Maternal cardiac adaptation to subsequent pregnancy in formerly pre-eclamptic women according to recurrence of pre-eclampsia

Reference ranges for third-trimester maternal cardiovascular function parameters measured in normotensive pregnant women using a non-invasive cardiac output monitor: A study based on data from the prospective PEACH cohort study

OBJECTIVE

We defined reference ranges for maternal cardiac output, systemic vascular resistance, and stroke volume measured in the third trimester of pregnancy using the Ultrasound Cardiac Output Monitor 1A.

DESIGN

Based on data from the prospective PEACH (PreEclampsia, Angiogenesis, Cardiac dysfunction and Hypertension) cohort study.

SETTING

Rigshospitalet and Hvidovre Hospital, Denmark.

SAMPLE

Normotensive pregnant women aged 18-45 years with singleton pregnancies, enrolled in the PEACH study in 2016-2018.

METHODS

We modelled cardiac output, systemic vascular resistance and stroke volume as a function of gestational age using multilevel linear models with fractional polynomials.

MAIN OUTCOME MEASURES

Unconditional and conditional reference ranges for cardiovascular parameters measured in gestational weeks 28-40.

RESULTS

Our study cohort included 405 healthy pregnant women who contributed 1210 cardiovascular function measurements for analysis. Maximum cardiac output and stroke volume values were measured in gestational weeks 30-32 and decreased over the third trimester, whereas systemic vascular resistance increased during the same period. We created reference ranges for eight combinations of maternal height, age and parity. We also created a simple calculator to allow for implementation of the reference ranges in clinical practice.

CONCLUSIONS

Our reference ranges allow the use of a bedside ultrasound device to non-invasively assess cardiac function in pregnancy and identify women at risk of complications. The unconditional ranges allow clinicians to evaluate isolated measurements and identify women needing follow-up. The conditional ranges incorporate information from previous measurements and improve monitoring over time.

Pathophysiology of Pre-Eclampsia-Two Theories of the Development of the Disease

Pre-eclampsia (PE) continues to be a leading cause of maternal and fetal mortality and morbidity. While substantial progress has been made in understanding the pathomechanisms of PE, the pathophysiology of the disease is still not fully understood. While the "two-stage model" of the development of PE is the most widely accepted theory, stating that the placenta is the main source of the disease, there are some other pathophysiological models of PE. Among these other theories, the one considering heart dysfunction as serving as the primary cause of PE seems to be gaining increasing prominence. In this review, we aim to elucidate these two divergent concepts concerning the development of PE. Despite some differences in their proposed pathomechanisms, both theories share vital pathophysiological elements in common. A central and critical component in both models is impaired placental perfusion, which appears to be a crucial phenomenon in PE. A comprehensive understanding of the different pathomechanisms involved in PE may be helpful in clinical practice, prompting a more individual approach to care of patients with PE.

Expert review: preeclampsia Type I and Type II

Pregnancy involves an interplay between maternal and fetal factors affecting changes to maternal anatomy and physiology to support the developing fetus and ensure the well-being of both the mother and offspring. A century of research has provided evidence of the imperative role of the placenta in the development of preeclampsia. Recently, a growing body of evidence has supported the adaptations of the maternal cardiovascular system during normal pregnancy and its maladaptation in preeclampsia. Debate surrounds the roles of the placenta vs the maternal cardiovascular system in the pathophysiology of preeclampsia. We proposed an integrated model of the maternal cardiac-placental-fetal array and the development of preeclampsia, which reconciles the disease phenotypes and their proposed origins, whether placenta-dominant or maternal cardiovascular system-dominant. These phenotypes are sufficiently diverse to define 2 distinct types: preeclampsia Type I and Type II. Type I preeclampsia may present earlier, characterized by placental dysfunction or malperfusion, shallow trophoblast invasion, inadequate spiral artery conversion, profound syncytiotrophoblast stress, elevated soluble fms-like tyrosine kinase-1 levels, reduced placental growth factor levels, high peripheral vascular resistance, and low cardiac output. Type I is more often accompanied by fetal growth restriction, and low placental growth factor levels have a measurable impact on maternal cardiac remodeling and function. Type II preeclampsia typically occurs in the later stages of pregnancy and entails an evolving maternal cardiovascular intolerance to the demands of pregnancy, with a moderately dysfunctional placenta and inadequate blood supply. The soluble fms-like tyrosine kinase-1-placental growth factor ratio may be normal or slightly disturbed, peripheral vascular resistance is low, and cardiac output is high, but these adaptations still fail to meet demand. Emergent placental dysfunction, coupled with an increasing inability to meet demand, more often appears with fetal macrosomia, multiple pregnancies, or prolonged pregnancy. Support for the notion of 2 types of preeclampsia observable on the molecular level is provided by single-cell transcriptomic survey of gene expression patterns across different cell classes. This revealed widespread dysregulation of gene expression across all cell types, and significant imbalance in fms-like tyrosine kinase-1 (FLT1) and placental growth factor, particularly marked in the syncytium of early preeclampsia cases. Classification of preeclampsia into Type I and Type II can inform future research to develop targeted screening, prevention, and treatment approaches.

