Maternal cardiovascular changes from pre-pregnancy to very early pregnancy

The Amount of Fluid Intake among Pregnant Women in China Increases with Pregnancy Progression: A Prospective Cohort Study

Fluid intake and hydration status during pregnancy may have influences on maternal and infant health. However, few studies have recorded and analyzed total fluid intake (TFI) levels during the whole pregnancy. This study mainly aimed to investigate the TFI levels of pregnant women in three trimesters, and further to assess their hydration status. The relationships of TFI and hydration status were also analyzed. A convenience sampling method was used to recruit pregnant women from the Haikou Maternity and Child Health Hospital in China in this prospective cohort study. A 7-day 24 h fluid intake questionnaire was used for recording the fluid intake of the participants in their three trimesters. Fasting blood samples and first morning urine samples were also collected and tested. Hydration status was evaluated using urine osmolality. Finally, 142 pregnant women completed the study. The median TFIs in the first, second, and third trimesters were 1336, 1477, and 1584 mL, respectively. The TFI levels increased with pregnancy progression (χ2 = 134.155, p < 0.05). Out of 142 participants, 100.0%, 97.2%, and 85.2% of participants did not reach the recommendation amount for an adequate TFI among Chinese pregnant women in the three trimesters, respectively (χ2 = 29.840, p < 0.05). Plain water was the main source of fluid intake, accounting for 92.0%, 94.2%, and 93.4% of TFI, respectively. The median values of dairy product intake were 61, 57, and 59 mL in the three trimesters. The frequency of participants without an optimal hydration status in the three trimesters was 71.8%, 76.1%, and 83.1%, respectively (χ2 = 29.909, p < 0.05). The participants of each trimester were divided into four groups according to quartiles of TFI, including participants with a lower fluid intake (LFI1 and LFI2) and higher fluid intake (HFI1 and HFI2). As the TFI values increased from the LFI1 group to the HFI2 group, the urine osmolality decreased (all p < 0.05). Moderate-intensity negative correlations were found between urine osmolality, hydration status, and TFI (all p < 0.05). It is suggested that fluid intake strategies should be promoted and health education should be conducted to improve the hydration status of pregnant women.

Placental syndromes and maternal cardiovascular health

The placental syndromes gestational hypertension, preeclampsia and intrauterine growth restriction are associated with an increased cardiovascular risk to the mother later in life. In this review, we argue that a woman's pre-conception cardiovascular health drives both the development of placental syndromes and long-term cardiovascular risk but acknowledge that placental syndromes can also contribute to future cardiovascular risk independent of pre-conception health. We describe how preclinical studies in models of preeclampsia inform our understanding of the links with later cardiovascular disease, and how current pre-pregnancy studies may explain relative contributions of both pre-conception factors and the occurrence of placental syndromes to long-term cardiovascular disease.

Anaphylaxis in Pregnancy

Anaphylaxis in pregnancy is a rare event, but has important implications for the pregnant patient and fetus. The epidemiology, pathophysiology, diagnosis, and treatment all carry important considerations unique to the pregnant patient. Common culprits of anaphylaxis are primarily medications, particularly antibiotics and anesthetic agents. Diagnosis can be difficult given the relative lack of cutaneous symptoms, and normal physiologic changes in pregnancy such as low blood pressure and tachycardia. Apart from patient positioning, treatment is similar to that of the general population, with a focus on prompt epinephrine administration.

Preeclampsia: Maternal cardiovascular function and optimising outcomes

Preeclampsia is associated with cardiac dysfunction, not only during the clinical phase of the disease, but also after delivery, with long term implications for both maternal and neonatal cardiovascular health. An abnormal cardiovascular phenotype also precedes conception, indicating that pre-existing cardiovascular dysfunction is associated with the development of preeclampsia. This review summarises the changes in cardiovascular function in preeclampsia, examining the evidence for when cardiovascular dysfunction develops and presenting the evidence for two phenotypes - one associated with fetal growth restriction, low cardiac output and high peripheral resistance, and a second associated with normal fetal growth, high cardiac output and low peripheral resistance. The presence of a cardiovascular phenotype that precedes conception demonstrates the potential for prevention of preeclampsia through cardiovascular optimisation at this stage. The two phenotypes mean therapy can be targeted to optimising cardiovascular function. The prevention and effective treatment of preeclampsia are essential aspects of improving maternal and neonatal cardiovascular health in the long term.

Changes in Vascular Function from Preconception to Postpartum Among Mongolian Women

Background: Pregnancy is associated with physiological changes to meet the metabolic demands of the growing fetus. To understand adverse pregnancy outcomes it is important to establish vascular changes throughout pregnancy. We examined longitudinal changes in vascular measurements from prepregnancy through postpartum. Materials and Methods: Seventy women planning to conceive in Ulaanbaatar, Mongolia enrolled in this prospective study. Within 6 months, 44 (63%) had conceived; of which 36 (82%) delivered. Ten (28%) developed complex pregnancies and were analyzed separately. Vascular measures included central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), augmentation index corrected for heart rate of 75 beats/minute (AIx-75), and pulse wave velocity (PWV). Measurements were performed at prepregnancy, second trimester (22-24 weeks), third trimester (34-36 weeks), and 2 months postpartum. Missing values (n = 0-6 per time period) were replaced by multiple imputation. A repeated measures analysis of variance analyzed changes within individual women over the four time points adjusted for age, parity, and body mass index. Results: We observed significant reductions from prepregnancy to second trimester for mean Alx-75 (17.1%-12.6%; p = 0.006) and cSBP (91.7-86.8 mmHg; p = 0.03) but not for cDBP or PWV. Both mean AIx-75 and cSBP increased in third trimester. In the postpartum, cSBP returned to prepregnancy levels, whereas AIx-75 exceeded prepregnancy levels, although this fell short of significance (p = 0.09). Similar vascular patterns were observed in women with complex pregnancies for AIx-75; however, PWV increased from the second trimester and remained higher through postpartum, although not significant. Conclusion: In Mongolian women, we observed a decrease in AIx-75 and cSBP from prepregnancy through second trimester, which resolved postpartum. These results provide an understanding of changes across pregnancies in an Asian country. Future studies should assess vascular changes across pregnancies to determine if it can predict conditions such as pre-eclampsia.

Systemic vascular resistance may influence the outcome of in vitro fertilization

Introduction: The number of pregnancies obtained through in vitro fertilization (IVF) techniques are increasing, and only few studies have investigated hemodynamic variations in women undergoing IVF techniques. The aim of this study was to evaluate the hemodynamic parameters in women undergoing IVF, to assess a possible correlation between hemodynamics and embryo implantation.Methods: 45 normotensive non-obese women, age ≤ 43 years, with idiopathic or tubal infertility, referred to the Reproductive Physiopathology and Andrology Unit, Sandro Pertini Hospital, Rome, during the period 2020/2021, underwent IVF techniques. All women were evaluated with Ultra Sonic Cardiac Output Monitor (USCOM) to detect hemodynamic parameters at two different stages: at the mid-luteal phase, before the beginning of IVF, and at the day of embryo transfer (dET). All demographics and hormonal parameters in both groups were comparable. The hemodynamic parameters were compared between women with a positive β-HCG test vs. those testing negative.Results: 11 out of 45 (24,5%) women obtained positive β-HCG test. All demographics and hormonal parameters were comparable in both groups. Women with a positive β-HCG test showed statistically lower systemic vascular resistance (SVR) at mid-luteal phase (868.61 ± 100.1 vs. 1009 ± 168.4) and dET (818,9 ± 104.5 vs 1038.52 ± 150.82 dynes × s/cm⁵).Conclusions: Hemodynamic assessment can identify a more favorable pre-pregnancy cardiovascular adaptation. Embryo implantation might be positively influenced by the hemodynamic parameters, e.g. lower SVR, before the beginning of IVF techniques, and during the window of implantation.

