Effect of Prenatal Yoga versus Moderate-Intensity Walking on Cardiorespiratory Adaptation to Acute Psychological Stress: Insights from Non-Invasive Beat-to-Beat Monitoring.

We recently reported enhanced parasympathetic activation at rest throughout pregnancy associated with regular yoga practice. The present study presents a secondary analysis of data collected within a prospective cohort study of 33 pregnant women practicing yoga once weekly throughout pregnancy and 36 controls not involved in formal pregnancy exercise programs. The objective was to assess the impact of prenatal yoga on the autonomic nervous system stress response. Healthy pregnant women with singleton pregnancies were recruited in the first trimester. There was no significant difference in the maternal body mass index (BMI) between the yoga group and the controls (24.06 ± 3.55 vs. 23.74 ± 3.43 kg/m2, p = 0.693). Women practicing yoga were older (28.6 ± 3.9 vs. 31.3 ± 3.5 years, p = 0.005) and more often nulliparous (26 (79%) vs. 18 (50%), p = 0.001). We studied heart rate variability (HRV) parameters in the time domain (SDNN, standard deviation of regular R-R intervals, and RMSSD, square root of mean squared differences of successive R-R intervals) and frequency domain (ln(LF/HF), natural logarithm of low-frequency to high-frequency power), as well as synchronization indices of heart rate, blood pressure and respiration during and immediately following acute psychological stress of a standardized mental challenge test. Measurements were performed once per trimester before and after yoga or a 30 min moderate-intensity walk. Statistical comparison was performed using three-way analyses of variance (p < 0.05 significant). Time domain HRV parameters during and following mental challenge in the yoga group were significantly higher compared to the controls regardless of the trimester (F = 7.22, p = 0.009 for SDNN and F = 9.57, p = 0.003 for RMSSD, respectively). We observed no significant differences in the yoga group vs. the controls in terms of ln(LF/HF) and synchronization indices. Regular prenatal yoga practice was associated with a significantly reduced sympathetic response to mental challenge and quicker recovery after acute psychological stress. These effects persisted throughout pregnancy with regular practice.

Disturbed Cardiorespiratory Adaptation in Preeclampsia: Return to Normal Stress Regulation Shortly after Delivery?

Women with pregnancies complicated by preeclampsia appear to be at increased risk of metabolic and vascular diseases in later life. Previous research has also indicated disturbed cardiorespiratory adaptation during pregnancy. The aim of this study was to follow up on the physiological stress response in preeclampsia several weeks postpartum. A standardized laboratory test was used to illustrate potential deviations in the physiological stress responding to mildly stressful events of the kind and intensity in which they regularly occur in further everyday life after pregnancy. Fifteen to seventeen weeks postpartum, 35 women previously affected by preeclampsia (19 mild, 16 severe preeclampsia), 38 women after uncomplicated pregnancies, and 51 age-matched healthy controls were exposed to a self-relevant stressor in a standardized stress-reactivity protocol. Reactivity of blood pressure, heart rate, stroke index, and systemic vascular resistance index as well as baroreceptor sensitivity were analyzed. In addition, the mutual adjustment of blood pressure, heart rate, and respiration, partitioned for influences of the sympathetic and the parasympathetic branches of the autonomic nervous system, were quantified by determining their phase synchronization. Findings indicated moderately elevated blood pressure levels in the nonpathological range, reduced stroke volume, and elevated systemic vascular resistance in women previously affected by preeclampsia. Despite these moderate abnormalities, at the time of testing, women with previous preeclampsia did not differ from the other groups in their physiological response patterns to acute stress. Furthermore, no differences between early, preterm, and term preeclampsia or mild and severe preeclampsia were observed at the time of testing. The findings suggest that the overall cardiovascular responses to moderate stressors return to normal in women who experience a pregnancy with preeclampsia a few weeks after delivery, while the operating point of the arterial baroreflex is readjusted to a higher pressure. Yet, their regulation mechanisms may remain different.

Effect of Prenatal Yoga on Heart Rate Variability and Cardio-Respiratory Synchronization: A Prospective Cohort Study.

The objective was to assess the effects of prenatal yoga on heart rate variability (HRV) and cardio-respiratory synchronization, used as proxies of autonomic nervous system activity. Sixty-nine healthy pregnant women were included; 33 in a yoga group attending at least one 90-min yoga class weekly throughout pregnancy, and 36 controls not involved in formal pregnancy exercise programs. Measurements of the time domain (SDNN, standard deviation of regular R-R intervals, and RMSSD, square root of mean squared differences of successive R-R intervals) and frequency domain (ln(LF/HF), natural logarithm of low-frequency to high-frequency power) HRV indices, as well as cardio-respiratory synchronization indexes were performed once per trimester before and after yoga or 30-min moderate-intensity walk. A statistical comparison was performed using a three-way analysis of the variance (p < 0.05 significant). Both the time domain and frequency domain HRV indices showed significant shifts towards parasympathetic dominance following yoga when compared to the controls throughout pregnancy (p = 0.002 for SDNN, p < 0.001 for RMSSD, and p = 0.006 for ln(LF/HF), respectively). There was a statistically non-significant trend towards higher synchronization between respiratory frequency and heart rate following yoga vs. controls (p = 0.057). Regular prenatal yoga was associated with enhanced parasympathetic activation persisting throughout pregnancy.

