Impaired maternal hemodynamics in morbidly obese women: a case-control study

Maternal Cardiac Function in Pregnancies with Metabolic Disorders

The obesity epidemic is growing and poses significant risks to pregnancy. Metabolic impairment can be associated with short- and long-term maternal and perinatal morbidity and mortality. The cardiovascular implications are known in those with metabolic disorder outside of pregnancy; however, little is known of the cardiac function in pregnancies complicated by obesity. Maternal cardiac adaptation plays a vital role in normal pregnancy and is known to be involved in the pathophysiology of adverse pregnancy outcomes. Bariatric surgery is the most successful treatment for sustainable weight loss and pre-pregnancy bariatric surgery can drastically change the maternal metabolic profile and pregnancy outcomes. In this review, we discuss the available evidence on maternal cardiac function in pregnancies affected by obesity and its associated consequences of gestational diabetes and hypertension (chronic and hypertensive disorders in pregnancy), as well as pregnancies following bariatric surgery.

Stretch-induced compliance mechanism in pregnancy-induced cardiac hypertrophy and the impact of cardiovascular risk factors

Pressure overload-induced hypertrophy compromises cardiac stretch-induced compliance (SIC) after acute volume overload (AVO). We hypothesized that SIC could be enhanced by physiological hypertrophy induced by pregnancy's chronic volume overload. This study evaluated SIC-cardiac adaptation in pregnant women with or without cardiovascular risk (CVR) factors. Thirty-seven women (1st trimester, 1stT) and a separate group of 31 (3rd trimester, 3rdT) women [healthy or with CVR factors (obesity and/or hypertension and/or with gestational diabetes)] underwent echocardiography determination of left ventricular end-diastolic volume (LVEDV) and E/e' before (T0), immediately after (T1), and 15 min after (T2; SIC) AVO induced by passive leg elevation. Blood samples for NT-proBNP quantification were collected before and after the AVO. Acute leg elevation significantly increased inferior vena cava diameter and stroke volume from T0 to T1 in both 1stT and 3rdT, confirming AVO. LVEDV and E/e' also increased immediately after AVO (T1) in both 1stT and 3rdT. SIC adaptation (T2, 15 min after AVO) significantly decreased E/e' in both trimesters, with additional expansion of LVEDV only in the 1stT. NT-pro-BNP increased slightly after AVO but only in the 1stT. CVR factors, but not parity or age, significantly impacted SIC cardiac adaptation. A distinct functional response to SIC was observed between 1stT and 3rdT, which was influenced by CVR factors. The LV of 3rdT pregnant women was hypertrophied, showing a structural limitation to dilate with AVO, whereas the lower LV filling pressure values suggest increased diastolic compliance.NEW & NOTEWORTHY The sudden increase of volume overload triggers an acute myocardial stretch characterized by an immediate rise in contractility by the Frank-Starling mechanism, followed by a progressive increase known as the slow force response. The present study is the first to characterize echocardiographically the stretch-induced compliance (SIC) mechanism in the context of physiological hypertrophy induced by pregnancy. A distinct functional adaptation to SIC was observed between first and third trimesters, which was influenced by cardiovascular risk factors.

Maternal cardiovascular adaptation to pregnancy in obese pregnant women

INTRODUCTION

Obesity is known to be associated with cardiovascular compromise and a major risk factor for the development of hypertensive disorders in pregnancy. However, little is known about the effect of obesity on maternal cardiac function. The aim of this study was to investigate the effect of obesity on the maternal cardiovascular system.

MATERIAL AND METHODS

This was a prospective, observational, longitudinal study. Pregnant women with booking body mass index (BMI) ≥30 kg/m2 were compared with pregnant women with normal booking BMI 20-24.9 kg/m2. Participants were seen at three time points during pregnancy; 12-14, 20-24 and 30-32 weeks. At all visits, maternal blood pressure (BP) was measured, and cardiac geometry and function were assessed using two-dimensional trans-thoracic echocardiography. Multilevel linear mixed-effects models were used for all the comparisons.

RESULTS

Fifty-nine pregnant women with obesity were compared with 14 pregnant women with normal BMI. In women with obesity, the maternal BP, heart rate and cardiac output were higher and peripheral vascular resistance was lower (p < 0.01 for all comparisons) compared with normal BMI women. Women with obesity had altered cardiac geometry with higher left ventricular end diastolic diameter, intraventricular septal thickness, posterior wall diameter, relative wall thickness and left ventricular mass (p < 0.001 for all comparisons). There was also evidence of impaired diastolic indices in the obese group with a lower E/A ratio, tissue Doppler imaging E' lateral and medial and higher left atrial volume (p < 0.01 for all comparisons). Finally, women with obesity had reduced longitudinal function, as assessed by mitral plane annular systolic excursion, between the second and third trimester of pregnancy, indicating possible early cardiac dysfunction in this group.

CONCLUSIONS

Obesity is associated with maternal hyperdynamic circulation, altered cardiac geometry and suboptimal diastolic function, compared with normal BMI pregnant women, and these factors may contribute to the increased risk of complications in obese pregnant women.

The impact of echocardiographic indexation to evaluate cardiac reverse remodeling throughout pregnancy and postpartum

INTRODUCTION AND OBJECTIVES

Echocardiography guidelines suggest normalizing left ventricular (LV) volumes and mass (LVM) to body size. During pregnancy, continuous weight variation impacts on body surface area (BSA) calculation, limiting the longitudinal analysis of cardiac remodeling (CR) and reverse remodeling (RR) variables. Our aim was to identify the most common indexing methodologies in the literature on pregnant populations through a systematic review; and, to compare four scaling methods: (i) none (absolute values); (ii) indexing to the BSA before pregnancy; (iii) allomeric indexing; and (iv) indexing to BSA measured at the same day of cardiac assessment, using an illustrative example.

METHODS

We performed a systematic review of CR and RR during pregnancy and post-partum, using two databases. We included studies reporting longitudinal echocardiographic analysis of cardiac chamber volumes in humans. We used a prospective cohort study of healthy pregnant women who underwent four echocardiographic evaluations during pregnancy and postpartum, as an illustrative example.

