Maternal blood pressure trajectories and associations with gestational age at birth: a functional data analytic approach

BACKGROUND

Research has revealed group-level differences in maternal blood pressure trajectories across pregnancy. These trajectories are typically constructed using clinical blood pressure data and multivariate statistical methods that are prone to bias and ignore the functional, dynamic process underlying a single blood pressure observation. The aim of this study was to use functional data analysis to explore blood pressure variation across pregnancy, and multivariate methods to examine whether trajectories are related to gestational age at birth.

METHODS

Clinical blood pressure observations were available from 370 women who participated in a longitudinal pregnancy cohort study conducted in Montreal, Quebec, Canada. Functional data analysis was used to smooth blood pressure data and then to conduct a functional principal component analysis to examine predominant modes of variation.

RESULTS

Three eigenfunctions explained greater than 95% of the total variance in blood pressure. The first accounted for approximately 80% of the variance and was characterized by a prolonged-decrease trajectory in blood pressure; the second explained 10% of the variance and captured a late-increase trajectory; and the third accounted for approximately 7% of the variance and captured a mid-decrease trajectory. The prolonged-decrease trajectory of blood pressure was associated with older, and late-increase with younger gestational age at birth.

CONCLUSION

Functional data analysis is a useful method to model repeated maternal blood pressure observations and many other time-related cardiovascular processes. Results add to previous research investigating blood pressure trajectories across pregnancy through identification of additional, potentially clinically important modes of variation that are associated with gestational age at birth.

The relationship of trait mindfulness to physical and psychological health during pregnancy

INTRODUCTION

Research on mindfulness has extended to the prevention of psychopathology and physical conditions during pregnancy. The purpose of this study was to investigate the relationship between trait mindfulness assessed in the first or early second trimester to health outcomes throughout pregnancy.

METHODS

A total of 510 women were recruited at McGill University-affiliated obstetrics clinics (average gestational age: 13.43 weeks, sd = 1.2). The Mindful Awareness and Attention Scale (MAAS) was administered at baseline. At three timepoints during pregnancy, participants completed the Perceived Stress Scale (PSS-10), the Edinburgh Postnatal Depression Scale (EPDS), the Prenatal Distress Questionnaire-revised (PDQR) and a measure of pregnancy symptom intensity and indicated whether they had been diagnosed with gestational diabetes or high blood pressure.

RESULTS

Higher MAAS scores predicted lower PSS, EPDS and PDQR scores and less severe physical discomforts throughout pregnancy. MAAS scores were a stronger predictor of PSS scores earlier in pregnancy. Logistic regressions found that trait mindfulness did not predict the presence of physical discomforts, diabetes or high blood pressure.

CONCLUSIONS

These results indicate that trait mindfulness is an important predictor of subjective stress, depression, anxiety and the severity of physical discomforts during pregnancy. These findings suggest that interventions earlier in pregnancy may increase the impact of mindfulness on maternal health.

Social Contagion of Vasovagal Symptoms in Blood Donors: Interactions With Empathy

BACKGROUND

Vasovagal reactions (VVRs) are commonly experienced in medical situations such as blood donation. Many believe that psychosocial contagion can contribute to the development of VVRs, but this is largely clinical lore.

PURPOSE

The goal of the present investigation was to examine the physiological effects of observing another experience a reaction, focusing on the potential moderating effects of empathy.

METHODS

This study was part of a randomized controlled trial of behavioral techniques on the prevention of VVRs in blood donors. The sample was composed of 530 healthy university students. Measures of symptoms were obtained with the Blood Donation Reactions Inventory (BDRI) and through observation. Physiological variables were measured using respiratory capnometry and a digital blood pressure monitor. The Affective and Cognitive Measure of Empathy was administered to 230 participants.

RESULTS

Donors who witnessed another experiencing a reaction were more likely to spontaneously report symptoms during the blood draw, to be treated for a reaction, to score higher on the BDRI, and to exhibit smaller compensatory heart rate increases. Donors with higher affective empathy reported more symptoms, exhibited hyperventilation, and were more likely to be treated. Donors with higher cognitive empathy were less likely to require treatment if they witnessed a reaction.