Association between Gestational Weight Gain and Risk of Hypertensive Disorders of Pregnancy among Women with Obesity: A Multicenter Retrospective Cohort Study in Japan

The relationship between weight gain during pregnancy and the onset of hypertensive disorders of pregnancy in women with pre-pregnancy obesity remains unclear. We examined the effects of weight gain during pregnancy on hypertensive disorders of pregnancy among women with pre-pregnancy body mass index (BMI) ≥ 25.0 kg/m². This multicenter retrospective cohort study included nullipara women who delivered at two units in Japan between 1 January 2013, and 31 December 2020. Singleton primipara (n = 3040) were categorized into two pre-pregnancy BMI groups: 25.0-<30.0, and ≥30.0 kg/m². Using multiple logistic regression analyses (reported as adjusted odds ratio and 95% confidence interval), gestational weight gain effects on overall hypertensive disorders of pregnancy, gestational hypertension, and pre-eclampsia were determined. Gestational weight gain increased hypertensive disorders of pregnancy (1.09, 1.03-1.16, p < 0.05) and pre-eclampsia risk (1.10, 1.01-1.20, p < 0.05) among the BMI 25.0-<30.0 kg/m² group and hypertensive disorders of pregnancy risk among the ≥30.0 kg/m² group (1.07, 1.00-1.05, p < 0.05). Using receiver operating characteristic curve analyses, among the BMI 25.0-<30.0 kg/m² group, for hypertensive disorders of pregnancy (area under the curve [AUC], 0.63, p < 0.05) and pre-eclampsia (AUC, 0.62; p < 0.05), the weight gain cut-off was 10.5 and 10.6 kg, with sensitivity/specificity of 0.47/0.73 and 0.50/0.73, respectively. For the BMI ≥30.0 kg/m² group (AUC, 0.63, p < 0.05), the cut-off was 3.5 kg (sensitivity/specificity, 0.75/0.49). The optimal gestational weight gain for reducing hypertensive disorders of pregnancy among women with a pre-pregnancy BMI > 25 kg/m² may facilitate personalized pre-conception counseling among women with obesity.

Influence of preconception carbohydrate intake on hypertensive disorders of pregnancy: The Japan Environment and Children's Study

AIM

Hypertensive disorders of pregnancy (HDP) are a crucial cause of morbidity and mortality. We aimed to examine whether preconception carbohydrate intake is associated with new-onset HDP and small for gestational age (SGA) births.

METHODS

We identified 93 265 normotensive (primiparous, 37 387; multiparous, 55 878) participants from the Japan Environmental Children's Study database who delivered between 2011 and 2014. After excluding participants with multiple gestations, preconception hypertension, and insufficient data, primiparous and multiparous participants were categorized into five groups according to their preconception carbohydrate-intake quintiles (Q1 and Q5 were the lowest and highest groups, respectively). Multiple logistic regression analysis was performed to identify the effect of preconception carbohydrate intake on early (<34 weeks) and late-onset (≥34 weeks) HDP and the incidence of SGA births.

RESULTS

With the middle carbohydrate intake group (Q3) as a reference, the risk for late-onset HDP among multiparous women was higher in the Q5 group (adjusted odds ratio [aOR] 1.31, 95% confidence interval [CI] 1.02-1.69). The incidence of SGA births was higher in the Q1 group among both primiparous (aOR 1.16, 95% CI 1.01-1.33) and multiparous women (aOR 1.16, 95% CI 1.02-1.32).

CONCLUSIONS

Excessive carbohydrate intake increases the incidence of HDP in multiparous women, while low-carbohydrate intake increases the incidence of SGA births. New recommendations for preconception carbohydrate intake are required to prevent major HDP-related complications.

Optimal gestational weight gain to reduce the risk of hypertension disorders of pregnancy among women with obesity: A single tertiary referral center study in Japan

AIM

To examine the effect of weight gain during pregnancy on hypertension disorders of pregnancy among women with a prepregnancy body mass index ≥30.0 kg/m² .

METHODS

This retrospective cohort study included 257 Japanese women (116 primipara; 141 multipara) with singleton pregnancies with a prepregnancy body mass index ≥ 30.0 kg/m² , who gave birth during 2013 to 2020 at Ohta Nishinouchi Hospital. Multiple logistic regression analyses were performed to identify the effect of gestational weight gain on early-onset (<34 weeks), late-onset (≥34 weeks), and overall hypertension disorders of pregnancy.

