Maternal hemodynamics early in labor: a possible link with obstetric risk?

Maternal Hemodynamics from Preconception to Delivery: Research and Potential Diagnostic and Therapeutic Implications: Position Statement by Italian Association of Preeclampsia and Italian Society of Perinatal Medicine

OBJECTIVE

 The Italian Association of Preeclampsia (AIPE) and the Italian Society of Perinatal Medicine (SIMP) developed clinical questions on maternal hemodynamics state of the art.

STUDY DESIGN

 AIPE and SIMP experts were divided in small groups and were invited to propose an overview of the existing literature on specific topics related to the clinical questions proposed, developing, wherever possible, clinical and/or research recommendations based on available evidence, expert opinion, and clinical importance. Draft recommendations with a clinical rationale were submitted to 8th AIPE and SIMP Consensus Expert Panel for consideration and approval, with at least 75% agreement required for individual recommendations to be included in the final version.

RESULTS

 More and more evidence in literature underlines the relationship between maternal and fetal hemodynamics, as well as the relationship between maternal cardiovascular profile and fetal-maternal adverse outcomes such as fetal growth restriction and hypertensive disorders of pregnancy. Experts agreed on proposing a classification of pregnancy hypertension, complications, and cardiovascular states based on three different hemodynamic profiles depending on total peripheral vascular resistance values: hypodynamic (>1,300 dynes·s·cm-5), normo-dynamic, and hyperdynamic (<800 dynes·s·cm-5) circulation. This differentiation implies different therapeutical strategies, based drugs' characteristics, and maternal cardiovascular profile. Finally, the cardiovascular characteristics of the women may be useful for a rational approach to an appropriate follow-up, due to the increased cardiovascular risk later in life.

CONCLUSION

 Although the evidence might not be conclusive, given the lack of large randomized trials, maternal hemodynamics might have great importance in helping clinicians in understanding the pathophysiology and chose a rational treatment of patients with or at risk for pregnancy complications.

KEY POINTS

· Altered maternal hemodynamics is associated to fetal growth restriction.. · Altered maternal hemodynamics is associated to complicated hypertensive disorders of pregnancy.. · Maternal hemodynamics might help choosing a rational treatment during hypertensive disorders..

Controlled ovarian stimulation leads to cardiovascular changes in patients undergoing in vitro fertilization

OBJECTIVE

To study hemodynamic changes along controlled ovarian stimulation in women undergoing in vitro fertilization.

STUDY DESIGN

Prospective observational cohort study conducted at Mother and Child Department of University Hospital Federico II, in Naples, Italy, between April 2021 and July 2022. Sixty-eight infertile patients undergoing controlled ovarian stimulation with gonadotropin, antagonist protocol and a fresh embryo transfer were included. Haemodynamic assessment was carried out using UltraSonic Cardiac Output Monitor at baseline (T1), estradiol peak (T2), fresh embryo-transfer day (T3). To evaluate relationships between quantitative variables and groups a Student T test for independent data was assessed. One-way analysis of variance (ANOVA) was used to determine the differences between the means of three time points (T1, T2 and T3) for quantitative variables. A mixed-model analysis of variance (ANOVA) was used to determine the differences between groups, among time points (T1, T2 and T3).

RESULTS

Sixty-eight patients were included. Significant differences over the three time points have been observed for CO (f = 3.78 l/min; p = 0.025), SVI (f = 3.56 ml/m2;p = 0.013), and RSVI (f = 4.84 dscm-5 m2; p = 0.009). No significant differences in trends have been found between beta hCG positive and beta hCG negative groups. There were no significant differences in maternal hemodynamic parameters at time-point T3 between patients treated with hCG 10,000 UI and with Triptorelin. Patients considered at increased risk of hyperstimulation reported a significant increase in SVI at baseline (26.9 ± 9.0 mL/m2 vs 21.9 ± 7.0 mL/m2; p = 0.010).

