Characterizing the Relationship between Uterine Activity and Placental Function Across Pregnancy with MRI

项目摘要/摘要 胎盘是一个重要的胎儿器官，起到给胎儿血液中的氧气、营养和清除废物的作用。 子宫。强大的母体血流灌注对这一功能是必不可少的，需要高容量、缓慢的血流以 胎盘。子宫收缩会暂时损害母体-胎盘的灌流，这是 发生在整个怀孕期间，也被称为Braxton Hicks宫缩。正常的健康胎儿 发达的胎盘有足够的胎盘储备能力，使Braxton Hicks宫缩和未成年人 血管病变不会显著影响必要的胎盘氧气转运。然而，在功能失调的情况下 储备不良的胎盘(如某些与胎儿宫内生长受限有关的胎盘) 这些事件可能会导致缺氧性压力。目前还缺乏关于这一影响的信息和量化数据。 人类怀孕时的产前子宫活动(Braxton Hicks收缩)，以及这些发现是否可能 有助于确定胎盘储备和功能的特征，并为将来的测试提供信息，以识别胎儿 胎盘功能障碍引起的分娩期间不良结局的风险。评估的新方法 人类子宫胎盘功能及宫缩对胎儿呼吸交换的影响 正常发育和IUGR胎儿的妊娠是必要的。在这里，我们将描述 布拉克斯顿·希克斯：分析妊娠期间胎盘氧合的时空变化 并监测这些胎盘氧合变化对胎儿运动和器官的影响 通过核磁共振进行氧合。我们的假设是Braxton Hicks宫缩期间胎盘血流的变化 与正常生长的胎儿相比，可能对IUGR胎儿的胎盘氧气运输有更大的影响。 如果成功，我们将确定宫缩期间胎盘和胎儿磁共振信号的变化是可能的 方法了解个体胎盘储备情况。这样的理解可能会使小说的发展 治疗方法和监测这些动态变化的能力对于评估 新奇的疗法。为此，我们提出了以下具体目标：目标1：描述布拉克斯顿·希克斯 宫缩和相关胎盘氧合在妊娠期间的变化 正常生长和IUGR胎儿。我们将使用T2*映射方法来表征胎盘氧合 并分析胎盘T2*的区域差异。然后我们将比较和关联 胎儿发育正常和胎儿宫内发育迟缓的妊娠。目的2：确定胎盘氧合的影响 妊娠期Braxton-Hicks宫缩对胎儿运动及脑、肝氧合的影响 正常生长和IUGR胎儿。我们将跟踪胎儿运动并确定胎儿大脑和肝脏的特征 使用T2*标测进行氧合。然后我们将比较和关联正常妊娠和正常妊娠的差异。 生长和IUGR胎儿。

PROJECT SUMMARY / ABSTRACT The placenta is a vital fetal organ that serves to oxygenate, nourish, and remove waste from fetal blood in utero. Robust maternal perfusion is essential for this function and requires high capacitance, slow blood flow to the placenta. Maternal-placental perfusion can be temporarily compromised by uterine contractions, which occur throughout pregnancy, also known as Braxton Hicks contractions. Healthy fetuses with normally developed placentas have enough placental reserve capacity that Braxton Hicks contractions and minor vascular pathology do not significantly affect necessary placental oxygen transport. However, in dysfunctional placentas with poor reserve (as in some placentas associated with intrauterine growth restriction-IUGR) these events may lead to hypoxic stress. There is a lack of information and quantitative data regarding the effect of antepartum uterine activity (Braxton Hicks contractions) in human pregnancies and whether these findings may help to characterize placental reserve and function and inform development of future tests to identify fetuses at risk for adverse outcomes during delivery mediated by placental dysfunction. New methods to assess uteroplacental function in humans and the impact of contractions on fetal respiratory exchange across pregnancy in pregnancies with normally growing and IUGR fetuses are needed. Here, we will characterize Braxton Hicks contractions across gestation, analyze spatiotemporal changes in placental oxygenation during these contractions and monitor the effect of these placental oxygenation changes on fetal movement and organ oxygenation via MRI. Our hypothesis is that the change in placental flow during Braxton Hicks contractions may have a larger impact on placental oxygen transport for IUGR fetuses compared to normally growing ones. If successful we will have identified placental and fetal MR signal changes during contractions as a possible method to understand individual placental reserve. Such understanding may enable the development of novel therapies and the ability to monitor changes in these dynamics is critical to the assessment of the impact of novel therapies. Towards this end, we propose the following specific aims: Aim 1: Characterize Braxton Hicks contractions and the associated change in placental oxygenation across gestation in pregnancies with normally growing and IUGR fetuses. We will characterize placental oxygenation using T2* mapping approach and analyze regional differences in placental T2*. Then we will compare and correlate differences in pregnancies with normally growing and IUGR fetuses. Aim 2: Determine the impact of placental oxygenation change during Braxton Hicks contractions on fetal motion and brain and liver oxygenation in pregnancies with normally growing and IUGR fetuses. We will track fetal motion and characterize fetal brain and liver oxygenation using T2* mapping. Then we will compare and correlate differences in pregnancies with normally growing and IUGR fetuses.