RESULTS

The prevalence of hypertension disorders of pregnancy in primiparas and multiparas was 28.4% and 11.3%, respectively. By multiple logistic regression analysis, gestational weight gain during pregnancy increased the risk of early-onset (adjusted odds ratio: 1.20, 95% confidence interval: 1.03-1.39, p < 0.05) and overall hypertension disorders of pregnancy (adjusted odds ratio: 1.12, 95% confidence interval: 1.03-1.22, p < 0.05) among primiparas. Based on receiver operating characteristic curve analyses for early-onset (area under the curve 0.67, 95% confidence interval: 0.56-0.78; p < 0.05) and overall hypertension disorders of pregnancy (area under the curve 0.76, 95% confidence interval: 0.61-0.91; p < 0.05) among primiparas, we determined the cut-off weight gain during pregnancy for early-onset and overall hypertension disorders of pregnancy as 3.85 kg, with sensitivity/specificity of 0.76/0.59 and 0.91/0.53, respectively.

CONCLUSION

We recommend that the optimal gestational weight gain for reducing HDP be under 3.85 kg. This information may facilitate personalized pre-conception counseling among women with obesity.

Maternal Cardiovascular Function Following a Pregnancy Complicated by Preeclampsia

Preeclampsia is a hypertensive pregnancy complication with an unknown etiology and high maternal burden worldwide. Burgeoning research has linked preeclampsia to adverse maternal health outcomes remote from pregnancy; however, the intermediary mechanisms responsible for this association have not been sufficiently established. In the present narrative review, we summarize leading evidence of structural and functional cardiovascular changes associated with prior preeclampsia, and how these changes may be linked to future maternal disease. KEY POINTS: · Prior preeclampsia is associated with subclinical structural and functional vascular changes remote from pregnancy.. · Maternal cardiac adaptations to preeclampsia may have long-term implications on cardiovascular health.. · Clinicians have an opportunity to minimize maternal disease risk following preeclampsia..

Noninvasive Cardiac Imaging in Formerly Preeclamptic Women for Early Detection of Subclinical Myocardial Abnormalities: A 2022 Update

Preeclampsia is a maternal hypertensive disease, complicating 2–8% of all pregnancies. It has been linked to a 2–7-fold increased risk for the development of cardiovascular disease, including heart failure, later in life. A total of 40% of formerly preeclamptic women develop preclinical heart failure, which may further deteriorate into clinical heart failure. Noninvasive cardiac imaging could assist in the early detection of myocardial abnormalities, especially in the preclinical stage, when these changes are likely to be reversible. Moreover, imaging studies can improve our insights into the relationship between preeclampsia and heart failure and can be used for monitoring. Cardiac ultrasound is used to assess quantitative changes, including the left ventricular cavity volume and wall thickness, myocardial mass, systolic and diastolic function, and strain. Cardiac magnetic resonance imaging may be of additional diagnostic value to assess diffuse and focal fibrosis and perfusion. After preeclampsia, sustained elevated myocardial mass along with reduced myocardial circumferential and longitudinal strain and decreased diastolic function is reported. These findings are consistent with the early phases of heart failure, referred to as preclinical (asymptomatic) or B-stage heart failure. In this review, we will provide an up-to-date overview of the potential of cardiac magnetic resonance imaging and echocardiography in identifying formerly preeclamptic women who are at high risk for developing heart failure. The potential contribution to early cardiac screening of women with a history of preeclampsia and the pros and cons of these imaging modalities are outlined. Finally, recommendations for future research are presented.

Postpartum blood pressure self-management following hypertensive pregnancy: protocol of the Physician Optimised Post-partum Hypertension Treatment (POP-HT) trial

INTRODUCTION

New-onset hypertension affects approximately 10% of pregnancies and is associated with a significant increase in risk of cardiovascular disease in later life, with blood pressure measured 6 weeks postpartum predictive of blood pressure 5-10 years later. A pilot trial has demonstrated that improved blood pressure control, achevied via self-management during the puerperium, was associated with lower blood pressure 3-4 years postpartum. Physician Optimised Post-partum Hypertension Treatment (POP-HT) will formally evaluate whether improved blood pressure control in the puerperium results in lower blood pressure at 6 months post partum, and improvements in cardiovascular and cerebrovascular phenotypes.

