Comparison of uteroplacental blood flow in normal and in intrauterine growth-retarded pregnancy. Measurements with Indium-113m and a computer-linked gammacamera

Uteroplacental blood flow was studied with a noninvasive method using indium-113m and a computer-linked gammacamera. The blood flow was determined from the ratio of the maximum and the rise time of the isotope accumulation curve of the placenta. Eight pregnancies with intrauterine growth retardation (IUGR) were compared with 11 normal pregnancies. In the IUGR group the mean placental blood flow was only 1/4 of corresponding mean values of the normal group. The difference was highly significant (p less than 0.01).     

Hypertension Induced by Episodic Reductions in Uteroplacental Blood Flow in Gravid Rat

Background. The etiology of preeclampsia remains unclear. Animal modeling of preeclampsia has been useful; however, no model to date represents episodic changes in uteroplacental blood flow that may occur in preeclampsia. Objective. To develop a gravid rat model characterized by episodic reductions in uteroplacental blood flow. Method. Pregnant Sprague Dawley rats were used and subjected to SHAM, reduced uterine perfusion pressure (RUPP), or aortic occlusion on gestational Day 14. Aortic occlusion surgery consisted of implantation of a silastic vascular occluder around the abdominal aorta and silver clips around the uterine–ovarian arteries. Aortic occlusion animals were subjected to five consecutive days of occlusion (40% reduction) each session lasting 1 h. On Day 21, maternal mean arterial pressure (MAP) and fetal morphology were assessed. For isolated blood vessels, resistance-sized mesenteric arteries were harvested and mounted on a pressure arteriograph. Result. Occluder animals experienced a 10 mmHg rise in MAP as compared to SHAM (p < 0.05), and RUPP MAP was significantly increased as compared to control subjects (p < 0.05). Pups from Occluder animals exhibited a decrease in fetal weight as compared to SHAM (p < 0.05), but an increase in fetal weight as compared to RUPP (p < 0.05). Myogenic reactivity of second-order mesenteric arteries increased in Occluder animals as compared to SHAM (p < 0.05), but were similar to that of RUPP. Conclusion. Episodic reductions in uteroplacental blood flow play a crucial role in the altered vascular reactivity seen in Occluder animals and may represent a new model to investigate the mechanisms associated with episodic reductions in uteroplacental blood flow in pathological pregnancies.     

Whole Blood Platelet Aggregation in Normal Pregnancy and Pre-Eclampsia

Platelet aggregation in whole blood in response to ADP, plasma beta-thromboglobulin (beta-TG) and thromboxane B₂ (TXB₂) levels, were evaluated in third-trimester patients with pre-eclanipsia (PE) (n=15) and in healthy third-trimester pregnant controls (n=43). 1 min after blood collection there was no difference in platelet response to ADP between PE and controls. Storage of blood unmasked hypoaggregability of platelets in PE implicating contribution of labile pro-aggregatory substance to ADP-induced aggregation tested at I min. Plasma TXB₂ in 10 controls (39.4 ± 8.7 pg/ml) was lower (p<0.05) than in 4 PE subjects (212.8 ± 130.0 pg/ml). Thus, seemingly normal aggregation of platelets to ADP in PE at I min after blood collection may be attributed to increased plasma level of TXA₂. Increased plasma level of beta-TG in PE (49.2 ± 7.0 ng/ml vs 27.3 ± 3.0 ng/ml; p<0.01) appears to be secondary to platelet consumption in which circulating TXA₂ may play a role.     