RESULTS

Twenty-seven studies were included, most studies indexed to BSA measured at each evaluation moment (n=21). Within-subjects design was the most reported to analyse longitudinal data (n=17). Indexation to the pre-pregnancy BSA or application of allometric indexes revealed a higher effect than BSA measured at each evaluation and an equal effect to not indexing using within-subjects design. The within-subjects designs also revealed a higher effect size value than the between-subjects design for longitudinal analysis of LVM adaptations during pregnancy and postpartum.

CONCLUSION(S)

This study concludes that indexation methods do not impact the clinical interpretation of longitudinal echocardiographic assessment but highlights the need to harmonize normalization procedures during pregnancy.

Associations between Maternal Nutritional Status, Hemodynamic Parameters, and Delivery Outcomes in Low-Risk Pregnancies: A Prospective Observational Study

Maternal nutritional status represents a pivotal predictor of pregnancy outcome. This prospective observational study investigates the associations between maternal characteristics and nutritional habits at term, hemodynamic parameters, and pregnancy outcomes. Healthy women with singleton uncomplicated pregnancies were enrolled at 36-41 gestational weeks. At enrollment, a nutritional score (0-10) was calculated in order to quantify maternal adherence to a healthy diet and lifestyle. Maternal hemodynamic parameters were assessed by using the Ultrasonic Cardiac Output Monitor (USCOM), including cardiac output (CO), systemic vascular resistance (SVR) and Smith-Madigan inotropy index (SMII). Pregnancy outcomes were recorded at delivery. Associations between maternal characteristics and nutritional score, hemodynamic parameters, and pregnancy outcomes were investigated by using multi-adjusted generalized linear models. In total, 143 pregnancies were enrolled. Pregestational body mass index (BMI) was positively associated with SVR, and negatively associated with CO and SMII. Additionally, a positive association was detected between the nutritional score and SMII. Finally, CO was positively associated with birth and placental weight, while RVS showed a negative association with birth and placental weight. This study shows that maternal derangements in nutritional status and habits are associated with a compromised hemodynamic profile at term, with additional impacts on intrauterine growth.

Impact of maternal obesity on resting muscle sympathetic nerve activity during uncomplicated pregnancy: a longitudinal assessment

Maternal obesity increases the risk of adverse pregnancy outcomes. The mechanisms that contribute to this elevated risk are unclear but may be related to greater activity of the sympathetic nervous system, which is associated with hypertensive disorders of pregnancy. We hypothesized that resting muscle sympathetic nerve activity (MSNA) would be greater in women with obesity during pregnancy when compared with normal-weight women. Blood pressure, heart rate, and MSNA were recorded during 5 min of supine rest in 14 normal-weight women [body mass index (BMI) 22.1 ± 2.1 (SD) kg/m2] and 14 women with obesity (BMI 33.9 ± 3.5 kg/m2) during (early and late) pregnancy and postpartum. All women had uncomplicated pregnancies. Resting MSNA burst frequency was not different between groups during early (normal weight 17 ± 10 vs. obesity 22 ± 15 bursts/min, P = 0.35) but was significantly greater in the obesity group during late pregnancy (23 ± 13 vs. 35 ± 15 bursts/min, P = 0.031) and not different postpartum (10 ± 6 vs. 9 ± 7 bursts/min, P = 0.74). These findings were also apparent when comparing burst incidence and total activity. Although still within the normotensive range, systolic blood pressure was greater in the obesity group across all time points (P = 0.002). Diastolic blood pressure was lower during pregnancy compared with postpartum (P < 0.001) and not different between groups (P = 0.488). Heart rate increased throughout pregnancy in both groups (P < 0.001). Our findings suggest that maternal obesity is associated with greater increases in sympathetic activity even during uncomplicated pregnancy. Future research is needed to determine if this is linked with an increased risk of adverse outcomes or is required to maintain homeostasis in pregnancy.NEW & NOTEWORTHY The impact of maternal obesity on resting muscle sympathetic nerve activity was examined during (early and late) and after uncomplicated pregnancy. Resting muscle sympathetic nerve activity is not different during early pregnancy or postpartum but is significantly elevated in women with obesity during late pregnancy when compared with normal-weight women. Future research is needed to determine if this is linked with an increased risk of adverse outcomes or is required to maintain homeostasis in pregnancy.

Does treatment modality affect measures of arterial stiffness in women with gestational diabetes?

OBJECTIVE

To investigate whether arterial stiffness (AS) differs between healthy women and women with gestational diabetes mellitus (GDM) managed by different treatment modalities.

METHODS

This was a prospective longitudinal cohort study comparing AS in pregnancies complicated by GDM and low-risk controls. AS was assessed by recording aortic pulse-wave velocity (AoPWV), brachial augmentation index (BrAIx) and aortic augmentation index (AoAIx) using the Arteriograph® at four gestational-age windows: 24 + 0 to 27 + 6 weeks (W1); 28 + 0 to 31 + 6 weeks (W2); 32 + 0 to 35 + 6 weeks (W3) and ≥ 36 + 0 weeks (W4). Women with GDM were considered both as a single group and as subgroups stratified by treatment modality. Data were analyzed using a linear mixed model on each AS variable (log-transformed) with group, gestational-age window, maternal age, ethnicity, parity, body mass index, mean arterial pressure and heart rate as fixed effects and individual as a random effect. We compared the group means including relevant contrasts and adjusted the P-values using Bonferroni correction.

RESULTS

The study population comprised 155 low-risk controls and 127 women with GDM, of whom 59 were treated with dietary intervention, 47 were treated with metformin only and 21 were treated with metformin + insulin. The two-way interaction term of study group and gestational age was significant for BrAIx and AoAIx (P < 0.001), but there was no evidence that mean AoPWV was different between the study groups (P = 0.729). Women in the control group demonstrated significantly lower BrAIx and AoAIx compared with the combined GDM group at W1-W3, but not at W4. The mean difference in log-transformed BrAIx was -0.37 (95% CI, -0.52 to -0.22), -0.23 (95% CI, -0.35 to -0.12) and -0.29 (95% CI, -0.40 to -0.18) at W1, W2 and W3, respectively. The mean difference in log-transformed AoAIx was -0.49 (95% CI, -0.69 to -0.30), -0.32 (95% CI, -0.47 to -0.18) and -0.38 (95% CI -0.52 to -0.24) at W1, W2 and W3, respectively. Similarly, women in the control group also demonstrated significantly lower BrAIx and AoAIx compared with each of the GDM treatment subgroups (diet, metformin only and metformin + insulin) at W1-W3. The increase in mean BrAIx and AoAIx seen between W2 and W3 in women with GDM treated with dietary management was attenuated in the metformin-only and metformin + insulin groups. However, the mean differences in BrAIx and AoAIx between these treatment groups were not statistically significant at any gestational-age window.

