Associations between mindfulness, psychological health and aspects of cardiovascular function in pregnancy

Abstract

Pregnancy is usually experienced as a meaningful part of life, though this transition can be a turbulent time. Research suggests that psychological distress during pregnancy can contribute to the development of medical conditions. Recently, mindfulness-based interventions (MBIs) have been studied for their potential role in mitigating psychological and physical health conditions in pregnancy. However, the relationships between trait mindfulness, the characteristic which these interventions purport to develop, and maternal physical and mental health remain unclear. In addition, most research on this topic has focused on evaluating long-term MBIs. Thus, the immediate effects of MBIs are not well-understood in this population. This dissertation consists of three studies which address the following objectives: (1) to examine the relationship between trait mindfulness and psychological and physical health in pregnancy, (2) to determine whether trait mindfulness is predictive of maternal blood pressure trajectories across pregnancy, and (3) to investigate the in-the-moment effects of an MBI on maternal heart rate, heart rate variability and mood.The purpose of Study One was to investigate the relationship between trait mindfulness to health outcomes throughout pregnancy. 510 women who were recruited at obstetrics clinics completed the Mindful Awareness and Attention Scale (MAAS) in the first or early second trimester. Higher MAAS scores predicted lower perceived stress, depression, and pregnancy-related distress scores and less severe physical discomforts throughout pregnancy. Trait mindfulness did not predict the diagnosis of diabetes or high blood pressure. These results indicate that trait mindfulness is a predictor of subjective stress during pregnancy.Study Two was conducted to address a key limitation in Study One, the use of a binary outcome measure as an index of blood pressure. In Study Two, we examined the potential relationship between trait mindfulness and blood pressure trajectories across pregnancy. Clinical blood pressure observations were obtained from 370 pregnant participants in the longitudinal study examined in Study One. Functional data analysis was used to smooth and quantify blood pressure curves. Functional regression analyses showed that trait mindfulness did not predict systolic nor diastolic blood pressure trajectories. Further research using a more inclusive measure of trait mindfulness or higher risk samples may lead to more nuanced results.Study Three examined the immediate effects of a presumably mindfulness-enhancing body scan meditation on maternal heart rate, heart rate variability (HRV), and mood, with particular attention to the moderating effects of trait mindfulness. It is possible that the effects of mindfulness on cardiovascular activity in pregnancy are more acute. 43 pregnant women participated in two sessions one week apart, where they were asked to follow a guided meditation recording or listen to an audiobook. Both the audiobook and the meditation increased high frequency HRV temporarily. Such activities may have cardiovascular benefits in women already predisposed to mindfulness, as these women experienced greater decreases in low frequency HRV and greater increases in high frequency HRV. In contrast, less mindful women experienced a greater decrease in negative affect, though the more mindful women reported less emotional distress overall. Heart rate was reduced to a greater degree by the meditation than the audiobook. These results suggest that MBIs may have beneficial effects on maternal health in pregnancy.In the general discussion, issues related to the measurement of trait mindfulness and the study of maternal health are discussed. Directions for future research are proposed. Taken together, this dissertation contributes to knowledge on how mindfulness might exert some influence on maternal cardiovascular and psychological health across pregnancy