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.

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.

Prevalence of iron deficiency in pregnant women: A prospective cross-sectional Austrian study.

The aim of the study was to determine, for the first time, in a prospective cross-sectional multicenter study, the prevalence of iron deficiency (ID) in an Austrian pregnant population. A cohort of 425 pregnant women was classified into four groups of different weeks of gestation. Group 1 was monitored longitudinally, while groups 2-4, iron status, were sampled only once. Evaluation of the prevalence of ID was performed by comparing the diagnostic criteria of the WHO to the cutoff proposed by Achebe MM and Gafter-Gvili A (Achebe) and the Austrian Nutrition Report (ANR). In comparison with the ANR, the prevalence of ID was lower in group 1 and higher in groups 2-4 (17.2% vs. 12.17%, 25.84%, 35.29%, and 41.76%, respectively) (p-values < .01 except group 1). According to WHO, the prevalence in group 1 was 12.17% at inclusion, 2 months later 31.7%, and further 2 months later 65.71%, respectively. According to Achebe, the number of cases doubled; for group 1, the number of cases rose from 13 to 42 (115 patients total); for groups 2-4, we observed an increase from 112 to 230 (340 patients total). This study reported a prevalence of around 12% at the beginning of pregnancy, which increased during pregnancy up to 65%. ID can have a massive impact on quality of life, justifying screening, as iron deficiency would be easy to diagnose and treat.

Treatment of preeclampsia at extremely preterm gestation with therapeutic plasma exchange.

AIMS: Different forms of apheresis have been proposed as potential therapeutic approaches to remove soluble Fms-like tyrosine kinase-1 (sFlt-1) and allow safe pregnancy prolongation in cases of extremely preterm preeclampsia. This is a follow-up study presenting our experiences with therapeutic plasma exchange (TPE) in 5 women with preeclampsia at < 28 weeks of gestational age. MATERIALS AND METHODS: All women received standard treatment for preeclampsia and 2 - 3 TPE treatments per week. Blood samples for sFlt-1 and placental growth factor (PlGF) measurements were collected before and after each TPE. RESULTS: Seventeen TPE procedures were performed, 2 - 5 per patient. TPE significantly reduced sFlt-1 (by 35 ± 6%), sFlt-1/PlGF ratio (by 24 ± 13%), and to a lesser degree also PlGF (by 12 ± 16%), with a rebound observed on day 1 post procedure. TPE procedures were well tolerated by pregnant women and fetuses. Stabilization of sFlt-1 allowed pregnancy prolongation for a median of 8 (range 2 - 14) days from first TPE and for a median of 10 (range 4 - 17) days from hospital admission. There were no signs of increased risks of adverse neonatal outcome associated with TPE. One neonate died due to extreme prematurity 3 days after delivery, 2 had bronchopulmonary dysplasia, and 1 had retinopathy of prematurity. CONCLUSION: This study provides new evidence of effective reduction in sFlt-1 and sFlt-1/PlGF ratio with TPE treatment, which seems to allow a clinically meaningful prolongation of pregnancy. Controlled studies are necessary to convincingly show the potential benefit of apheresis treatment in preeclampsia at extremely preterm gestation.

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.

Therapeutic plasma exchange and dextran-sulfate plasma adsorption as extracorporeal treatments of extremely preterm preeclampsia with fetal growth restriction.

AIM: To evaluate effectiveness and safety of therapeutic plasma exchange (TPE) and dextran-sulfate plasma adsorption (DSA) for extracorporeal removal of soluble Fms-like tyrosine kinase-1 (sFlt-1) as part of expectant management of preeclampsia at extremely preterm gestational age. METHODS: Retrospective case series of six patients with preeclampsia at <28 weeks of gestation, treated with DSA or TPE. Laboratory results, clinical characteristics and neonatal outcomes were collected from charts and National Perinatal Information System. RESULTS: Fetal growth restriction (FGR) was diagnosed in all cases. Pregnancy was prolonged for a median of 14 (range 5-74) days from admission and 10 (3-73) days from first apheresis. A mixed effects model showed a decrease in sFlt-1 and sFlt-1/PlGF ratio during DSA/TPE (significant effect of time [before/after]), which was comparable between DSA and TPE (no effect of procedure type). Median absolute reduction in sFlt-1 was 42% (inter-quartile range [IQR] 13%-57%) during DSA and 34% (16%-40%) during TPE; for sFlt-1/PlGF ratio it was 29% (22%-36%) and 38% (29%-42%), respectively. All procedures were well tolerated by fetuses. Anaphylactoid reaction, often with angioedema, occurred in 4/6 patients undergoing DSA and was attributed to bradykinin activation. One patient developed wound hematoma after cesarean section, possibly attributed to depletion coagulopathy. CONCLUSIONS: As potential novel treatment of early preeclampsia, a non-selective and widely available TPE was comparable to DSA regarding sFlt-1 reduction but was associated with fewer side-effects. Both seem to allow maternal stabilization and pregnancy prolongation even when early preeclampsia is complicated by FGR.