Unaffected Memory and Inhibitory Functioning Several Weeks Postpartum in Women with Pregnancy Complicated by Preeclampsia.

Several studies reported impaired cognitive functioning after pregnancy complicated by preeclampsia. The present study examined cognitive and executive functioning in women with preeclampsia at a time at which immediate effects of gestation have resolved, brain damage due to other risk factors have not yet manifested, and impairments may thus primarily occur as a result of the huge stress induced by the potentially life threatening condition. Verbal learning/memory (California Verbal Learning Test) and inhibitory functioning (Mittenecker Pointing Test) of 35 women with preeclampsia and 38 women with uncomplicated pregnancy were followed over five measurement time points during the period from 16 to 48 weeks postpartum. A further control group comprised 40 women with no history of recent pregnancy. The groups did not differ in their verbal learning/memory performance. Higher levels of currently experienced everyday-life stress were associated with poorer inhibitory control/greater stereotypy in responding, but this effect was not directly connected with pregnancy complications. Taken together, the findings do not indicate rapid-onset cognitive impairment after preeclampsia, brought about by its extremely stressful nature or other factors that take effect during gestation. Deficits observed in later life may develop on a long-term basis through late-diagnosed hypertension and unfavorable lifestyle factors. The large time window in which exaggerated cognitive decline can be prevented or mitigated should be utilized for the control of risk factors and interventions to improve lifestyle where appropriate.

Differences in Hemodynamic, Hormonal and Heart Rate Variability Parameters in Complication-Free Pregnancies Compared to Individuals with Gestational Diabetes Mellitus and Preeclampsia: An Observational Retrospective Analysis.

To investigate differences in hemodynamic, hormonal and heart rate variability parameters in women following complication-free pregnancies (healthy), preeclampsia and gestational diabetes mellitus (GDM) after giving childbirth. Data of 60 women (healthy: n = 29, age 32.7 ± 4.5 years, BMI 24.2 ± 4.3 kg/m2; preeclampsia: n = 16, age 35.3 ± 4.4 years, 28.5 ± 6.4 kg/m2; GDM, n = 15, age 32.3 ± 6.0 years, BMI 26.4 ± 6.2 kg/m2) were included. Two visits were conducted 16 and 48 weeks after giving childbirth. Hair samples were taken for analysis of cortisol and testosterone. ECG and blood pressure were recorded at each visit. Data were analyzed via RM-ANOVA and post-hoc testing (p ≤ 0.05). Heart rate increased from visit 1 to visit 2, whereas SDNN decreased (both p = 0.03). RMSSD showed an increased trend for groups (p = 0.06). Testosterone in the GDM group was significantly higher compared to the other groups (p = 0.002). Cortisol levels were significantly higher following post-hoc testing GDM was different compared to healthy individuals (p = 0.02). Hemodynamic changes from week 16 to week 48 did not differ between groups (p > 0.05). No differences between individuals with preeclampsia and healthy individuals were found for all hemodynamic parameters (p > 0.05). The study showed higher levels of chronic stress indicators in GDM measured via heart rate variability and cortisol compared to women with a history of preeclampsia and healthy women.

An automated method for the determination of the sFlt-1/PIGF ratio in the assessment of preeclampsia.

OBJECTIVE: The angiogenic and antiangiogenic factors soluble fms-like tyrosine kinase (sFlt)-1 and placental growth factor (PIGF) have been implicated in the mechanisms of disease responsible for preeclampsia (PE). Moreover, it has been proposed that the concentrations of these markers in maternal serum/plasma may have predictive value. This study evaluates a newly developed Elecsys (Roche, Penzberg, Germany) assay for sFlt-1 and PIGF and tests the value of the sFlt-1/PIGF ratio in the assessment of PE. STUDY DESIGN: This multicenter case-control study included 351 patients: 71 patients with PE and 280 gestational age-matched control subjects from 5 European study centers. A total of 595 serum samples were measured for sFlt-1 and PIGF using an automated platform. RESULTS: Maternal serum concentrations of sFlt-1 and PIGF significantly separated healthy women and women with PE. The sFlt-1/PIGF ratio had an area under the receiver operating characteristic curve of 0.95. The best performance was obtained in the identification of early-onset PE (area under the receiver operating characteristic curve of 0.97). CONCLUSION: Measurement of sFlt-1 and PIGF and calculation of sFlt-1/PIGF ratio can be performed quickly and in a platform available in clinical laboratories. This is a substantial step forward in bringing the determination of these analytes to clinical practice in obstetrics. We propose that sFlt-1, PIGF, and sFlt-1/PIGF ratio may be of value in the prediction of PE and in the differential diagnosis of patients with atypical presentations of PE, and perhaps in the differential diagnosis of women with chronic hypertension suspected to develop superimposed PE.