CONCLUSIONS

Pregnancies complicated by GDM demonstrate significantly higher AS compared with low-risk pregnancies regardless of treatment modality. Our data provide the basis for further investigation into the association of metformin therapy with changes in AS and risk of placenta-mediated diseases. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Maternal haemodynamics in Hypertensive Disorders of Pregnancy under antihypertensive therapy (HyperDiP): study protocol for a prospective observational case-control study

INTRODUCTION

Hypertensive disorders of pregnancy (HDP) are associated with a high incidence of maternal and perinatal morbidity and mortality. HDP, in particular pre-eclampsia, have been determined as risk factors for future cardiovascular disease. Recently, the common hypothesis of pre-eclampsia being a placental disorder was challenged as numerous studies show evidence for short-term and long-term cardiovascular changes in pregnancies affected by HDP, suggesting a cardiovascular origin of the disease. Despite new insights into the pathophysiology of HDP, concepts of therapy remain unchanged and evidence for improved maternal and neonatal outcome by using antihypertensive agents is lacking.

METHODS AND ANALYSIS

A prospective observational case-control study, including 100 women with HDP and 100 healthy controls, which will assess maternal haemodynamics using the USCOM 1A Monitor and Arteriograph along with cardiovascular markers (soluble fms-like kinase 1/placental-like growth factor, N-terminal pro-B type natriuretic peptide) in women with HDP under antihypertensive therapy, including a follow-up at 3 months and 1 year post partum, will be conducted over a 50-month period in Vienna. A prospective, longitudinal study of cardiovascular surrogate markers conducted in Oslo will serve as a comparative cohort for the Vienna cohort of haemodynamic parameters in pregnancy including a longer follow-up period of up to 3 years post partum. Each site will provide a dataset of a patient group and a control group and will be assessed for the outcome categories USCOM 1A measurements, Arteriograph measurements and Angiogenic marker measurements. To estimate the effect of antihypertensive therapy on outcome parameters, ORs with 95% CIs will be computed. Longitudinal changes of outcome parameters will be compared between normotensive and hypertensive pregnancies using mixed-effects models.

ETHICS AND DISSEMINATION

Ethical approval has been granted to all participating centres. Results will be published in international peer-reviewed journals and will be presented at national and international conferences.

Assessing maternal cardiac function by obstetricians: technique and reference ranges

BACKGROUND

A strong body of evidence has now coalesced indicating that some obstetrical syndromes may result from maladaptive responses of the maternal cardiovascular system. Longitudinal studies have shown that these changes are complex and present before the clinical recognition of preeclampsia and fetal growth restriction, suggesting that hemodynamic maladaptation may play an etiologic role in obstetrical complications. Chronic hypertension is one of the most frequent complications of pregnancy, and recent evidence suggests that control of mild hypertension in early pregnancy improves outcome. The management of chronic hypertension can be improved by understanding specific cardiovascular hemodynamic abnormalities such as increased cardiac output or increased systemic vascular resistance, which can respond to either beta or calcium channel blockers, depending on the hemodynamic findings. Evaluation of maternal cardiac function has not been previously available to obstetrical healthcare providers using diagnostic ultrasound equipment used for fetal evaluation.

OBJECTIVE

Obstetrical ultrasound machines may be configured for various probes (endovaginal, abdominal, 3D/4D, and cardiac). This study used a cardiac probe placed in the suprasternal notch to image and measure the descending aorta diameter and the velocity time integral using pulsed and continuous wave Doppler ultrasound in normal pregnant women between 11 and 39 weeks of gestation. These measurements were followed by computation of maternal left ventricular preload, afterload, contractility, and blood flow.

STUDY DESIGN

This was a prospective cross-sectional study. A total of 400 pregnant women were recruited between 11 and 39 weeks of gestation. Imaging of the maternal aortic arch was performed by placing a cardiac probe in the suprasternal notch to identify the aortic arch using 2D and color Doppler ultrasound. The end-systolic diameter of the aorta was measured at the junction of the left subclavian artery with the descending aorta, which was followed by insonation of the descending aorta to obtain the Doppler waveform. Following insonation of the descending aorta, measurements of the aortic diameter, velocity time integral, ejection time, mean pressure gradient, heart rate, maternal weight and height, and systolic and diastolic blood pressures were entered into an Excel spreadsheet to compute the following: (1) preload measurements of stroke volume, stroke volume index, and stroke work index; (2) afterload measurements of systemic vascular resistance and the potential-to-kinetic energy ratio; (3) contractility measurements of inotropy and the Smith-Madigan inotropy index; and (4) blood flow measurements of cardiac output and the cardiac output index. Fractional polynomial regression analysis was performed for each of the above measurements using gestational age as the independent variable.

RESULTS

The diastolic and mean arterial blood pressure decreased from 11 to 18 weeks of gestation and then increased until term. The afterload measurements demonstrated similar characteristics, as all values decreased from 11 weeks until the mid and late second trimester, after which all values increased until term. Changes in contractility demonstrated an increase from 11 weeks to 25 to 28 weeks, followed by a decline until term. Changes in blood flow demonstrated an increase from 11 to 27 weeks and then declined until term. The continuous wave Doppler values were greater than the pulsed Doppler values except for the contractility measurements. Examples of abnormal cardiac measurements were identified in pregnant patients with hypertension and fetal growth restriction. An Excel calculator was created to provide quick computation of z-score measurements and their corresponding centiles described in this study.

CONCLUSION

The technique for evaluation of maternal cardiac function described in this study would allow screening of maternal left ventricular preload, afterload, contractility, and blood flow in the obstetrical clinical milieu once a cardiac probe is acquired for obstetrical ultrasound machines used for fetal evaluation. The above measurements would allow the clinician to select appropriate hypertensive medication on the basis of the results of the evaluation of the maternal left ventricle.

Impact of maternal height, weight at presentation and gestational weight gain on cardiac adaptation in pregnancy

OBJECTIVE

To compare longitudinal maternal hemodynamic changes throughout gestation between different groups stratified according to weight at presentation and assess the relative influence of height, weight at presentation and gestational weight gain on cardiac adaptation.