METHODS AND ANALYSIS

POP-HT is an open-label, parallel arm, randomised controlled trial involving 200 women aged 18 years or over, with a diagnosis of pre-eclampsia or gestational hypertension, and requiring antihypertensive medication at discharge. Women are recruited by open recruitment and direct invitation around time of delivery and randomised 1:1 to, either an intervention comprising physician-optimised self-management of postpartum blood pressure or, usual care. Women in the intervention group upload blood pressure readings to a 'smartphone' app that provides algorithm-driven individualised medication-titration. Medication changes are approved by physicians, who review blood pressure readings remotely. Women in the control arm follow assessment and medication adjustment by their usual healthcare team. The primary outcome is 24-hour average ambulatory diastolic blood pressure at 6-9 months post partum. Secondary outcomes include: additional blood pressure parameters at baseline, week 1 and week 6; multimodal cardiovascular assessments (CMR and echocardiography); parameters derived from multiorgan MRI including brain and kidneys; peripheral macrovascular and microvascular measures; angiogenic profile measures taken from blood samples and levels of endothelial circulating and cellular biomarkers; and objective physical activity monitoring and exercise assessment. An additional 20 women will be recruited after a normotensive pregnancy as a comparator group for endothelial cellular biomarkers.

ETHICS AND DISSEMINATION

IRAS PROJECT ID 273353. This trial has received a favourable opinion from the London-Surrey Research Ethics Committee and HRA (REC Reference 19/LO/1901). The investigator will ensure that this trial is conducted in accordance with the principles of the Declaration of Helsinki and follow good clinical practice guidelines. The investigators will be involved in reviewing drafts of the manuscripts, abstracts, press releases and any other publications arising from the study. Authors will acknowledge that the study was funded by the British Heart Foundation Clinical Research Training Fellowship (BHF Grant number FS/19/7/34148). Authorship will be determined in accordance with the ICMJE guidelines and other contributors will be acknowledged.

TRIAL REGISTRATION NUMBER

NCT04273854.

An integrated model of preeclampsia: a multifaceted syndrome of the maternal cardiovascular-placental-fetal array

Maternal tolerance of the semiallogenic fetus necessitates conciliation of competing interests. Viviparity evolved with a placenta to mediate the needs of the fetus and maternal adaptation to the demands of pregnancy and to ensure optimal survival for both entities. The maternal-fetal interface is imagined as a 2-dimensional porous barrier between the mother and fetus, when in fact it is an intricate multidimensional array of tissues and resident and circulating factors at play, encompassing the developing fetus, the growing placenta, the changing decidua, and the dynamic maternal cardiovascular system. Pregnancy triggers dramatic changes to maternal hemodynamics to meet the growing demands of the developing fetus. Nearly a century of extensive research into the development and function of the placenta has revealed the role of placental dysfunction in the great obstetrical syndromes, among them preeclampsia. Recently, a debate has arisen questioning the primacy of the placenta in the etiology of preeclampsia, asserting that the maternal cardiovascular system is the instigator of the disorder. It was the clinical observation of the high rate of preeclampsia in hydatidiform mole that initiated the focus on the placenta in the etiology of the disease. Over many years of research, shallow trophoblast invasion with deficient remodeling of the maternal spiral arteries into vessels of higher capacitance and lower resistance has been recognized as hallmarks of the preeclamptic milieu. The lack of the normal decrease in uterine artery resistance is likewise predictive of preeclampsia. In abdominal pregnancies, however, an extrauterine pregnancy develops without remodeling of the spiral arteries, yet there is reduced resistance in the uterine arteries and distant vessels, such as the maternal ophthalmic arteries. Proponents of the maternal cardiovascular model of preeclampsia point to the observed maternal hemodynamic adaptations to pregnancy and maladaptation in gestational hypertension and preeclampsia and how the latter resembles the changes associated with cardiac disease states. Recognition of the importance of the angiogenic-antiangiogenic balance between placental-derived growth factor and its receptor soluble fms-like tyrosine kinase-1 and disturbance in this balance by an excess of a circulating isoform, soluble fms-like tyrosine kinase-1, which competes for and disrupts the proangiogenic receptor binding of the vascular endothelial growth factor and placental-derived growth factor, opened new avenues of research into the pathways to normal adaptation of the maternal cardiovascular and other systems to pregnancy and maladaptation in preeclampsia. The significance of the "placenta vs heart" debate goes beyond the academic: understanding the mutuality of placental and maternal cardiac etiologies of preeclampsia has far-reaching clinical implications for designing prevention strategies, such as aspirin therapy, prediction and surveillance through maternal hemodynamic studies or serum placental-derived growth factor and soluble fms-like tyrosine kinase-1 testing, and possible treatments to attenuate the effects of insipient preeclampsia on women and their fetuses, such as RNAi therapy to counteract excess soluble fms-like tyrosine kinase-1 produced by the placenta. In this review, we will present an integrated model of the maternal-placental-fetal array that delineates the commensality among the constituent parts, showing how a disruption in any component or nexus may lead to the multifaceted syndrome of preeclampsia.

