Increasing Maternal Blood Pressure with Ephedrine Increases Uterine Artery Blood Flow Velocity during Uterine Contraction

2002 ◽  
Vol 96 (3) ◽  
pp. 612-616 ◽  
Author(s):  
Laurent Ducros ◽  
Philippe Bonnin ◽  
Bernard P. Cholley ◽  
Eric Vicaut ◽  
Moncef Benayed ◽  
...  
Keyword(s):  
Blood Flow ◽  
Flow Velocity ◽  
Uterine Artery ◽  
Uterine Contraction ◽  
Perfusion Pressure ◽  
Resistance Index ◽  
Hemodynamic Parameters ◽  
Uterine Blood Flow ◽  
Uterine Contractions ◽  
Uterine Perfusion

Background During labor, ephedrine is widely used to prevent or to treat maternal arterial hypotension and restore uterine perfusion pressure to avoid intrapartum fetal asphyxia. However, the effects of ephedrine on uterine blood flow have not been studied during uterine contractions. The purpose of the study was to assess the effects of ephedrine on uterine artery velocities and resistance index using the Doppler technique during the active phase of labor. Methods Ten normotensive, healthy parturients with uncomplicated pregnancies at term received intravenous ephedrine during labor to increase mean arterial pressure up to a maximum of 20% above their baseline pressure. Peak systolic and end-diastolic Doppler flow velocities and resistance indices were measured in the uterine artery before and immediately after administration of bolus intravenous ephedrine and after ephedrine washout. Umbilical and fetal middle cerebral arterial resistance indices and fetal heart rate were also calculated. Results After ephedrine administration, mean arterial pressure increased by 17 +/- 4%. End-diastolic flow velocity in the uterine artery at peak amplitude of uterine contraction was restored to 74% of the value observed in the absence of contraction. The systolic velocity was totally restored, and the uterine resistance index was significantly decreased, compared with the values in the absence of contraction. Between uterine contractions, ephedrine induced similar but less marked effects. Fetal hemodynamic parameters were not altered by ephedrine administration. Conclusions Bolus administration of intravenous ephedrine reversed the dramatic decrease in diastolic uteroplacental blood flow velocity and the increase in resistance index during uterine contraction, without altering fetal hemodynamic parameters. This suggests that the increase in uterine perfusion pressure during labor could in part restore uterine blood flow to the placenta during uterine contraction.

Measurement of Uterine Blood Flow and Uterine Metabolism

1958 ◽  
Vol 195 (3) ◽  
pp. 614-620 ◽  
Author(s):  
N. S. Assali ◽  
K. Dasgupta ◽  
A. Kolin ◽  
L. Holms
Keyword(s):  
Blood Flow ◽  
Uterine Contraction ◽  
Uterine Blood Flow ◽  
Progressive Decrease ◽  
Flow Meter ◽  
Induced Labor ◽  
Uterine Contractions ◽  
Uterine Involution ◽  
Pregnant Sheep

Uterine blood flow has been measured with a chronically implanted miniature electromegnetic flow meter in unanesthetized pregnant sheep and dogs during spontaneous and oxytocin induced labor and followed in the same animal for several postpartum days. In either spontaneous or oxytocin induced labor, uterine contractions are accompanied by a significant decrease in uterine blood flow and relaxations by the return of the flow to or higher than control values. The decrease is roughly proportional to the intensity of uterine contraction. When the contraction is of a tetanic nature and not followed by relaxation, uterine ischemia is so severe that the fetus might succumb. After the delivery of the fetus and before the expulsion of the placenta, uterine blood flow falls slightly. However, after separation and expulsion of the placenta, uterine blood flow falls precipitously. Thereafter, a very slight and progressive decrease continues for several days paralleling uterine involution.

scholarly journals Role of uterine artery Doppler in assessment of unexplained infertility

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Carmen Ali zarad ◽  
Mohamed Hafez Mohamed ◽  
Waleed Said Abo Shanab
Keyword(s):  
Blood Flow ◽  
Uterine Artery ◽  
Resistance Index ◽  
Unexplained Infertility ◽  
Control Group ◽  
Uterine Blood Flow ◽  
Uterine Artery Doppler ◽  
Flow Impedance ◽  
Doppler Indices ◽  
And Control