Rheological and Physiological Consequences of Conversion of the Maternal Spiral Arteries for Uteroplacental Blood Flow during Human Pregnancy

Physiological conversion of the maternal spiral arteries is key to a successful human pregnancy. It involves loss of smooth muscle and the elastic lamina from the vessel wall as far as the inner third of the myometrium, and is associated with a 5–10-fold dilation at the vessel mouth. Failure of conversion accompanies common complications of pregnancy, such as early-onset preeclampsia and fetal growth restriction. Here, we model the effects of terminal dilation on inflow of blood into the placental intervillous space at term, using dimensions in the literature derived from three-dimensional reconstructions. We observe that dilation slows the rate of flow from 2 to 3 m/s in the non-dilated part of an artery of 0.4–0.5 mm diameter to approximately 10 cm/s at the 2.5 mm diameter mouth, depending on the exact radius and viscosity. This rate predicts a transit time through the intervillous space of approximately 25 s, which matches observed times closely. The model shows that in the absence of conversion blood will enter the intervillous space as a turbulent jet at rates of 1–2 m/s. We speculate that the high momentum will damage villous architecture, rupturing anchoring villi and creating echogenic cystic lesions as evidenced by ultrasound. The retention of smooth muscle will also increase the risk of spontaneous vasoconstriction and ischaemia–reperfusion injury, generating oxidative stress. Dilation has a surprisingly modest impact on total blood flow, and so we suggest the placental pathology associated with deficient conversion is dominated by rheological consequences rather than chronic hypoxia.     

Measuring Venous Capacitance and Blood Flow in Pregnancy

Summary: Forearm or calf venous plethysmography has been used in pregnant women to examine the effects of pregnancy on the vascular system and more recently to measure blood flow changes in response to intra-arterial infusion of vasoactive substances. To examine the assumption that venous capacitance and blood flow measurements are the same in the forearm and calf, venous plethysmography was conducted simultaneously on the forearm and calf in normal (NP) and hypertensive pregnant women (HTP) in their third trimester and in normal nonpregnant women (N). Ail studies were made on the right forearm and calf with subjects in the left lateral recumbent position. There was no significant difference between venous capacitance in the forearm (median: 124 times 10³rruV100mIVmrnHg for both NP and HTP) and leg (134 [NP] and 106 [HTP] x lO'mL/lOOmlVmmHg) for both pregnant groups but venous capacitance in the nonpregnant group was greater in the leg than arm (174 versus 112 x lO'mUlOOmL/mmHg, p <0.001). Blood flow was similar in the leg and forearm (median: 4.9 versus 3.9mL/100mL/min respectively) in nonpregnant women. Forearm blood flow was also similar to calf flow in NP women (6.2 versus 4.3mL/100mL/min respectively) but greater man calf blood flow in HTP (9.7 versus 5.3ml7100mL/min, p <0.01). Using left lateral recumbency, forearm and calf vein capacitances are similar in pregnant women, in contrast to nonpregnant women. Blood flow is higher in the forearm than the calf only in hypertensive pregnant women. These observations should be borne in mind when interpreting studies of regional blood flow in pregnancy.     

Measurements of Blood Pressure, Oedema and Proteinuria in a Pregnant Population of New Zealand

Summary: This is the first report of the largest study of blood pressure measurement in pregnancy in a New Zealand population using standardized definitions and methodology. Over 3,800 women who delivered in an 8-month period in the Wellington region were included in the study. Blood pressure measurement and the presence of oedema and proteinuria were recorded from booking until delivery and in the puerperium. Only 2.7% of women were unable to be contacted after delivery for details on outcomes. The results established normal ranges for blood pressure throughout pregnancy. The data show that Mood pressure greater than 140/90 until 35 weeks' gestation is outside 2 standard deviations at all gestations and justifies using these measurements as the definition of hypertension in pregnancy. The fall in blood pressure in the 2nd trimester was less than 1 mm Ffg per week in both the systolic and diastolic pressures. This fall was smaller than previously recorded in other studies. Gestational hypertension was the commonest blood pressure abnormality occurring in 15.2% of the population. This represented 69% of the pregnant women with a hypertensive disorder. The overall incidence of both gestational hypertension and preeclampsia was 18.5% which is higher than reported in other parts of the world. In this study obesity was significantly associated with hypertensive disorders in pregnancy. An arm circumference of >33 cm, one of the measurements of obesity, was found in 6.8% of the study population. Even after the effect of arm circumference was taken into account, hypertensive disorders were also more common in Pacific Island women. Ankle oedema was significantly associated with the development of both gestational hypertension and preeclampsia but the incidence of oedema was noted in only 11.9% of the subjects.     