l-Citrulline supplementation during pregnancy improves perinatal and postpartum maternal vascular function in a mouse model of preeclampsia

Preeclampsia is a spontaneously occurring pregnancy complication diagnosed by new-onset hypertension and end-organ dysfunction with or without proteinuria. This pregnancy-specific syndrome contributes to maternal morbidity and mortality and can have detrimental effects on fetal outcomes. Preeclampsia is also linked to increased risk of maternal cardiovascular disease throughout life. Despite intense investigation of this disorder, few treatment options are available. The aim of this study was to investigate the potential therapeutic effects of maternal l-citrulline supplementation on pregnancy-specific vascular dysfunction in the male C57BL/6J × female C57BL/6J C1q-/- preeclampsia-like mouse model. l-Citrulline is a nonessential amino acid that is converted to l-arginine to promote smooth muscle and blood vessel relaxation and improve nitric oxide (NO)-mediated vascular function. To model a preeclampsia-like pregnancy, female C57BL/6J mice were mated to C1q-/- male mice, and a subset of dams was supplemented with l-citrulline throughout pregnancy. Blood pressure, systemic vascular glycocalyx, and ex vivo vascular function were investigated in late pregnancy, and postpartum at 6 and 10 mo of age. Main findings show that l-citrulline reduced blood pressure, increased vascular glycocalyx volume, and rescued ex-vivo vascular function at gestation day 17.5 in this preeclampsia-like model. The vascular benefit of l-citrulline also extended postpartum, with improved vascular function and glycocalyx measures at 6 and 10 mo of age. l-Citrulline-mediated vascular improvements appear, in part, attributable to NO pathway signaling. Taken together, l-citrulline supplementation during pregnancy appears to have beneficial effects on maternal vascular health, which may have translational implications for improved maternal cardiovascular health.

Association between pre-pregnancy calcium intake and hypertensive disorders during the first pregnancy: the Japan environment and children's study

BACKGROUND

Determining the appropriate preconception care to reduce the occurrence of hypertensive disorder of pregnancy (HDP) remains a challenge in modern obstetrics. This study aimed to examine the association between pre-pregnancy calcium (Ca) intake and HDP in normotensive primiparas.

METHODS

We used data from the Japan Environment Children's study (JECS), which is the largest birth cohort study. A total of 33,894 normotensive Japanese primiparas were recruited for JECS between January 2011 and March 2014. Participants were categorized into five groups according to pre-pregnancy Ca intake quintiles (Q1 and Q5 were the lowest and highest Ca intake groups, respectively) to compare their basic background and obstetrics outcome. Multiple logistic regressions were performed to identify the effect of pre-pregnancy Ca intake on HDP, early onset HDP, and late-onset HDP, using Ca intake thresholds of 500, 550, 650, 700, 1000, 1500, and 1500 mg.

RESULTS

We found significant differences in maternal background among the Ca intake groups; in particular, there were more participants with low socioeconomic status, indicated by low education level and low household income, and smokers in the lowest Ca intake group. Multiple logistic regression did not show any significant difference with regard to HDP, early onset HDP, and late-onset HDP in each Ca intake threshold.

CONCLUSIONS

Despite considerable recommendations concerning Ca intake for women of reproductive age, the present study indicates that pre-pregnancy Ca intake was not associated with an increased risk of new-onset hypertension among primiparas during pregnancy. Further studies examining the effect of other pre-pregnancy dietary factors on obstetric outcomes should be considered in the formulation of earlier preventive strategies for primiparas.

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).

Changes over-time in blood pressure of women with preeclampsia compared to those with normotensive pregnancies: A 15 year population-based cohort study

OBJECTIVES

To estimate the incidence of hypertension and the trend of systolic and diastolic blood pressure changes and relating factors influencing women with and without prior preeclampsia (PE).

STUDY DESIGN

This prospective population based study included a total of 3022 eligible women (355 with PE and 2667 non-PE) recruited from participants of the Tehran Lipid and Glucose Study (TLGS) who were assessed for progression to subsequent hypertension over 15-year follow up. Pooled logistic regression model was utilized to estimate odds ratio (OR) of hypertension. The generalized estimating equation (GEE) was used to evaluate the trend of changes in hypertension parameters over time.

RESULTS

At the end of follow-ups, 109 women (30.7%) in the PE group and 575 (21.5%) in the non-PE group had hypertension. The total cumulative incident rate of hypertension was 34/1000 person-years for PE groups and 22/1000 person years for non-PE groups (P < 0.001). Pooled logistic regression analysis showed that compared to non-PE women, OR of hypertension progression in women with PE was 3.70 after adjustment for age, body mass index (BMI), parity, triglycerides (TG) and high-density lipoprotein (HDL-C) (P-value < 0.001). Based on GEE analysis, mean changes of systolic and diastolic blood pressure in PE women increased by 4.66 and 2.55 mmHg, respectively, compared to the non-PE group, after adjustment for age, and BMI at baseline (P < 0.001), although the interaction term (follow-up year × PE) was not statistically significant.

