OBJECTIVE: To study the arterial pressure waveform in the descending thoracic aorta during pregnancy in both normal and compromised fetuses. DESIGN: The pressure pulsation waveform propagated along the vascular tree, and acting laterally on the arterial wall, produces a corresponding change in the vessel diameter. The distance between diametrically opposite ...

BACKGROUND: Women with uterine fibromyomas may suffer from dysmenorrhea, menorrhagia or infertility, which all may be due to an effect of the fibroids on uterine activity. The effect of myomectomy on uterine contractility is unknown. METHODS: In women undergoing myomectomy because of dysmenorrhea, menorrhagia or infertility, intrauterine pressure was recorded ...

OBJECTIVE: This study was designed to evaluate if fetal diastolic cardiac function is compromised in small-for-gestational-age (SGA) fetuses with documented fetal well-being at the biophysical profile. STUDY DESIGN: We have compared indices of diastolic cardiac flow in singleton SGA fetuses with forward diastolic flow in the umbilical artery at Doppler ...

OBJECTIVES: To evaluate the effect of fetal behavioral states on the relationship between fetal heart rate (FHR) and middle cerebral artery resistance index (MCA RI) in normal fetuses. METHODS: The FHR and MCA RI of 10 normal cases from 37 to 40 weeks of gestation were recorded consecutively over a ...

OBJECTIVE: To evaluate the performance and verify the safety of the Koala Intrauterine Pressure Catheter (IUPC) in clinical use. STUDY DESIGN: Twenty IUP Koala Catheters were placed in laboring women. IUPC monitoring provided diagnostic information in assessing the pressures generated by the myometrium during the labor and delivery process. Information ...

Detection of the intravascular placement of epidural catheters is an important but difficult task. In this study, we evaluated maternal and fetal hemodynamic responses to intravenous (i.v.) and epidural injection of isoproterenol (ISO), a proposed chronotropic test dose, in gravid ewes. Near-term, chronically instrumented, gravid ewes with single fetuses were ...

OBJECTIVE: The goal was to study the effects on uterine contractility, blood pressure, and heart rate of thyrotropin-releasing hormone given antenatally in combination with glucocorticoids to accelerate fetal maturation. STUDY DESIGN: A placebo-controlled, randomized, double-blind study was performed involving 30 women whose pregnancies were followed up at the University Hospital ...

OBJECTIVES: Our purpose was to determine the effect of magnesium sulfate infusion on nonlabor uterine contractures and corticotropin-induced preterm uterine contractions in pregnant sheep. STUDY DESIGN: Fetal and maternal vascular catheters and uterine electromyographic electrodes were surgically placed in 15 pregnant sheep between 118 and 125 days' gestation. After 3 ...

OBJECTIVES: The study aimed to determine whether an inherent difference in vascular resistance between the liver and the ductus venosus influences the distribution of umbilical blood to the two sections of the circulation. STUDY DESIGN: Flow was measured in vitro in six fetal sheep liver preparations, perfused at varying pressures ...

OBJECTIVE: To evaluate the impact of the oviduct, uterine, and in vitro environments on zona pellucida thinning in the mouse embryo. DESIGN: Female mice were stimulated with pregnant mare serum gonadotropin and mated and hCG injection. Unilateral oviduct ligation was performed on day 2 of gestation using the dorsal approach. ...

BACKGROUND: To assess the relationship between placental inflammation, umbilical artery Doppler waveforms and fetal biophysical profile score, umbilical artery Doppler studies and fetal biophysical evaluations were performed in 24 preterm pregnants with premature rupture of membranes (PPROM). SUBJECTS: After delivery, the placentas were microscopically examined and two subgroups were formed ...

OBJECTIVE: This study compared late-pregnant radial uterine arteries that supplied the placenta versus the myoendometrium to evaluate differences in active and passive mechanical properties. STUDY DESIGN: Pressurized segments of placental versus myoendometrial radial uterine arteries from late-pregnant (day 28 to 30) New Zealand White rabbits (n = 12) were compared ...