METHODS

This was a prospective, longitudinal study assessing maternal hemodynamics using bioreactance technology at 11 + 0 to 13 + 6, 19 + 0 to 24 + 0, 30 + 0 to 34 + 0 and 35 + 0 to 37 + 0 weeks' gestation. Women were divided into three groups according to maternal weight at presentation at the first visit at 11 + 0 to 13 + 6 weeks: Group 1, &lt; 60.0 kg (n = 421); Group 2, 60.0-79.7 kg (n = 904); Group 3, &gt; 79.7 kg (n = 427). A multilevel linear mixed-effects model was used to compare the repeated measures of hemodynamic variables, correcting for demographics, medical and obstetric history, pregnancy complications, maternal weight and time of evaluation. The linear mixed-effects model was then repeated using maternal height, weight at presentation and gestational weight gain Z-scores, and the standardized coefficients were used to evaluate the relative impact of each of these demographic parameters on longitudinal changes of maternal hemodynamics.

RESULTS

Compared with Group 1, women in Group 3 demonstrated higher cardiac output (CO), heart rate (HR) and mean arterial pressure (MAP) throughout pregnancy. Groups 2 and 3 had higher stroke volume (SV) than Group 1 at the first visit, but their SV plateaued between the first and second visits and demonstrated an earlier significant decrease from the second visit to the third visit when compared with Group 1. Compared with Groups 1 and 2, there was a higher prevalence of pre-eclampsia, gestational hypertension and gestational diabetes in Group 3. Maternal height was the most important contributor to CO, peripheral vascular resistance (PVR), SV and HR, while weight at presentation was the most important contributor to MAP. Gestational weight gain was the second most important characteristic influencing the longitudinal changes of PVR and SV.

CONCLUSIONS

Women with greater weight at presentation have a pathological hemodynamic profile, with higher CO, HR and MAP compared to women with lower weight at presentation. Height is the main determinant of CO, SV, HR and PVR, weight is the main determinant of MAP, and gestational weight gain is the second most important determinant of SV and PVR. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Maternal body weight and estimated circulating blood volume: a non-linear approach

Postpartum haemorrhage continues to be a leading cause of morbidity and mortality in the obstetric population worldwide, especially in patients at extremes of body weight. Quantification of blood loss has been considered extensively in the literature. However, these volumes must be contextualised to appreciate the consequences of blood loss for individual parturients. Knowledge of a patient's peripartum circulating blood volume is essential to allow accurate interpretation of the significance of haemorrhage and appropriate resuscitation. Greater body weight in obesity can lead to overestimation of blood volume, resulting in inappropriately high thresholds for blood product transfusion and delays in treatment. The most recent Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK (MBRRACE-UK) surveillance report demonstrated the risk to this population, with more than half of all maternal mortality recorded in parturients who were either overweight or obese. Current linear calculations used to estimate circulating blood volumes based on patients' weights could be contributing to this phenomenon, as blood volume increases at a disproportional rate to body composition. In this review, we summarise the relevant physiology and explore the existing literature on the estimation of circulating blood volume, both during pregnancy and in obesity. Building on key works and principal findings, we present a practical, nonlinear approach to the adjustment of estimated blood volume with increasing body mass. This clinical tool aims to reduce the clinical bias influencing the management of obstetric haemorrhage in a population already at increased risk of morbidity and mortality. Discussion of the limitations of this approach and the call for further research within this field completes this review.

Obesity in pregnancy is a predictor of persistent subclinical myocardial dysfunction over postpartum period

PURPOSE

No previous study provided a complete functional evaluation of all cardiac chambers in pregnant women with obesity. Moreover, the impact of cardiovascular changes associated with obesity in pregnancy on maternal outcome is unclear.

METHODS

46 consecutive pregnant women with obesity, defined by body mass index (BMI) ≥ 30 Kg/m2, and 83 age- (35.5 ± 4.1 vs. 34.1 ± 5.1 yrs, p = 0.11), ethnicity- (caucasian 65.2 vs. 66.3%, p = 0.90) and gestational week-matched (36.3 ± 1.7 vs. 36.5 ± 1.5 wks, p = 0.49) pregnant women without obesity (BMI < 30 Kg/m2) were examined in the first trimester (12-14 weeks), third trimester (36-38 weeks) and 6-10 weeks postpartum. All women underwent obstetric visit, blood tests and transthoracic echocardiography implemented with two-dimensional speckle tracking echocardiography analysis of biventricular and biatrial myocardial deformation indices at the three time points. Outcome was persistent subclinical myocardial dysfunction, defined as an absolute value of left ventricular global longitudinal strain (LV-GLS) less negative than - 20%, in postpartum.

RESULTS

Despite normal biventricular systolic function, all myocardial strain indices were significantly lower in pregnant women with obesity than controls. At 8.2 ± 2.2 weeks postpartum, LV-GLS remained less negative than - 20% in 86.9% of women with obesity in pregnancy. Maternal age (OR 1.68, 95%CI 1.14-2.48), third trimester BMI (OR 7.17, 95%CI 1.77-28.9) and third trimester neutrophil-to-lymphocyte ratio (NLR) (OR 1.75, 95%CI 1.22-2.51) were independently associated with outcome. Maternal age ≥ 35 years, BMI ≥ 30 Kg/m2 and NLR ≥ 5.5 were the optimal cut-off values for predicting persistent subclinical myocardial dysfunction in postpartum.

CONCLUSIONS

Pregnant women with obesity, age ≥ 35 yrs and low chronic inflammation have significantly increased risk of persistent subclinical myocardial dysfunction over postpartum.

Maternal cardiovascular potential and kinetic energy indices in pre-eclamptic and small-for-gestational-age pregnancies

OBJECTIVE

Non-invasive assessment of maternal cardiovascular potential and kinetic energy can be used to derive potential-to-kinetic-energy ratio (PKR) and Smith-Madigan inotropic index (SMII), which reflect the balance between blood pressure and blood flow. The aim of this study was to evaluate PKR and SMII in pregnancies complicated by hypertensive disorders of pregnancy (HDP) and/or small-for-gestational-age (SGA) birth.