CONCLUSION

This study demonstrated increased chances of developing hypertension among women with prior PE, particularly in those who develop additional risk factors in their later life, compared to the non-PE women. While the trajectory of blood pressure change over time is similar between women with and without preeclampsia, women with a history of preeclampsia consistently have higher levels of blood pressure.

Learning from experience: cellular and molecular bases for improved outcome in subsequent pregnancies

The frequencies of preeclampsia, fetal growth restriction, fetal demise, and low birthweight are lower in subsequent pregnancies. Enhanced maternal cardiovascular adaptation, shorter first and second stages of labor, and more robust lactation also have been observed in subsequent as compared with first pregnancies. We sought to investigate the cellular and molecular bases for better outcomes in subsequent pregnancies. Based on the knowledge that specialized immune cells at the maternal-fetal interface, decidual natural killer cells, promote development of the placental bed and conversion of the spiral arteries by secreting a myriad of angiogenic and growth factors, we asked whether decidual natural killer cells differ in subsequent as compared with first pregnancies. This idea stemmed from recent studies suggesting that natural killer cells, although part of the innate immune system, possess some features of adaptive immunity, including a certain type of immune cell memory, termed trained immunity. We found that decidual natural killer cells from parous women "remember pregnancy" and differ from decidual natural killer cells of primigravidae. Compared with the decidual natural killer cells of first pregnancy, these cells, that we termed pregnancy-trained decidual natural killer cells, express greater levels of the natural killer receptors NKG2C and leukocyte immunoglobulin-like receptor B1, which interact with ligands expressed on invasive trophoblasts. Furthermore, they secrete greater levels of several growth factors, including vascular endothelial growth factor α as well as interferon-γ, augmenting remodeling of the placental bed. We propose that this pregnancy-trained memory dwells in the epigenome, where memory of stimuli is known to persist even when the stimulus is no longer present. This epigenetic memory apparently resides in endometrial natural killer cells between pregnancies. We suggest that this trained memory, which we coined pregnancy-trained decidual natural killer cells, may be the missing link in the immune basis for enhanced subsequent pregnancy. Epigenetic memory (chromatin modification) also may afford a global explanation for additional findings of enhanced maternal cardiovascular adaptation, shorter first and second stages of labor, and more robust lactation. Understanding the molecular and cellular bases of improved outcomes of subsequent pregnancy may lead to the development of treatment modalities designed for women at high risk for pregnancy disorders originating at the maternal-fetal interface.

Early-Pregnancy Circulating Antioxidant Capacity and Hemodynamic Adaptation in Recurrent Placental Syndrome: An Exploratory Study

BACKGROUND/AIMS

Placental syndromes (PS) refer to pregnancy complications that include gestational hypertension, (pre)eclampsia, HELLP syndrome, and/or placental insufficiency-induced fetal growth restriction. These disorders are characterized by increased oxidative stress. This study aims to test the hypothesis that the abnormal hemodynamic adaptation to pregnancy, typical for early PS pregnancy, is accompanied by abnormal maternal levels of antioxidants relative to those in normal pregnancy.

METHODS

Before, and at 12, 16, and 20 weeks pregnancy, we measured trolox equivalent antioxidant capacity (TEAC), uric acid (UA), and TEACC (TEAC corrected for UA) in maternal serum of former PS patients, who either developed recurrent PS (rPS; n = 16) or had a normal next pregnancy (non-rPS; n = 23). Concomitantly, we also measured various hemodynamic variables.

RESULTS

rPS differed from non-rPS by higher TEACC levels before pregnancy (178 vs. 152 µM; p = 0.02) and at 20 weeks pregnancy (180 vs. 160 µM; p = 0.04). Only non-rPS responded to pregnancy by significant rises in hemodynamic measures.

CONCLUSION

These data indicate that rPS pregnancies are preceded by an increase in antioxidant capacity, presumably induced by subclinical vascular injury and low-grade chronic inflammation.

Preeclampsia: The Relationship between Uterine Artery Blood Flow and Trophoblast Function

Maternal uterine artery blood flow is critical to maintaining the intrauterine environment, permitting normal placental function, and supporting fetal growth. It has long been believed that inadequate transformation of the maternal uterine vasculature is a consequence of primary defective trophoblast invasion and leads to the development of preeclampsia. That early pregnancy maternal uterine artery perfusion is strongly associated with placental cellular function and behaviour has always been interpreted in this context. Consistently observed changes in pre-conceptual maternal and uterine artery blood flow, abdominal pregnancy implantation, and late pregnancy have been challenging this concept, and suggest that abnormal placental perfusion may result in trophoblast impairment, rather than the other way round. This review focuses on evidence that maternal cardiovascular function plays a significant role in the pathophysiology of preeclampsia.