CONCLUSION

These results suggest that psychosocial contagion of physical symptoms can occur. The moderating effects of empathy differed depending on the subtype of empathy. Perhaps a better cognitive understanding of how other people are feeling functions as a coping response, whereas feeling sympathetic about others' distress increases one's own.

Vagal Tone Biofeedback: Respiratory and Non-respiratory Mediated Modulations of Vagal tone Challenged by Cold Pressor Test

Deficient parasympathetic activity to the heart has been hypothesized to underlie some forms of cardiovascular disease. Consequently, this experiment attempted to induce non- respiratory mediated increases in cardiac parasympathetic activity. Thirty-nine subjects were asked to increase their vagal tone using biofeedback, paced breathing, biofeedback plus paced breathing, or quiet sitting. The cold pressor test was used to examine the relative efficacy of vagal tone increase to mitigate cardiovascular reactivity. Repeated measures ANOVAs and t-tests revealed significant increases in vagal tone for the paced breathing, and biofeedback plus paced breathing groups, relative to controls. However, the quality of these increases could not be tested using the cold pressor test because the test failed to produce homogeneous cardiac reactivity.

Parasympathetic Response Patterns are Associated with Metabolic Syndrome Among Older Women but Not Men

Background

Little is known about the role of physiological stress responses in metabolic syndrome (MetS).

Purpose

To examine whether patterns of autonomic response to psychological stress are associated with MetS and whether this association is moderated by sex

Methods

1121 men and women (M_age = 65.3 ± 6.77 years) with and without coronary artery disease (CAD) underwent an anger recall stressor task. Heart rate and heart-rate variability (HRV; HF, LF/HF) were assessed. Clusters of participants showing similar patterns of response across baseline, stress, and recovery periods were created using ACECLUS and FASTCLUS in SAS. Logistic regressions included clusters and interaction between clusters and sex as independent variables, controlling for relevant covariates. ANCOVAs were conducted in secondary analyses utilizing a continuous composite representation of MetS.

Results

Men and women showing greater tonic and phasic HR elevations were more likely to meet MetS criteria (OR = 1.45, [95% CI = 1.02–2.07], p = .037). HF-HRV cluster interacted significantly with sex (p < .001) to predict MetS. In women, those with significant parasympathetic withdrawal to stress and poor recovery were more likely to have MetS than women with a more moderate response (OR = 2.56, [95% CI = 1.23–5.41], p = .013). Women who displayed stress-related parasympathetic activation were also at greater risk of MetS (OR = 2.30, [95% CI = 1.30–4.07], p = .004). Results using a continuous measure of MetS were generally consistent with these findings.

Conclusion

Among older participants with CAD or other noncardiovascular disease, hyperreactivity to stress was associated with greater prevalence of MetS, particularly in women. Consistent with emerging literature, women who showed blunting or activation of parasympathetic responses to stress were similarly at greater risk.

The Association Between Pregnancy-Specific Anxiety and Exclusive Breastfeeding Status Early in the Postpartum Period

BACKGROUND

Exclusive breastfeeding is recommended for the first 6 months of life and has significant benefits for both mother and child. Pregnancy-specific anxiety is a distinct and definable syndrome that has been identified as a robust predictor of pregnancy outcomes, but whether it is associated with exclusive breastfeeding status has not been determined.

RESEARCH AIMS

To examine the association between pregnancy-specific anxiety in each trimester of pregnancy and exclusive breastfeeding status early in the postpartum period.

METHODS

Data were available from 412 women who participated in a longitudinal pregnancy cohort study. Pregnancy-specific anxiety and exclusive breastfeeding status were assessed using an online self-report questionnaire.

RESULTS

Logistic regression analyses showed that a one-unit increase in pregnancy-specific anxiety in the first (OR = 0.94, 95% CI [0.90, 0.98]) and third (OR = 0.95, 95% CI [0.91, 0.99]) trimester of pregnancy was associated with a 5-6% decrease in the odds of exclusive breastfeeding at 6-8 weeks postpartum.

CONCLUSIONS

Pregnancy-specific anxiety was associated with lower odds of exclusive breastfeeding at 6-8 weeks postpartum. Prenatal interventions designed to increase exclusive breastfeeding duration may benefit from the incorporation of strategies that help reduce worries and concerns unique to the pregnancy experience.

