Repercussões agudas do exercício físico materno sobre os parâmetros hemodinâmicos útero-placentários e fetais / Impact of acute maternal exercise on uteroplacental and fetal hemodynamics patterns

A atividade física está associada a diversos benefícios para a saúde física e mental. Entre as gestantes, a prática de exercícios físicos ganhou maior ênfase nas últimas décadas, porém, ainda persistem controvérsias quanto à possibilidade da ocorrência de potenciais efeitos lesivos ao feto. Esta revisão avaliou os estudos existentes que investigaram os efeitos agudos dos exercícios físicos maternos sobre os parâmetros hemodinâmicos útero-placentários e fetais. Verifica-se que ocorrem graus de desvio do fluxo sanguíneo para a musculatura esquelética solicitada durante o exercício. Esse efeito é acompanhado de vasoconstrição visceral e provável redução do fluxo uterino. Entretanto, em gestações normais, mecanismos compensatórios atuam no leito vascular útero-placentário e no feto, garantindo a homeostase das trocas gasosas e impedindo efeitos deletérios da hipoxia fetal. A análise dos estudos desta revisão permite conlcuir que os exercícios considerados de moderada intensidade em gestações não complicadas parecem ser seguros e podem ser recomendados.

Physical activity is associated with several benefits to physical and mental health. Among pregnant women, the practice of physical exercises has gained more emphasis over the last few decades, but controversy still persists regarding the possible occurrence of potential damaging effects on the fetus. The present systematic review evaluated existing studies that investigated the acute effects of maternal physical exercise on the hemodynamic uteroplacental and fetal parameters. The occurrence of varied degrees of blood flow deviation to the skeletal muscle involved in exercise was detected. This occurrence of varied degrees of blood flow deviation to the skeletal muscle involved in exercise was detected. This effect is accompanied by visceral vasoconstriction and by a probable reduction of uterine flow. However, in normal pregnancies, compensatory mechanisms may act on the uteroplacental vascular bed and on the fetus, in order to guarantee the homeostasis of gas exchanges and prevent deleterious effects of fetal hypoxia. Analysis of the studies reviewed in this survery permits us to conclude that exercises of moderate intensity in uncomplicated pregnancies seem to be safe and can be recommended.

Evaluación fetal intraparto: análisis crítico de la evidencia / Fetal intrapartum surveillance: critical appraisal of evidence

La evaluación de la condición fetal intraparto constituye uno de los principales desafíos de la obstetricia. En un intento por mejorar la discreta capacidad diagnóstica del registro electrónico intraparto de la frecuencia cardiaca fetal, se han ideado y desarrollado métodos complementarios de vigilancia fetal intraparto. El objetivo del presente artículo es realizar un análisis crítico de estos métodos complementarios de vigilancia fetal intraparto, respecto de su rendimiento diagnóstico y de su utilidad clínica, para concluir si se justifica la incorporación de alguno(s) de ellos como estándar de la práctica clínica habitual.

Dopplervelocimetria do ducto venoso: importância clínica / The Clinical importance of ductus venosus blood flow

O estudo do sistema venoso fetal, particularmente do ducto venoso, tem sido intensamente pesquisado. O ducto venoso apresenta localização privilegiada e relação direta com eventos hemodinâmicos fetais. Devido a seu importante papel na regulação da circulação fetal, alterações significativas na velocidade de fluxo no ducto venoso, podem ser observadas em fetos com descompensação hemodinâmica associada ou não a defeitos cardíacos. A investigação da velocimetria e da morfologia da onda de fluxo no ducto pode ser utilizada como método complementar no primeiro trimestre para rastreamento precoce de determinadas anomalias cromossômicas. Além disso, alterações na velocidade de fluxo podem estar relacionadas com diversas doenças como hipoxia grave, anemia, cardiopatias, arritmias e transfusão feto-fetal

Papel da serotonina no desenvolvimento cardíaco / The role of serotonin in the heart development

A serotonina (5-HT), além de sua ação como neurotransmissor, participa do desenvolvimento do organismo. Durante o desenvolvimento do coração. agonistas e antagonistas serotonimérgicos podem provocar alterações morfogenéticas nas células desse órgão. A serotonina também atua como sinalizador morfogenético tipo dose-dependente, durante a formação do coração. No presente trabalho foi feita uma revisão da participação da serotonina no desenvolvimento cardíaco.