METHODS

This was a prospective study that enrolled women with a singleton pregnancy between 5 and 41 weeks' gestation. Women who developed HDP and/or SGA underwent cardiovascular profiling from 20 weeks. To establish reference ranges for PKR and SMII, women without any pre-existing medical problems at the time of booking who did not develop HDP, SGA or other complications during pregnancy were also recruited for cardiovascular profiling. Measurements of cardiovascular parameters were obtained using a non-imaging ultrasound cardiac output monitor.

RESULTS

A total of 688 women completed the study, including 626 controls, 21 cases with HDP, 19 cases with SGA and 22 cases with HDP and SGA. PKR was significantly elevated in pregnancies with placental dysfunction compared with controls (HDP only, 29.81 ± 9.5; HDP and SGA, 44.33 ± 24.27; SGA only, 31.05 ± 13.14; vs controls, 22.30 ± 7.93; all P < 0.05). SMII values were significantly lower only in cases affected by SGA alone when compared with controls (1.47 ± 0.23 W/m² vs 1.75 ± 0.40 W/m² ; P < 0.005). These differences remained statistically significant when the analysis was undertaken using multiples of the median values corrected for gestational age.

CONCLUSIONS

The findings of this study suggest that point-of-care non-invasive cardiovascular profiling using PKR and SMII may help distinguish between pregnancies affected by specific placental disorders and those exhibiting healthy cardiovascular adaptation to pregnancy. Women with HDP and/or SGA appear to have distinctive PKR and SMII profiles that reflect low kinetic energy in pregnancies with SGA and high potential energy in pregnancies affected by HDP. Finally, non-invasive assessment of potential and kinetic cardiovascular energy demonstrates physiological high-flow and low-resistance adaptation in uncomplicated pregnancies. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Is conventional cardiac examination adequate for obese pregnant women? A prospective case-control study

OBJECTIVE

Obesity in pregnancy shows short- and long-term adverse effects for both mother and baby. We aimed to investigate the effects of obesity on cardiac functions in the third trimester of pregnancy.

MATERIALS AND METHODS

A prospective case-control study where the pregnant women at the third trimester of pregnancy were divided into two groups: obese (BMI≥30) and the controls (BMI<30). All participants underwent conventional 2D and speckle-tracking echocardiography, while structural and functional cardiac parameters were measured. The unpaired t-test or the Mann-Whitney-U test were used to compare values between the two groups. p ≤ 0.05 was outlined to be statistically significant.

RESULTS

Forty-one obese pregnant women and 41 healthy and normal-weight pregnant controls were recruited. The mean BMI was 24.6 ± 2.4 kg/m² in the controls and 38.5 ± 5.4 kg/m² in the obese group. SV was significantly higher in obese patients (p = 0.02). SVI was markedly lower in the obese group (p < 0.01). CO and Cardiac Index were significantly higher in obese patients compared to the controls (p < 0.01). TVRI was significantly higher in the obese group than the controls. EF was similar between the two groups (p = 0.33). LVM and LVMI were significantly higher in obese patients than the controls (p = 0.024 and p = 0.01). Diastolic dysfunction was present in 3 (7.3%) controls; 21 (51.2%) of the obese women demonstrated diastolic dysfunction, and it was significantly higher than the controls (p < 0.01). LV-GLS and LV-GCS were substantially lower in the obese group (p < 0.01). RV-FAC and RV-GS were markedly lower in the obese group (p < 0.01). TAPSE was similar in obese and control groups (p = 00.17).

CONCLUSION

Obesity in pregnancy is associated with increased subclinical systolic and diastolic dysfunction, which cannot be detected by standard 2D methods.

Surgery in the Obese Pregnant Patient

This chapter reviews issues which complicate surgery in obese pregnant patients. Maternal obesity is prevalent in the United States and is associated with numerous adverse health outcomes. When surgery is indicated during pregnancy, the presence of maternal obesity increases surgical risks for both the fetus and mother. Specific risks are identified and strategies to avoid them are evaluated. The prognosis and management of pregnant women who have undergone bariatric surgery is also discussed, and practical guidelines for obstetric management of these patients are presented.

Subclinical cardiac performance in obese and overweight women as a potential risk factor of preeclampsia

OBJECTIVES

Failure to increase cardiac output owing to suboptimal cardiac performance in obese women may contribute to placental hypoperfusion, and therefore subsequently to the abnormal placental development. The aim of this study was to evaluate the relationship between left ventricle (LV) function in overweight and obese pregnant women and parameters of blood flow in uterine arteries.

STUDY DESIGN AND MAIN OUTCOME MEASURES

We conducted a prospective cohort study, which included consecutive 87 women with singleton pregnancy - 56 women with normal weight and 31 overweight and obese women. During pregnancy blood pressure, echocardiography and the assessment of blood flow in uterine arteries - pulsatility index (PI) and resistance index (RI) were assessed on two visits (V): V1 between 10 and 14 weeks and V2 between 25 and 30 weeks of gestation. A stepwise logistic regression analysis was performed to determine the independent predictors of upper quartile of RI and PI during V2 in the study population.

RESULTS

The multivariate logistic regression analysis showed that LVCI and LV mass measured on V1 were the only independent predictors of upper quartile of RI during V2, whereas LVCI was the only independent predictor of upper quartile of PI during V2.

CONCLUSIONS

Subclinical left ventricle dysfunction in obese and overweight women, present from the first trimester, may contribute to placental hypoperfusion and higher resistance in uterine arteries later during pregnancy. This may lead in some women to preeclampsia.

The impact of obesity on haemodynamic profiles of pregnant women beyond 34 weeks' gestation

OBJECTIVE

We aimed to compare the haemodynamic profiles of obese and non-obese pregnant women, alongside describing the haemodynamic changes that occur in hypertensive disorders of pregnancies with an Appropriate for Gestational Age Fetus (HDP-AGA) beyond 34 weeks' gestation.

STUDY DESIGN

In this prospective case-control study, maternal haemodynamic assessment was carried out by a trained operator using an UltraSonic Cardiac Output Monitor during a routine clinical assessment after 34 weeks of gestation. Indexed and non-indexed parameters were evaluated.

MAIN OUTCOME MEASURES

Maternal hemodynamic parameters.