Maternal Venous Hemodynamic Dysfunction in Proteinuric Gestational Hypertension: Evidence and Implications

This review summarizes current knowledge from experimental and clinical studies on renal function and venous hemodynamics in normal pregnancy, in gestational hypertension (GH) and in two types of preeclampsia: placental or early-onset preeclampsia (EPE) and maternal or late-onset (LPE) preeclampsia, presenting at <34 weeks and ≥34 weeks respectively. In addition, data from maternal venous Doppler studies are summarized, showing evidence for (1) the maternal circulation functioning closer to the upper limits of capacitance than in non-pregnant conditions, with intrinsic risks for volume overload, (2) abnormal venous Doppler measurements obtainable in preeclampsia, more pronounced in EPE than LPE, however not observed in GH, and (3) abnormal venous hemodynamic function installing gradually from first to third trimester within unique pathways of general circulatory deterioration in GH, EPE and LPE. These associations have important clinical implications in terms of screening, diagnosis, prevention and management of gestational hypertensive diseases. They invite for further hypothesis-driven research on the role of retrograde venous congestion in the etiology of preeclampsia-related organ dysfunctions and their absence in GH, and also challenge the generally accepted view of abnormal placentation as the primary cause of preeclampsia. The striking similarity between abnormal maternal venous Doppler flow patterns and those observed at the ductus venosus and other abdominal veins of the intra-uterine growth restricted fetus, also invites to explore the role of venous congestion in the intra-uterine programming of some adult diseases.

Epigenetics and Preeclampsia: Programming of Future Outcomes

Pregnancy is known to induce rapid, progressive, and substantial changes to the cardiovascular system, ultimately facilitating successful pregnancy outcomes. Women who develop hypertensive disorders during pregnancy are considered to have "failed" the cardiovascular stress test of pregnancy and likely represent a subpopulation with inadequate cardiovascular accommodation. Preeclampsia is a serious complication with a myriad of manifestations in both mother and offspring. This pregnancy syndrome is a polygenic disease and has now been linked to a greater incidence of cardiovascular disease. Moreover, offsprings born to preeclamptic mothers exhibit an elevated risk of cardiovascular disease, stroke, and mental disorders during adulthood. This suggests that preeclampsia not only exposes the mother and the fetus to complications during pregnancy but also programs chronic diseases during adulthood in the offspring. The etiology of preeclampsia remains unknown, with various theories being suggested to explain its origin. It is primarily thought to be associated with poor placentation and entails excessive maternal inflammation and endothelial dysfunction. It is well established now that the maternal immune system and the placenta are involved in a highly choreographed cross talk that underlies adequate spiral artery remodeling required for uteroplacental perfusion and free flow of nutrients to the fetus. Although it is not clear whether immunological alterations occur early during pregnancy, studies have proposed that dysregulated systemic and placental immunity contribute to impaired angiogenesis and the onset of preeclampsia. Recently emerged strong evidence suggests a potential link among epigenetics, microRNAs (miRNAs), and pregnancy complications. This chapter will focus on important aspects of epigenetics, immunological aspects, and cardiovascular and vascular remodeling of preeclampsia.

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.

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.

Cardiac output assessment in pregnancy: comparison of two automated monitors with echocardiography

OBJECTIVE

To compare non-invasive hemodynamic measurements obtained in pregnant and postpartum women using two automated cardiac output monitors against those obtained by two-dimensional (2D) transthoracic echocardiography (TTE).

METHODS

This was a cross-comparison study into which we recruited 114 healthy women, either with normal singleton pregnancy (across all three trimesters) or within 72 hours following delivery. Cardiac output estimations were obtained non-invasively using two different monitors, Ultrasound Cardiac Output Monitor (USCOM®, which uses continuous-wave Doppler analysis of transaortic blood flow) and Non-Invasive Cardiac Output Monitor (NICOM®, which uses thoracic bioreactance), and 2D-TTE. The performance of each monitor was assessed relative to that of TTE by calculating bias, precision, 95% limits of agreement and mean percentage difference (MPD). Intraobserver repeatability was assessed for both monitors and interobserver reproducibility was assessed for USCOM, NICOM being operator-independent.