Arterial stiffness measurements in pregnancy as a predictive tool for hypertensive disorders of pregnancy and preeclampsia: Protocol for a systematic review and meta-analysis

Hypertensive disorders of pregnancy (HDPs) are a leading cause of maternal morbidity and mortality worldwide. Unfortunately, accurate early clinical screening methods for the development of these disorders are lacking. Arterial stiffness (AS) is an important hemodynamic indicator of vascular health that has shown promising results for the prediction of HDP onset. Past systematic reviews in the field have reported an increase in AS indices in women who develop HDPs and have highlighted the potential of AS measurements as a predictive tool early in pregnancy. The most recent systematic review, including papers up to 2015, assessed the differences in AS parameters between women with and without pregnancy complications. Since then, there has been a substantial influx of published research on the topic and a growing interest in the incorporation of AS measurements into clinical practice. Thus, we propose a systematic review and meta-analysis that is more inclusive to all HDP subsets and various hemodynamic indices of vascular health to provide a comprehensive overview of the current state of evidence. Specifically, we aim to evaluate these measures in women who develop HDPs compared to normotensive pregnancies to determine which measures are most associated with and/or can predict the development of HDPs. Major databases (Medline, Embase, The Cochrane Library, Web of Science, PubMed, and CINAHL), grey literature (Google Scholar) and clinical trials (clinicaltrials.gov) will be searched to identify studies that report AS and hemodynamic measurements in pregnant women with and without HDPs. No restrictions will be made on study type or year. Articles will be independently evaluated by three authors to determine eligibility based on inclusion and exclusion criteria. Methodological quality of included studies will be assessed. Pooled analyses will be conducted using a random-effects model. Publication bias and between-study heterogeneity will also be assessed. Sources of heterogeneity will be explored by sensitivity, subgroup, and/or meta-regression analyses. Results from this study will be shared through scientific conferences and publications in scientific journals. The analysis of potential AS and hemodynamic markers for HDP onset will help inform the development of screening guidelines and clinically relevant cut-off values of AS and hemodynamic markers for HDP risk, guiding future research. There are no applicable ethical considerations to the writing of this protocol.

Blood pressure adjustments throughout healthy and hypertensive pregnancy: A systematic review and meta-analysis

Gestational hypertensive complications are preceded by deviant hemodynamic adjustments affecting blood pressure. Our objective was to determine the timing and magnitude of changes in blood pressure during singleton normotensive and hypertensive pregnancies. PubMed (NCBI) and Embase (Ovid) databases were searched for relevant studies up to November 2019. Studies reporting original blood pressure measurements during pregnancy together with a non-pregnant reference measurement were included. Studies including women with a history of cardiovascular or metabolic disease, or women using antihypertensive drugs were excluded. Pooled mean differences between pregnant and non-pregnant women, and absolute blood pressure values were calculated for predefined gestational intervals in normotensive and hypertensive pregnancy, using a random-effects model. Meta-regression analysis was used to analyze group differences in adjustments. In early normotensive pregnancy, both systolic and diastolic blood pressure decreased, reaching their maximum reduction of -4 mmHg (95%CI -6 to -1 mmHg) and -4 mmHg (95%CI, -5 to -3 mmHg), respectively in the second trimester. Thereafter, blood pressure gradually increased towards non-pregnant values. All absolute blood pressure measurements throughout normotensive pregnancy were below 130/80 mmHg. In hypertensive pregnancies, only diastolic blood pressure decreased early in pregnancy. In conclusion, this meta-analysis showed a clinically moderate, but significant mid-pregnancy drop in blood pressure during normotensive pregnancy. Reference curves with absolute values underscore the current liberal cut-off limit for gestational hypertension. A lack of a mid-pregnancy systolic blood pressure drop might reflect increased vascular resistance in women destined to develop hypertensive pregnancy complications.

The Nine Month Stress Test: Pregnancy and Exercise - Similarities and Interactions

Of all physiological systems, the cardiovascular system takes on the most profound adaptation in pregnancy to support fetal growth and development. The adaptations that arise are systemic and involve structural and functional changes that can be observed at the cerebral, central, peripheral, and microvascular beds. This includes, although is not limited to increased heart rate, stroke volume and cardiac output with negligible change to blood pressure, reductions in vascular resistance and cerebral blood flow velocity, systemic artery enlargement, enhanced endothelial function. All of this takes place to accommodate blood volume expansion and ensure adequate fetal and maternal oxygen delivery. In some instances, the demand placed on the vasculature can manifest as cardiovascular maladaptation and thus, cardiovascular complications can arise. Exercise is recommended in pregnancy because of its powerful ability to reduce the incidence and severity of cardiovascular complications in pregnancy. However, the mechanism by which it acts is poorly understood. The first aim of this review is to describe the systemic adaptations that take place in pregnancy. Secondly, this review aims to describe the influence of exercise on these systemic adaptations. It is anticipated that this review can comprehensively capture the extent of knowledge in this area while identifying areas that warrant further investigation.

Newborns of Mothers with Venous Disease during Pregnancy Show Increased Levels of Lipid Peroxidation and Markers of Oxidative Stress and Hypoxia in the Umbilical Cord

Chronic venous disease (CVD) encompasses a set of disorders of the venous system that have a high prevalence in Western societies and are associated with significant sociohealth costs. Pregnancy is a period in which different hormonal and haemodynamic changes occur that lead to significant changes in the cardiovascular system, increasing the risk of developing venous problems, especially during the third trimester of gestation. In turn, CVD involves a series of local and systemic alterations that can have negative repercussions in pregnancy. In this context, the role of oxidative stress in the pathophysiology of this condition has been shown to significantly affect other vascular structures during pregnancy, such as the placenta. However, the effects of oxidative stress on the umbilical cord in women with CVD have not yet been fully elucidated. Thus, the objective of this study was to analyse the gene and protein expression of the enzymes NOX-1, NOX-2 and iNOS, which are involved in the production of reactive oxygen and nitrogen species, respectively. Similarly, the presence of hypoxia-inducible factor 1-alpha (HIF-1α) in the umbilical cord in women with CVD was compared to that of pregnant control women, and the levels of the lipid peroxidation marker malonyldialdehyde (MDA) in cord tissue and blood was also analysed. Our results support a significant increase in the enzymes NOX-1, NOX-2 and iNOS and HIF-1α and MDA in the umbilical cord tissue and blood of women with CVD. For the first time, our work demonstrates an increase in oxidative stress and cellular damage in the umbilical cords of pregnant women who develop this condition, deepening the understanding of the consequences of CVD during pregnancy.

