BLOOD PRESSURE REGULATION, STRESS AND MATERNAL OXYTOCIN RESPONSE

描述（由申请人提供）：分娩后的第一年对许多母亲来说是高度紧张的，但“结合激素”催产素（OT）活性的增强可能会降低血压（BP）、交感神经和皮质酮活性，以及应激行为，同时在母婴接触过程中增加积极影响和中枢奖励通路的激活。目前在美国，大约60%的新妈妈在一年内重返工作岗位，这增加了母亲的总工作量，同时显著减少了婴儿早期母婴接触的时间。在3项转化研究中，我们发现，在实验室压力源中与婴儿温暖接触后降低OT水平的母亲在压力之前、期间和之后的血压水平高于升高OT的母亲；排卵减少的母亲更有可能是奶瓶喂养的而不是母乳喂养的。年幼婴儿（< 5个月）的母亲的高OT反应也与家中的低动态血压有关。初步数据显示，婴儿小于5个月的非裔美国母亲较低的OT反应可能与提前返回家庭以外的工作有关。我们假设，在产后一年内，母亲OT活动的减少与母婴互动频率的减少和他们之间温暖的身体接触（包括母乳喂养）的减少有关，而增加这种接触对母亲和婴儿都有益。因此，我们将招募120对母婴（其中48对是非裔美国人）来解决以下问题：在产后2-3个月，与未重返工作岗位的母亲相比，与未断奶的母亲相比，与母乳喂养的婴儿进行温暖接触后的OT反应是否更低？2. 之前与婴儿的身体接触是诱发母亲OT增加的必要条件，还是没有接触的面对面互动同样有效？3. 使用一项前瞻性的双组研究，在2-3个月和1岁时进行测试，在初始测试时较高的母亲OT反应是否与较低的在家动态血压、较高的母亲依恋评分和更高质量的母婴互动相关，并且它是否预测1岁时更高质量的互动？所有120名母亲将接受2天的24小时血压监测，因此工作母亲在与婴儿在一起的一天和与婴儿分开的一天进行监测。产妇OT反应也与当天24小时尿儿茶酚胺和皮质醇有关。此外，在试点可行性部分，将同时获得母亲和婴儿的唾液和尿液的OT测量与母亲的血液来源的OT，提供初步测试的能力，以评估OT活性与非侵入性获得的样本。这项研究将深入了解早期母婴互动的频率和类型对影响其生理、行为和情感反应的神经行为通路的影响，这可能对母亲和儿童的健康和福祉产生深远的影响。

DESCRIPTION (provided by applicant): The first year after childbirth is highly stressful for many mothers, but enhanced activity of the "bonding hormone" oxytocin (OT) may decrease blood pressure (BP), sympathetic and corticosterone activity, and stress behavior, while increasing positive affect and activation of central reward pathways during mother- infant contact. Currently in the US, roughly 60% of new mothers return to work within the first year, increasing the mother's total workload while markedly decreasing the time available for mother-infant contact in the child's early life. In 3 translational studies, we found that mothers who decreased their OT levels during a lab stressor that followed warm contact with their infants had higher BP levels before, during and after stress than mothers who increased OT; OT decrease mothers were more likely to be bottle- than breast- feeders. Higher OT response of mothers with young infants (< 5 months) was also related to lower ambulatory BP at home. Preliminary data suggests that lower OT response in African American mothers with infants less than 5 months old may be linked to early return to work outside the home. We hypothesize that during the first year postpartum, decreased maternal OT activity is related to less frequent mother-infant interactions and less warm physical contact between them (including breast-feeding), and that increasing such contacts are beneficial for both mother and infant. Thus, we will recruit 120 mother-infant dyads (including 48 African American) to address the following questions: 1. At 2-3 months postpartum, is OT response after warm infant contact lower in mothers who have vs. have not returned to work, and who have vs. have not weaned their infants from breast feeding? 2. Is prior physical touch with their infant essential to elicit maternal OT increases, or is face-to-face interaction without touch equally effective? 3. Using a prospective, within-dyad study with testing at 2-3 months and again at 1 year, is higher maternal OT response at initial testing associated with lower ambulatory BP at home, and with higher maternal attachment scores and higher quality mother-infant interaction, and does it predict higher quality interaction at age 1 year? All 120 mothers will undergo 2 days of 24-hour BP monitoring, so that working mothers are monitored on a day spent with vs. a day spent apart from their babies. Maternal OT response will also be related to 24-hour urinary catecholamine and cortisol on both days. Also, in a pilot feasibility component, mother and infant salivary and urinary measures of OT will be obtained concurrently with maternal blood- derived OT, to provide initial tests of the capability to assess OT activity with non-invasively obtained samples. This research will provide insights into the effect of the frequency and type of early mother-infant interactions on neurobehavioral pathways influencing their physiological, behavioral and affective responses, which may have profound implications for the health and well-being of both mother and child.