Expectancies mediate the relationship between perceived injustice and return to work following whiplash injury: A 1-year prospective study

BACKGROUND

Emerging evidence suggests that perceived injustice is a risk factor for work disability in individuals with whiplash injury. At present, however, little is known about the processes by which perceived injustice impacts on return to work. The purpose of this study was to examine whether expectancies mediated the relationship between perceived injustice and return to work in patients with whiplash injury.

METHOD

One hundred and fifty-two individuals (81 men, 71 women) with a primary diagnosis of whiplash injury completed self-report measures of pain intensity, perceived injustice and return-to-work expectancies following admission to a rehabilitation programme. Work status was assessed 1 year after discharge.

RESULTS

Consistent with previous research, high scores on a measure of perceived injustice were associated with prolonged work disability. Results indicated that high perceptions of injustice were associated with low return-to-work expectancies. Causal mediation analyses revealed that expectancies fully mediated the relationship between perceived injustice and return to work.

CONCLUSION

The findings suggest that intervention techniques designed to target expectancies could improve return-to-work outcomes in patients with whiplash injury. Discussion addresses the processes by which expectancies might impact on return-to-work outcomes and the manner in which negative return-to-work expectancies might be modified through intervention.

SIGNIFICANCE

The study confirms that expectancies are the mechanism through which perceived injustice impacts return to work following whiplash injury. The findings suggest that interventions designed to specifically target return-to-work expectancies might improve rehabilitation outcomes in patients with whiplash injury.

Respiratory and hemodynamic contributions to emotion-related pre-syncopal vasovagal symptoms

Vasovagal reactions are conventionally understood as resulting from systemic changes in cardiovascular activity; however, there exists a complementary perspective focused on specific changes in cerebral vasoconstriction associated with hyperventilation-induced hypocapnia. The present study investigated the role of cardiovascular and respiratory activity in self-reported pre-syncopal vasovagal reactions to a surgery video in a sample of 49 healthy women. Participants who indicated more previous real-life episodes of dizziness reported experiencing significantly more symptoms in the laboratory consistent with a vasovagal response. They also showed lower total peripheral resistance and higher pre-ejection period in general, suggesting lower sympathetic nervous system activity. Significant decreases in end-tidal carbon dioxide (P_ETCO₂) occurred during the surgery video among susceptible participants, without significant increases in respiration rate. Further, participants who experienced reductions from the neutral video in P_ETCO₂, systolic blood pressure, or both, reported vasovagal symptoms during the surgery video. The results suggest that patterns of respiration associated with decreases in P_ETCO₂ may contribute to vasovagal symptoms reported in non-clinical groups as well as those with blood-injection-injury phobia and are associated with susceptibility to dizziness.

Attitudes and Attributions Related to Psychological Symptomatology in Indian Immigrant Women

This study explored the patterns of attitudes and attributions associated with relatively high and low distress among a sample of (N = 104) immigrant women from India living in Montreal. Results showed the high distress group to be less satisfied with their roles in the home and in the job market, to be more in favor of modem sex roles, to want less to pass on traditional sex roles to their children, to attribute success and failure more to their own personal characteristics and less to destiny, and to perceive more racial discrimination in society. The findings underline the value of differentiating between aspects of immigration and incorporating social psychological variables in studies of possible links between immigration and distress.

The vasovagal response during confrontation with blood-injury-injection stimuli: the role of perceived control

The vasovagal response (VVR) is a common medical problem, complicating and deterring people from various procedures. It is an unusual stress response given the widespread decreases in physiological activity. Nevertheless, VVR involves processes similar to those observed during episodes of strong emotions and pain. We hypothesized that heightened perceived control would reduce symptoms of VVR. Eighty-two young adults were randomly assigned to perceived control or no perceived control conditions during exposure to a stimulus video of a mitral valve surgery, known to trigger VVR in non-medical personnel. Perceived control was manipulated by allowing some participants to specify a break time, though all received equivalent breaks. Outcomes included subjective symptoms of VVR, anxiety, blood pressure, heart rate, and other measures derived from impedance cardiography. Compared to participants with perceived control, participants with no perceived control reported significantly more vasovagal symptoms and anxiety, and experienced lower stroke volume, cardiac output, and diastolic blood pressure. Participants who were more fearful of blood were more likely to benefit from perceived control in several measures. Perceived control appears to reduce vasovagal symptoms. Results are discussed in terms of cognition and emotion in VVR.