Uteroplacental blood flow in pregnant women with hypertension and recurrent spontaneous abortion.

Uterine velocimetry was performed in 13 pregnant women with pregnancy induced hypertension (PIH) and in 15 pregnant women with recurrent spontaneous abortion syndrome (RSA-S). Measurement were performed on both uterine arteries and averaged. 75% of PIH group had RI 95th percentile from the first measurement (20 weeks gestation). In the RSA-S group, RI was between 75th and 95th percentile, suggesting an almost pathological vascularization.     

妊娠期肝内胆汁淤积症患者脐血流检测与围产儿预后

目的 :探讨妊娠期肝内胆汁淤积症 (ICP)患者胎儿脐动脉血流阻抗特点及围产儿结局的影响。方法 :用胎儿脐血流检测仪检测 4 3例 ICP患者和 5 8例正常孕妇胎儿脐动脉血流阻力指标。结果 :ICP患者胎儿脐动脉血流阻力指标及围产儿结局不良的发生率均明显升高。结论 :ICP患者应常规进行胎儿脐动脉血流阻力检测 ,以便及时处理以改善ICP患者围产儿预后     

妊娠滋养细胞肿瘤子宫病灶彩色多普勒血流显像动态观察

目的探讨化疗前后妊娠滋养细胞肿瘤(GTT)血流动力学变化.方法利用彩色多普勒血流显像图(CDBFI)动态检测18例GTT患者化疗前及每疗程化疗后子宫动脉,病灶内血流指数,并选取同期20例非孕正常妇女子宫动脉阻力指数作为对照.结果GTT患者化疗前子宫动脉及病灶内血流呈现低阻状态;化疗后随hCG的下降,CDBFI示整个血流逐渐减少,病灶内血流丰富区范围缩小,子宫动脉及病灶内血流参数逐渐恢复正常.化疗前和1～3疗程化疗后子宫动脉处RI明显低于正常非孕妇女(P＜0.01),4疗程化疗后子宫动脉RI与正常非孕妇女相近.结论彩色多普勒血流显像图检查对妊娠滋养叶肿瘤的诊断有帮助,通过动态观察可间接估价患者对化疗的敏感性.     

Cerebral Blood Flow and Metabolism in Ovine Fetuses During Asphyxia Resulting in Seizures

Severe fetal asphyxia can cause neurologic damage, but little is known about cerebral oxidative metabolism under these conditions. This study was designed to measure cerebral blood flow and oxygen consumption during severe global asphyxia in fetal sheep, asphyxiated to the point at which seizure activity subsequently occurred. Six sheep were chronically instrumented with fetal electrodes, fetal and maternal vascular catheters, and an adjustable occluder on the maternal common hypogastric artery. Measurements were made of fetal arterial blood gases, blood pressure, heart rate electrocorticogram (ECoG), nuchal muscle electromyogram (EMG), and regional blood flow (radioactive microspheres) during control, and at 30 and 60 min after complete occlusion of the maternal hypogastric artery. The ECoG became isoelectric, and the fetuses developed a marked respiratory and metabolic acidosis, the pH falling to 6.99 ± 0.03, the pCO₂ rising to 73 ± 11 mm Hg, and base excess falling to ?16 ± 1 mEq/L at 60 min of occlusion. Control fetal arterial blood pressure was 52 ± 9 mm Hg and did not change significantly with asphyxia at 60 min. Cerebral cortical blood flow was 127 ± 54 ml/100 g/min at control, and 204 ± 130 ml/100 g/min at 60 min of asphyxia. Cerebral oxygen consumption was 201 ± 50 μM/100 g/min at control, and 76 ± 57 μM/100 g/min at 60 min of asphyxia (P < 0.05), i.e., 45% of control. All 6 fetuses had episodic seizure activity based on ECoG and nuchal EMG activity, beginning 50 ± 47 min after release of the occluder. This seizure activity continued for 24-36 h. This study shows that 60 min of asphyxia associated with suppressed ECoG activity and severe acidosis induced neuronal damage, manifesting as seizure activity, and that this occurred when cerebral oxidative metabolism was reduced to ≤50% of control.     

