Maternal demographics and hemodynamics for the prediction of fetal growth restriction at booking, in pregnancies at high risk for placental insufficiency

A Bayesian Network model of pregnancy outcomes for England and Wales

Efforts to fully exploit the rich potential of Bayesian Networks (BNs) have hitherto not seen a practical approach for development of domain-specific models using large-scale public statistics which have the potential to reduce the time required to develop probability tables and train the model. As a result, the duration of projects seeking to develop health BNs tend to be measured in years due to their reliance on obtaining ethics approval and collecting, normalising, and discretising collections of patient EHRs. This work addresses this challenge by investigating a new approach to developing health BNs that combines expert elicitation with knowledge from literature and national health statistics. The approach presented here is evaluated through the development of a BN for pregnancy complications and outcomes using national health statistics for all births in England and Wales during 2021. The result is a BN that when validated using vignettes against other common types of predictive models including logistic regression and nomograms produces comparable predictions. The BN using our approach and large-scale public statistics was also developed in a project with a duration measured in months rather than years. The unique contributions of this paper are a new efficient approach to BN development and a working BN capable of reasoning over a broad range of pregnancy-related conditions and outcomes.

Machine learning: a new era for cardiovascular pregnancy physiology and cardio-obstetrics research

The maternal cardiovascular system undergoes functional and structural adaptations during pregnancy and postpartum to support increased metabolic demands of offspring and placental growth, labor, and delivery, as well as recovery from childbirth. Thus, pregnancy imposes physiological stress upon the maternal cardiovascular system, and in the absence of an appropriate response it imparts potential risks for cardiovascular complications and adverse outcomes. The proportion of pregnancy-related maternal deaths from cardiovascular events has been steadily increasing, contributing to high rates of maternal mortality. Despite advances in cardiovascular physiology research, there is still no comprehensive understanding of maternal cardiovascular adaptations in healthy pregnancies. Furthermore, current approaches for the prognosis of cardiovascular complications during pregnancy are limited. Machine learning (ML) offers new and effective tools for investigating mechanisms involved in pregnancy-related cardiovascular complications as well as the development of potential therapies. The main goal of this review is to summarize existing research that uses ML to understand mechanisms of cardiovascular physiology during pregnancy and develop prediction models for clinical application in pregnant patients. We also provide an overview of ML platforms that can be used to comprehensively understand cardiovascular adaptations to pregnancy and discuss the interpretability of ML outcomes, the consequences of model bias, and the importance of ethical consideration in ML use.

The "Preeclampsia and Hypertension Target Treatment" study: a multicenter prospective study to evaluate the effectiveness of the antihypertensive therapy based on maternal hemodynamic findings

BACKGROUND

Despite major advances in the pharmacologic treatment of hypertension in the nonpregnant population, treatments for hypertension in pregnancy have remained largely unchanged over the years. There is recent evidence that a more adequate control of maternal blood pressure is achieved when the first given antihypertensive drug is able to correct the underlying hemodynamic disorder of the mother besides normalizing the blood pressure values.

OBJECTIVE

This study aimed to compare the blood pressure control in women receiving an appropriate or inappropriate antihypertensive therapy following the baseline hemodynamic findings.

STUDY DESIGN

This was a prospective multicenter study that included a population of women with de novo diagnosis of hypertensive disorders of pregnancy. A noninvasive assessment of the following maternal parameters was performed on hospital admission via Ultrasound Cardiac Output Monitor before any antihypertensive therapy was given: cardiac output, heart rate, systemic vascular resistance, and stroke volume. The clinician who prescribed the antihypertensive therapy was blinded to the hemodynamic evaluation and used as first-line treatment a vasodilator (nifedipine or alpha methyldopa) or a beta-blocker (labetalol) based on his preferences or on the local protocols. The first-line pharmacologic treatment was retrospectively considered hemodynamically appropriate in either of the following circumstances: (1) women with a hypodynamic profile (defined as low cardiac output [≤5 L/min] and/or high systemic vascular resistance [≥1300 dynes/second/cm2]) who were administered oral nifedipine or alpha methyldopa and (2) women with a hyperdynamic profile (defined as normal or high cardiac output [>5 L/min] and/or low systemic vascular resistances [<1300 dynes/second/cm2]) who were administered oral labetalol. The primary outcome of the study was to compare the occurrence of severe hypertension between women treated with a hemodynamically appropriate therapy and women treated with an inappropriate therapy.

RESULTS

A total of 152 women with hypertensive disorders of pregnancy were included in the final analysis. Most women displayed a hypodynamic profile (114 [75.0%]) and received a hemodynamically appropriate treatment (116 [76.3%]). The occurrence of severe hypertension before delivery was significantly lower in the group receiving an appropriate therapy than in the group receiving an inappropriately treated (6.0% vs 19.4%, respectively; P=.02). Moreover, the number of women who achieved target values of blood pressure within 48 to 72 hours from the treatment start was higher in the group who received an appropriate treatment than in the group who received an inappropriate treatment (70.7% vs 50.0%, respectively; P=.02).

CONCLUSION

In pregnant individuals with de novo hypertensive disorders of pregnancy, a lower occurrence of severe hypertension was observed when the first-line antihypertensive agent was tailored to the correct maternal hemodynamic profile.

Construction of prediction model for fetal growth restriction during first trimester in an Asian population

OBJECTIVE

To construct a prediction model for fetal growth restriction (FGR) during the first trimester of pregnancy and evaluate its screening performance.

