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June 1, 2005
Abstract
Starting in the left cardiac ventricle the reader is taken on a guided tour on a fetal erythrocyte as measured by Doppler ultrasound. Up in the ascending aorta we move through the aortic isthmus to the descending aorta and the internal umbilical arteries, which fuse around the umbilical cord. With fresh oxygen from the placenta our erythrocyte moves in an accelerating continous flow along the umbilical vein to the ductus venosus. After having reached the left ventricle again it now passes through a coronary artery to the right atrium and eventually the ductus arteriosus or the pulmonary circulation. Concepts of pulsatility, impedance and resistance are presentet in the context of their clinical applicability in Doppler waveforms of various fetal vessels.
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June 1, 2005
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Fetal RV function is critical for survival and normal cardiovascular development. Doppler can be used to assess function. Combined with wise use of imaging techniques, the cause of abnormalities can be assessed. Both congenital heart defects and other cardiovascular defects can lead to hydrops and death. Serial semi-quantiation of fetal heart failure can be done with a Cardiovascular Profile score.
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June 1, 2005
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Introduction: Congestive heart failure (CHF) may be present in fetuses with hydrops fetalis (HF) and the severity is difficult to quantitate. Differential ventricular dysfunction may be present in the fetus with CHF. A non-geometric measure of ventricular function that is not afterload dependent would be useful to measure the severity of myocardial dysfunction. Methods: Tei-index (isovolumetric time/ejection time) was measured prenatally in 23 normals (24–34 weeks gestational age-GA) and in 7 with HF (24–34 weeks GA). Prenatal CHF severity was graded by a 10 point cardiovascular (CV) score (2 points each for absence of hydrops, normal venous Doppler, heart function, arterial Doppler, and heart size, and 10/10 = normal). A paired student t-test was used to compare RV and LV and nonpaired t-test compared HF and normals. Tei-index and CV score were correlated. Results: Tei-index normals were 0.38 ± 0.04 in the right ventricle (RV) and 0.41 ± 0.05 in the left ventricle (LV) and there were no significant RV-LV or gestational age (GA) differences. Among HF fetuses, RV and LV Tei-indices were both significantly increased (0.54 and 0.92) and not significantly different. CV score ranged from 2 to 8 (mean 5.43 out of 10) and correlated inversely with Tei-index (r = −0.52, r = −0.68). Conclusion: Hydrops fetalis is associated with biventricular dysfunction and congestive heart failure. Tei-index correlates with CV score obtained within two weeks of delivery or intrauterine death. Tei-index may be useful in the serial assessment of myocardial dysfunction in the fetus with hydrops.
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June 1, 2005
Abstract
Knowledge of fetal hemodynamic physiology has developed enormously during the last two decades due to Doppler ultrasound. Some of this knowledge has been utilized for routine surveillance of high-risk pregnancies. The prediction of fetal hypoxia before the development of life lasting sequel is of major importance, especially in the very premature case with absent end-diastolic blood flow in the umbilical artery before lung maturity. This review gives an overview of the present knowledge in this field.
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June 1, 2005
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Doppler ultrasound, ultrasound M-mode analysis, fetal electrocardiography, and fetal magnetocardiography are methods by which the fetal heart can be monitored non-invasively. In this paper, they are evaluated and compared. Customarily, it is solely the fetal heart rate, which is monitored using the Doppler ultrasound technique since it is both simple to use and cheap. However, this method inherently produces an averaged heart rate and therefore cannot give the beat-to-beat variability. Fetal electrocardiography has similar advantages, but in addition offers the potential for monitoring beat-to-beat variability and performing electrocardiogram morphological analysis. Its disadvantage is that its reliability is only 60 %, although it is the only technique that offers truly long-term ambulatory monitoring. Ultrasound M-mode analysis allows a estimation of atrial and ventricular coordination, as well as an estimation of PR intervals. Bradycardias, supraventricular tachycardias, extra systoles are readily diagnosed using this method although timing will be inaccurate. Fetal magnetocardiograms can be detected reliably and used for accurate beat-to-beat measurements and morphological analysis. Consequently, they can be used for the classification of arrhythmias and the diagnosis of a long QT syndrome and some congenital heart diseases.
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June 1, 2005
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Understanding the nature of the offspring from conception to birth is the fundamental requirement upon which clinical practice and laboratory research of Perinatal Medicine is based. Thus, definition of the person is essential, and “personhood” is not an arbitrary convention. Rather, it is a verity of nature, known and documented by biologists and understandable to all.