Uteroplacental circulation and functional status of the fetoplacental unit in risk pregnancies with special reference to late gestosis

Trial to define position and variability of radioisotope functional diagnostics of placental perfusion in comparison with urinary estrogen excretion by serial examinations. - In case of placental insufficiency estrogen values are significantly reduced starting from the 32nd to 35th gestational week as compared with normal values. In general, placenta perfusion shows delayed half-life periods of the increase in activity in all risk pregnancies beginning from the 28th week of pregnancy. A direct correlation between estrogen values and placenta perfusion can only be detected in cases of chronic placental insufficiency with intrauterine growth retardation. A prolonged perfusion time reveals a fetal hypotrophy in 53% of the cases. Late gestosis takes the first place about all risk pregnancies, connected with placental insufficiency in 30% of the cases. The tendency towards a development of placental insufficiency can be early detected by determination of placental perfusion time.     

两种剂量来曲唑与克罗米芬对多囊卵巢综合征患者子宫卵巢血流动力学的影响

目的:探讨2种剂量来曲唑(LE)与克罗米芬(CC)对多囊卵巢综合征(PCOS)患者子宫卵巢血流动力学的影响。方法:2种剂量LE与CC治疗90例PCOS不孕症患者,随机分CC组(A组,n=32,50 mg/d)、低剂量LE组(B组,n=30,2.5 mg/d)和高剂量LE组(C组,n=28,5.0 mg/d)。同时以28例正常育龄妇女作为对照组(D组)。经阴道超声监测子宫卵巢血流的参数,比较排卵率、妊娠率。结果:①LE的2个剂量组子宫卵巢血流均出现类似正常育龄妇女的周期性血流变化;②C组方案治疗PCOS有较高的排卵率和妊娠率。结论:来曲唑改善了PCOS患者的子宫卵巢血流供应,5.0 mg可能有更好的促排卵效果。     

妊娠早期子宫动脉血流的变化及其对妊娠结局的影响

目的:探讨妊娠早期子宫动脉血流的变化及其对妊娠结局的影响。方法:对1 87例妊娠妇女在孕10周、20周和30周分别监测子宫动脉血流动力学参数搏动指数(PI)、阻力指数(RI)和收缩期峰值流速/舒张末期流速(S/D)。结果:157例正常妊娠组孕早期的子宫动脉RI、PI和S/D值和子宫动脉舒张早期切迹数均低于不良妊娠结局组(n=30),其差异有显著性。结论:彩色多普勒超声监测子宫动脉血流动力学参数有助于预测和评估妊娠结局。     

Maternal Cerebral Blood Flow and Glucose Metabolism in Pregnancies Complicated by Severe Preeclampsia

Objective. To investigate maternal cerebral blood flow and glucose metabolism in pregnancies complicated by severe preeclampsia compared to normal pregnancies. Methods. A prospective study was conducted including six women with severe preeclampsia and nine normotensive women. Transcranial Doppler (TCD) was performed pre- and postoperatively. The anterior, middle, and posterior cerebral arteries (ACA, MCA, PCA) were selected for study; the cerebral perfusion pressure (CPP) and cerebral flow index (CFI) were calculated for each vessel. To evaluate the cerebral glucose metabolism, F-18 fluorodeoxyglucose positron emission tomography was performed postoperatively. Results. The preoperative CFI in each artery was similar in the comparisons between the two groups. However, the CPP in the MCA and the PCA was higher in the patients with severe preeclampsia. Compared to the preoperative values, the postoperative CPP and CFI in the ACA and the MCA were significantly increased in the severe preeclampsia group, while they were significantly decreased in the control group. Overall, the regional cerebral glucose uptake was not significantly different in comparisons between the two groups. In addition, there was no correlation between the cerebral Doppler indices and their corresponding regional cerebral glucose uptake. Conclusions. Severe preeclampsia was associated with an increase in the cerebral blood flow and perfusion pressure, particularly during the postpartum period, but it was not associated with a significant change in the cerebral glucose metabolism.     