METHODS

This was a prospective cohort study of singleton pregnancies that underwent routine ultrasound screening at 11 to 13 + 6 weeks at the Affiliated Suzhou Hospital of Nanjing Medical University between January 2019 and April 2022. Basic clinical information, ultrasound indicators and serum biomarkers of pregnant women were collected. Fetal weight assessment was based on the fetal growth curve for the Southern Chinese population. FGR was diagnosed according to Delphi consensus criteria. Least absolute shrinkage and selection operator (lasso) regression was used to select variables for inclusion in the model. Discrimination, calibration and clinical effectiveness of the model were evaluated in training and validation cohorts.

RESULTS

A total of 1188 pregnant women were included, of whom 108 had FGR. Lasso regression identified seven predictive features, including history of maternal hypertension, maternal smoking or passive smoking, gravidity, uterine artery pulsatility index, ductus venosus pulsatility index and multiples of the median values of placental growth factor and soluble fms-like tyrosine kinase-1. The nomogram prediction model constructed from these seven variables accurately predicted FGR, and the area under the receiver-operating-characteristics curve in the validation cohort was 0.82 (95% CI, 0.74-0.90). The calibration curve and Hosmer-Lemeshow test demonstrated good calibration, and the clinical decision curve and clinical impact curve supported its practical value in a clinical setting.

CONCLUSION

The multi-index prediction model for FGR has good predictive value during the first trimester. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

An update on maternal cardiac hemodynamics in fetal growth restriction and pre-eclampsia

Pre-eclampsia and fetal growth restriction (FGR) have been long related to primary placental dysfunction, caused by abnormal trophoblast invasion. Nevertheless, emerging evidence has led to a new hypothesis for the origin of pre-eclampsia and FGR. Suboptimal maternal cardiovascular adaptation has been shown to result in uteroplacental hypoperfusion, ultimately leading to placental hypoxic damage with secondary dysfunction. In this review, we summarize current evidence on maternal cardiac hemodynamics in FGR and pre-eclampsia. We also discuss the different approaches for antihypertensive treatment according to the hemodynamic phenotype observed in pre-eclampsia and FGR.

Maternal Low Volume Circulation Relates to Normotensive and Preeclamptic Fetal Growth Restriction

This narrative review summarizes current evidence on the association between maternal low volume circulation and poor fetal growth. Though much work has been devoted to the study of cardiac output and peripheral vascular resistance, a low intravascular volume may explain why high vascular resistance causes hypertension in women with preeclampsia (PE) that is associated with fetal growth restriction (FGR) and, at the same time, presents with normotension in FGR itself. Normotensive women with small for gestational age babies show normal gestational blood volume expansion superimposed upon a constitutionally low intravascular volume. Early onset preeclampsia (EPE; occurring before 32 weeks) is commonly associated with FGR, and poor plasma volume expandability may already be present before conception, thus preceding gestational volume expansion. Experimentally induced low plasma volume in rodents predisposes to poor fetal growth and interventions that enhance plasma volume expansion in FGR have shown beneficial effects on intrauterine fetal condition, prolongation of gestation and birth weight. This review makes the case for elevating the maternal intravascular volume with physical exercise with or without Nitric Oxide Donors in FGR and EPE, and evaluating its role as a potential target for prevention and/or management of these conditions.

Fetal Growth Restriction: Does an Integrated Maternal Hemodynamic-Placental Model Fit Better?

In recent years, a growing interest has arisen regarding the possible relationship between adverse pregnancy outcomes (APOs) and inadequate maternal hemodynamic adaptations to the pregnancy. A possible association between "placental syndromes," such as preeclampsia (PE) and fetal growth restriction (FGR), and subsequent maternal cardiovascular diseases (CVD) later in life has been reported. The two subtypes of FGR show different pathogenetic and clinical features. Defective placentation, due to a poor trophoblastic invasion of the maternal spiral arteries, is believed to play a central role in the pathogenesis of early-onset PE and FGR. Since placental functioning is dependent on the maternal cardiovascular system, a pre-existent or subsequent cardiovascular impairment may play a key role in the pathogenesis of early-onset FGR. Late FGR does not seem to be determined by a primary abnormal placentation in the first trimester. The pathological pathway of late-onset FGR may be due to a primary maternal cardiovascular maladaptation: CV system shows a flat profile and remains similar to those of non-pregnant women. Since the second trimester, when the placenta is already developed and increases its functional request, a hypovolemic state could lead to placental hypoperfusion and to an altered maturation of the placental villous tree and therefore to an altered fetal growth. Thus, this review focalizes on the possible relationship between maternal cardiac function and placentation in the development of both early and late-onset FGR. A better understanding of maternal hemodynamics in pregnancies complicated by FGR could bring various benefits in clinical practice, improving screening and therapeutic tools.

Hemodynamic findings in normotensive women with small-for-gestational-age and growth-restricted fetuses

INTRODUCTION

Fetal growth restriction (FGR) in most instances is a consequence of primary placental dysfunction due to inadequate trophoblastic invasion. Maternal cardiac maladaptation to pregnancy has been proposed as a possible determinant of placental insufficiency and impaired fetal growth. This study aimed to compare the maternal hemodynamic parameters between normotensive women with small-for-gestational-age (SGA) and FGR fetuses and to evaluate their correlation with neonatal outcome.

MATERIAL AND METHODS

An observational cohort study including singleton pregnancies referred to our tertiary care center due to fetal smallness. At the time of diagnosis, fetuses were classified as SGA or FGR according to the Delphi consensus criteria, and pregnant women underwent hemodynamic assessment using a cardiac output monitor. A group of women with singleton uncomplicated pregnancies ar ≥35 weeks of gestation were recruited as controls. Cardiac output, systemic vascular resistance, stroke volume, and heart rate were measured and compared among the three groups (controls vs FGR vs SGA). The correlation between antenatal findings and neonatal outcome was also evaluated by multivariate logistic regression analysis.