History of Preeclampsia Adds to the Deleterious Effect of Chronic Stress on the Cardiac Ability to Flexibly Adapt to Challenge.

Preeclampsia, a pregnancy-specific disorder, presents a major health problem during gestation, but is also associated with increased risk for cardiovascular complications in later life. We aimed to investigate whether chronic stress experience and preeclampsia may have additive adverse effects on the cardiac ability to flexibly adapt to challenge, that is, to mount an appropriately vigorous heart rate response to an acute psychological challenge, or whether they may perhaps have synergistic effects (e.g., mutual augmentation of effects). Blunted cardiac responding to challenge has been linked to poor health outcomes in the longer term. Women previously affected by preeclampsia and women after uncomplicated pregnancies were tested 15-17 weeks post-partum in a standardized stress-reactivity protocol, while cardiovascular variables were simultaneously recorded. Changes in heart rate and blood pressure in response to the stressor were analyzed with regard to the effects of history of preeclampsia and chronic stress experience. Findings indicated blunted cardiac responses in women with higher chronic stress experience (p = 0.020) and, independently from that, in women with a history of preeclampsia (p = 0.018), pointing to an additive nature of the effects of preeclampsia and chronic stress on impaired cardiovascular functioning. Consequently, if both are present, a history of preeclampsia may add to the already deleterious effects of the experience of chronic stress. The additive nature of the effects suggests that stress-reducing interventions, albeit they will not eliminate the heightened cardiovascular risk in patients with a history of preeclampsia, may improve their overall prognosis by avoiding further accumulation of risk.

Hemodynamic evaluation in pregnancy: limitations of impedance cardiography.

Impedance cardiography (ICG) has been proposed to estimate the stroke volume (SV) and cardiac output (CO) in various medical indications. The aim of this study was to explore the reliability of ICG during pregnancy with respect to SV and CO measurements. Blood pressure, heart rate and thoracic impedance were monitored during the course of pregnancy and related ICG patterns analyzed. We determined thoracic impedance (Z(0)), left ventricular ejection time (LVET) and the maximum value of the first derivative of the impedance waveform (dZ/dt)(max) beat-to-beat. The two main components of non-invasive SV estimation, LVET and (dZ/dt)(max), decreased in week 35 relative to week 12 by 7.6% ± 4.8% and by 36.0% ± 14.0%, respectively, based on a decrease in R-R interval of 9.9% ± 9.7%, whereas changes in Z(0) did not play a significant role. Furthermore, the decrease of (dZ/dt)(max) was greater in the third compared to the second trimester of pregnancy. Taking into account an 18.2% ± 6.8% body weight increase, the calculated SV decreased in week 35 relative to week 12 by 19.2% ± 14.3%. The normalized term ((dZ/dt)(max))/Z(0) explained 85-94% of the variance of SV change after week 20. These results were confirmed for fixed R-R interval at a constant value across the repeated measurements. Based on beat-to-beat analysis of the main components of non-invasive SV estimation by ICG, measured repeatedly throughout normal pregnancy, we conclude that SV calculations render invalid data. Our findings strongly suggest that CO cannot be reliably assessed with ICG in pregnant women.

Changes in haemodynamic and autonomous nervous system parameters measured non-invasively throughout normal pregnancy.

OBJECTIVE: To examine non-invasively haemodynamic and autonomous parameters throughout normal pregnancy. STUDY DESIGN: We used the Task Force Monitor 3040i system to retrieve, record, and calculate haemodynamic as well as autonomous parameters. 20 healthy women were included and scheduled for longitudinal examinations throughout normal pregnancy. Heart rate (HR), blood pressure (BP), stroke volume (SV), cardiac output (CO), systemic vascular resistance (SVR), heart rate variability (HRV), blood pressure variability (BPV), and baroreceptor sensitivity (BRS) were measured. Measurements were performed at gestational week 10(+0)-13(+6), 15(+0)-18(+6), 20(+0)-22(+6), and >30(+0). RESULTS: HR increased during gestation showing a significant increase at III versus I trimester (74 bpm vs. 88 bpm, P<.05). Mean arterial pressure remained stable until III trimester, when a significant increase compared to I trimester could be noted (78 mm Hg vs. 86 mm Hg, P<.05). SV and CO remained relatively stable in I and II trimester, and in III trimester significant decreases were observed. In contrast, SVR increased significantly at III trimester (P<.001). Whereas HRV and BPV did not change at different gestational ages, BRS was significantly lower in III trimester compared to I trimester values (P<.05). CONCLUSION: The non-invasive determination of cardiovascular and autonomous parameters throughout pregnancy is possible and the results of this pilot study can serve as basic parameters for classifying and assessing cardiovascular and autonomous changes in pathological conditions in pregnancy such as hypertensive disorders.