The Evaluation of Clitoral Blood Flow and Sexual Function in Elite Female Athletes

IntroductionClitoral blood flow measurements using clitoral color Doppler ultrasound have been performed with increasing frequency either in order to assessment of female sexual function/dysfunction. The trials to evaluate the sexual function in healthy subjects, especially in the subgroup of female elite athletes, are limited.AimThe aim of the study was to evaluate whether elite female athletes and sedentary healthy females differ in their clitoral blood flow and sexual function as an expression of their physical fitness status.MethodsTwenty-five female elite athletes (Group I) and healthy female subjects (Group II) were enrolled as volunteers in the study. All women were instructed to complete the Female Sexual Function Index (FSFI) questionnaire. Each subject underwent high definition color Doppler ultrasonography to measure the clitoral blood flow parameters.Main Outcome MeasuresThe effect of physical activity on clitoral blood flow and sexual life in women.ResultsMean age, mean age of menarche, mean marriage age, and body mass index were similar for both groups. In Group I, the mean peak systolic velocity and end-diastolic velocity were higher than those of Group II, whereas the mean RI was similar for both groups. There were statistically significant differences for total FSFI score and all domain scores, except desire domain, between both groups.ConclusionIn elite female athletes as compared with sedentary healthy females, better clitoral blood flow and better sexual function were demonstrated. Therefore it seems superior physical fitness correlates with better sexual function. Karatas OF, Baltaci G, Ilerisoy Z, Bayrak O, Cimentepe E, Irmak R, and Unal D. The evaluation of clitoral blood flow and sexual function in elite female athletes.     

来曲唑联合氯米芬对PCOS患者子宫卵巢血流动力学影响

目的:经阴道超声观察来曲唑联合氯米芬(CC)治疗多囊卵巢综合征(PCOS)的血流动力学变化,探讨来曲唑联合CC治疗PCOS的临床价值。方法:来曲唑联合CC治疗49例PCOS患者,经阴道超声观察子宫内膜厚度,优势卵泡个数,子宫动脉和优势侧卵巢基质收缩期血流峰值(PSV)、舒张末期血流速(EDV)、搏动指数(PI)、阻力指数(RI)及卵巢基质血流信号数。结果:来曲唑联合CC治疗PCOS有较高排卵率和妊娠率,使PCOS患者形成了子宫卵巢血流的周期性变化。结论:来曲唑联合CC用药能改善PCOS的子宫卵巢血流,促进PCOS患者排卵,利于妊娠并能减少流产的发生。     

Uteroplacental Doppler flow velocity waveform indices in normal pregnancy: a statistical exercise and the development of appropriate reference values.

In a prospective cross-sectional study, we examined 154 normal pregnant women and measured the systolic to diastolic (S/D) ratio and resistance index (RI) in the umbilical artery and both uterine arteries. Placental location with respect to laterality was determined by real-time ultrasound. In patients with unilateral placental location, each uterine artery was evaluated according to its relationship with the placenta. Doppler flow velocity waveforms were obtained by a continuous wave Doppler device. Kolmogorov D tests revealed that RI values follow gaussian distribution, but that S/D values were markedly skewed to the right. There was a significant negative linear relationship between gestational age and umbilical artery RI and a significant negative curvilinear relationship between gestational age and umbilical artery (S/D (r = 0.83, p less than 0.001; and r = -0.79, p less than 0.001, respectively). Confidence bands for umbilical artery RI were developed based on the linear model with gestational age (fitted umbilical artery RI = 0.97199 - 0.01045*gestational age). Confidence bands for umbilical artery S/D were derived from the corresponding RI values by means of the functional relationship S/D = 1/(1 - RI). The RI and S/D values of the uterine arteries declined until 24 to 25 weeks' gestation and remained unchanged thereafter. This relationship, however, was not statistically significant (r = -0.10, p = 0.22). The placental uterine artery is different from the nonplacental quantitatively and qualitatively.(ABSTRACT TRUNCATED AT 250 WORDS)