OBJECTIVE: To assess the advantage of applying uterine fundal pressure to assist transvaginal sonographic imaging of early second-trimester fetal anatomy. METHODS: One hundred consecutive patients with singleton fetuses underwent routine transvaginal sonographic assessment of fetal anatomy between 13 and 17 weeks' gestation. If the entire fetal anatomy including cardiac outflow ...

OBJECTIVE: To identify the source of umbilical venous velocity pulsations, times of transmission from the atrial contraction pressure waveform to velocity waves in the inferior vena cava, ductus venosus, intra-abdominal umbilical vein, and intra-amniotic umbilical vein were examined. METHODS: Five lamb fetuses at 125-135 days' gestation were instrumented with solid ...

In many westernized countries, the caesarean section role has now reached 15% or more, most commonly because of slow progress in labour. In order for labour to result in a vaginal delivery, the uterine cervix must dilate to allow the foetus to travel through the birth canal. This process is ...

BACKGROUND: Ultrastructural changes of the embryonic heart have been described, and quantitative studies have reported the changes of cellular organelles in late fetal and postnatal development. However, no specific data are available on the quantitative morphology of the individual segments and intersegmental junctions of the early embryonic heart, although these ...

The objective of the present study was to determine the characteristics of Doppler flow velocity wave forms in branch pulmonary arteries in relation to gestational age. A total of 111 singleton normal pregnancies were studied during the second half of pregnancy using a combined color-coded Doppler and two-dimensional real-time ultrasound ...

OBJECTIVE: To evaluate the effects of intravascular transfusion (IVT) on the fetal umbilical arterial pressure (UAP) in pregnancies complicated by red cell alloimmunization. STUDY DESIGN: UAP and amniotic fluid pressures (AFP) were measured immediately before and after IVT. Mean UAP was calculated by computing 1/3 (systolic blood pressure - diastolic ...

There is periparturitional increase of prostaglandin E2 (PGE2) in the plasma and amniotic fluid of humans. PGE2 increases uterine contractions and also increases uterine blood flow to sustain the contractions. A question arises as to what role PGE2 plays in human placental circulation. It may regulate feto-placental blood flow and ...

The electromechanical activity of the uterus was studied in 18 healthy women (mean age 38.3+/-14.2 SD years; 8 were nulliparous, 10 multiparous) aiming at characterizing a normal electrohysterogram. Two monopolar silver-silver chloride electrodes were applied to the uterine and one to the cervical mucosa. The uterine pressure was measured by ...

Compression of the fetal thorax by the uterine wall is one of the theories proposed to explain the mechanism of lung hypoplasia in association with oligohydramnios. However, the reduction in the intrathoracic space and the evidence of compression on the fetal thorax have not been demonstrated in detail. Therefore an ...

OBJECTIVES: Our purpose was to determine whether neuronal damage results after total umbilical cord occlusion of increasing duration in midgestation fetal sheep. STUDY DESIGN: We performed total umbilical cord occlusion during 10 (n = 11), 15 (n = 8), or 20 (n = 4) minutes in chronically instrumented midgestation fetal ...

OBJECTIVE: To determine whether the need for fetal scalp pH sampling is decreased by the scalp stimulation test and whether redefinition of reactivity and presence of variability further decrease the need for scalp pH sampling. METHODS: One hundred eight women with fetal heart rate (FHR) patterns suggestive of acidosis underwent ...

We have tested the hypothesis that the limited fetal ventricular distensibility is not only an intrinsic cardiac characteristic but is also contributed to by the pressure exerted by the intrathoracic organs. To this purpose we have studied the diastolic cardiac function by Doppler velocimetry in 11 fetuses during fetal breathing ...

BACKGROUND: Retarded growth in utero has been linked with high blood pressure and other risk factors for cardiovascular disease in adult life. However, the influence on fetal growth of the maternal blood pressure during pregnancy is not well defined. In a prospective study, we examined the relation between maternal ambulatory ...