Prorenin periconceptionally and in pregnancy: Does it have a physiological role?

Pregnancy demands major cardiovascular, renal and endocrine changes to provide an adequate blood supply for the growing fetus. The renin-angiotensin-aldosterone system plays a key role in this adaptation process. One of its components, prorenin, is released in significant amounts from the ovary and uteroplacental unit. This review describes the sources of prorenin in the periconception period and in pregnancy, including its modulation by in-vitro fertilization protocols, and discusses its potential effects, among others focusing on preeclampsia. It ends with discussing the long-term consequences, even in later life, of inappropriate renin-angiotensin-aldosterone system activity in pregnancy and offers directions for future research. Ultimately, a full understanding of the role of prorenin periconceptionally and during pregnancy will help to develop tools to diagnose and/or prevent reproductive complications.

Cardiac output and peripheral vascular resistance during normotensive and hypertensive pregnancy - a systematic review and meta-analysis

BACKGROUND

In-depth insight into haemodynamic changes during normotensive pregnancy may help identify women at risk for gestational hypertensive complications.

OBJECTIVES

To determine the magnitude of changes in cardiac output and its determinants stroke volume and heart rate, and total peripheral vascular resistance during singleton normotensive and hypertensive pregnancies.

SEARCH STRATEGY

PubMed (NCBI) and Embase (Ovid) databases were searched from their inception up to November 2019.

SELECTION CRITERIA

Studies reporting original measurements of haemodynamic parameters during pregnancy together with a non-pregnant reference measurement. Studies including women using antihypertensive medication were excluded.

DATA COLLECTION AND ANALYSIS

Pooled mean differences between pregnant and non-pregnant women, and absolute values of haemodynamic parameters were calculated for predefined gestational intervals using a random-effects model in normotensive and hypertensive pregnancy. Meta-regression analysis was used to analyse group differences in adjustments and absolute values during pregnancy.

MAIN RESULTS

In normotensive pregnancies, cardiac output increased from the first weeks on, reaching its highest level early in the third trimester (mean difference, 1.41 l·min¹ ; 95% CI 1.18-1.63 l·min^-1 ). In parallel, vascular resistance decreased progressively until its nadir in the early third trimester (mean difference, -331 dyn·sec^-1 ·cm^-5 ; 95% CI -384 to -277 dyn·sec^-1 ·cm^-5 ) and then increased slightly at term. In hypertensive pregnancies, the initial cardiac output increase was higher and vascular resistance did not change throughout gestation compared with reference values.

CONCLUSIONS

Hemodynamic changes in women who eventually develop hypertensive complications are substantially different. Serial monitoring and plotting against developed normograms can identify women at risk and may allow timely intervention.

TWEETABLE ABSTRACT

Monitoring haemodynamic changes in pregnancy helps identify women at risk for hypertensive complications.

Prorenin periconceptionally and in pregnancy: Does it have a physiological role?

Pregnancy demands major cardiovascular, renal and endocrine changes to provide an adequate blood supply for the growing fetus. The renin-angiotensin-aldosterone system plays a key role in this adaptation process. One of its components, prorenin, is released in significant amounts from the ovary and uteroplacental unit. This review describes the sources of prorenin in the periconception period and in pregnancy, including its modulation by in-vitro fertilization protocols, and discusses its potential effects, among others focusing on preeclampsia. It ends with discussing the long-term consequences, even in later life, of inappropriate renin-angiotensin-aldosterone system activity in pregnancy and offers directions for future research. Ultimately, a full understanding of the role of prorenin periconceptionally and during pregnancy will help to develop tools to diagnose and/or prevent reproductive complications.

Kidney Physiology in Pregnancy

A woman's body undergoes a myriad of changes throughout the course of a normal gestation. The kidneys play a central role in driving adjustments that guarantee maternal and fetal well-being, including a dramatic increase in glomerular filtration rate, alterations in tubular function, and changes in electrolyte and acid/base handling. Early in gestation, systemic vasodilation, driven by both a change in quantity of and response to various hormones, leads to increased renal blood flow and glomerular filtration rate. Vasodilation also results in activation of the renin-angiotensin-aldosterone axis, which combined with changing tubular handling causes alterations in total body stores of electrolytes and total body water, resulting in a lower serum sodium concentration. In addition, mild proteinuria, glucosuria, and a decrease in serum calcium and magnesium are common. The primary acid/base change seen in pregnancy is a mild respiratory alkalosis due to progesterone effects. This article provides an overview of the current understanding of the healthy response of the kidneys to pregnancy, an understanding of which is key to caring for the pregnant patient, and early identification of alterations that may indicate underlying kidney pathology in pregnancy.

A Protocol for Evaluating Vital Signs and Maternal-Fetal Parameters Using High-Resolution Ultrasound in Pregnant Mice

Pregnancy is a unique physiological state in which two individuals coexist: the mother and the fetus. Disruption of maternal-fetal crosstalk leads to pregnancy and neonatal pathologies. Therefore, assessing maternal-fetal well-being is essential for understanding the physiological and pathological processes occurring during pregnancy. Herein, we provide a protocol that allows for the determination of body temperature, blood pressure, and the evaluation of uterine and umbilical arteries as well as maternal and fetal heart rate using high-resolution ultrasound in pregnant mice.

For complete details on the use and execution of this protocol, please refer to Gomez-Lopez et al. (2020).

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Assessing maternal-fetal well-being is critical for studying pregnancy in mice

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Evaluation of maternal-fetal parameters improves translational value

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High-resolution ultrasound of uterine and umbilical arteries can predict pathology

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This protocol is suitable for evaluating pregnancy disease and treatments in mice

Pregnancy-specific transcriptional changes upon endotoxin exposure in mice

Objectives Pregnant women are more susceptible to certain infections; however, this increased susceptibility is not fully understood. Herein, systems biology approaches were utilized to elucidate how pregnancy modulates tissue-specific host responses to a bacterial product, endotoxin. Methods Pregnant and non-pregnant mice were injected with endotoxin or saline on 16.5 days post coitum (n=8-11 per group). The uterus, cervix, liver, adrenal gland, kidney, lung, and brain were collected 12 h after injection and transcriptomes were measured using microarrays. Heatmaps and principal component analysis were used for visualization. Differentially expressed genes between groups were assessed using linear models that included interaction terms to determine whether the effect of infection differed with pregnancy status. Pathway analysis was conducted to interpret gene expression changes. Results We report herein a multi-organ atlas of the transcript perturbations in pregnant and non-pregnant mice in response to endotoxin. Pregnancy strongly modified the host responses to endotoxin in the uterus, cervix, and liver. In contrast, pregnancy had a milder effect on the host response to endotoxin in the adrenal gland, lung, and kidney. However, pregnancy did not drastically affect the host response to endotoxin in the brain. Conclusions Pregnancy imprints organ-specific host immune responses upon endotoxin exposure. These findings provide insight into the host-response against microbes during pregnancy.