CONCLUSION

According to the results of our study, during controlled ovarian stimulation with antagonist protocol, patients undergo significant changes in maternal cardiovascular parameters over a very short period.

Nitric oxide donor increases umbilical vein blood flow and fetal oxygenation in fetal growth restriction. A pilot study

INTRODUCTION

To evaluate the maternal and fetal hemodynamic effects of treatment with a nitric oxide donor and oral fluid in pregnancies complicated by fetal growth restriction.

METHODS

30 normotensive participants with early fetal growth restriction were enrolled. 15 participants were treated until delivery with transdermal glyceryl trinitrate and oral fluid intake (Treated group), and 15 comprised the untreated group. All women underwent non-invasive assessment of fetal and maternal hemodynamics and repeat evaluation 2 weeks later.

RESULTS

In the treated group, maternal hemodynamics improved significantly after two weeks of therapy compared to untreated participants. Fetal hemodynamics in the treated group showed an increase in umbilical vein diameter by 18.87 % (p < 0.01), in umbilical vein blood flow by 48.16 % (p < 0.01) and in umbilical vein blood flow corrected for estimated fetal weight by 30.03 % (p < 0.01). In the untreated group, the characteristics of the umbilical vein were unchanged compared to baseline. At the same time, the cerebro-placental ratio increased in the treated group, while it was reduced in the untreated group, compared to baseline values. The treated group showed a higher birthweight centile (p = 0.03) and a lower preeclampsia rate (p = 0.04) compared to the untreated group.

DISCUSSION

The combined therapeutic approach with nitric oxide donor and oral fluid intake in fetal growth restriction improves maternal hemodynamics, which becomes more hyperdynamic (volume-dominant). At the same time, in the fetal circuit, umbilical vein flow increased and fetal brain sparing improved. Although a modest sample size, there was less preeclampsia and a higher birthweight suggesting beneficial maternal and fetal characteristics of treatment.

Placentation and complications of ART pregnancy. An update on the different possible etiopathogenic mechanisms involved in the development of obstetric complications

INTRODUCTION

Infertile couples' percentage is increasing all over the world, especially in Italy, with high number of children born in our country through assisted reproductive techniques (ART). However, pregnancies obtained by ART have increased potential obstetrical risks which could be caused by fetus-placenta unit development, most of all due to placentation's evolution. These can be reassumed into miscarriage, chromosomal abnormalities, preterm delivery, multiple pregnancy, IUGR, placenta previa, abruptio placentae, preeclampsia and hypertensive disorders, postpartum hemorrhage.

METHODS

The aim of this article is to evaluate hypothetic mechanism involved in placentation process and in the etiopathology of ART pregnancies disorders, giving an updating overview of different etiopathogenetic pathways and features. On this scenario, we create an updated review about the etiopathogenesis of abnormal placentation in ART pregnancies.

RESULTS

Several features and different etiopathogenetic characteristic might impact differently such as advanced maternal age, poor ovarian reserve, oocyte quality and causes of subfertility themselves, and the ART techniques itself, as hormonal medical treatments and laboratory techniques such as gamete and embryo laboratory culture, cryopreservation versus fresh ET, number of embryos transferred.

CONCLUSION

To further explore the molecular mechanisms behind placentation in ART pregnancies, further studies are necessary to gain a better understanding of the various aspects involved, particularly those which are not fully comprehended. This could prove beneficial to clinicians in both ART care and obstetric care, as it could help to stratify obstetrical risk and decrease complications in women undergoing ART, as well as perinatal disorders in their children. Correct placentation is essential for a successful pregnancy for both mother and baby.

Association of the key immunological and hemodynamic determinants with cervix ripening in pregnant women

OBJECTIVE

Aim: To investigate a correlation between cervical ripening, the immunological features and the hemodynamic characteristics of the cervix during the preparation for vaginal labor.