RESULTS

A total of 51 women with fetal smallness were assessed at 34.8 ± 2.6 weeks. SGA and FGR were diagnosed in 22 and 29 cases, respectively. The control group included 61 women assessed at 36.5 ± 0.8 weeks of gestation. Women with FGR had a lower cardiac output Z-score (respectively, -1.3 ± 1.2 vs -0.4 ± 0.8 vs -0.2 ± 1.0; P < .001) and a higher systemic vascular resistance Z-score (respectively, 1.2 ± 1.2 vs 0.2 ± 1.1 vs -0.02 ± 1.2; P < .001) compared with both SGA and controls, whereas no difference in the hemodynamic parameters was found between women with SGA and controls. The incidence of neonatal intensive care unit admission did not differ between SGA and FGR fetuses (18.2% vs 41.4%; P = .13), but FGR fetuses had a longer hospitalization compared with SGA fetuses (14.2 ± 17.7 vs 4.5 ± 1.6 days; P = .02). Multivariate analysis showed that the cardiac output Z-score at diagnosis (P = .012) and the birthweight Z-score (P = .007) were independent predictors of the length of neonatal hospitalization.

CONCLUSIONS

Different maternal hemodynamic profiles characterize women with SGA or FGR fetuses. Furthermore, a negative correlation was found between the maternal cardiac output and the length of neonatal hospitalization.

Hemodynamic Complications in Pregnancy: Preeclampsia and Beyond

Normal pregnancy is a complex and dynamic process that requires significant adaptation from the maternal system. Failure of this adaptive process in pregnancy contributes to many pregnancy related disorders, including the hypertensive disorders of pregnancy. This article discusses placental development and how abnormalities in the process of vascular remodeling contribute to the multisystem maternal and fetal disease that is preeclampsia and fetal growth restriction. We review some of the consequences of this condition on the mother and fetus, aspects of the clinical management of preeclampsia and how it can influence both mother and infant in the postnatal period and beyond.

Central hemodynamics are associated with fetal outcomes in pregnancies of advanced maternal age

OBJECTIVES

Age is a known risk factor for both maternal cardiovascular disease and adverse outcomes in pregnancy. We aimed to characterize the hemodynamic profiles in pregnancies of advanced maternal age (AMA) and correlate these with fetal outcomes.

STUDY DESIGN

This was a prospective observational study of pregnancies undergoing antenatal testing. Maternal hemodynamics were measured non-invasively using an imaging probe at the descending aorta and the Uscom BP + arm cuff utilizing pulse pressure wave analysis. The Wilcoxon rank-sum test, Fisher's exact test, and Spearman rank correlation test were used for statistical analysis in R.

MAIN OUTCOME MEASURES

Hemodynamic measurements, neonatal birthweight.

RESULTS

Twenty-one AMA and twenty-four control patients were enrolled. Mean age ± SD was 39 ± 3.22 in the AMA cohort and 28 ± 4.32 in the control cohort (p < 0.001). AMA patients were evaluated at a later gestational age (36 4/7 weeks) compared to control (34 1/7 weeks, p = 0.02). Between groups, there was no difference in BMI, race, hypertensive disease, diabetes, asthma, drug use, or indication for antenatal testing. 38% (AMA) and 37% (control) had hypertensive disorders of pregnancy. In AMA patients but not control patients, cardiac output (r = 0.52, p = 0.01), systemic vascular resistance (r = -0.53, p = 0.01), and systemic vascular resistance index (r = -0.62, p = 0.002) were significantly correlated with neonatal birthweight percentile.

CONCLUSIONS

Hemodynamic alterations consistent with a low output, high resistance cardiovascular circuit were associated with lower birthweight in AMA, but not in control pregnancies.

The effect of parity on longitudinal maternal hemodynamics

BACKGROUND

Parous women have a lower risk for pregnancy complications, such as preeclampsia or delivery of small-for-gestational-age neonates. However, parous women are a heterogeneous group of patients because they contain a low-risk cohort with previously uncomplicated pregnancies and a high-risk cohort with previous pregnancies complicated by preeclampsia and/or small for gestational age. Previous studies examining the effect of parity on maternal hemodynamics, including cardiac output and peripheral vascular resistance, did not distinguish between parous women with and without a history of preeclampsia or small for gestational age and reported contradictory results.

OBJECTIVE

The objective of the study was to compare maternal hemodynamics in nulliparous women and in parous women with and without previous preeclampsia and/or small for gestational age.

STUDY DESIGN

This was a prospective, longitudinal study of maternal hemodynamics, assessed by a bioreactance method, measured at 11⁺⁰ to 13⁺⁶, 19⁺⁰ to 24⁺⁰, 30⁺⁰ to 34⁺⁰, and 35⁺⁰ to 37⁺⁰ weeks' gestation in 3 groups of women. Group 1 was composed of parous women without a history of preeclampsia and/or small for gestational age (n = 632), group 2 was composed of nulliparous women (n = 829), and group 3 was composed of parous women with a history of preeclampsia and/or small for gestational age (n = 113). A multilevel linear mixed-effects model was performed to compare the repeated measures of hemodynamic variables controlling for maternal characteristics, medical history, and development of preeclampsia or small for gestational age in the current pregnancy.