Study protocol for a prospective cohort study to investigate Hemodynamic Adaptation to Pregnancy and Placenta-related Outcome: the HAPPO study

INTRODUCTION

The importance of cardiovascular health in relation to pregnancy outcome is increasingly acknowledged. Women who develop certain pregnancy complications, in particular preeclampsia, are at higher risk for future cardiovascular disease. Independent of its outcome, pregnancy requires a substantial adaptive response of the maternal cardiovascular system. In the Hemodynamic Adaptation to Pregnancy and Placenta-related Outcome (HAPPO) study, we aim to examine longitudinal maternal haemodynamic adaptation to pregnancy from the preconception period onwards. We hypothesise that women who will develop adverse pregnancy outcomes have impaired cardiovascular health before conception, leading to haemodynamic maladaptation to pregnancy and diminished uteroplacental vascular development.

METHODS AND ANALYSIS

In this prospective cohort study embedded in the Rotterdam periconception cohort, 200 women with a history of placenta-related pregnancy complications (high-risk group) and 100 women with an uncomplicated obstetric history (low-risk group) will be included. At five moments (preconception, first, second and third trimester and postdelivery), women will undergo an extensive examination of the macrocirculatory and microcirculatory system and uteroplacental vascular development. The main outcome measures are differences in maternal haemodynamic adaptation to pregnancy between women with and without placenta-related pregnancy complications. In a multivariate linear mixed model, the relationship between maternal haemodynamic adaptive parameters, (utero)placental vascularisation indices and clinical outcomes (occurrence of pregnancy complications, embryonic and fetal growth trajectories, miscarriage rate, gestational age at delivery, birth weight) will be studied. Subgroup analysis will be performed to study baseline and trajectory differences between high-risk and low-risk women, independent of subsequent pregnancy outcome.

ETHICS AND DISSEMINATION

This study protocol was approved by the Medical Ethics Committee of the Erasmus MC, Rotterdam, the Netherlands (MEC 2018-150). Results will be disseminated to the medical community by publications in peer-reviewed journals and presentations at scientific congresses. Also, patient associations will be informed and the public will be informed by dissemination through (social) media.

TRIAL REGISTRATION NUMBER

NL7394 (www.trialregister.nl).

Ambulatory Blood Pressure Trajectory and Perceived Stress in Relation to Birth Outcomes in Healthy Pregnant Adolescents

OBJECTIVE

An early decline in resting blood pressure (BP), followed by an upward climb, is well documented and indicative of a healthy pregnancy course. Although BP is considered both an effector of stress and a clinically meaningful measurement in pregnancy, little is known about its trajectory in association with birth outcomes compared with other stress effectors. The current prospective longitudinal study examined BP trajectory and perceived stress in association with birth outcomes (gestational age (GA) at birth and birth weight (BW) percentile corrected for GA) in pregnant adolescents, a group at risk for stress-associated poor birth outcomes.

METHODS

Healthy pregnant nulliparous adolescents (n = 139) were followed from early pregnancy through birth. At three time points (13-16, 24-27, and 34-37 gestational weeks ±1 week), the Perceived Stress Scale was collected along with 24-hour ambulatory BP (systolic and diastolic) and electronic diary reporting of posture. GA at birth and BW were abstracted from medical records.

RESULTS

After adjustment for posture and pre-pregnancy body mass index, hierarchical mixed-model linear regression showed the expected early decline (B = -0.18, p = .023) and then increase (B = 0.01, p < .001) of diastolic BP approximating a U-shape; however, systolic BP displayed only an increase (B = 0.01, p = .010). In addition, the models indicated a stronger systolic and diastolic BP U-shape for early GA at birth and lower BW percentile and an inverted U-shape for late GA at birth and higher BW percentile. No effects of perceived stress were observed.

CONCLUSIONS

These results replicate the pregnancy BP trajectory from previous studies of adults and indicate that the degree to which the trajectory emerges in adolescence may be associated with variation in birth outcomes, with a moderate U-shape indicating the healthiest outcomes.

A Review of the Actions of Endogenous and Exogenous Vasoactive Substances during the Estrous Cycle and Pregnancy in Rats

Vascular endothelium plays a key role in regulating cardiovascular homeostasis by controlling the vascular tone. Variations in sex hormones during the reproductive cycle of females affect the homeostasis of the cardiovascular system. Also, the evidence shows that estrogens show a cardioprotective effect. On this basis, this study describes some vascular responses induced by vasoactive substances during the estrous cycle in rats. We obtained the information available on this topic from the online databases that included scientific articles published in the Web of Science, PubMed, and Scielo. Many investigations have evaluated the vasoactive response of substances such as acetylcholine and norepinephrine during the estrous cycle. In this review, we specifically described the vascular response to vasoactive substances in rats during the estrous cycle, pregnancy, and in ovariectomized rats. In addition, we discussed the existence of different signaling pathways that modulate vascular function. The knowledge of these effects is relevant for the optimization and development of new treatments for some vascular pathologies.

Pharmacotherapy for hypertension in pregnant patients: special considerations

INTRODUCTION

Hypertensive disorders of pregnancy (HDP) represent a major cause of maternal, fetal and neonatal morbidity and mortality and identifies women at risk for cardiovascular and other chronic diseases later in life. When antihypertensive drugs are used during pregnancy, their benefit and harm to both mother and fetus should be evaluated.

AREAS COVERED

This review summarizes the pharmacological characteristics of the recommended antihypertensive drugs and their impact on mother and fetus when administered during pregnancy and/or post-partum. Drugs were identified using MEDLINE and the main international Guidelines for the management of HDP.

EXPERT OPINION

Although there is a consensus that severe hypertension should be treated, treatment of mild hypertension without end-organ damage (140-159/90-109 mmHg) remains controversial and there is no agreement on when to initiate therapy, blood pressure targets or recommended drugs in the absence of robust evidence for the superiority of one drug over others. Furthermore, the long-term outcomes of in-utero antihypertensive exposure remain uncertain. Therefore, evidence-based data regarding the treatment of HDP is lacking and well designed randomized clinical trials are needed to resolve all these controversial issues related to the management of HDP.

Maternal arterial stiffness and fetal cardiovascular physiology in diabetic pregnancy

OBJECTIVES

In mothers with pregestational or gestational diabetes, abnormal arterial stiffness (stiffer arteries) has been reported. The impact of abnormal maternal arterial stiffness on placental and fetal cardiovascular physiology is unknown. The purpose of this study was to determine the impact of maternal diabetes on maternal arterial stiffness and the association with fetal cardiovascular physiology as measured by fetal echocardiography.

METHODS

Between December 2013 and January 2017 a prospective study was conducted on diabetic (but otherwise healthy) and non-diabetic, healthy pregnant mothers aged 18-40 years at 20-28 weeks' gestation who had a normal fetal cardiac echocardiogram and obstetric ultrasound. Clinical data were collected by means of a patient questionnaire and measurement of blood pressure, height, weight, arterial augmentation index (AIx) and placental and fetal cardiovascular parameters were collected by fetal echocardiography. Descriptive statistics were calculated. Comparisons were made using parametric and non-parametric tests between controls and diabetic mothers.