To examine the cardiovascular effects on the fetus of an elevated umbilical vascular resistance resulting in fetal hypoxemia, we embolized the fetal side of the placenta in pregnant sheep and measured cardiovascular and hormonal changes and cellular growth in fetal heart. Chronically catheterized fetal sheep were embolized (n = 6) ...

This study aimed at testing the hypothesis that lower uterine arterial (UA) Doppler indices are caused by increased uterine volume rather than the presence of myoma. Uterine volumes were calculated and uterine and/or myomal arterial pulsatility index (PI) and resistance index (RI) were obtained by transvaginal color Doppler ultrasonography. The ...

To study the effect of vaginal distension on the uterus, the uterine pressure was measured in 20 healthy female volunteers (mean age 34.3 +/- 7.8 years; 7 nulli-, 13 multiparous) by means of a manometric tube perfused by a pneumohydraulic system. Vaginal distension was induced by a 12 F condom-ended ...

The aim of this study was to determine whether asphyxia induced by clinically relevant, brief repetitive umbilical cord occlusions is associated with cerebral compromise. Chronically instrumented fetal lambs were studied at 126.5 +/- 2.8 d of gestation (mean +/- SD, term 147 d). Occlusions were performed 1 out of every ...

OBJECTIVE: Brief repetitive total umbilical cord occlusions were used to induce fetal asphyxia and to evaluate the interrelationships with hypotension and fetal heart rate decelerations. STUDY DESIGN: In 21 chronically instrumented fetal lambs (gestational age 126.8 +/- 0.6 days), repetitive total umbilical cord occlusion was performed 1 out of 2.5 ...

To determine whether there is any correlation between sudden decrease in barometric pressure and onset of labor, a non-experimental, retrospective study at a 948-bed tertiary care hospital was done. Pregnant patients of 36 weeks gestation or more who presented with spontaneous onset of labor during the 48 hours surrounding the ...

To investigate the effects of medetomidine on late pregnant goats, medetomidine induced changes in maternal or fetal circulation and acid-base balance, as well as changes in intrauterine pressure (IUP) and uterine blood flow (UBF), were studied. Intramuscular administration of medetomidine (40 micrograms/kg b.w.) decreased the heart rate (HR) and arterial ...

In utero breathing activity is present periodically, but it must become continuous at birth. We investigated the effect of hypercapnia and of hypercapnia combined with central cooling on fetal breathing in seven chronically instrumented fetal lambs of 131-134-d gestation, using an extracorporeal membrane oxygenation (ECMO) system to control fetal blood ...

1. In pregnant rats, chronic NO-synthase inhibition induces the development of a pre-eclamptic syndrome, characterized by an increase in maternal blood pressure, a loss of vascular refractoriness to pressor stimuli, a reduction in litter size and a decrease in pups (and maternal) weight. We investigated whether a NO-donor, molsidomine, administered ...

Cerebral arteries show significant developmental and artery-specific changes in noradrenergic-mediated contraction. To test the hypothesis that these changes result from differences in the density of alpha 1-adrenergic receptors (alpha 1-ARs) and/or norepinephrine (NE)-induced inositol 1,4,5-trisphosphate [Ins(1,4,5)P3,IP3] synthesis, we quantified these variables and the NE-induced contraction in the common carotid artery ...

RESULTS OF UNDERNUTRITION BEFORE BIRTH: Animal studies have shown that undernutrition before birth leads to persisting changes in blood pressure and in a range of other physiological, metabolic and structural parameters. Studies in humans have shown that men and women whose birthweights were at the lower end of the normal ...

We examined blood pressure and heart rate (HR) in relation to glucose and arterial PO2 (PaO2) at approximately 121 days (early) and at approximately 140 days (late) gestation in 12 growth-restricted and 10 control fetal lambs. Mild growth restriction (relative to maternal weight) was produced by withdrawal of 25 ml/day ...