RESULTS

Obese and non-obese women did not differ for non-indexed parameters (Cardiac Output, Stroke Volume, Systemic Vascular Resistance). Using indexed parameters, corrected for Body Surface Area, obese women presented significantly lower Cardiac Index z-score (-0.23 ± 0.5 vs 0.26 ± 1.2; p = 0.004), Stroke Volume Index z-score (-0.27 ± 0.8 vs 0.31 ± 1.0; p < 0.0001) and significantly higher Systemic Vascular Resistance Index (0.16 ± 0.8 vs -0.36 ± 0.7; p < 0.0001). In obese women, HDP-AGA (n = 19) had significantly higher Systemic Vascular Resistance Index z-score (1.26 ± 1.7 vs 0.16 ± 0.8; P = 0.009) and significantly lower Stroke Volume Index (-0.68 ± 0.8 vs -0.27 ± 0.8; 0.049).

CONCLUSION

Using indexed parameters, differences in haemodynamic profiles between obese and non obese women can be highlighted. Obese women seem to present a cardiac maladapation to the pregnancy (reduced cardiac index and stroke volume and increased vascular resistance) that could explain the increased risk of complications in this subgroup.

Maternal cardiovascular function and risk of intrapartum fetal compromise in women undergoing induction of labor: pilot study

OBJECTIVE

Identification of the fetus at risk of intrapartum compromise has many benefits. Impaired maternal cardiovascular function is associated with placental hypoperfusion predisposing to intrapartum fetal distress. The aim of this study was to assess the predictive accuracy of maternal hemodynamics for the risk of operative delivery due to presumed fetal compromise in women undergoing induction of labor (IOL).

METHODS

In this prospective cohort study, patients were recruited between November 2018 and January 2019. Women undergoing IOL were invited to participate in the study. A non-invasive ultrasonic cardiac output monitor (USCOM-1A®) was used for cardiovascular assessment. The study outcome was operative delivery due to presumed fetal compromise, which included Cesarean or instrumental delivery for abnormal fetal heart monitoring. Regression analysis was used to test the association between cardiovascular markers, as well as the maternal characteristics, and the risk of operative delivery due to presumed fetal compromise. Receiver-operating-characteristics-curve analysis was used to assess the predictive accuracy of the cardiovascular markers for the risk of operative delivery for presumed fetal compromise.

RESULTS

A total of 99 women were recruited, however four women were later excluded from the analysis due to semi-elective Cesarean section (n = 2) and failed IOL (n = 2). The rate of operative delivery due to presumed fetal compromise was 28.4% (27/95). Women who delivered without suspected fetal compromise (controls) were more likely to be parous, compared to those who had operative delivery due to fetal compromise (52.9% vs 18.5%; P = 0.002). Women who underwent operative delivery due to presumed fetal compromise had a significantly lower cardiac index (median, 2.50 vs 2.60 L/min/m² ; P = 0.039) and a higher systemic vascular resistance (SVR) (median, 1480 vs 1325 dynes × s/cm⁵ , P = 0.044) compared to controls. The baseline model (being parous only) showed poor predictive accuracy, with an area under the curve of 0.67 (95% CI, 0.58-0.77). The addition of stroke volume index (SVI) < 36 mL/m² , SVR > 7.2 logs or SVR index (SVRI) > 7.7 logs improved significantly the predictive accuracy of the baseline model (P = 0.012, P = 0.026 and P = 0.012, respectively).

CONCLUSION

In this pilot study, we demonstrated that prelabor maternal cardiovascular assessment in women undergoing IOL could be useful for assessing the risk of intrapartum fetal compromise necessitating operative delivery. The addition of SVI, SVR or SVRI improved significantly the predictive accuracy of the baseline antenatal model. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Pre-Pregnancy Obesity, Excessive Gestational Weight Gain, and the Risk of Pregnancy-Induced Hypertension and Gestational Diabetes Mellitus

Excessive pre-pregnancy weight is a known risk factor of pregnancy complications. The purpose of this analysis was to assess the relationship between several categories of maternal weight and the risk of developing hypertension and diabetes in pregnancy, and the relationship of these complications with the results of the newborn. It was carried out in a common cohort of pregnant women and taking into account the influence of disturbing factors. Our analysis was conducted in a prospective cohort of 912 Polish pregnant women, recruited during 2015-2016. We evaluated the women who subsequently developed diabetes with dietary modification (GDM-1) (n = 125) and with insulin therapy (GDM-2) (n = 21), as well as the women who developed gestational hypertension (GH) (n = 113) and preeclampsia (PE) (n = 24), compared to the healthy controls. Odds ratios of the complications (and confidence intervals (95%)) were calculated in the multivariate logistic regression. In the cohort, 10.8% of the women had pre-pregnancy obesity (body mass index (BMI) ≥ 30 kg/m²), and 36.8% had gestational weight gain (GWG) above the range of the Institute of Medicine recommendation. After correction for excessive GWG and other confounders, pre-pregnancy obesity (vs. normal BMI) was associated with a higher odds ratio of GH (AOR = 4.94; p < 0.001), PE (AOR = 8.61; p < 0.001), GDM-1 (AOR = 2.99; p < 0.001), and GDM-2 (AOR = 11.88; p <0.001). The threshold risk of development of GDM-2 occurred at lower BMI values (26.9 kg/m²), compared to GDM-1 (29.1 kg/m²). The threshold point for GH was 24.3 kg/m², and for PE 23.1 kg/m². For GWG above the range (vs. GWG in the range), the adjusted odds ratios of GH, PE, GDM-1, and GDM-2 were AOR = 1.71 (p = 0.045), AOR = 1.14 (p = 0.803), AOR = 0.74 (p = 0.245), and AOR = 0.76 (p = 0.672), respectively. The effect of maternal edema on all the results was negligible. In our cohort, hypertension and diabetes were associated with incorrect birth weight and gestational age at delivery. Conclusions: This study highlights the importance and influence of excessive pre-pregnancy maternal weight on the risk of pregnancy complications such as diabetes and hypertension which can impact fetal outcomes.

Independent influences of maternal obesity and fetal sex on maternal cardiovascular adaptation to pregnancy: a prospective cohort study

Background/Objectives

Successful pregnancy requires the de novo creation of low-resistance utero-placental and feto-placental circulations and incomplete remodeling of this vasculature can lead to maternal or fetal compromise. Maternal BMI and fetal sex are known to influence vascular compliance and placental development, but it is unknown if these are independent or synergistic effects. Here we aim to investigate the impact of maternal obesity, fetal sex, and any interaction thereof on maternal cardiovascular adaptation to pregnancy, by assessing the physiological drop of uterine artery doppler pulsatility (UtA-PI) and umbilical artery doppler pulsatility index (UA-PI) over gestation.