RESULTS

Twenty-three healthy pregnant controls and 43 diabetic pregnant women (22 with pregestational and 21 with gestational diabetes) were included in the study. Maternal AIx was higher in those with diabetes than in healthy controls (12.4 ± 10.6% vs 4.6 ± 7.9%; P = 0.003). Fetal aortic valve (AoV) velocity time integral (VTI) was higher in fetuses whose mothers had diabetes than in those with non-diabetic mothers (7.7 ± 1.9 cm vs 6.3 ± 3.0 cm; P = 0.022). Left ventricular (LV) myocardial performance index (MPI) was lower in diabetic pregnancies than in controls (0.40 ± 0.09 vs 0.46 ± 0.11; P = 0.021). Umbilical artery (UA) resistance index (RI) was lower in diabetic pregnancies with glycated hemoglobin (HbA1c) levels ≥ 6.5% than in those with HbA1c levels < 6.5% (0.69 ± 0.06, n = 15 vs 0.76 ± 0.08, n = 21; P = 0.009) but not at higher HbA1C cut-offs. No correlation between AIx and AoV-VTI, LV-MPI or UA-RI was found.

CONCLUSIONS

Arterial stiffness is higher in pregnant women with diabetes than in controls. Fetuses of diabetic mothers show altered cardiovascular parameters, with higher AoV-VTI and lower LV-MPI, which are markers of myocardial function. Placental function assessed by UA-RI was normal despite differences between groups. Arterial stiffness did not correlate with placental or fetal cardiovascular variables. Instead, the findings are likely to represent a shared response to the environment of abnormal glucose metabolism. The clinical significance of these findings is yet to be determined. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Arterial stiffness during controlled ovarian hyperstimulation and early pregnancy in women exposed to assisted reproduction

INTRODUCTION

Female sex hormones have vasorelaxing effects in non-pregnant and pregnant women. We aimed to investigate the effect of controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF), and early pregnancy, on arterial stiffness as assessed by digital pulse wave analysis (DPA), hypothesizing reduced arterial stiffness as an effect of increased estrogen levels.

MATERIAL AND METHODS

A total of 68 women undergoing IVF were examined with DPA before conception and during IVF treatment with COH and embryo transfer (ET), and in gestational week seven in 19 women who became pregnant. Heart rate (HR), mean arterial pressure (MAP) and the DPA variables cardiac ejection elasticity index (EEI), b/a, dicrotic index (DI), d/a and aging index (AI) were measured.

RESULTS

HR was significantly increased at all measuring points (p ≤ 0.003) but MAP only at ET (p 0.007). DPA variables representing large arteries (EEI, b/a) and peripheral arteries (DI, but not d/a), and the global variable AI, indicated increased arterial stiffness at ET compared with baseline (p ≤ 0.035). No DPA variable was significantly changed at pregnancy measurements compared to baseline.

CONCLUSION

During COH for IVF treatment, DPA showed no changes in arterial stiffness during the follicular phase or in early pregnancy, but increased arterial stiffness in central and peripheral arteries in the early luteal phase. The result suggests a hormonal hemodynamic activation counteracting the effects of estrogen.

Reducing Psychological Stress in Peripartum Women With Heart Rate Variability Biofeedback: A Systematic Review

Peripartum women are exposed to a variety of stressors that have adverse health consequences for the maternal-child dyad (e.g., impaired bonding). To combat these adverse health consequences, heart rate variability biofeedback (HRVBF) may be implemented by holistic nurses to aid peripartum women experiencing a high level of stress. A systematic review was completed using the guidelines established in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. To be included in the review, studies had to meet the following criteria: (a) published scientific articles, (b) studies published in English, (c) experimental, quasi-experimental, or case reports, (d) use of HRVBF as the main treatment, (e) use of psychological stress as a dependent variable, and (f) studies published until December 2017. The major findings of this review can be described as follows: (a) HRVBF and psychological stress in peripartum women are related concepts, (b) peripartum women who completed HRVBF report a reduction in stress compared with participants who did not receive HRVBF, and (c) there is currently no information on the effectiveness of HRVBF on psychological stress in the first and early second trimester of pregnancy. Overall, this systematic review of the literature provides objective evidence that HRVBF may be a potential beneficial adjuvant treatment for stress management in peripartum women.

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 12^th 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.

Early and late preeclampsia are characterized by high cardiac output, but in the presence of fetal growth restriction, cardiac output is low: insights from a prospective study

BACKGROUND

Preeclampsia and fetal growth restriction are considered to be placentally mediated disorders. The clinical manifestations are widely held to relate to gestation age at onset with early- and late-onset preeclampsia considered to be phenotypically distinct. Recent studies have reported conflicting findings in relation to cardiovascular function, and in particular cardiac output, in preeclampsia and fetal growth restriction.

OBJECTIVE

We conducted this study to examine the possible relation between cardiac output and peripheral vascular resistance in preeclampsia and fetal growth restriction.

STUDY DESIGN

We investigated maternal cardiovascular function in relation to clinical subtype in 45 pathological pregnancies (14 preeclampsia only, 16 fetal growth restriction only, 15 preeclampsia and fetal growth restriction) and compared these with 107 healthy person observations. Cardiac output was the primary outcome measure and was assessed using an inert gas-rebreathing method (Innocor), from which peripheral vascular resistance was derived; arterial function was assessed by Vicorder, a cuff-based oscillometric device. Cardiovascular parameters were normalized for gestational age in relation to healthy pregnancies using Z scores, thus allowing for comparison across the gestational range of 24-40 weeks.

RESULTS

Compared with healthy control pregnancies, women with preeclampsia had higher cardiac output Z scores (1.87 ± 1.35; P = .0001) and lower peripheral vascular resistance Z scores (-0.76 ± 0.89; P = .025); those with fetal growth restriction had higher peripheral vascular resistance Z scores (0.57 ± 1.18; P = .04) and those with both preeclampsia and fetal growth restriction had lower cardiac output Z scores (-0.80 ± 1.3 P = .007) and higher peripheral vascular resistance Z scores (2.16 ± 1.96; P = .0001). These changes were not related to gestational age of onset. All those affected by preeclampsia and/or fetal growth restriction had abnormally raised augmentation index and pulse wave velocity. Furthermore, in preeclampsia, low cardiac output was associated with low birthweight and high cardiac output with high birthweight (r = 0.42, P = .03).

CONCLUSION

Preeclampsia is associated with high cardiac output, but if preeclampsia presents with fetal growth restriction, the opposite is true; both conditions are nevertheless defined by hypertension. Fetal growth restriction without preeclampsia is associated with high peripheral vascular resistance. Although early and late gestation preeclampsias are considered to be different diseases, we show that the hemodynamic characteristics of preeclampsia were unrelated to gestational age at onset but were strongly associated with the presence or absence of fetal growth restriction. Fetal growth restriction more commonly coexists with preeclampsia at early gestation, thus explaining the conflicting results of previous studies. Furthermore, antihypertensive agents act by reducing cardiac output or peripheral vascular resistance and are administered without reference to cardiovascular function in preeclampsia. The underlying pathology (preeclampsia, fetal growth restriction, preeclampsia and fetal growth restriction) defines cardiovascular phenotype, providing a rational basis for choice of therapy in which high or low cardiac output or peripheral vascular resistance is the predominant feature.