RESULTS

In groups 1 and 2, cardiac output increased with gestational age to a peak at 32 weeks and peripheral vascular resistance showed a reversed pattern with its nadir at 32 weeks; in group 1, compared with group 2, there was better cardiac adaptation, reflected in higher cardiac output and lower peripheral vascular resistance. In group 3 there was a hyperdynamic profile of higher cardiac output and lower peripheral vascular resistance at the first trimester followed by an earlier sharp decline of cardiac output and increase of peripheral vascular resistance from midgestation. The incidence of preeclampsia and small for gestational age was highest in group 3 and lowest in group 1.

CONCLUSION

There are parity-specific differences in maternal cardiac adaptation in pregnancy.

Maternal hemodynamics in screen-positive and screen-negative women of the ASPRE trial

OBJECTIVE

To compare maternal hemodynamics and perinatal outcome, in pregnancies that do not develop pre-eclampsia (PE) or deliver a small-for-gestational-age (SGA) neonate, between those identified at 11-13 weeks' gestation as being screen positive or negative for preterm PE, by a combination of maternal factors, mean arterial pressure, uterine artery pulsatility index, serum placental growth factor and pregnancy associated plasma protein-A.

METHODS

This was a prospective longitudinal cohort study of maternal cardiovascular function, assessed using a bioreactance method, in women undergoing first-trimester screening for PE. Maternal hemodynamics and perinatal outcome were compared between screen-positive and screen-negative women who did not have a medical comorbidity, did not develop PE or pregnancy-induced hypertension and delivered at term a live neonate with birth weight between the 5^th and 95^th percentiles. A multilevel linear mixed-effects model was used to compare the repeated measures of cardiac variables, controlling for maternal characteristics.

RESULTS

The screen-negative group (n = 926) had normal cardiac function changes across gestation, whereas the screen-positive group (n = 170) demonstrated static or reduced cardiac output and stroke volume and higher mean arterial pressure and peripheral vascular resistance with advancing gestation. In the screen-positive group, compared with screen-negative women, birth-weight Z-score was shifted toward lower values, with prevalence of delivery of a neonate below the 35^th , 30^th or 25^th percentile being about 70% higher, and the rate of operative delivery for fetal distress in labor also being higher.

CONCLUSION

Women who were screen positive for impaired placentation, even though they did not develop PE or deliver a SGA neonate, had pathological cardiac adaptation in pregnancy and increased risk of adverse perinatal outcome. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Pentaerythrityltetranitrate (PETN) improves utero- and feto-placental Doppler parameters in pregnancies with impaired utero-placental perfusion in mid-gestation - a secondary analysis of the PETN-pilot trial

AIM

In pregnancies complicated by impaired utero-placental perfusion, pentaeritrithyltetranitrate (PETN) has been shown to reduce the risk of severe fetal growth restriction (FGR) and perinatal death by 39%. The effect is most likely related to the vasodilatative influence of PETN. To assess its impact on utero-placental and fetal perfusion, we analyzed the Doppler parameters measured during the PETN pilot-trial.

METHODS

One hundred and eleven pregnancies presenting impaired utero-placental resistance at mid-gestation were included in the trial. Fifty-four women received PETN, while 57 received a placebo. Doppler velocimetry measurements were monitored biweekly. Statistical analysis was performed using a mixed linear model.

RESULTS

Within the first week of treatment, the mean pulsatility index (PI) of the uterine artery (UtA) dropped more prominently in the PETN group [-0.20, 95% confidence interval (CI): -0.34 to -0.05, P=0.007). The adjusted relative risk (RR) for abnormal cerebro-placental ratio (CPR) was significantly reduced by PETN [RR 0.412 (95% CI: 0.181-0.941)]. Kaplan-Meier analysis demonstrates the postponement of absent end-diastolic flow (AED), absent or reverse end-diastolic flow (ARED), brain sparing and abnormal cerebroplacental ratio (CPR) in the PETN group.

CONCLUSION

The demonstrated effect of PETN on utero-placental and feto-placental perfusion strengthens the evidence for a positive impact in pregnancies complicated by impaired placental perfusion and might explain the effect on neonatal outcome, as shown in the PETN-pilot trial.

Maternal hemodynamics, fetal biometry and Doppler indices in pregnancies followed up for suspected fetal growth restriction

OBJECTIVES

To assess whether, in a cohort of patients with a small-for-gestational-age (SGA) fetus with estimated fetal weight ≤ 10^th percentile, maternal hemodynamics, fetal biometry and Doppler indices at presentation can predict the subsequent development of an abnormal fetal Doppler index or delivery of a baby with birth weight < 3^rd percentile.

METHODS

This was a prospective observational cohort study conducted at a specialist clinic for the management of pregnancies with a SGA fetus at King's College Hospital, London, UK. The study population comprised 86 singleton pregnancies with a SGA fetus, presenting at a median gestational age of 32 (range, 26-35) weeks. We measured maternal cardiac function using a non-invasive transthoracic bioreactance monitor, as well as mean arterial pressure, fetal biometry, and umbilical artery (UA), fetal middle cerebral artery (MCA) and uterine artery (UtA) pulsatility indices (PI), and the deepest vertical pool of amniotic fluid. Z-scores of these variables were calculated based on reported reference ranges and the values were compared between pregnancies with evidence of an abnormal fetal Doppler index at presentation (Group 1), those that had developed an abnormal Doppler index at a subsequent visit (Group 2) and those that did not develop an abnormal Doppler index throughout pregnancy (Group 3). Abnormal fetal Doppler was defined as UA-PI > 95^th percentile and/or MCA-PI < 5^th percentile. Differences in measured variables at presentation were also compared between pregnancies delivering a baby with birth weight < 3^rd percentile and those delivering a baby with birth weight ≥ 3^rd percentile. Multivariate logistic regression analysis was used to determine significant predictors of birth weight < 3^rd percentile and evolution from normal to abnormal fetal Doppler.