Failure of intensive fetal monitoring and ultrasound in reducing the stillbirth rate

Although highly popularized among obstetricians, there are conflicting results regarding the efficacy of high-resolution ultrasound and other fetal well-being tests on improving neonatal outcome and morbidity. To assess the impact of unrestricted fetal well-being tests and sonographic evaluations on the stillbirth rate, we evaluated a total of 1,810 pregnancies 20 weeks of gestation or more from a single private clinic serving a mixed population of high and low-risk patients. All patients were performed high-resolution sonography during each trimester of pregnancy. In addition, on each prenatal visit, fetal heart rate, position and amniotic fluid index were documented by a limited sonographic scan. Further sonographic studies were done whenever deemed necessary depending on the clinical situation. Biophysical profiles were performed in the third trimester at any time a risk factor was identified, and repeated as frequently as estimated necessary. All cases of fetal death in utero were documented and the associated maternal risk factors assessed. A total of 14 stillbirths occurred among the 1,810 patients. The stillbirth rate for this population was determined to be 7.7/1000 births (U.S. national average of 6.7-7.8/1000 births). The most common associated maternal complications were Diabetes (4 cases) and Antiphospholipid syndrome (3 cases). All except for one fetus lost at 37 weeks had at least one identifiable maternal risk factor. These results prove that intensive fetal surveillance, even when unrestricted by economic concerns, has limited effectiveness in avoiding fetal demise. This is most probably due to acute placental and cord accidents that cannot be detected promptly enough or that are simply unavoidable.

Evaluation of ventricular myocardial velocities and heart motion of the fetal heart by tissue Doppler image.

Fetal echocardiogram has developed into a reliable tool for prenatal diagnosis of congenital heart disease. It is also used to evaluate ventricular function. Recently, Tissue Doppler Imaging (TDI) has been introduced to evaluate ventricular functions especially in ischaemic heart disease. The objective of this study was to evaluate myocardial velocities and heart motions of the normal fetal heart by using TDI. The TDI was preformed in 28 fetal hearts with a gestational age of 20-35 wks (Mean 29 +/- 3.7 wks) to evaluate myocardial velocities and heart motion. The Toshiba, Power Vision, machine with 3.75 and 5 MHz transducers was used with an appropriate setting of colour-coded tissue velocities. The apical four chamber and apical or parasternal long axis views were the standard planes for measuring myocardial velocities and evaluating the heart motions. The results showed the myocardial velocities of the posterior wall of the left ventricle during the early, mid, and late systolic phases were 1.5 +/- 0.2, 2.1 +/- 0.9, and 1.0+0.5 cm/sec and early, mid, and late diastolic phases were 1.3 +/- 0.7, 1.9 +/- 0.8, and 1.1 +/- 0.7 cm/sec respectively. The myocardial velocity of the anterior wall of the right ventricle during the early, mid, and late systolic phases were 1.7 +/- 0.9, 1.7 +/- 0.6, and 1.0 +/- 0.6 cm/sec and early, mid, and late diastolic phases were 1.1 +/- 0.6, 1.8 +/- 0.7, and 1.5 +/- 1.0 cm/sec respectively. The myocardial velocity of the interventricular septum could not be measured due to the abnormal septal motion and the total fetal heart movement during the cardiac cycle. The fetal heart had anterior displacement during systole and posterior translation during diastole and also had counter-clockwise rotation during the systolic phase. CONCLUSION: Using the TDI to evaluate myocardial velocities of the fetal heart is limited by the angle of ultrasound beam and the total fetal heart motion. The fetal heart movement is similar to the newborn or young adult heart.