Experimental preeclampsia in rats affects vascular gene expression patterns

Normal pregnancy requires adaptations of the maternal vasculature. During preeclampsia these adaptations are not well established, which may be related to maternal hypertension and proteinuria. The effects of preeclampsia on the maternal vasculature are not yet fully understood. We aimed to evaluate gene expression in aortas of pregnant rats with experimental preeclampsia using a genome wide microarray. Aortas were isolated from pregnant Wistar outbred rats with low-dose LPS-induced preeclampsia (ExpPE), healthy pregnant (Pr), non-pregnant and low-dose LPS-infused non-pregnant rats. Gene expression was measured by microarray and validated by real-time quantitative PCR. Gene Set Enrichment Analysis was performed to compare the groups. Functional analysis of the aorta was done by isotonic contraction measurements while stimulating aortic rings with potassium chloride. 526 genes were differentially expressed, and positive enrichment of “potassium channels”, “striated muscle contraction”, and “neuronal system” gene sets were found in ExpPE vs. Pr. The potassium chloride-induced contractile response of ExpPE aortic rings was significantly decreased compared to this response in Pr animals. Our data suggest that potassium channels, neuronal system and (striated) muscle contraction in the aorta may play a role in the pathophysiology of experimental preeclampsia. Whether these changes are also present in preeclamptic women needs further investigation.

Hypertensive Disorders in Pregnancy and the Risk of Subsequent Cardiovascular Disease

BACKGROUND

Hypertensive disorders in pregnancy (HDP) have been shown to predict later risk of cardiovascular disease (CVD). However, previous studies have not accounted for subsequent pregnancies and their complications, which are potential confounders and intermediates of this association.

METHODS

A cohort of 146 748 women with a first pregnancy was constructed using the Clinical Practice Research Datalink. HDP was defined using diagnostic codes, elevated blood pressure readings, or new use of an anti-hypertensive drug between 18 weeks' gestation and 6 weeks post-partum. The study outcomes were incident CVD and hypertension. Marginal structural Cox models (MSM) were used to account for time-varying confounders and intermediates. Time-fixed exposure defined at the first pregnancy was used in secondary analyses.

RESULTS

A total of 997 women were diagnosed with incident CVD, and 6812 women were diagnosed with hypertension or received a new anti-hypertensive medication during the follow-up period. Compared with women without HDP, those with HDP had a substantially higher rate of CVD (hazard ratio (HR) 2.2, 95% confidence interval (CI) 1.7, 2.7). In women with HDP, the rate of hypertension was five times that of women without a HDP (HR 5.6, 95% CI 5.1, 6.3). With overlapping 95% CIs, the time-fixed analysis and the MSM produced consistent results for both outcomes.

CONCLUSIONS

Women with HDP are at increased risk of developing subsequent CVD and hypertension. Similar estimates obtained with the MSM and the time-fixed analysis suggests that subsequent pregnancies do not confound a first episode of HDP and later CVD.

Pre-eclampsia: the Potential of GSNO Reductase Inhibitors

PURPOSE OF REVIEW

Pre-eclampsia remains a leading worldwide cause of maternal death and of perinatal morbidity. There remains no definitive treatment except delivery of the fetus.

RECENT FINDINGS

Recent insights into the cardiovascular changes that are evident prior to, during, and persist after pre-eclampsia have improved understanding of the underlying pathophysiology-disruption of normal endothelial function and decreased nitric oxide bioavailability. S-nitrosoglutathione (GSNO) is an endogenous S-nitrosothiol that acts as a NO pool and, by replenishing or preventing the breakdown of GSNO, endothelial dysfunction can be ameliorated. GSNO reductase inhibitors are a novel class of drug that can increase NO bioavailability. GSNO reductase inhibitors have demonstrated improvement of endothelial dysfunction in animal models, and in vivo human studies have shown them to be well tolerated. GSNOR inhibitors offer a potentially promising option for the management of pre-eclampsia.

Change in maternal cardiac output from preconception to mid-pregnancy is associated with birth weight in healthy pregnancies

OBJECTIVE

Birth weight (BW) is thought to be determined by maternal health and genetic, nutritional and placental factors, the latter being influenced by anatomical development and perfusion. Maternal cardiovascular changes contribute to uteroplacental perfusion; however, they have not yet been investigated in relation to fetal growth or BW. Our aim was to explore the relationship between maternal cardiovascular adaptation, fetal growth and BW in healthy pregnancies.

METHODS

This was a longitudinal prospective study of women planning to conceive a pregnancy. Maternal cardiac output (CO), cardiac index (CI), pulse-wave velocity, aortic augmentation index, central blood pressure and peripheral vascular resistance were assessed prior to pregnancy and at 6, 23 and 33 weeks' gestation. Fetal growth was assessed using serial ultrasound measurements of biometry.

RESULTS

In total, 143 women volunteered to participate and were eligible for study inclusion. A total of 101 women conceived within 18 months and there were 64 live births with normal pregnancy outcome. There were positive correlations between BW and the pregnancy-induced changes in CO (ρ = 0.4, P = 0.004), CI (ρ = 0.3, P = 0.02) and peripheral vascular resistance (ρ = 0.3, P = 0.02). There were significant associations between second-to-third-trimester fetal weight gain and the prepregnancy-to-second-trimester increase in CO (Δ, 0.8 ± 1.2 L/min; ρ = 0.3, P = 0.02) and CI (Δ, 0.4 ± 0.6 L/min/m² ; ρ = 0.3, P = 0.04) and reduction in aortic augmentation index (Δ, -10 ± 9%; ρ = -0.3, P = 0.04).

CONCLUSIONS

In healthy pregnancy, incremental changes in maternal CO in early pregnancy are associated with third-trimester fetal growth and BW. It is plausible that this association is causative as the changes predate third-trimester fetal growth and eventual BW. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal study of vascular structure and function during normal pregnancy

OBJECTIVE

To examine alterations in maternal vascular structure and function during normal pregnancy.

METHODS

We assessed brachial and central blood pressure, pulse-wave velocity and augmentation index (by pulse-wave analysis and applanation tonometry), common carotid artery structure (by ultrasonography) and endothelial function in the brachial artery (by postischemic hyperemia-induced flow-mediated vasodilatation by glyceryl trinitrate) and in the forearm skin microcirculation (by laser Doppler perfusion imaging during iontophoretic administration of acetylcholine and sodium nitroprusside) in 52 healthy nulliparous women at 14, 24 and 34 weeks' gestation, and at 9 months postpartum.

RESULTS

During pregnancy, brachial and central systolic and diastolic blood pressures initially decreased but subsequently increased (all P < 0.05). Flow-mediated vasodilatation in the brachial artery increased during early pregnancy (P < 0.05), whereas non-specific vasodilatation by glyceryl trinitrate decreased (P < 0.01), indicating improved endothelial function. Thus, endothelial function index (forearm blood flow/glyceryl trinitrate) increased during pregnancy (0.30 ± 0.18 in the non-pregnant state at 9 months postpartum and 0.51 ± 0.19, 0.61 ± 0.39 and 0.49 ± 0.30 in the first, second and third trimesters, respectively) (P < 0.001). Endothelium-dependent skin microvascular reactivity to acetylcholine also increased (P < 0.01). Carotid-femoral pulse-wave velocity decreased during pregnancy (5.88 ± 0.91 m/s in the non-pregnant state and 5.55 ± 0.67, 5.12 ± 0.66 and 5.62 ± 0.74 m/s in the first, second and third trimesters, respectively) (P < 0.001).