RESULTS

Following exclusions due to poor-quality results of a monitor or TTE, or for medical reasons, our analysis included 98 women (29 in the first trimester, 25 in the second and 21 in the third, and 23 postpartum). For cardiac output estimation, when compared with TTE, USCOM had a bias ranging from 0.4 to 0.9 L/min. The MPD of USCOM was 29% in the third-trimester cohort. NICOM had a bias ranging from -1.0 to 0.6 L/min, with a MPD of 32% in the third-trimester group. There was limited agreement between the cardiac output monitors and TTE in the first and second trimesters, with a MPD of 38% for USCOM in both first and second trimesters, and 71% and 61% for NICOM in first and second trimesters, respectively. For cardiac output estimation using USCOM, we found excellent intraobserver repeatability (intraclass correlation coefficient (ICC), 0.97; 95% CI, 0.95-0.98) and interobserver reproducibility (ICC, 0.90; 95% CI, 0.81-0.94), and the repeatability for NICOM was comparable (ICC, 0.95; 95% CI, 0.93-0.97).

CONCLUSIONS

We found good agreement of both USCOM and NICOM when compared with 2D-TTE, specifically in the third trimester of pregnancy. Both devices had good intraobserver repeatability and either had good interobserver reproducibility or were operator-independent. Future studies should take into account the significant differences in the precise maternal hemodynamic values obtained by these devices, and consider developing device-specific reference ranges in pregnancy and the postpartum period. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The role of placental histopathological lesions in predicting recurrence of preeclampsia

OBJECTIVE

We aimed to study the role of placental pathology in the prediction of preeclampsia (PE) recurrence.

METHODS

The medical records and pathological placental reports of all women diagnosed with PE, during 2008-2015, were reviewed. The study population was divided according to the outcome of their subsequent pregnancy: those who did (recurrence group) or did not (no-recurrence group) develop recurrent PE. Data regarding maternal characteristics and placental maternal/fetal vascular malperfusion lesions, of the initial pregnancies, were compared. Two prediction models were generated for PE recurrence.

RESULTS

Compared to the no-recurrence group (n = 130), the recurrence group (n = 96) was characterized by lower gestational age (p < 0.001), longer inter-pregnancy interval (p = 0.012), and higher rate of severe features (p < 0.001). By logistic regression analysis composite maternal (aOR = 3.05, 95%CI 1.39-6.71, p = 0.005), fetal (aOR = 9.31, 95%CI 3.9-22.1, p < 0.001), and concurrent maternal + fetal (aOR = 13.94, 95%CI 5.08-38.21, p < 0.001), vascular malperfusion lesions were found to be independently associated with recurrence. A clinical prediction model accounted for 20.8% of PE recurrence (R²  = 0.208, AUC = 0.732), while a clinical-pathological model accounted for 34.2% of recurrence (R²  = 0.342, AUC = 0.80).

CONCLUSION

Placental maternal and fetal vascular malperfusion lesions are independently associated with increased risk for PE recurrence. A clinical-pathological prediction model for recurrence of PE is superior to a prediction model based merely on clinical factors. © 2016 John Wiley & Sons, Ltd.

Persistent Maternal Cardiac Dysfunction After Preeclampsia Identifies Patients at Risk for Recurrent Preeclampsia

The purpose of our study was to assess cardiac function in nonpregnant women with previous early preeclampsia before a second pregnancy to highlight the cardiovascular pattern, which may take a risk for recurrent preeclampsia. Seventy-five normotensive patients with previous preeclampsia and 147 controls with a previous uneventful pregnancy were enrolled in a case-control study and submitted to echocardiographic examination in the nonpregnant state 12 to 18 months after the first delivery. All patients included in the study had pregnancy within 24 months from the echocardiographic examination and were followed until term. Twenty-two (29%) of the 75 patients developed recurrent preeclampsia. In the nonpregnant state, patients with recurrent preeclampsia compared with controls and nonrecurrent preeclampsia had lower stroke volume (63 ± 14 mL versus 73 ± 12 mL and 70 ± 11 mL, P<0.05), cardiac output (4.6 ± 1.2 L versus 5.3 ± 0.9 L and 5.2 ± 1.0 L, P<0.05), higher E/E' ratio (11.02 ± 3.43 versus 7.34 ± 2.11 versus 9.03 ± 3.43, P<0.05), and higher total vascular resistance (1638 ± 261 dyne · s(-1) · cm(-5) versus 1341 ± 270 dyne · s(-1) · cm(-5) and 1383 ± 261 dyne · s(-1) · cm(-5), P<0.05). Left ventricular mass index was higher in both recurrent and nonrecurrent preeclampsia compared with controls (30.0 ± 6.3 g/m(2.7) and 30.4 ± 6.8 g/m(2.7) versus 24.8 ± 5.0 g/m(2.7), P<0.05). Signs of diastolic dysfunction and different left ventricular characteristics are present in the nonpregnant state before a second pregnancy with recurrent preeclampsia. Previous preeclamptic patients with nonrecurrent preeclampsia show left ventricular structural and functional features intermediate with respect to controls and recurrent preeclampsia.