Abstract Background The study aimed to compare the values of uterine artery Doppler indices including resistance index (RI), pulsatility index (PI), and systolic/diastolic (S/D) ratios in fertile female and female with unexplained infertility and investigate their association with unexplained infertility. This study included 70 women divided into two groups. Study group included 40 women with unexplained infertility and control group included 30 fertile women. Results The mean ages of study and control groups were 26.9 and 28.5 years respectively. In infertile group, the mean values of uterine arteries resistance index (RI), pulsatility index (PI), and systolic/diastolic (S/D) ratios were 0.9, 2.9, and 8.0 respectively. In the fertile control group, mean RI and PI values and S/D ratio were 0.6, 1.5, and 2.7 respectively. There was statistically significant difference as regards RI, PI, and S/D ratios between study and control groups. The best cut off values of RI, PI, and S/D ratios for predicting increased uterine blood flow impedance were more than 0.67, 1.95, and 3 respectively with sensitivity of 100%, 95%, and 100% respectively, specificity of 96.7%, 86.7%, and 96.7% respectively, and diagnostic accuracy of 98.6%, 91.42%, and 98.57% respectively. Conclusion Uterine artery Doppler indices mean values were higher in unexplained infertility women than fertile women. Uterine artery Doppler indices have high sensitivity and specificity for diagnosis of high uterine blood flow impedance. High uterine blood flow impedance diagnosed by uterine artery Doppler may contribute in the etiology of unexplained infertility. Uterine artery Doppler should be included in investigation of unexplained infertility.

Effect of altitude on uterine artery blood flow during normal pregnancy

1995 ◽  
Vol 79 (1) ◽  
pp. 7-14 ◽  
Author(s):  
S. Zamudio ◽  
S. K. Palmer ◽  
T. Droma ◽  
E. Stamm ◽  
C. Coffin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Birth Weight ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Uterine Artery ◽  
Flow Distribution ◽  
External Iliac Artery ◽  
Artery Blood Flow ◽  
Uterine Blood Flow ◽  
Infant Birth

To determine whether uterine blood flow was reduced and indexes of pelvic blood flow distribution altered in normotensive pregnancy at high (3,100 m) compared with low altitude (1,600 m), we measured uterine, common iliac, and external iliac artery blood flow velocities and diameters in women during pregnancy and again postpartum. Pregnancy increased uterine artery diameter, blood flow velocity, and volumetric flow at both altitudes. Uterine artery blood flow velocity was greater (69.0 +/- 2.2 vs. 59.4 +/- 3.0 cm/s; P < 0.005) but diameter was smaller at 3,100 m than at 1,600 m (2.5 +/- 0.3 mm vs. 3.4 +/- 0.2 mm; P < 0.005), resulting in volumetric flow that was one-third lower at week 36 of pregnancy (203 +/- 48 vs. 312 +/- 22 ml/min, respectively; P < 0.01). Pregnancy increased common iliac blood flow velocity and decreased external iliac artery blood flow velocity at both altitudes. The uterine artery received a smaller percent of common iliac flow at 3,100 than at 1,600 m (46 +/- 7 vs. 74 +/- 6%; P < 0.005). Gestational age was similar but birth weight was lower at 3,100 m than at 1,600 m. Among subjects at 1,600 m, variation in uterine blood flow velocity correlated positively with infant birth weight. We concluded that reduced uterine blood flow and altered pelvic blood flow distribution during pregnancy at high altitude likely contributed to the altitude-associated reduction in infant birth weight.

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

1997 ◽  
Vol 74 (2) ◽  
pp. 121-124 ◽  
Author(s):  
Yuichiro Nakai ◽  
Motoharu Imanaka ◽  
Junko Nishio ◽  
Takeshi Maeda ◽  
Ayako Ozaki ◽  
...  
Keyword(s):  
Blood Flow ◽  
Caesarean Section ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Uterine Blood Flow ◽  
Early Postpartum
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