CONCLUSION

During normal pregnancy, the blood volume expansion necessary for sufficient fetal growth is accommodated by early and marked changes in the matvascular system. This seems to be dependent on normal adaptive endothelial and vascular function. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Why non-invasive maternal hemodynamics assessment is clinically relevant in early pregnancy: a literature review

Background

The maternal cardiovascular system adapts quickly when embryo implantation is recognized by the body. Those adaptations play an important role, as a normal cardiovascular adaptation is a requirement for a normal course of pregnancy. Disturbed adaptations predispose to potential hypertensive disorders further in pregnancy [1–3]. This report aims to briefly inform the obstetricians, general practitioners and midwives, who are the key players in detecting and treating hypertensive disorders during pregnancy.

Methods

The PubMed database was used as main tool to find studies involving clearly defined first trimester hemodynamic changes in normal pregnancies and hypertensive pregnancies. In addition, the bibliographies of these studies were investigated for further relevant literature.

Results

A comprehensive overview is given concerning the normal adaptations in the cardiovascular tree in a first trimester pregnancy. Additionally, signs of abnormal cardiovascular changes observed in first trimester are described together with the normal reference range for each non-invasive, easily applicable technique for maternal hemodynamics assessment.

Conclusions

With a combination of techniques, it is possible to integrate and evaluate the maternal heart, veins and arteries at 12 weeks of pregnancy. Applying those techniques into the daily clinic opens perspectives to prevention and prophylactic treatment, aiming for a reduction of the risk for hypertension during pregnancy.

Volume regulatory hormones and plasma volume in pregnant women with sickle cell disorder

Background:

Sickle cell disease (haemoglobin SS (HbSS)) mainly affects those of West African origin and is associated with hypervolaemia. Plasma volume rises by up to 50% in normal pregnancy but was previously found to be paradoxically contracted in late sickle cell pregnancy. The renin–angiotensin–aldosterone system is activated very early in human pregnancy to support the plasma volume expansion. We hypothesised that activation of the renin–angiotensin–aldosterone system would be blunted in pregnant women with sickle cell disease.

Materials and methods:

We measured plasma volume and concentrations of plasma renin, angiotensinogen, aldosterone and other volume-related hormones in a cross-sectional study of pregnant and non-pregnant Nigerian women with HbSS or HbAA.

Results:

Plasma volume was higher in non-pregnant HbSS than HbAA women, but had not risen by 16 weeks, unlike plasma volume in HbAA women. The concentration of plasma renin also rose significantly less by 16 weeks in HbSS; angiotensinogen and aldosterone concentrations increased.

Conclusions:

The lower plasma renin concentration at 16 weeks with HbSS could be either primary or secondary to vasoconstriction related to inadequate vasodilator activity. The contracted plasma volume might then stimulate aldosterone synthesis by non-angiotensin II dependent stimulation. Studies of vasodilators such as nitric oxide, vasodilator eicosanoids or the PlGF/VEGF/sFlT-1 axis in pregnant HbSS and HbAA women will test this hypothesis.

Maternal Cardiovascular Function in Normal Pregnancy

The aim of this study was to investigate cardiac functional status in pregnancy using a comprehensive approach taking into account the simultaneous changes in loading and geometry, as well as maternal age and anthropometric indices. This was a prospective cross-sectional study of 559 nulliparous pregnant women assessed at 4 time points during pregnancy and at 1 year postpartum. All women underwent conventional echocardiography and tissue Doppler velocities and strain rate analysis at multiple cardiac sites. Mean arterial pressure and total vascular resistance index significantly decreased (both P <0.001) during the first 2 trimesters of pregnancy and increased thereafter. Stroke volume index and cardiac index showed the opposite trend compared with mean arterial pressure and total vascular resistance index (both P <0.05). Myocardial and ventricular function were significantly enhanced in the first 2 trimesters but progressively declined thereafter. By the end of pregnancy, significant chamber diastolic dysfunction and impaired myocardial relaxation was evident in 17.9% and 28.4% of women, respectively, whereas myocardial contractility was preserved. There was full recovery of cardiac function at 1 year postpartum. Cardiovascular changes during pregnancy are thought to represent a physiological adaptation to volume overload. The findings of a drop in stroke volume index, impaired myocardial relaxation with diastolic dysfunction, and a tendency toward eccentric remodeling in a significant proportion of cases at term are suggestive of cardiovascular maladaptation to the volume-overloaded state in some apparently normal pregnancies. These unexpected cardiovascular findings have important implications for the management of both normal and pathological pregnancy states.

Preeclampsia and Vascular Function: A Window to Future Cardiovascular Disease Risk

Preeclampsia affects ∼3%-7% of all pregnancies and is the third leading cause of maternal mortality globally. Growing evidence indicates that preeclampsia results from vascular dysfunction, which also increases the risk for future cardiovascular events. Until recently, preeclampsia was considered a disorder limited to pregnancy, which fully resolved with the delivery of the placenta; however, it is now clear that women with a history of preeclampsia have approximately double the risk of future cardiovascular events compared to women with normotensive pregnancies. The aims of this review were to describe the hemodynamic and vascular changes that occur in normal and preeclamptic pregnancies, to review noninvasive methods to test vascular function, and to discuss the associated increased cardiovascular disease risk related to preeclampsia.

Maternal clinic and home blood pressure measurements during pregnancy and infant birth weight: the BOSHI study

This prospective cohort study compared measurements of maternal home blood pressure (HBP) with clinic blood pressure (CBP) before 20 weeks' gestation to determine associations with the risk of delivering a lower birth weight infant. A total of 605 Japanese women were included. Exposures were initial CBP, made between 10 weeks 0 days and 19 weeks 0 days, and HBP for comparison made within 1 week of CBP. Outcome was infant's birth weight, categorized and ranked as follows: ⩾3500 g, 3000-3499 g, 2500-2999 g and <2500 g. The proportional odds model with possible confounding factors was applied to compare the associations between CBP and HBP on infant birth weight. When both CBP and HBP were included simultaneously, the adjusted odds ratios (ORs) per 1 standard deviation (1s.d.) increase in clinic and home diastolic BP (DBP) were 1.06 (95% confidence interval (CI): 0.87-1.30) and 1.28 (95% CI: 1.04-1.58), respectively. The adjusted ORs per 1s.d. increase in clinic and home mean arterial pressure (MAP) were 1.02 (95% CI: 0.83-1.24) and 1.29 (95% CI: 1.04-1.59), respectively. Systolic BP measurement was not associated with infant birth weight. In conclusion, high maternal home DBP and MAP before 20 weeks' gestation was associated with a higher risk of lower infant birth weight than clinic DBP and MAP. Therefore, in addition to CBP, it may be worth having pregnant women measure HBP to determine the risk of lower infant birth weight.