RESULTS

In the study population, 14 (16%) cases were in Group 1, 19 (22%) in Group 2 and 53 (62%) in Group 3. Birth weight was < 3^rd percentile in 39 (45%) cases and ≥ 3^rd percentile in 47 (55%). There was decreased cardiac output and stroke volume and increased peripheral vascular resistance compared with a normal population, and the deviations from normal were most marked in Group 1. Pregnancies with birth weight < 3^rd percentile, compared with those with birth weight ≥ 3^rd percentile, had greater deviations from normal in fetal biometry, maternal cardiac output, stroke volume, heart rate, peripheral vascular resistance and UtA-PI. Multivariate logistic regression analysis demonstrated that, in the prediction of birth weight < 3^rd percentile, maternal hemodynamic profile provided significant improvement to the prediction provided by maternal demographics, fetal biometry, UtA-PI, UA-PI and MCA-PI (difference between areas under receiver-operating characteristics curves, 0.18 (95% CI, 0.06-0.29); P = 0.002). In contrast, there was no significant independent contribution from maternal hemodynamics in the prediction of the subsequent development of abnormal fetal Doppler.

CONCLUSIONS

In pregnancies with a SGA fetus, there is decreased maternal cardiac output and stroke volume and increased peripheral vascular resistance, and the deviations from normal are most marked in cases of redistribution in the fetal circulation and reduced amniotic fluid volume. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Maternal hemodynamics in normal pregnancy and in pregnancy affected by pre-eclampsia

OBJECTIVES

To determine if, in a high-risk group of women in the first half of pregnancy, those who develop pre-eclampsia (PE) with fetal growth restriction (FGR) demonstrate distinct hemodynamics compared with those with PE in the absence of FGR (PE only).

METHODS

Cardiac output (CO), peripheral vascular resistance (PVR) and mean arterial pressure (MAP) were measured at the first hospital visit at 9-24 weeks' gestation in 69 women who had chronic hypertension and 67 who had had a hypertensive disorder in a previous pregnancy. These women were divided into five groups according to pregnancy outcome. In total, 19 subsequently developed PE only, 22 developed PE with FGR, 17 developed pregnancy-induced hypertension, 39 had chronic hypertension without PE or FGR and 39 had had a hypertensive disorder in a previous pregnancy without PE, pregnancy-induced hypertension or FGR in the index pregnancy. The hemodynamic values in each of these groups were compared with those in a cohort of 300 low-risk women with normal pregnancy.

RESULTS

In all the high-risk groups, PVR and MAP were higher than in women with a normal pregnancy, but CO was lower in the group of women with PE and FGR, whereas in the other high-risk groups, it was not significantly different from normal.

CONCLUSIONS

In women who develop PE, there is evidence of high PVR and MAP from the first half of pregnancy, whilst PE and FGR are associated with failure in physiological expansion of CO. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Effect of change in posture on maternal functional hemodynamics at 35-37 weeks' gestation

OBJECTIVES

To evaluate the effect of posture change from the supine to the sitting position and before and after passive leg raising on maternal functional hemodynamics in pregnant women at 35-37 weeks' gestation, and to compare the changes in pregnancies that subsequently developed pre-eclampsia (PE) or gestational hypertension (GH) with those that remained normotensive.

METHODS

In 2764 singleton pregnancies at 35-37 weeks' gestation, maternal cardiovascular parameters were measured using an automated non-invasive cardiac monitor. The hemodynamic response to a change from the supine to the sitting position and before and after passive leg raising in the left lateral position was examined and compared between women who subsequently developed PE or GH and those who remained normotensive.

RESULTS

In normotensive singleton pregnancies at 35-37 weeks' gestation, both change from the supine to the sitting position and passive leg raising were associated with an increase in cardiac index and stroke volume index and a decrease in total peripheral resistance index; there was a small increase in mean arterial pressure with both postural changes and a slight decrease in heart rate with passive leg raising. In pregnancies that subsequently developed PE or GH, compared with normotensive pregnancies, cardiac index and stroke volume index were lower and total peripheral resistance index was higher. In general, change from the supine to the sitting position and passive leg raising were associated with similar but less marked changes in cardiovascular parameters as in normotensive pregnancies.

CONCLUSIONS

Paradoxically, in late third-trimester normal pregnancy, both change from the supine to a sitting position and passive leg raising may result in an increase in preload with a consequent increase in cardiac and stroke volume indices and a decrease in total peripheral resistance index. In pregnancies that develop PE or GH, the effects of postural change on cardiovascular parameters are similar but less marked than in normotensive pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Skeletal Muscle Damage in Intrauterine Growth Restriction

Intrauterine growth restriction (IUGR) represents a rate of fetal growth that is less than average for the population and the growth potential of a specific infant. IUGR produces infants who are small for gestational age (SGA) but also appropriate for gestational age (AGA). It refers to growth less than expected for gestational age and is most often under 10th percentiles for age. It develops during the late second and third trimesters of gestation. The etiology of IUGR is multifactorial. One of the most important factors which leads to IUGR is a decrease of nutrients and oxygen delivered to the fetus by the placenta. The growth of adipose tissue and skeletal muscle is limited by the declined fetal nutrient supply later in gestation. IUGR affects about 24% of babies born in developing countries. Worldwide, IUGR is the second cause of perinatal morbidity and mortality behind the premature birth and a major predisposing factor to metabolic disorders throughout postnatal life, even at adult age. Skeletal muscle represents about 35-40% of the body mass and plays an essential role in metabolic homeostasis, being responsible for 65% of fetal glucose consumption. A reduction in skeletal muscle growth characterizes IUGR fetuses compared to normal weight neonates. The decrease in muscle mass is not compensated after birth and persists until adulthood. This is a review of the literature, a neonatological, clinical point of view on the effects of IUGR on striated muscles. The available studies on this subject are currently the results of experimental research on animals, and information about the human fetus and newborn are scarce.

