infusion. We used a 4-MHz continuous-wave Doppler probe (Multigon 500A) with a 200 Hz thump filter to detect uterine blood flow velocity. We recorded the velocimetry data for uterine relaxation and contraction during five time periods: pre-epidural insertion, 1, 2, and 4 h post-epidural infusion, and after delivery of fetus. Our data showed that the velocimetric indices of uterine vascular resistance were significantly increased 1, 2, and 4 h after epidural infusion when compared with the pre-epidural level; these returned to the baseline after delivery. Continuous epidural analgesia with bupivacaine 0.075% increases the resistance of uterine artery and therefore possibly reduces the uterine blood flow.

Assessment of volume preload on uteroplacental blood flow during epidural anaesthesia for Caesarean section

Epidural and spinal anaesthesia are the preferred mode of anaesthesia for Caesarean section. Volume preloading is recommended to prevent maternal hypotension and a reduction in uteroplacental blood flow, although positive effects of volume preloading on maternal cardiac output and arterial pressure are debatable. Doppler measurements of the umbilical artery beyond deriving pulsatility indices are not routinely performed. After Institutional Review Board approval and written informed consent, 14 consecutiVe women with epidural anaesthesia for Caesarean section received either hydroxyethyl starch 500 mL or gelatine 500 mL. Haemodynamic variables monitored were maternal arterial pressure, maximal blood flow velocity and pulsatility indices of the uterine artery derived from Doppler measurements. Maternal arterial pressure and pulsatility indices in both groups did not change from baseline after intravenous colloid infusion. However, uterine blood flow increased significantly in both groups. The effectiveness of volume preloading may therefore be better described by changes in maximum uterine blood flow velocity than by pulsatility indices or maternal arterial pressure.

Low-dose Aspirin does not Increase Pregnancy Rates and Uterine Artery Blood Flow Velocity in Male-factor Infertility Patients Undergoing Intracytoplasmic Sperm Injection

Objective: To determine the effects of low-dose aspirin on uterine artery blood flow velocity and pregnancy rate in an unselected group of patients undergoing intracytoplasmic sperm injection (ICSI). Material(s) and Method(s): A total of 126 ICSI procedures were analyzed prospectively. Inclusion criteria allowed only first-trial couples with long-standing infertility caused by a male factor. Besides the exclusion of female factors, the patient population was unselected. The aspirin (+) (n = 66) group received 80 mg aspirin beginning on the first day of the gonadotropin stimulation, and the aspirin (-) (n = 60) group received no treatment. Result(s): Duration of stimulation, serum levels of estradiol on the hCG day; total medication dosage of gonadotropin; numbers of mature oocytes collected; numbers of embryos transferred, were not significantly different. Clinical pregnancy rates were 25.0% versus 26.5% in aspirin treated and untreated groups (P＞ 0.05). Uterine artery pulsatility index (P1) and resistant index (RI) values on the hCG day were 2.30±0.50 and 0.80±0.05 in aspirin treated group versus 2.20±0.48 and 0.80±0.11 in aspirin untreated group, respectively (P＞ 0.05). Conclusion(s): Low-dose aspirin (80 mg) appears to have no beneficial effect on uterine blood flow velocity and pregnancy rates in an unselected group of patients undergoing ICSI for male factors infertility.

P-080. Oocyte donation programme: influence of age and aetiology and improvement of uterine blood flow velocity and pregnancy outcome after low-dose aspirin treatment

P-080. Oocyte donation programme: influence of age and aetiology and improvement of uterine blood flow velocity and pregnancy outcome after low-dose aspirin treatment

Low-dose aspirin treatment improves ovarian responsiveness, uterine and ovarian blood flow velocity, implantation, and pregnancy rates in patients undergoing in vitro fertilization: a prospective, randomized, double-blind placebo-controlled assay