Ultrasonographic demonstration of fetal cardiac activity in threatened abortion and its prognostic significance

To evaluate the prognostic value of detecting fetal heart activity in cases of threatened abortion occurring early in the first trimester, and consequently to demonstrate the importance of ultrasonography in the routine management of vaginal bleeding in early pregnancy. Two hundred and sixteen patients were enrolled in this study. They were all seen in the first attack of vaginal bleeding, occurring in the first trimester. Fetal cardiac activity was demonstrated by the use of abdominal ultrasound on the first visit. They all had singleton pregnancy. There was neither history of recurrent abortion, nor intake of anticoagulant drugs. The patients were then seen weekly or whenever bleeding recurred. No drugs were given. Out of the 216 cases, 193 [89.4%] continued to full-term delivery. Twenty three cases [10.6%] aborted during the first or second trimester. Premature delivery, congenital abnormalities and cesarean section rates were not significantly different from the expected averages of the general population. Eighteen of these 23 cases of fetal loss started bleeding in the late weeks of the first trimester [10th - 12th week]. At the first attack of vaginal bleeding occurring in the first trimester, if the cervix is closed and a living fetus could be demonstrated, the pregnancy should be considered viable and the outlook for fetal survival is favorable. Sonographic demonstration of fetal cardiac activity is assuring, indicating a low risk of subsequent abortion and a favorable prognosis

Pearson's fetal movement count (FMC) and antepartum fetal heart rate testing (AFHRT) for antepartum fetal well-being.

To evaluate the accuracy of Pearson's fetal movement count (FMC) and antepartum fetal heart rate testing (AFHRT) in 380 high risk pregnancies at Rajavithi Hospital in 1994, the result of the 4 test FMC, AFHRT, FMC + AFHRT (serial test), and FMC + AFHRT (parallel test) were compared in sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), false positive rate (FPR), false negative rate (FNR) and accuracy. All tests had equal specificity and FPR. FMC + AFHRT (serial test) had the highest value of sensitivity (66.67%) but lowest value of FNR, NPV and accuracy (33.33%, 40%, 72.73% respectively). PPV was 100 per cent in AFHRT and FMC + AFHRT (serial test). FMC might be used as a first line antepartum fetal well being screening test.

Fetal heart rate monitoring by magnetocardiograms

The magnetic field produced by the fetal heart magnetocardiogram (FMCG) was measured by a single channel SQUID biogradiometer in an unshielded environment. FMCG amplitude ranged from 1 to 4 pT. Instantaneous fetal heart rate and averaged FMCG waveforms were computed. Spectral analysis was used to quantify fetal heart rate variability, and revealed peaks from 0.5 to 1.0 Hz, consistent with respiratory sinus arrhythmia. The duration of the QRS complex was approximately 50 msec, and its amplitude and shape showed strong spatial variation. Signal-to-noise ratio was inadequate for the study of P and T waves. These data show that this relatively simple and inexpensive instrument can be used for noninvasive in utero investigation of fetal heart activity without requiring a special environment.

Cardiologia fetal / Fetal cardiology

A cardiologia fetal clinica iniciou, há mais de vinte anos atrás, com a ecocardiografia fetal, cujo impacto sobre a medicina fetal foi fundamentamente para a compreensäo da fisiologia e fisiopatologia do feto humano. Como os conhecimentos anteriores provinham de estudos feitos, principalmente, com fetos de carneiros, muitas vezes näo se sabia se eram equivalentes no feto humano, motivando, entäo, com o advento do ecofetal, a realizaçäo de inúmeros trabalhos de pesquisa clínica e experimental...

Role of foetal echocardiography in predicting perinatal outcome.

To establish foetal cardiovascular parameters as predictors of perinatal outcome in pregnancy, M-Mode, 2-D echocardiography and pulse Doppler study was performed at 24-32 weeks of gestation in 65 pregnancies. These pregnancies were followed up for perinatal outcome. The studied population included 24 normal pregnancies, 21 pregnant women with heart disease (14 rheumatic and 7 congenital heart disease) and 20 high risk pregnancies (bad obstetric history in 7, suspected intrauterine growth retardation in 4, hypertensive disease of pregnancy in 6 and diabetes mellitus in 3). There was no perinatal mortality. Two foetuses were born with complete heart block and one with a small ventricular septal defect; 6 neonates had intrauterine growth retardation and two of these had neonatal asphyxia with APGAR score less than 6 at one minute. Anatomically normal heart was correctly diagnosed in all 64 foetuses and ventricular septal defect was detected antenatally in one. Antenatal diagnosis of complete heart block was correctly made in two foetuses. One new born with complete heart block required a permanent pacemaker, which was implanted. The ratio of peak velocity across mitral valve during atrial systole (A) to peak velocity during early diastolic ventricular filling (E) was chosen to correlate with perinatal outcome. The ratio was less than 1.0 in 6 foetuses, all of whom were subsequently confirmed to have intrauterine growth retardation. In normal pregnancies A/E ratio was more than 1.0. We conclude that foetal echocardiography is a useful tool for predicting perinatal outcome and may be helpful in screening patients who require specific perinatal management.