Challenges in cardiology research in pregnancy

ABSTRACT 

Research in pregnancy is challenging as it involves a special ‘vulnerable’ group due to the involvement of the mother and the fetus. These challenges, which are inherent in studying pregnancy in physiologic and pathologic states, have contributed to the scant research in pregnancy. Until recently, most studies in pregnancy were nonrandomized and retrospective in nature, representing prevailing clinical standards of practice and clinicians’ biases. Prospective studies were generally limited to single centers, comprising of small sample sizes and were observational in nature, rather than randomized studies involving therapy. Ethical and legal factors, research mandates, patient factors, the protracted nature of pregnancy, institutional commitment to research, interdisciplinary clinical and research collaboration, funding support, administrative issues and the level of involvement of national cardiac and obstetric and gynecological societies have been barriers to research in pregnancy in developed countries. Even prospective observational studies are difficult to perform due the difficulties involved with obtaining consent, study recruitment and follow-up. Misconceptions regarding research have led to a lack of participation by women. The longitudinal nature of prospective studies in pregnancy, the problems associated with enrolling women before pregnancy and in the first trimester and the failure to understand the commitment required by the patient, as well as many social factors, have led to increased drop-out rates during pregnancy, as well as difficulty with follow-up in the post-partum state. These factors, along with the failure to supplement funding support due to longer study periods than anticipated, have led to studies of small sample sizes. Understanding patient factors that lead to a lack of participation in research or dropping out following initial consent could help make research participation more conducive for pregnant women. The involvement of national societies in the planning and funding of multicenter studies, interdepartmental and interinstitutional collaboration, institutional and extramural funding support and patient incentives are crucial for shortening study duration and ensuring adequacy of sample sizes for successful research in pregnancy. National health service structures, such as those found in Europe and Canada, makes multicenter collaboration for prospective studies more feasible than for countries such as the USA, in which the fees-for-service system is used. Utilization of telemedicine and handheld ultrasound systems and participation in prospective multicenter registries could not only improve the clinical care of pregnant women in underdeveloped countries, but also provide a platform for research during pregnancy. Multicenter and even global registries supported by European cardiac societies have been formed recently that are beginning to bring forth much-needed data regarding pathological states, such as peripartum cardiomyopathy and pregnancy in congenital heart disease. Such studies are largely confined to non-US countries and have started seeing participation from underdeveloped countries. Studies on pregnancy in connective tissue disorders, older women, post-chemoradiation therapy or organ transplantation and in the HIV state remain limited.

Longitudinal changes in maternal hemodynamics in a population at risk for pre-eclampsia

OBJECTIVE

To investigate longitudinal changes in maternal hemodynamics from the first trimester onward in women who develop pre-eclampsia (PE) or gestational hypertension (GH).

METHODS

This was a prospective longitudinal study of singleton pregnancies identified by screening at 11 + 0 to 13 + 6 weeks' gestation as being at high risk for PE. Measurements of augmentation index (AIx), pulsed wave velocity (PWV) and aortic systolic blood pressure (SBPao) were taken every 4 weeks until delivery. Values were compared between women who developed preterm PE requiring delivery before 37 weeks, term PE or GH, and those who remained normotensive.

RESULTS

A total of 1198 observations were recorded in 245 women, including 181 who were normotensive, 22 with preterm PE, 22 with term PE and 20 with GH. In the normotensive group, there was a U-shaped relationship between AIx and gestational age with a trough at 25 weeks' gestation, whereas changes in levels of PWV or SBPao were minimal, with a mild increase from 25 and 30 weeks' gestation onward, respectively. In the GH and preterm PE groups, compared to the normotensive group, SBPao was higher and the difference did not change significantly with gestational age. In the term PE group, SBPao did not differ significantly from that in the normotensive group. In the preterm PE group compared to the normotensive group, PWV and AIx were significantly higher from 16-17 weeks' gestation onward and the difference increased with gestational age in both cases. In the term PE and GH groups, PWV and AIx did not differ significantly from normal.

CONCLUSION

This study describes temporal changes in AIx, PWV and SBPao in normotensive pregnant women and in women who develop PE or GH.

MATERNAL CARDIAC TWIST PRE-PREGNANCY: POTENTIAL AS A NOVEL MARKER OF PRE-ECLAMPSIA

Healthy pregnancy is characterised by progressive physiological adaptation of the maternal cardiovascular (CV) system that facilitates optimal fetal development. The adaptations that constitute a healthy or normal progression are not always evident, and, in particular, CV adaptation to pregnancy is highly individualised. Some women develop pregnancy-related CV dysfunction such as pre-eclampsia (PE). Typically, PE is diagnosed by the development of hypertension and proteinuria after 20 weeks of pregnancy and is the leading cause of maternal and perinatal mortality and morbidity. Despite continued efforts to improve the understanding of the aetiology, pathophysiology and subsequently treatment for the disease, CV changes in PE are not well understood. PE before 34 weeks (early onset PE) is believed to differ in pathogenesis from late onset PE (>34 weeks) and can be characterised by a haemodynamic profile of increased systemic vascular resistance (SVR) and lower cardiac output (CO). Early onset PE is more often associated with uteroplacental insufficiency and significant adverse maternal and perinatal outcomes. In contrast, late onset PE (>34 weeks) involves an increased CO and lower SVR and is less likely to be associated with uteroplacental insufficiency and adverse perinatal outcomes. It is not known if PE develops secondary to the CV maladaptation in pregnancy or if a preexisting CV dysfunction predisposes some women to develop PE. Screening, diagnosis and disease management would be vastly improved if more were known about the onset of the maladaptive process associated with PE. To date, a combination of maternal factors including medical history, body mass index, age, parity and blood pressure (BP) have been used to predict the development of PE. In the first trimester, arterial stiffness is significantly increased in women who develop PE. Current hypotheses speculate that CV dysfunction is evident very early in pregnancy in PE and precedes the clinical manifestation at a later stage but whether CV dysfunction is present before pregnancy remains to be elucidated.

Changes in maternal posterior and anterior cerebral artery flow velocity during pregnancy and postpartum--a longitudinal study

BACKGROUND

To evaluate the normal range of blood flow velocity in the maternal anterior (ACA) and posterior cerebral arteries (PCA) along the normal pregnancy and postpartum period.

METHODS

Transcranial Doppler ultrasound was used to measure the systolic, diastolic, and mean blood velocities in the ACA and PCA during normal gestation. The resistance and pulsatility indices were calculated. Data were analyzed using multilevel modeling, incorporating random effects models, to construct mean and percentile curves.

RESULTS

We performed 355 measurements on 59 patients, which showed that systolic and mean velocity in the ACA decreased, whereas diastolic velocity increased in the PCA during normal pregnancy. Resistance and pulsatility indices in both vessels increased to a maximum in the second trimester, decreased during the third trimester, and increased during the postpartum period.

CONCLUSIONS

This study provides normative data for ACA and PCA velocity and indices during pregnancy and postpartum, demonstrating changes in velocity that suggest a shift of cerebral blood flow from the anterior to the posterior cerebral circulation.