Objective: To determine the effects of low-dose aspirin on ovarian response, uterine and ovarian blood flow velocity, and implantation and pregnancy rates in patients undergoing IVF. Design: Prospective, randomized, double-blind placebo-controlled assay. Setting: Department of Reproductive Medicine, CER Medical Institute, Buenos Aires, Argentina. Patient(s): Two hundred ninety-eight infertile patients (mean [± SD] age, 35.6 ± 4.09 years) undergoing IVF cycles. Intervention(s): In the treatment group, 149 patients underwent controlled ovarian hyperstimulation and received a daily dose of 100 mg of aspirin. In the control group, 149 patients underwent controlled ovarian hyperstimulation in association with placebo. Main Outcome Measure(s): Number of follicles, number of oocytes retrieved, serum E 2 levels, uterine and ovarian pulsatility index, cancellation rate, number of embryos transferred, and implantation and pregnancy rates. Result(s): There were statistically significant differences between the treatment group and the control group, respectively, in the number of follicles (19.8 ± 7.2 versus 10.2 ± 5.3), number of oocytes retrieved (16.2 ± 6.7 versus 8.6 ± 4.6), serum E 2 levels (2,923.8 ± 1,023.4 versus 1,614.3 ± 791.7 pg/mL), uterine pulsatility index (1.22 ± 0.34 versus 1.96 ± 0.58), ovarian pulsatility index (1.18 ± 0.31 versus 1.99 ± 0.56), pregnancy rate (45% versus 28%), and implantation rate (17.8% versus 9.2%). Conclusion(s): Low-dose aspirin treatment significantly improves ovarian responsiveness, uterine and ovarian blood flow velocity, and implantation and pregnancy rates in IVF patients.

Uterine blood flow velocity waveforms during early postpartum course following Caesarean section

Objective: To assess the change of uterine blood flow after Caesarean section. Study Design: Doppler flow velocity waveforms were acquired from the uterine arteries and small arteries near the myometrial wound detected by transvaginal power Doppler ultrasonography in 23 patients on the 3rd, 6th and 9th postoperative days. Results: The resistance index for the uterine artery did not show any change during the study period, while that for the small arteries slightly decreased. Conclusion: Uterine blood flow resistance after Caesarean section did not show any change during the early postpartum period.

The Effects of the Epidural Anesthesia for Cesarean Section on Maternal Uterine and Fetal Umbilical Blood Flow Velocity Waveform

The Effects of the Epidural Anesthesia for Cesarean Section on Maternal Uterine and Fetal Umbilical Blood Flow Velocity Waveform

Uteroplacental and luteal circulation in normal first-trimester pregnancies: Doppler ultrasonographic and morphologic study

OBJECTIVE: Our purpose was to establish reference data representative of normal findings at transvaginal color and spectral Doppler ultrasonographic examination of the uteroplacental and luteal circulation in the first trimester and to relate the Doppler findings to morphologic data. STUDY DESIGN: A cross-sectional study was performed of 64 uncomplicated pregnancies of 5 to 11 completed gestational weeks terminated by legal abortion for psychosocial reasons. Doppler examinations of the main uterine arteries, subchorionic arteries, intrachorionic area, and corpus luteum were performed. Abortion material was examined morphologically. RESULTS: In the uterine and subchorionic arteries blood flow velocity increased and pulsatility index values decreased with advancing gestation. Arterial or venous Doppler shift spectra were recorded from the intrachorionic area in 91% (58/64) of the pregnancies. Intrachorionic arterial blood flow velocities and pulsatility index values were low and did not change with advancing gestation; the mean time-averaged maximum velocity, peak systolic velocity, and pulsatility index values were 4.6 cm/sec, 6.0 cm/sec, and 0.47, respectively. Morphologic examination showed trophoblast plugs in the spiral arteries to consistently manifest multiple spaces containing red blood cells at the choriodecidual junction. CONCLUSION: Blood flow velocity in the uteroplacental arteries increases and pulsatility index values decrease with advancing gestation, indicating a steady increase in uterine perfusion during the first trimester. Our findings suggest intervillous flow to be present as early as the first trimester. (A M J O BSTET G YNECOL 1996;174:768-75.)

Alterations in Maternal-Fetal Doppler Flow Velocity Waveforms in Preterm Labor Patients Undergoing Magnesium Sulfate Tocolysis

To evaluate the effects of magnesium on fetal hemodynamics in mothers treated with magnesium sulfate for preterm labor.Twenty women who presented to the Carolinas Medical Center in preterm labor between 24-35 weeks' gestation were enrolled in the study. Pulsed-wave Doppler measurements were made from the fetal middle cerebral artery, the fetal umbilical artery, and the maternal uterine arteries before the initiation of magnesium sulfate tocolysis and during its intravenous administration. Baseline measurements were compared with intra-therapy measurements using paired t tests.During the administration of magnesium sulfate, the fetal middle cerebral artery diastolic blood flow velocity decreased significantly (P = .05) and the maternal uterine artery diastolic blood flow velocity increased significantly (P = .01). There were no significant changes in the umbilical artery diastolic blood flow measurements. These findings remained the same after adjusting for gestational age, estimated fetal weight, frequency of contractions, serum magnesium level at the time of the intra-therapy Doppler study, and maternal blood pressure.The alterations in fetal hemodynamics during magnesium sulfate administration suggest a physiologic normalization process related to the stressed preterm infant and the preterm labor process itself.