The interaction between anxiety and depressive symptoms on brachial artery reactivity in cardiac patients

The association between anxiety, depression, and endothelial function (EF) was assessed in a sample of 295 cardiac outpatients (n=222 men; mean age=59). Patients were administered the Beck Depression Inventory-II and the State-Trait Anxiety Inventory, trait scale. EF was assessed through forearm hyperemic reactivity, a nuclear medicine variation of the flow-mediated dilatation technique, which calculates the rate of uptake ratio (RUR) between hyperaemic and non-hyperaemic arms. Neither effect of anxiety (F=1.40, p=.24) nor depression (F=2.66, p=.10) was found in a model predicting EF, however there was an interaction (F=4.11, p=.04). Higher anxiety and lower depressive symptoms were associated with superior RUR compared to lower anxiety and lower depressive symptoms. Anxiety had no influence on RUR in those patients with higher depressive symptoms, who generally displayed the lowest levels of RUR, i.e., poor function. It is speculative whether this potential protective role of anxiety may be guided by behavioral or physiological mechanisms.

Donor anxiety, needle pain, and syncopal reactions combine to determine retention: a path analysis of two-year donor return data

BACKGROUND

Efforts to expand the donor pool by recruiting younger donors have resulted in higher numbers of initial donations, but retention of young donors continues to be challenging.

STUDY DESIGN AND METHODS

Path analysis was used to examine the simultaneous relationships among syncopal reactions, donation anxiety, needle pain, donor satisfaction, and donation intention in predicting repeat donation. Participants included 421 first- and second-time donors recruited for a study comparing the effects of predonation water loading with and without the use of applied muscle tension during donation (52% female, 60.8% first-time donor, mean age 20.3 years). For this longitudinal follow-up study, donor database records were accessed 2 years after the index donation to assess repeat donation.

RESULTS

Results of a series of path analyses demonstrated the influential role of donor anxiety in shaping donor retention (final model χ(2) = 35.75, root mean square error of approximation 0.03, comparative fit index 0.98, weighted root mean square residual 0.74). First, anxiety exerted a direct negative influence on donation intention, the proximal and sole direct predictor of repeat donation. Second, anxiety increased the likelihood of donor-reported needle pain, adversely affecting donation satisfaction and, subsequently, donation intention. Finally, anxiety was associated with donor ratings of syncopal reactions through its impact on needle pain, which also contributed to decreased donation intention.

CONCLUSION

These results provide novel evidence that donation anxiety plays a central role in shaping future donation behavior. Individual differences in anxiety must be considered when developing and testing strategies to enhance blood donor retention.

Cognitive depressive symptoms associated with delayed heart rate recovery following interpersonal stress in healthy men and women

Among cardiac patients, research suggests that somatic depressive symptoms are more strongly associated with altered cardiovascular responses to stress than cognitive depressive symptoms. This study sought to determine whether this was also the case in healthy individuals. One hundred and ninety-nine adults from the community completed the Beck Depression Inventory II (BDI-II) and underwent psychological laboratory stressors while their blood pressure, heart rate, and heart rate variability were monitored. A cognitive-affective factor and somatic-affective factor were identified within the BDI-II, but only the cognitive factor was associated with reduced heart rate recovery following the stressors in multivariate analyses examining both factors simultaneously. This suggests that cognitive depressive symptoms may be more strongly related to altered stress physiology following psychological stressors.

The effects of blood-draw and injection stimuli on the vasovagal response

Vasovagal reactions (VVR) are common, complicating and deterring people from various medical procedures. A recent perspective (R. R. Diehl, ) suggests that VVR developed from the adaptive process of hemorrhagic fainting, perhaps as a means of preparing for anticipated blood loss. The primary goal of this study was to compare vasovagal symptoms during intravenous-injection and blood-draw videos. Sixty-two young adults watched the videos. Vasovagal symptoms were assessed with self-report, blood pressure, and heart rate variability. As predicted, participants reported more vasovagal symptoms and anxiety following the blood-draw video. Sympathetic nervous system activity (low- to high-frequency ratio) decreased during both videos but significantly more during the blood-draw video, although this could be reversed by the Applied Tension technique. Results are discussed in terms of the relevance of specific stimuli and emotions in VVR.