The use of adrenaline added to bupivacaine during epidural analgesia for labour is controversial. The effects of epidural analgesia with bupivacaine containing adrenaline on maternal blood pressure and heart rate, uterine activity, progress of labour, fetal heart rate and Apgar scores, were assessed using visual analogue pain scores, upper level ...

OBJECTIVE: Transmission pulse oximetry (TPO) is not a practical method of intrapartum fetal monitoring of arterial oxygen saturation. Reflectance pulse oximetry (RPO) requires a sensor applied to the skin of the fetal head and may be a useful technique. During labor, various degrees of pressure will be exerted on the ...

Breast sucking pressure has been only partially characterized in humans and its quantitative relationships with milk transfer and endocrine maternal responses are unknown. A method to record sucking pressure and milk transfer during complete sucking episodes is described. A tubing connected at one end to a pressure transducer was attached ...

To determine the effects of chronic maternal undernutrition on postnatal somatic growth and blood pressure, pregnant dams were randomly assigned to one of two dietary treatment groups. A control group was fed ad libitum throughout pregnancy and a restricted group was fed 30% of ad libitum intake. From birth, feeding ...

The value of intravenous crystalloid administration in preventing spinal-induced hypotension in the parturient has recently been questioned. Also, the association between increasing crystalloid volume and decreasing postpartum colloid osmotic pressure (COP) raises concern regarding the risk of maternal and fetal pulmonary edema. To study the dose-response effect of varying amounts ...

The anticonvulsant magnesium and the antihypertensives clonidine and nifedipine are extensively used for the clinical treatment of preeclampsia and eclampsia. Little, however, is known about the possible effects of these agents on human fetal-placental vascular resistance. We therefore examined the actions of these agents on the human fetal placental vascular ...

We tested the hypothesis that increased oxytocin is a necessary mechanism for the mediation of androstenedione (delta 4A)-induced myometrial contractions by investigating the effects of maternal treatment with the oxytocin antagonist atosiban on in vivo delta 4A-induced contractions. In four monkeys (group I), maternal estradiol, oxytocin, and myometrial contractions were ...

OBJECTIVE: To investigate the relation between the rise in intrauterine pressure and rise in fetal head to cervix force in normal, slow and induced labour. DESIGN: Prospective observational study. SETTING: The labour ward of a London teaching hospital. PARTICIPANTS: Forty patients were recruited from the antenatal clinic and labour ward ...

OBJECTIVE: Our goal was to determine the effect of chronic and acute umbilical-placental embolization on placental hemodynamic and fetal heart rate patterns in relation to fetal oxygenation in the near-term ovine fetus. STUDY DESIGN: Daily fetal placental embolization was performed during 10 days in 9 sheep fetuses until fetal arterial ...

OBJECTIVE: The purpose of this study was to determine the extent of placental transfer of the angiotensin-converting enzyme inhibitor enalaprilat and the effects on maternal and fetal cardiovascular parameters. STUDY DESIGN: Between gestational days 122 and 126 (term 167 days) five rhesus macaques underwent surgery for implantation of maternal and ...

Adult hypertension has been linked to fetal growth. This study investigates whether this link is evident in the newborn. We measured blood pressure by oscillometry in 248 healthy neonates on day 3/4 of life. Antenatal data and neonatal measurements were obtained from hospital records. Elevated neonatal blood pressure correlated with ...

We tested the hypothesis that the llama fetus has a blunted cardiovascular chemoreflex response to hypoxemia by investigating the effects of acute hypoxemia on perfusion pressure, heart rate, and the distribution of the combined ventricular output in 10 chronically instrumented fetal llamas at 0.6-0.7 gestation. Four llama fetuses had the ...

Recent epidemiological studies have linked low birth weight with the later occurrence of cardiovascular and metabolic disorders, particularly hypertension. We have proposed that fetal exposure to excess maternal glucocorticoids may underpin this association. Normally, the fetus is protected from maternal glucocorticoids by placental 11beta-hydroxysteroid dehydrogenase (11beta-HSD). We have previously shown ...