Longitudinal maternal hemodynamics in pregnancies affected by fetal growth restriction

OBJECTIVE

Fetal growth restriction (FGR) is a powerful determinant of poor perinatal outcome. From our previous work in pregnancies at high risk of development of hypertension we found impaired cardiovascular adaptation early in gestation in those destined to deliver growth-restricted infants. In this study, we monitored serially maternal hemodynamics from the first to third trimester in a similar high-risk cohort, in order to determine whether this distinct hemodynamic profile found at presentation persisted throughout pregnancy in those complicated by FGR.

METHODS

This was a prospective observational study based at a specialist antenatal hypertension clinic at a tertiary hospital in London. Maternal hemodynamics were evaluated serially using a non-invasive bioreactance method in pregnant women referred to the clinic with a history of chronic hypertension or a history of hypertensive disorder in a previous pregnancy. Differences in maternal hemodynamic parameters were compared between women who delivered a baby with a birth weight ≥ 10^th vs < 10^th percentile and ≥ 5^th vs < 5^th percentile.

RESULTS

Eighty-four pregnant women were included in the study. Mean gestational age at presentation was 14.3 weeks. Sixteen women delivered babies with a birth weight < 10^th percentile and 11 with a birth weight < 5^th percentile. In pregnancies with a birth weight ≥ 10^th percentile, longitudinal maternal hemodynamics showed a pattern consistent with well-established physiological changes in pregnancy, i.e. a reduction in vascular resistance and an increase in cardiac output with advancing gestation until mid-pregnancy. However, women who delivered babies with a birth weight < 10^th percentile showed a static pattern with no change during gestation and lower cardiac output and higher peripheral vascular resistance. Similar differences were seen when the 5^th percentile was used to discriminate between appropriately-grown and growth-restricted babies.

CONCLUSION

Serial assessment of maternal hemodynamics in high-risk women identifies distinctive trends associated with pregnancies destined to deliver babies with birth weights < 10^th and < 5^th percentiles. These pregnancies have a suppressed and static maternal cardiac output and stroke volume, and have consistently raised peripheral vascular resistance. This suggests that, in women with chronic hypertension or a history of hypertensive disorder in a previous pregnancy, FGR is associated with a primary and persistent failure of maternal cardiovascular adaptation in pregnancy. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Longitudinal hemodynamics in acute phase of treatment with labetalol in hypertensive pregnant women to predict need for vasodilatory therapy

OBJECTIVE

Hypertensive pregnant women who do not respond to treatment with labetalol to control blood pressure (BP), but require vasodilatory therapy, progress rapidly to severe hypertension. This could be delayed by early recognition and individualized treatment. In this study, we sought to create prediction models from data at presentation and at 1 h and 24 h after commencement of treatment to identify patients who will not have a sustained response to labetalol and therefore need vasodilatory therapy.

METHODS

The study population comprised 134 women presenting with hypertension at a UK hospital. Treatment with oral labetalol was administered when BP was > 150/100 mmHg or > 140/90 mmHg with systemic disease. BP and hemodynamic parameters were recorded at presentation and at 1 h and 24 h after commencement of treatment. Labetalol doses were titrated to maintain BP around 135/85 mmHg. Women with unresponsive BP, despite labetalol dose maximization (2400 mg/day), received additional vasodilatory therapy with nifedipine. Binary logistic and longitudinal (mixed-model) data analyses were performed to create prediction models anticipating the likelihood of hypertensive women needing vasodilatory therapy. The prediction models were created from data at presentation and at 1 h and 24 h after treatment, to assess the value of central hemodynamics relative to the predictive power of BP, heart rate and demographic variables at these intervals.

RESULTS

Twenty-two percent of our cohort required additional vasodilatory therapy antenatally. These women had higher rates of severe hypertension and delivered smaller babies at earlier gestational ages. The unresponsive women were more likely to be of black ethnicity, had higher BP and peripheral vascular resistance (PVR), and lower heart rate and cardiac output (CO) at presentation. Those who needed vasodilatory therapy showed an initial decrease in BP and PVR, which rebounded at 24 h, whereas BP and PVR in those who responded to labetalol showed a sustained decrease at 1 h and 24 h. Stroke volume and CO did not decrease during the acute phase of treatment in either group. The best model for prediction of the need for vasodilators was provided at 24 h by combining ethnicity and longitudinal BP and heart rate changes. The model achieved a detection rate of 100% for a false-positive rate of 20% and an area under the receiver-operating characteristics curve of 0.97.

