Fetal hemodynamics evaluated by Doppler velocimetry in the second half of pregnancy

Costa, Antônio Gadelha da; Filho, Francisco Mauad; Spara, Patrícia; Gadelha, Eduardo Barreto; Netto, Pedro Vieira Santana

doi:10.1016/j.ultrasmedbio.2005.04.009

Cited by 16 publications

(11 citation statements)

References 14 publications

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“…Another objective of this study was the determination the reference values in percentiles for MCA-PSV. The authors observed a progressive increase in MCA-PSV in the second half of pregnancies, in the same manner as observed by Gadelha da Costa et al (23) , Kurmanavicius et al (24) and Bahlmann et al (25) . In a comparison with the study developed by Gadelha da Costa et al (23) who have also evaluated a sample of the Brazilian population, the authors of the present study similar values for MCA-PSV in the period between the 22nd and 34th weeks.…”

Section: Discussionsupporting

confidence: 77%

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Intervalos de referência do pico de velocidade sistólica da artéria cerebral média fetal na população brasileira

2008

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OBJETIVO: Determinar uma curva de referência baseada em múltiplos da mediana para o pico de velocidade sistólica da artéria cerebral média fetal. MATERIAIS E MÉTODOS: Realizou-se estudo de corte transversal com 143 gestantes normais entre 23 e 35 semanas. Realizou-se varredura bidimensional em corte axial do crânio fetal, incluindo os tálamos e o septo pelúcido, e em seguida acionou-se o modo color Doppler, visualizando-se a artéria cerebral média. O Doppler pulsátil foi disposto próximo à origem deste vaso, utilizando-se ângulo de insonação de menos de 20°. Para avaliar a correlação do pico de velocidade sistólica da artéria cerebral média com a idade gestacional, utilizou-se o coeficiente de correlação de Person (r). Por meio de modelos de regressão, construiu-se uma tabela de múltiplos da mediana para o pico de velocidade sistólica da artéria cerebral média em cada idade gestacional avaliada, e adicionalmente determinaram-se valores de referência para essa variável. RESULTADOS: Observou-se forte correlação entre o pico de velocidade sistólica da artéria cerebral média e a idade gestacional (r = 0,70; p = 0,001). Determinaram-se valores do pico de velocidade sistólica da artéria cerebral média para os seguintes múltiplos da mediana: 1,0; 1,29; 1,5; 1,55. Determinaram-se os percentis 2,5 e 97,5 para o pico de velocidade sistólica da artéria cerebral média, variando de 24,33 cm²/s a 78,36 cm²/s. CONCLUSÃO: Um nomograma do pico de velocidade sistólica da artéria cerebral média fetal foi determinado.

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Section: Discussionsupporting

confidence: 77%

“…This same exponential model has been obtained by Alshimmiri et al (22) with 300 normal fetuses. However, in the study developed by Gadelha da Costa et al (23) , the authors obtained a linear relation between MCA-PSV and gestational age: MCA-PSV: 21.47 + 2.16GA.…”

Section: Discussionmentioning

confidence: 89%

Intervalos de referência do pico de velocidade sistólica da artéria cerebral média fetal na população brasileira

2008

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“…3,40,41 Angiogenesis plays such a critical role in implantation that a single dose of an anti-angiogenic compound (AGM-1470) administered before or shortly after implantation will result in resorption of all embryos in mice. 42 In humans, umbilical blood flow velocity, as measured by Doppler ultrasound, increases and resistance decreases throughout the last half of gestation, 43 in part reflecting the formation of new blood vessels. Embryonic death and blighted ova have been demonstrated to occur when chorionic villous vascularization is deficient 44 and increased uterine vascular resistance and reduced uterine blood flow are predictors of high-risk pregnancies.…”

Section: Discussionmentioning

confidence: 99%

Relaxin increases human endothelial progenitor cell NO and migration and vasculogenesis in mice