Subjects/Methods

Nulliparous women with a singleton pregnancy participating in a prospective cohort study (n = 4212) underwent serial UtA-PI and UA-PI measurements at 20-, 28- and 36-weeks gestation. Linear mixed regression models were employed to investigate the influence of maternal BMI, fetal sex and interactions thereof on the magnitude of change in UtA-PI and UA-PI.

Results

Throughout gestation, UtA-PI was higher for male fetuses and UA-PI was higher for female fetuses. The physiological drop of UtA-PI was significantly smaller in overweight (change −24.3% [95%CI −22.3, −26.2]) and obese women (change −21.3% [−18.3, −24.3]), compared to normal-weight women (change −25.7% [−24.3, −27.0]) but did not differ by fetal sex. The physiological drop in UA-PI was greater for female than male fetuses (–32.5% [−31.5, −33.5] vs. −30.7% [−29.8, −31.7]) but did not differ by maternal BMI. No interactions between maternal BMI and fetal sex were found.

Conclusions

Maternal cardiovascular adaptation to pregnancy is independently associated with maternal BMI and fetal sex. Our results imply sexual dimorphism in both maternal cardiovascular adaptation and feto-placental resistance.

Cardiac Structure and Function in Morbidly Obese Parturients: An Echocardiographic Study

BACKGROUND

The increasing prevalence of obesity worldwide is a major threat to global health. Cardiac structural and functional changes are well documented for obesity as well as for pregnancy, but there is limited literature on morbidly obese parturients. We hypothesized that there are both cardiac structural and functional differences between morbidly obese pregnant women and pregnant women of normal body mass index (BMI).

METHODS

This prospective cross-sectional study was performed in 2 referral maternity units in Cape Town, South Africa, over a 3-month period. Forty morbidly obese pregnant women of BMI ≥40 kg·m (group O) were compared to 45 pregnant women of BMI ≤30 kg·m (group N). Cardiac structure and function were assessed by transthoracic echocardiography, according to the recommendations of the British Society of Echocardiography. The 2-sample t-test with unequal variances was used for the comparison of the mean values between the groups.

RESULTS

Acceptable echocardiographic images were obtained in all obese women. Statistical significance was defined as P < .0225 after applying the Benjamini-Hochberg correction for multiple testing. Mean (standard deviation) mean arterial pressure was higher in group O (91 [8.42] vs 84 [9.49] mm Hg, P < .001). There were no between-group differences in heart rate, stroke volume, or cardiac index (84 [12] vs 79 [13] beats·minute, P = .103; 64.4 [9.7] vs 59.5 [13.5] mL, P = .069; 2551 [474] vs 2729 [623] mL·minute·m, P = .156, for groups O and N, respectively). Stroke volume index was lower, and left ventricular mass was higher in group O (30.14 [4.51] vs 34.25 [7.00] mL·m, P = .003; 152 [24] vs 115 [29] g, P < .001). S' septal was lower in group O (8.43 [1.20] vs 9.25 [1.64] cm·second, P = .012). Considering diastolic function, isovolumetric relaxation time was significantly prolonged in group O (73 [15] vs 61 [15] milliseconds, P < .001). The septal tissue Doppler index E' septal was lower in group O (9.08 [1.69] vs 11.28 [3.18], P < .001). There were no between-group differences in E' average (10.7 [2.3] vs 12.0 [2.7], P = .018, O versus N) or E/E' average (7.85 [1.77] vs 7.27 [1.68], P = .137, O versus N). Right ventricular E'/A' was lower in group O (1.07 [0.47] vs 1.29 [0.32], P = .016).

CONCLUSIONS

Cardiac index did not differ between obese pregnant women and those with normal BMI. Their increased left ventricular mass and lower stroke volume index could indicate a limited adaptive reserve. Obese women had minor decreases in septal left ventricular tissue Doppler velocity, but the E/E' average values did not suggest clinically significant diastolic dysfunction.

Obesity in pregnancy causes a volume overload in third trimester

BACKGROUND

Obesity is a major risk factor for cardiovascular diseases. In this study, we aimed to investigate the maternal circulatory differences during pregnancy between obese and normal weight women.

MATERIALS AND METHODS

The functioning of the maternal circulation (arteries, veins, heart and body fluid) was assessed by ECG-Doppler ultrasound, impedance cardiography (ICG) and bio-impedance during pregnancy in obese women (BMI ≥30 kg/m² ) and normal weight, nonobese women (BMI 20-25 kg/m² ). In this observational study, 232 assessments were performed in the obese group, whereas 919 assessments were performed in the nonobese group.

RESULTS

Relative to nonobese women, the overall cardiovascular function in obese women during first and second trimester is consistent with a high volume/low-resistance circulation. In third trimester, cardiac output of obese women decreases from 9.2 (8.2-10.7) L/min to 8.5 (7.6-9.6) L/min (P = .037) whereas this is not true in the nonobese women (from 7.8 (7-8.5) L/min to 7.8 (6.8-8.9) L/min, P = .536). Simultaneously, the persistently lower peripheral vascular resistance in obese vs nonobese women disappears (880 (761-1060) dyn.sec/cm⁵ vs 928 (780-1067).

CONCLUSIONS

The circulatory gestational adaptations between nonobese and obese women were generally similar. The findings in the third trimester suggest that a pregnancy in obese women start as a state of high volume/low resistance, gradually shifting to a volume overload with decrease of cardiac output and disappearance of low vascular resistance. This evolution makes obese women vulnerable for gestational hypertensive diseases.

Influence of maternal characteristics and gestational age on hemodynamic indices: NICOM device-specific reference ranges

OBJECTIVES

To construct reference ranges for stroke volume, cardiac output and systemic vascular resistance (SVR) in normal pregnancy for the NICOM® device, and to explore associations between maternal characteristics and these hemodynamic variables.

METHODS

This was a prospective cohort study of healthy singleton pregnancies between 10 and 40 weeks' gestation attending a tertiary referral hospital between September 2012 and May 2018. Measurements of stroke volume, cardiac output and SVR were obtained throughout pregnancy using NICOM, a non-invasive device based on bioreactance technology. NICOM device-specific reference ranges were created with respect to gestational age and maternal characteristics. Once the distribution of the data had been determined with respect to the gestational age, patient characteristics were added to the model to test whether they provided a significant improvement in prediction of the median value. The effect was assessed of maternal weight, height, smoking status, conception using assisted reproductive technology, nulliparity and ethnicity.