PATIENTS AND METHODS

Materials and Methods: We examined 75 pregnant women at different gestational age. General clinical and immunological studies were conducted in order to check serum concentration of cytokines IL-6, IL-1β, and TNF-α. Ultrasound and Doppler study were used to determine resistance index and systolic-diastolic ratio of blood flow in the common uterine artery as well as the descending and ascending parts and cervical stromal arteries.

RESULTS

Results: Pregnant women with high cervical ripening score had high concentrations of the major proinflammatory cytokines (IL-1β, IL-6, and TNF-α). Analysis of the of the cervical blood flow indicators of the studied groups showed significant differences in the indices of vascular resistance in the vessels that feed the cervix. Our data showed a significant correlation between the cervix ripening and both the serum levels of the studied cytokines and the level of peripheral vascular resistance indices in the common uterine arteries of the cervix, and the blood flow indices in the cervical stromal vessels.

CONCLUSION

Conclusions: Our study shows that the process of preparing the woman's body for labor is associated with immunological adjustment and increased hemodynamics of the cervix. We report that cervical ripening is associated with the immunological components and hemodynamic parameters of the cervix at late-stage pregnancy. Measuring cervix ripening and the accompanied changes in cytokine levels and hemodynamic parameters will form a more accurate assessment of birth preparedness and labor complications.

The cardiac-fetal-placental unit: fetal umbilical vein flow rate is linked to the maternal cardiac profile in fetal growth restriction

BACKGROUND

The functional maternal-fetal hemodynamic unit includes fetal umbilical vein flow and maternal peripheral vascular resistance.

OBJECTIVE

This study investigated the relationships between maternal and fetal hemodynamics in a population with suspected fetal growth restriction.

STUDY DESIGN

This was a prospective study of normotensive pregnancies referred to our outpatient clinic for a suspected fetal growth restriction. Maternal hemodynamics measurement was performed, using a noninvasive device (USCOM-1A) and a fetal ultrasound evaluation to assess fetal biometry and velocimetry Doppler parameters. Comparisons among groups were performed with 1-way analysis of variance with Student-Newman-Keuls correction for multiple comparisons and with Kruskal-Wallis test where appropriate. The Spearman rank coefficient was used to assess the correlation between maternal and fetal hemodynamics. Pregnancies were observed until delivery.

RESULTS

A total of 182 normotensive pregnancies were included. After the evaluation, 54 fetuses were classified as growth restricted, 42 as small for gestational age, and 86 as adequate for gestational age. The fetus with fetal growth restriction had significantly lower umbilical vein diameter (P<.0001), umbilical vein velocity (P=.02), umbilical vein flow (P<.0001), and umbilical vein flow corrected for fetal weight (P<.01) than adequate-for-gestational-age and small-for-gestational-age fetuses. The maternal hemodynamic profile in fetal growth restriction was characterized by elevated systemic vascular resistance and reduced cardiac output. The umbilical vein diameter was positively correlated to maternal cardiac output (r_s=0.261), whereas there was a negative correlation between maternal systemic vascular resistance (r_s=-0.338) and maternal potential energy-to-kinetic energy ratio (r_s=-0267). The fetal umbilical vein time averaged max velocity was positively correlated to maternal cardiac output (r_s=0.189) and maternal inotropy index (r_s=0.162), whereas there was a negative correlation with maternal systemic vascular resistance (r_s=-0.264) and maternal potential energy-to-kinetic energy ratio (r_s=-0.171). The fetal umbilical vein flow and the flow corrected for estimated fetal weight were positively correlated with maternal cardiac output (r_s=0.339 and r_s=0.297) and maternal inotropy index (r_s=0.217 and r=0.336), whereas there was a negative correlation between maternal systemic vascular resistance (r_s=-0.461 and r_s=-0.409) and maternal potential energy-to-kinetic energy ratio (r_s=-0.336 and r_s=-0.408).