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.

Preeclampsia before fetal viability in women with primary antiphospholipid syndrome- materno-fetal outcomes in a series of 7 cases.

INTRODUCTION: Preeclampsia complicates about 10-17 % of pregnancies with antiphospholipid syndrome (APS). It is often severe and might occur sometimes at early gestation. The development of preeclampsia before fetal viability is a huge challenge for obstetricians and demands an intensive discussion regarding the therapeutical options. PATIENTS AND METHODS: We retrospectively reviewed the data of 7 women with primary APS who developed preeclampsia before 24 weeks of gestation. Plasma exchange had been performed in four of the cases and two women received corticosteroids. One of the women had received 20 mg of pravastatin daily, starting at 18 weeks of gestation. Neonatal outcome was: live birth in four cases and IUFD in three cases. The main pediatric complications were noted in a 28-week-old premature born boy, who developed severe IRDS and thrombocytopenia. At the present time, the boy continues to have a retarded status. DISCUSSION: This retrospective analysis revealed that women with APS can develop severe preeclampsia even before 20 weeks of gestation. Several management options for prolongation of pregnancy such as plasma exchange, pravastatin, LMHW, hydroxychloroquine/HCQ, or TNF-alpha blocker should be discussed with the patients. Optimal management of preeclampsia before 24 weeks of gestation usually depends on weighing the maternal and fetal complications from expectant management with prolongation of pregnancy versus the predominant fetal and neonatal risks of extreme prematurity from "aggressive" management with immediate delivery.

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.

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.

Maternal cardiovascular and endothelial function from first trimester to postpartum.

OBJECTIVE: To explore noninvasively the complex interactions of the maternal hemodynamic system throughout pregnancy and the resulting after-effect six weeks postpartum. METHODS: Eighteen women were tested beginning at the 12th week of gestation at six time-points throughout pregnancy and six weeks postpartum. Heart rate, heart rate variability, blood pressure, pulse transit time (PTT), respiration, and baroreceptor sensitivity were analyzed in resting conditions. Additionally, hemoglobin, asymmetric and symmetric dimethylarginine and Endothelin (ET-1) were obtained. RESULTS: Heart rate and sympathovagal balance favoring sympathetic drive increased, the vagal tone and the baroreflex sensitivity decreased during pregnancy. Relative sympathetic drive (sympathovagal balance) reached a maximum at 6 weeks postpartum whereas the other variables did not differ compared to first trimester levels. Postpartum diastolic blood pressure was higher compared to first and second trimester. Pulse transit time and endothelial markers showed no difference throughout gestation. However, opposing variables PTT and asymmetric dimethylarginine (ADMA) were both higher six weeks postpartum. CONCLUSIONS: The sympathetic up regulation throughout pregnancy goes hand in hand with a decreased baroreflex sensitivity. In the postpartum period, the autonomic nervous system, biochemical endothelial reactions and PTT show significant and opposing changes compared to pregnancy findings, indicating the complex aftermath of the increase of blood volume, the changes in perfusion strategies and blood pressure regulation that occur in pregnancy.

Heart rate variability and baroreceptor reflex sensitivity in early- versus late-onset preeclampsia.