Fetal echocardiography--norms for M-mode measurements.

M-mode echocardiography was performed in 110 normal fetuses to study the norms for various cardiac parameters at varying gestational ages. The measurements were done in normal pregnancies with gestation varying from 14-38 weeks. The parameters studied were aortic root diameter, left atrial and right ventricular outflow tract dimensions, left and right ventricular cavity dimensions, and left ventricular, septal and right ventricular wall thickness. The values were analysed statistically by linear regression analysis and 95 per cent confidence limits were derived. It was found that values for right and left ventricles increased with gestation such that at term both ventricles were equal in size. The aorta and left atrium also increased with increasing gestation but the value for left atrium increased more than that of aorta giving increased left atrium to aorta ratio. These values could be utilised as norms for Indian fetuses and could help in detecting abnormalities of size.

Ecocardiografia fetal: experiência inicial / Fetal echocardiography: initral experience

De julho de 1985 a outubro de 1987 foram realizados 146 ecocardiogramas de coraçöes fetais. A idade materna variou de 15 a 46 anos (média de 26) e a idade gestacional variou de 12 a 41 semanas (média de 29). As gestantes foram divididas em três grupos: grupo I - com 88 gestantes sem patologias; grupo II - com 40 gestantes portadoras de doenças diversas (cardiopatias adquiridas, hipertensäo arterial sistêmica e diabete); grupo III - com 18 gestantes com cardiopatias congênitas. Em quatro casos (2,7%) de gestantes do grupo I, a ecocardiografia fetal foi realizada por indicaçäo do obstetra, devido a detecçäo de alteraçöes do ritmo cardíaco fetal. Em dois desses havia alteraçöes anatômicas do coraçäo: um com átrio único com defeito do septo atrioventricular forma parcial, confirmado no ecocardiograma pós-natal e outro com transposiçäo corrigida das grandes artérias com displasia tipo Ebstein da valva tricuspide, sendo confirmado apenas a segunda anomalia no exame pós-parto. Em um caso (0,7%) de gestanes do grupo III, detectou-se defeito do septo atrioventricular forma total confirmado pelo ecocardiograma pós-parto. O estudo ecocardiográfico fetal é um método confiável para o diagnóstico intra-útero de cardiopatias congênitas possibilitando uma adequada assistência ao recém-nato, além de permitir o acompanhamento evolutivo do crescimento das estruturas cardíacas através das medidas das dimensöes

Fundamentos fisiológicos para a análise da freqüência cardíaca fetal / Physiologic aspects for fetal heart rate analysis

Säo considerados aspectos fisiológicos básicos à compreensäo dos padröes da freqüência cardíaca fetal e enfatizados os fatores responsáveis pelo seu controle

Test de tolerância a las contracciones inducidas con la estimulación del pezon / Tolerance test to the induced contractions with stimulation of the nipples

El test de tolerancia a las contracciones inducidas por ocitocina, es un recurso universalmente difundido para conocer la reserva fetal de oxígeno. En esta experiencia, el test de Pose se realizó haciendo masajear digitalmente los pezones de las pacientes, desencadenándose reflejo de Ferguson y liberación de ocitocina por la hipófisis, logrando así la dinámica requerida; prescindiendo de ocitocina endovenosa exógena. Comparamos capacidad predictiva del test con: N.S.T.; score de Apgar al 1' - 5' y 10'; distress intraparto y morbimortalidad exógena. Participaron 93 embarazos de 38 semanas o más, efectuándose 110 N.S.T. y 114 test con estimulación del pezón. En las conductas tomadas para estos pacientes no participó el resultado del test estudiado. El test demostró ser útil particularmente en distress intraparto y complicaciones cordonales. Además ahorró costos y tiempo de realización, por prescindir de infusión intravenosa. No hubo falsos negativos. Aconsejamos control médico al realizar por las hipertonías observadas