CONCLUSION

Maternal and fetal hemodynamic parameters were different in the 3 groups of fetuses: fetal growth restriction, small for gestational age, and adequate for gestational age. Maternal hemodynamic parameters were closely and continuously correlated with fetal hemodynamic features. In particular, a maternal hemodynamic profile with high systemic vascular resistance, low cardiac output, reduced inotropism, and hypodynamic circulation was correlated with a reduced umbilical vein flow and increased umbilical artery pulsatility index. The mother, placenta, and fetus should be considered as a single cardiac-fetal-placental unit. The correlations of systemic vascular resistance, cardiac output, and inotropy index with umbilical artery impedance indicate the key role of these 3 parameters in placental vascular tree development. The umbilical vein flow rate and, therefore, the placental perfusion seems to be influenced not only by these three parameters but also by the maternal cardiovascular kinetic energy.

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.

Maternal cardiovascular function in the prediction of fetal distress in labor: a prospective cohort study

OBJECTIVE

To explore the strength of association and the diagnostic accuracy of maternal hemodynamic parameters detected noninvasively in predicting an adverse perinatal outcome in labor.

METHODS

Prospective cohort study of singleton women undergoing antepartum care at 37-39 weeks of gestation. A noninvasive ultrasonic cardiac output monitor (USCOM®) was used for cardiovascular assessment. The study outcome was a composite score of adverse perinatal outcome, which included at least one of the following variables: Cesarean or instrumental delivery for abnormal fetal heart monitoring, umbilical artery pH <7.10 or admission to neonatal special care unit. Attending clinicians were blinded to maternal cardiovascular indices. Multivariate logistic regression and area under the curve (AUC) analyses were used to test the diagnostic accuracy of different maternal and ultrasound characteristics in predicting adverse perinatal outcome.

RESULTS

A total of 133 women were recruited. The rate of adverse perinatal outcome was 25.6% (34/133). Women who delivered without abnormal perinatal outcome (controls) were more likely to be parous, compared to those who had an adverse perinatal outcome (44.4 vs. 73.5%; p = .005). Control women had significantly lower systemic vascular resistance (SVR) (median, 1166 vs. 1352 dynes × s/cm5, p = .023) and SVR index (SVRI) (median, 2168 vs. 2627 dynes × s/cm5/m2, p = .039) compared to women who had an adverse perinatal outcome. In this latter group the prevalence of SV <50 ml was significantly higher than in the control group (38.2% (13/34) vs. 11.1%, (11/99) p = .0012). At multivariable logistic regression analysis, SVR (aOR 1.307; 95% CI 1.112-2.23), SV <50 ml (aOR 4.70; 95% CI 1.336-12.006) and parity (3.90: 95% CI 1.545-10.334) were the only variables independently associated with adverse perinatal outcome. A model considering only SVR showed an AUC of 0.631. Integration of SVR with SV <50 ml and parity significantly improves the diagnostic performance of SVR alone to predict adverse outcome (AUC 0.732; p = .016).

CONCLUSION

Pre-labor modifications of maternal cardiovascular variables are associated with adverse perinatal outcome. However, their predictive accuracy for perinatal compromise is low, and thus their use as standalone screening test for adverse perinatal outcome in singleton pregnancies at term is not supported.

Maternal hemodynamics for the identification of early fetal growth restriction in normotensive pregnancies

We aimed at testing systemic vascular resistance (SVR) for the correct identification of early fetal growth restriction (FGR). 61 normotensive patients, gestational age 29 + 0-32 + 0, with suspected diagnosis of early FGR, were submitted to USCOM and to an ultrasound evaluation. 24 patients met the criteria of FGR, and 9 patients developed umbilical artery Doppler alterations. SVR>1006 dyn s·cm^-5 correctly identified patients with a subsequent diagnosis of FGR, whereas SVR>1222 dyn s·cm^-5 was related to FGR with subsequent umbilical artery Doppler alterations. These data might be important to introduce USCOM in the clinical practice to identify and treat FGR.