Segal¹,

Sautina²,

Li³

et al. 2012

Blood

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The ovarian peptide hormone, relaxin, circulates during pregnancy, contributing to profound maternal vasodilation through endothelial and nitric oxide (NO)-dependent mechanisms. Circulating numbers of bone marrow-derived endothelial cells (BMDECs), which facilitate angiogenesis and contribute to repair of vascular endothelium, increase during pregnancy. Thus, we hypothesized that relaxin enhances BMDEC NO production, circulating numbers, and function. Recombinant human relaxin-2 (rhRLX) stimulated PI3K/Akt B-dependent NO production in human BMDECs within minutes, and activated BMDEC migration that was inhibited by L-N G -nitroarginine methyl ester. In BMDECs isolated from relaxin/ insulin-like family peptide receptor 2 gene (Rxfp2) knockout and wild-type mice, but not Rxfp1 knockout mice, rhRLX rapidly increased NO production. Similarly, rhRLX increased circulating BMDEC number in Rxfp2 knockout and wild-type mice, but not Rxfp1 knockout mice as assessed by colony formation and flow cytometry. IntroductionDramatic changes in systemic and renal hemodynamics occur during pregnancy. There is a marked decrease in systemic vascular resistance and reciprocal increases in cardiac output and global arterial compliance, accompanied by a modest decline in mean arterial pressure. The renal circulation participates in this maternal vasodilatory response; consequently, renal plasma flow and glomerular filtration rate rise by 80% and 50%, respectively. Although understanding of the mechanisms underlying these maternal adaptations to pregnancy is incomplete, there is increasing evidence that the ovarian peptide hormone relaxin plays a key role. 1 Originally isolated from the ovary by Hisaw, 2 relaxin was named for its ability to relax the pubis symphysis in some species. In nonhuman primates, it was subsequently shown by the same investigators to cause morphologic changes in endothelial cells of endometrial blood vessels consistent with hypertrophy and hyperplasia, and enlargement of arterioles and capillaries. 3 Humans have 3 relaxin genes, designated relaxin-1, -2, and -3. 4 Rats and mice each have 2 relaxin genes designated relaxin-1 and -3. Human relaxin-2, as well as rat and mouse relaxin-1 gene products, are true orthologs, insofar as they are secreted by the corpus luteum during pregnancy and circulate. Humans, rats, and mice have 1 relaxin receptor, the LGR7 (leucine rich repeat-containing G protein coupled) receptor recently renamed relaxin/insulin-like family peptide 1 receptor, RXFP1. Although human relaxin may also bind to the LGR8 receptor (RXFP2), albeit with reduced affinity, 5 the preferred ligand for RXFP2 is insulin-like 3 (INSL3). Recently, 2 new receptors have been described for relaxin-3, GPCR135 and 142, 6 although GPCR142 is a pseudogene in rats.Infusion of recombinant human relaxin-2 (rhRLX) in nonpregnant conscious female and male rats significantly decreases renal and systemic vascular resistances, and increases cardiac output, renal blood flow, glomerular filtration, and global arterial compliance, ...

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“…Similarly, in sheep and cows, umbilical (fetal placental) blood flow increases dramatically throughout pregnancy, such that it keeps pace with fetal growth throughout the last half of gestation (Rudolph & Heymann, 1970; Bell et al 1986; Reynolds et al 1986; Reynolds & Ferrell, 1987; Molina et al 1991). Although not measured directly, umbilical blood flow velocity increases and resistance decreases throughout the last half of gestation in humans (Gadelha Da Costa et al 2005). Not only do absolute utero‐placental flows increase throughout pregnancy, but importantly, the proportion of the total uterine and umbilical blood flows received by the caruncular and cotyledonary tissues, respectively, also increases as gestation progresses (Makowski et al 1968 a , b ; Rosenfeld et al 1974; Meschia, 1983).…”

Section: The Importance Of Placental Blood Flow and Vascularity To Nomentioning

confidence: 99%

Evidence for altered placental blood flow and vascularity in compromised pregnancies

Reynolds

Caton

Redmer

et al. 2006

The Journal of Physiology

313

196

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The placenta is the organ that transports nutrients, respiratory gases, and wastes between the maternal and fetal systems. Consequently, placental blood flow and vascular development are essential components of normal placental function and are critical to fetal growth and development. Normal fetal growth and development are important to ensure optimum health of offspring throughout their subsequent life course. In numerous sheep models of compromised pregnancy, in which fetal or placental growth, or both, are impaired, utero-placental blood flows are reduced. In the models that have been evaluated, placental vascular development also is altered. Recent studies found that treatments designed to increase placental blood flow can 'rescue' fetal growth that was reduced due to low maternal dietary intake. Placental blood flow and vascular development are thus potential therapeutic targets in compromised pregnancies.

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Fetal hemodynamics evaluated by Doppler velocimetry in the second half of pregnancy

Cited by 16 publications

References 14 publications

Intervalos de referência do pico de velocidade sistólica da artéria cerebral média fetal na população brasileira

Intervalos de referência do pico de velocidade sistólica da artéria cerebral média fetal na população brasileira

Relaxin increases human endothelial progenitor cell NO and migration and vasculogenesis in mice

Evidence for altered placental blood flow and vascularity in compromised pregnancies

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