OBJECTIVE: To determine whether there are differences in autonomic nervous system function in early- versus late-onset preeclampsia. METHODS: Matched case-control study. Cases were defined as singleton pregnancies with preeclampsia at < 34+0 weeks of gestation (early-onset preeclampsia) and ≥ 34+0 weeks of gestation (late-onset preeclampsia). For each case in each of the preeclampsia subgroups, three "control"uncomplicated singleton pregnancies were matched by maternal age, height, and week of gestation. Blood pressure and heart rate were measured continuously for 30 minutes in each participant. Baroreceptor reflex sensitivity (assessed using sequence technique), time and frequency domain heart rate variability measures, as SDNN, RMSSD, LFRRI, HFRRI and LF/HFRRI of R-R intervals, were compared between groups (p<0.05 significant). RESULTS: 24 women with preeclampsia (10 with early-onset and 14 with late-onset preeclampsia) and 72 controls were included in the study. SDNN, RMSSD and HFRRI were significantly higher in the late-onset preeclampsia group compared to gestational age matched controls (p = 0.033, p = 0.002 and p = 0.018, respectively). No significant differences in SDNN RMSSD and HFRRI between early-onset preeclampsia group and gestational age matched controls were observed (p = 0.304, p = 0.325 and p = 0.824, respectively). Similarly, baroreceptor reflex sensitivity was higher in late-onset preeclampsia compared to controls at ≥ 34 weeks (p = 0.037), but not different between early-onset preeclampsia compared to controls at < 34 weeks (p = 0.50). CONCLUSIONS: Heart rate variability and baroreceptor reflex sensitivity are increased in late- but not early-onset preeclampsia compared to healthy pregnancies. This indicates a better autonomic nervous system mediated adaptation to preeclampsia related cardiovascular changes in late-onset disease.

Systemic vascular resistance and endogenous inhibitors of nitric oxide synthesis in early- compared to late-onset preeclampsia: preliminary findings.

OBJECTIVE: To examine systemic vascular resistance index (SVRI), asymmetric (ADMA) and symmetric dimethylarginine (SDMA) levels in preeclampsia at different gestations. METHODS: Twenty-four preeclamptic patients (14 at ≥ 34 weeks') and 72 matched healthy controls were included. SVRI was calculated from impedance cardiography measurements. ADMA and SDMA levels were determined using enzyme-linked immunosorbent assay. RESULTS: SVRI and SDMA were higher in preeclampsia overall, in early onset and late onset compared to controls. SVRI was correlated with ADMA and SDMA, respectively. CONCLUSIONS: Early-onset and late-onset preeclampsia are both characterized by increased systemic vascular resistance and elevated levels of nitric oxide synthesis inhibitors.

Extending the scope of pooled analyses of individual patient biomarker data from heterogeneous laboratory platforms and cohorts using merging algorithms.

BACKGROUND: A common challenge in medicine, exemplified in the analysis of biomarker data, is that large studies are needed for sufficient statistical power. Often, this may only be achievable by aggregating multiple cohorts. However, different studies may use disparate platforms for laboratory analysis, which can hinder merging. METHODS: Using circulating placental growth factor (PlGF), a potential biomarker for hypertensive disorders of pregnancy (HDP) such as preeclampsia, as an example, we investigated how such issues can be overcome by inter-platform standardization and merging algorithms. We studied 16,462 pregnancies from 22 study cohorts. PlGF measurements (gestational age ⩾20 weeks) analyzed on one of four platforms: R&D Systems, AlereTriage, RocheElecsys or AbbottArchitect, were available for 13,429 women. Two merging algorithms, using Z-Score and Multiple of Median transformations, were applied. RESULTS: Best reference curves (BRC), based on merged, transformed PlGF measurements in uncomplicated pregnancy across six gestational age groups, were estimated. Identification of HDP by these PlGF-BRCs was compared to that of platform-specific curves. CONCLUSIONS: We demonstrate the feasibility of merging PlGF concentrations from different analytical platforms. Overall BRC identification of HDP performed at least as well as platform-specific curves. Our method can be extended to any set of biomarkers obtained from different laboratory platforms in any field. Merged biomarker data from multiple studies will improve statistical power and enlarge our understanding of the pathophysiology and management of medical syndromes.

Phase synchronization of hemodynamic variables at rest and after deep breathing measured during the course of pregnancy.