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June 1, 2005
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In order to clarify the genetic background of recurrent spontaneous abortion, the frequency of HLA-A, -B, and -C alleles was analyzed in eighty-nine patients with a history of unexplained primary recurrent abortion. The frequency of each HLA-A, -B, and -C antigen allele was calculated in patients with recurrent abortion and their husbands, and compared with the frequencies in the general population represented by 207 individuals in the Niigata district of Japan. The incidence of individuals homozygous for the HLA-A, -B, and -C alleles was also compared between the patient group and the control group. The frequency of HLA-B35 in the patient group (5 of 89, 5.6 %) was significantly lower than in the general population (40 of 207, 19.3 %) (Odds Ratio, 0.25; 95 % Confidence Interval, 0.0920.65; P < 0.005; Pc, not significant). The fre- quencies of other HLA-A, -B, and -C alleles were not significantly different between the patient group and the general population. No significant difference in the frequency of HLA-A, -B, and -C alleles was observed between the husband group and the general population. The incidence of individuals homozygous for HLA-A, -B, or -C alleles in the patient group was not significantly different from the general population. The significantly lower frequency of HLA-B35 in patients with unexplained recurrent abortion suggests that the Th2- associated immune reactions may be lacking in such patients, as it has been reported that an enhanced Th2 response in conjunction with a decreased T Th1 response is a common immune reaction in HLA-B35-positive individuals.
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June 1, 2005
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Aim: This study was designed to investigate the hemodynamics of the uteroplacental circulation in normal and pre-eclamptic pregnancies using the biomagnetometer SQUID. Method: Twenty-two pregnancies complicated by preeclampsia and 49 normal pregnancies were included in this study. All were near term. Biomagnetic signals were recorded from the uterine arteries. After statistical Fourier analysis, the findings were designated in terms of spectral amplitudes as high (140–300 fT/√Hz), low (50–110 fT/√Hz) and borderline (111–139 fT/√Hz). Results: The uterine artery waveforms and the corresponding spectral densities were of high amplitudes in most (89.7 %) normal pregnancies and of low amplitudes in most (81.8 %) pregnancies complicated by preeclampsia (p < 0.005). These findings were of statistical significance and were correlated with fetal heart rate (FHR) monitoring, pH, Apgar score at 1 and 5 minutes and birth weight percentiles: high amplitude cases were related with normal FHR patterns, pH > 7.25, Apgar score >7 and birth weight > 75 th percentile, while low amplitude recordings were connected with abnormal FHR patterns, pH < 7.25, Apgar score < 7, and birth weight < 10 th percentile (8 cases) and < 50 th percentile (10 cases). Conclusion: Biomagnetic measurement of the uterine artery flow, is a promising procedure in assessing fetal health, especially in high-risk pregnancies.
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June 1, 2005
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The aim of this study was to assess if albumin infusion in hypotensive, preterm infants improved blood pressure (BP), metabolic acidosis and core peripheral temperature difference, indicating that such infants had been hypovolemic. Thirty-seven infants, median gestational age 27 weeks (range 23–34) were studied. Their mean BP, core-peripheral temperature difference, pH and base deficit prior to and post albumin infusion were compared. Albumin infusion was associated with BP elevation (p < 0.01) and a small reduction in the base deficit (p < 0.01), but no significant changes overall in the pH or peripheral core temperature difference. Similar results were seen if only 34 infants less than or equal to 4 days of age treated for their first episode of hypotension were considered, although in that group there was also a modest rise in pH (p < 0.02). These data suggest clinically relevant hypovolemia is uncommon in hypotensive, preterm ventilated infants and hence volume expanders are inappropriate routine first therapy.
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June 1, 2005
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Monochorionic monoamnionic pregnancies are rare and have a poor obstetric prognosis. A single amniotic sac promotes cord knotting and entanglement with a high risk of fetal anoxia. The response to this risk has been obstetric management consisting of routine cesarean section at 32 weeks of gestation or when pulmonary maturity is attained. This approach is called into question by the series of seven monochorionic monoamnionic pregnancies we present here. Such pregnancies do indeed require increased surveillance to term, but we think it is possible to apply the usual obstetric management of twin pregnancies.
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June 1, 2005
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July 27, 2005