CONCLUSION

Maternal demographics and hemodynamic changes in the acute phase of labetalol monotherapy provide a powerful tool to identify hypertensive pregnant patients who are unlikely to have their BP controlled by this therapy and will consequently need additional vasodilatory therapy. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

RESUMEN OBJETIVO

Las embarazadas hipertensas que no responden al tratamiento con labetalol para el control de la presión arterial (PA), pero que requieren terapia vasodilatadora, evolucionan rápidamente hacia una hipertensión severa. Ésta se puede retrasar mediante un diagnóstico precoz y un tratamiento individual. En este estudio se ha tratado de crear modelos de predicción a partir de datos al inicio del tratamiento y al cabo de 1 hora y de 24 horas después del mismo, para identificar a las pacientes que no mostrarán una respuesta constante al labetalol y que por lo tanto necesitarán terapia vasodilatadora. MÉTODOS: La población de estudio incluyó 134 mujeres con hipertensión en un hospital del Reino Unido. El tratamiento con labetalol por vía oral se administró cuando la PA fue >150/100 mm de Hg o >140/90 mm de Hg con enfermedad multisistémica. Se registró la PA y los parámetros hemodinámicos tanto al inicio como al cabo de 1 h y de 24 h después del inicio del tratamiento. Las dosis de Labetalol se ajustaron para mantener la PA en torno a los 135/85 mm de Hg. Las mujeres cuya PA no produjo respuesta, a pesar de haberles administrado la dosis máxima de labetalol (2400 mg/día), recibieron terapia vasodilatadora adicional con nifedipino. Se realizaron análisis de datos mediante logística binaria y longitudinal (modelo mixto), para crear modelos de predicción con los que pronosticar la probabilidad de la necesidad de terapia vasodilatadora en mujeres hipertensas. Los modelos de predicción se crearon a partir de datos al inicio y al cabo de 1 hora y 24 horas del tratamiento, para evaluar el valor de los parámetros hemodinámicos principales con respecto a la capacidad predictiva de la PA, la frecuencia cardíaca y las variables demográficas en estos intervalos.

RESULTADOS

El 22 % de la cohorte necesitó terapia vasodilatadora adicional antes del parto. Estas mujeres tuvieron tasas más altas de hipertensión grave y neonatos más pequeños en edades gestacionales más tempranas. Las mujeres que no respondieron al tratamiento fueron con más frecuencia de raza negra, tuvieron la PA y la resistencia vascular periférica (RVP) más alta, y la frecuencia cardíaca y el gasto cardíaco (GC) más bajos al inicio del tratamiento. Aquellas que necesitaron terapia vasodilatadora mostraron un descenso inicial de la PA y la RVP, que se recuperó al cabo de 24 h, mientras que la PA y la RVP en las que respondieron al labetalol mostraron una disminución constante al cabo de 1 h y de 24 h. El volumen sistólico y el GC no disminuyeron durante la fase aguda del tratamiento en ninguno de los grupos. El mejor modelo para la predicción de la necesidad de vasodilatadores se obtuvo a las 24 h mediante la combinación de la etnia con los cambios longitudinales de la PA y la frecuencia cardíaca. El modelo alcanzó una tasa de detección del 100% para una tasa de falsos positivos del 20% y un área bajo la curva de características operativas del receptor de 0,97. CONCLUSIÓN: Los datos demográficos maternos y los cambios hemodinámicos en la fase aguda de la monoterapia con labetalol constituyen una herramienta poderosa para identificar a las pacientes embarazadas hipertensas con pocas probabilidades de que se les pueda controlar su PA mediante esta terapia y que por lo tanto necesitarán terapia vasodilatadora adicional. : 、(blood pressure,BP),。。,1 h24 h,。 : 134。BP>150/100 mmHgBP>140/90 mmHg。1 h24 hBP。,BP135/85 mmHg。BP,()。logistic(),。1 h24 h,,BP、。 : 22%。。,BP(peripheral vascular resistance,PVR),(cardiac output,CO)。BPPVR,24 h,1 h24 hBPPVR。CO。24hBP。100%,20%,0.97。 : ,BP。.

Maternal cardiac function at 35-37 weeks' gestation: relationship with birth weight

OBJECTIVE

To evaluate the relationship between maternal cardiovascular parameters and neonatal birth weight and examine the potential value of these parameters in improving the prediction of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) neonates provided by maternal characteristics and medical history.

METHODS

In 2835 singleton pregnancies maternal characteristics and medical history were recorded and maternal cardiovascular parameters were measured. The observed measurements of cardiovascular parameters were expressed as multiples of the normal median (MoM) values after adjustment for those characteristics found to provide a substantial contribution to their measurement. Regression analysis was used to determine the significance of association between the normalized values of the cardiovascular parameters with birth-weight Z-score. Multivariable logistic regression analysis was then used to determine if the maternal factors, fetal biometry and maternal cardiovascular parameters had a significant contribution to predicting SGA and LGA neonates. The performance of screening was determined by the area under receiver-operating characteristics curves (AUC).

RESULTS

In the study population there were significant positive associations between maternal cardiac output and heart rate with neonatal birth-weight Z-score, and significant negative associations between total peripheral resistance and mean arterial pressure (MAP) with neonatal birth-weight Z-score. In pregnancies delivering SGA neonates (n = 249 (8.8%)), cardiac output and heart rate were lower and total peripheral resistance and MAP were higher, whereas in pregnancies delivering LGA neonates (n = 292 (10.3%)) cardiac output and heart rate were higher and total peripheral resistance and MAP were lower. The performance of screening for delivery of SGA neonates achieved by maternal characteristics and fetal biometry was not improved by the measurement of maternal cardiovascular parameters. There was a small but significant improvement in the performance of screening for delivery of LGA neonates by maternal factors and fetal biometry with the addition of maternal heart rate (comparison of AUC, P = 0.0095).