BACKGROUND: The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations. METHODOLOGY: Continuous monitoring of heart rate (R-R interval; derived from the 3-lead electrocardiography), blood pressure, and thoracic impedance was carried out in thirty-six women at six time-points throughout pregnancy. In order to quantify in addition to the longitudinal effects on baseline levels throughout gestation the immediate adaptive heart rate and blood pressure changes at each time point, a simple reflex test, deep breathing, was applied. Consequently, heart rate variability and blood pressure variability in the low (LF) and high (HF) frequency range, respiration and baroreceptor sensitivity were analyzed in resting conditions and after deep breathing. The adjustment of the rhythms of the R-R interval, blood pressure and respiration partitioned for the sympathetic and the parasympathetic branch of the autonomic nervous system were quantified by the phase synchronization index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators. RESULTS: Heart rate and LF/HF ratio increased throughout pregnancy and these effects were accompanied by a continuous loss of baroreceptor sensitivity. The increases in heart rate and LF/HF ratio levels were associated with an increasing decline in the ability to flexibly respond to additional demands (i.e., diminished adaptive responses to deep breathing). The phase synchronization index γ showed that the observed effects could be explained by a decreased coupling of respiration and the cardiovascular system (HF components of heart rate and blood pressure). CONCLUSIONS/SIGNIFICANCE: The findings suggest that during the course of pregnancy the individual systems become increasingly independent to meet the increasing demands placed on the maternal cardiovascular and respiratory system.

Low placental weight and risk for fetal distress at birth.

UNLABELLED: Abstract Objective: The objective of this study was to assess whether low placental weight is associated with higher risk of emergency delivery (cesarean section and vacuum-assisted delivery). METHODS: This was a retrospective cohort study, including 657 normally developed term pregnancies. A strict methodology was used to provide reliable and reproducible placental weight measurement. Fetal heart rate patterns were analyzed according to the guidelines of the Royal College of Obstetricians and Gynecologists. Linear and logistic multiple regression analyses were used to assess risk factors for emergency delivery. RESULTS: Nulliparity, placental weight <10th percentile, and delivery after 40 weeks of gestation remain significantly associated with higher risk of emergency delivery for non-reassuring fetal status in the multivariable model [odds ratio (OR) 5.13, 95% confidence interval (CI) 2.85-9.22, P<0.001; OR 2.46, 95% CI 1.49-4.06, P<0.001; OR 2.23, 95% CI 1.26-4.51, P=0.01, respectively]. In the group of women who had an emergency delivery, 17.3% had a placental weight <10th percentile, which was significantly different to the group of women who delivered normally (9.4%, P≤0.04). If only emergency cesarean sections were analyzed, the percentage of women with placental weight <10th percentile was 37.5% in the cesarean section group compared to 9.8% in women who delivered normally (P≤0.001). CONCLUSION: This study suggests that, in clinically normally developed term pregnancies, placental weight <10th percentile is associated with an increased risk for emergency delivery during labor. These results warrant further prospective studies for potential use in clinical practice.

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.

The sFlt-1/PlGF ratio in different types of hypertensive pregnancy disorders and its prognostic potential in preeclamptic patients.

OBJECTIVE: The soluble fms-like tyrosine kinase (sFlt-1)/placental growth factor (PlGF) ratio is a reliable tool in the assessment of preeclampsia. We tested the hypothesis that the sFlt-1/PlGF ratio is able to identify women at risk for imminent delivery. We characterized the sFlt-1/PlGF ratio in different types of hypertensive pregnancy disorders. STUDY DESIGN: We investigated 388 singleton pregnancies with normal pregnancy outcome, 164 with PE, 36 with gestational hypertension, and 42 with chronic hypertension. sFlt-1 and PlGF were measured in serum samples. RESULTS: Patients with preeclampsia had a significantly increased sFlt-1/PlGF ratio as compared with controls and with patients with chronic and gestational hypertension in <34 weeks and ≥34 weeks (P < .001). Time to delivery was significantly reduced in women with preeclampsia in the highest quartile of the sFlt-1/PlGF ratio (P < .001). CONCLUSION: The sFlt-1/PlGF ratio allows the identification of women at risk for imminent delivery and is a reliable tool to discriminate between different types of pregnancy-related hypertensive disorders.