RESULTS

We included 411 women in this study. The relationships between cardiac variables and gestational age observed in the NICOM-specific reference ranges are consistent with previous findings, with increasing cardiac output values until around 35 weeks and a decrease thereafter until term, and decreasing SVR until around 36 weeks, followed by an increase towards 40 weeks. Stroke volume showed a small linear increase across gestation with lower variability in observations close to term. Maternal weight, height and age were associated with cardiac output (all P < 0.05) and SVR (all P < 0.01), whilst maternal weight and height were associated with stroke volume (both P < 0.001). Ethnicity was significantly associated with stroke volume (P = 0.001) but not with cardiac output or SVR.

CONCLUSIONS

This study presents device-specific reference ranges for stroke volume, cardiac output and SVR for the NICOM device in healthy pregnancy and describes the maternal characteristics that are associated with the values of these hemodynamic measurements. Studies using NICOM in pregnancy can use these ranges in order to evaluate observations relative to those expected in uncomplicated pregnancy conditional on maternal characteristics. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Cardiac maladaptation in obese pregnant women at term

OBJECTIVE

Obesity is an increasing problem worldwide, with well recognized detrimental effects on cardiovascular health; however, very little is known about the effect of obesity on cardiovascular adaptation to pregnancy. The aim of the present study was to compare biventricular cardiac function at term between obese pregnant women and pregnant women with normal body weight, utilizing conventional echocardiography and speckle-tracking assessment.

METHODS

This was a prospective case-control study of 40 obese, but otherwise healthy, pregnant women with a body mass index (BMI) of ≥ 35 kg/m² and 40 healthy pregnant women with a BMI of ≤ 30 kg/m² . All women underwent a comprehensive echocardiographic examination and speckle-tracking assessment at term.

RESULTS

Obese pregnant women, compared with controls, had significantly higher systolic blood pressure (117 vs 109 mmHg; P = 0.002), cardiac output (6.73 vs 4.90 L/min; P < 0.001), left ventricular (LV) mass index (74 vs 64 g/m² ; P < 0.001) and relative wall thickness (0.43 vs 0.37; P < 0.001). Diastolic dysfunction was present in five (12.5%) controls and 16 (40%) obese women (P = 0.004). In obese women, compared with controls, LV global longitudinal strain (-15.59 vs -17.61%; P < 0.001), LV endocardial (-17.30 vs -19.84%; P < 0.001) and epicardial (-13.10 vs -15.73%; P < 0.001) global longitudinal strain as well as LV early diastolic strain rate (1.05 vs 1.24 /s; P = 0.006) were all significantly reduced. No differences were observed in the degree of LV twist and torsion between the two groups.

CONCLUSIONS

Morbidly obese, but otherwise healthy, pregnant women at term had significant LV hypertrophy with evidence of diastolic dysfunction and impaired deformation indices compared with pregnant women of normal weight. These findings are likely to represent a maladaptive response of the heart to volume overload in obese pregnancy. The impact of theses changes on pregnancy outcome and long-term maternal outcome is unclear. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Methods and considerations concerning cardiac output measurement in pregnant women: recommendations of the International Working Group on Maternal Hemodynamics

Cardiac output (CO), along with blood pressure and vascular resistance, is one of the most important parameters of maternal hemodynamic function. Substantial changes in CO occur in normal pregnancy and in most obstetric complications. With the development of several non-invasive techniques for the measurement of CO, there is a growing interest in the determination of this parameter in pregnancy. These techniques were initially developed for use in critical-care settings and were subsequently adopted in obstetrics, often without appropriate validation for use in pregnancy. In this article, methods and devices for the measurement of CO are described and compared, and recommendations are formulated for their use in pregnancy, with the aim of standardizing the assessment of CO and peripheral vascular resistance in clinical practice and research studies on maternal hemodynamics. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Maternal hemodynamics in normal pregnancy: reference ranges and role of maternal characteristics

OBJECTIVES

The main aim of this study was to construct reference ranges of maternal central hemodynamic parameters during pregnancy. The second aim was to determine the maternal and pregnancy characteristics that influence these hemodynamic parameters.

METHODS

This was a prospective cohort study of low-risk pregnant women attending for routine antenatal care at St George's Hospital, London, UK. Exclusion criteria included any medical disorder present at the time of study recruitment, or development of hypertension or intrauterine fetal growth restriction following study recruitment. Stroke volume (SV), cardiac output (CO) and systemic vascular resistance (SVR) were obtained using non-invasive cardiac output monitoring (USCOM-1A®). USCOM-1A utilizes a non-imaging probe in the suprasternal notch to obtain velocity-time integrals of transaortic blood flow at the left ventricular outflow tract. Once the distribution of the data with respect to gestational age had been determined, maternal characteristics were added to the model to test whether they provided a significant improvement in the prediction of the median value.

RESULTS

The study included 627 women with a singleton pregnancy. The estimated median CO was constant for a maternal age above 32 years, but was around 0.5 L/min higher for women aged ≤ 25 years (P < 0.001). Maternal weight (P < 0.001) and height (P < 0.001) significantly affected CO values and there was a significant interaction (P = 0.002) between them. In women with a height of less than 1.60 m, there was no association between median CO and weight; however, in those with a height exceeding 1.60 m, an increase in weight was associated with an increase in CO. SV was primarily associated with height (P < 0.001), although some positive association with weight (P < 0.001) could also be observed within the normal body-mass-index range. Greater height (P < 0.001) was associated with lower median values of SVR, with an estimated difference of around 120 dynes × s/cm⁵ between 1.60 m and 1.80 m. Advancing maternal age was associated with higher median SVR, with an estimated difference of around 50 dynes × s/cm⁵ between 25 and 35 years. Smokers had a lower SVR by 73.5 (95% CI, 8.6-138.4) dynes × s/cm⁵ .

CONCLUSION

Maternal hemodynamics are influenced significantly by maternal age, height and weight. We provide USCOM-1A-specific reference ranges and a calculator for SV, CO and SVR in uncomplicated pregnancies that correct for maternal age, height and weight. This should enable clinical application and comparison in both uncomplicated and pathological pregnancies. 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.