CONCLUSIONS

There are significant associations between maternal cardiac output, heart rate, total peripheral resistance and MAP and neonatal birth-weight Z-score; such findings reflect the close relationship between maternal cardiac function and fetal demands. However, assessment of these parameters at 35-37 weeks' gestation is unlikely to improve substantially the performance of screening for SGA or LGA neonates provided by a combination of maternal factors and fetal biometry. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiovascular function at 35-37 weeks' gestation: relation to maternal characteristics

OBJECTIVE

To examine the possible effects of maternal characteristics and obstetric and medical history on maternal cardiovascular parameters at 35-37 weeks' gestation.

METHODS

In 3013 singleton pregnancies at 35-37 weeks, maternal characteristics and medical history were recorded; uterine artery pulsatility index, mean arterial pressure (MAP) and maternal cardiovascular parameters were measured. Multivariable regression analysis was used to determine significant predictors of the cardiovascular parameters among gestational age (GA), maternal characteristics and medical history.

RESULTS

Multivariable regression analysis demonstrated that significant independent prediction of log₁₀ cardiac output and log₁₀ cardiac power was provided by GA, maternal age, weight, weight gain from the first trimester, height, racial origin, smoking, assisted conception and previous neonatal birth-weight Z-score in parous women. For log₁₀ total peripheral resistance, significant prediction was provided by GA, maternal age, height, racial origin, chronic hypertension, diabetes mellitus, assisted conception, previous neonatal birth-weight Z-score and prior pre-eclampsia (PE) in parous women. For log₁₀ stroke volume, significant prediction was provided by maternal age, height, racial origin, smoking, chronic hypertension and diabetes mellitus. For heart rate, significant prediction was provided by GA, weight, weight gain, height, racial origin, chronic hypertension, previous neonatal birth-weight Z-score and prior PE in parous women. For log₁₀ MAP, significant prediction was provided by maternal weight, racial origin, family history of PE, chronic hypertension and diabetes mellitus. For log₁₀ thoracic fluid capacity, significant prediction was provided by GA, maternal age, weight, height, racial origin and systemic lupus erythematosus or antiphospholipid syndrome. For log₁₀ ventricular ejection time, significant prediction was provided by GA, weight, height and racial origin.

CONCLUSION

Maternal cardiovascular parameters are affected by maternal characteristics and medical and obstetric history, and they should therefore be converted into multiples of the normal median adjusted for significant independent predictors before their inclusion in combined screening for PE. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiac function at 35-37 weeks' gestation: prediction of pre-eclampsia and gestational hypertension

OBJECTIVE

To investigate the potential value of combining maternal factors with multiples of the normal median values of maternal cardiovascular parameters at 35-37 weeks' gestation in the prediction of pre-eclampsia (PE) and gestational hypertension (GH).

METHODS

In 2764 singleton pregnancies maternal characteristics and medical history were recorded; uterine artery pulsatility index (UtA-PI), mean arterial pressure (MAP) and maternal cardiovascular parameters were measured. Multivariable logistic regression analysis was then used to determine if the maternal factors and maternal cardiovascular parameters made a significant contribution to predicting PE and GH. The performance of screening was determined by the area under receiver-operating characteristics curves.

RESULTS

In pregnancies that subsequently delivered with PE or GH, total peripheral resistance and MAP were higher and maternal cardiac output was lower, mainly owing to a decrease in heart rate in PE and a decrease in stroke volume in GH. The increases in total peripheral resistance and MAP were inversely related to gestational age at delivery. The performance of screening for PE and GH achieved by maternal characteristics and medical history was improved by the inclusion of MAP, but not by UtA-PI or maternal cardiovascular parameters.

CONCLUSIONS

In women developing term PE total peripheral resistance and MAP are increased and maternal cardiac output is reduced. However, assessment of maternal cardiac function at 35-37 weeks' gestation is unlikely to improve the performance of screening for PE provided by maternal factors and MAP alone. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Apelin in Normal Pregnancy and Pregnancies Complicated by Placental Insufficiency

INTRODUCTION

Apelin is a potent inotropic agent and causes endothelium-mediated vasodilation. Its cardiovascular profile suggests a role in the regulation of gestational hemodynamics.

METHODS

We longitudinally assessed maternal serum apelin levels and hemodynamics (cardiac output and total peripheral resistance) between 20 and 34 weeks gestation in 18 women at high risk of placental dysfunction. Placental apelin staining was assessed by immunohistochemistry in placentas from uncomplicated pregnancies (n = 6), preterm deliveries (n = 6), preeclampsia (PET, n = 8), and isolated intrauterine growth restriction (IUGR, n = 8). Placental apelin gene expression was assessed by quantitative polymerase chain reaction.

RESULTS

In the high-risk cohort, 4 fetuses developed isolated IUGR and 6 women developed PET. We obtained a median of 5 (range 2-9) hemodynamic and apelin measurements per woman. Apelin levels throughout gestation were best fitted by a quadratic curve. Apelin levels between 20 and 26 weeks gestation correlated with total peripheral resistance (r = .57, P = .01) and showed a trend toward an inverse correlation with stroke volume (r = -.42, P = .08). Apelin serum levels were 30% lower in pregnancies complicated by IUGR than in uncomplicated pregnancies or in women with preeclampsia (P = .009). Placental apelin gene expression was similar in IUGR, PET, preterm, and term normal placentas. Apelin staining was seen both in syncytiotrophoblast and stroma of the placental villi. In IUGR placentas, apelin staining was strongly decreased in both compartments compared to normals. Preeclamptic placentas showed an intermediate staining.

CONCLUSIONS

Apelin levels mirror the cardiovascular changes seen in pregnancy. Serum and placental apelin levels are decreased in IUGR.