Hemodynamic assessment in patients with preterm premature rupture of the membranes (pPROM)

OBJECTIVE

The aim of this study was to assess the hemodynamic differences in women with pPROM versus physiological pregnancies.

STUDY DESIGN

This was a prospective case control study of 15 patients with pPROM and 45 controls. Patients and controls were submitted at enrollment to a non-invasive hemodynamic evaluation with UltraSonic Cardiac Output Monitor (USCOM), and to blood tests to check white blood cells count and C-reactive protein (CRP) levels. We followed pPROM patients until delivery noting fetal/neonatal and maternal unfavorable outcomes (maternal fever, APGAR 1' and 5'< 7, stillbirth).

RESULTS

Patients with pPROM showed higher values of cardiac output (9.1 ± 2.3 vs 7.1 ± 0.85, p < 0.01), lower systemic vascular resistances (792.1 ± 162 vs 1006.2 ± 110.7, p < 0.01), higher minute distance (32.3 ± 7.8 vs 25 ± 2.8, p < 0.01), lower Potential to Kinetic Energy Ratio (16.5 ± 5.3 vs 22.4 ± 6.8, p < 0.01), higher heart rate (97.5 ± 15.4 vs 82.4 ± 12, p < 0.01) and higher oxygen delivery (1313.2 ± 325.8 vs 1080.7 ± 151.8, p < 0.01) vs. controls. Six out of 15 pPROM patients had an unfavorable outcome. There were no significant differences in CRP levels and WBC count at admission in the two pPROM subgroups, whereas maternal hemodynamics was characterized by lower SVR (718 ± 72 vs 863 ± 123, p = 0.02) in subsequently complicated patients.

CONCLUSIONS

Maternal hemodynamics is altered in pPROM patients, with a lower Systemic Vascular Resistance and higher Cardiac Output vs. controls. This hyperdynamic circulation appears to anticipates the changes of serum markers of inflammation (CRP, WBC count) and seems to be more pronounced at admission in pPROM patients developing unfavorable outcomes.

Systemic vascular resistance may influence the outcome of in vitro fertilization

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

Hypertensive disorders and maternal hemodynamic changes in pregnancy: monitoring by USCOM® device

Hypertensive disorders are quite common, complicating about 10% of pregnancies, while preeclampsia occurs in 2-8% of cases. The most recognized etiopathogenetic factor for the development of preeclampsia is deficient remodeling of the spiral arteries during trophoblastic invasion. Recently, some authors speculated about the "cardiovascular origin of preeclampsia"; in particular, they postulate that placental dysfunction is not the primum movens of preeclampsia, but it could be caused by a failure of the maternal cardiovascular system to adapt to the pregnancy itself. Moreover, several studies have also shown that developing preeclampsia in pregnancy is associated with an increased risk of cardiovascular disease later in life. Due to the importance of this pathology, it would be crucial to have an effective screening in order to implement a prophylaxis; for this purpose, it could be useful to have an accurate and noninvasive device for the assessment of maternal hemodynamic variables. USCOM^® (Ultrasonic Cardiac Output Monitor) is a noninvasive Doppler ultrasonic technology which combines accuracy, reproducibility, noninvasiveness, and a fast learning curve. Maternal hemodynamic evaluation is important in order to monitor the changes that the maternal organism encounters, in particular a reduction in blood pressure, a decrease in total peripheral resistances, and an increase in cardiac output, resulting in a hyperdynamic circle. These hemodynamic modifications are lacking in pregnancies complicated by preeclampsia. For these reasons, it is crucial to have a tool that allows these parameters to be easily evaluated in order to identify those women at higher risk of hypertensive complications and more severe outcomes.

Maternal hemodynamics and computerized cardiotocography during labor with epidural analgesia

PURPOSE

To analyze the mechanisms involved in the fetal heart rate (FHR) abnormalities after the epidural analgesia in labor.

METHODS

A prospective unblinded single-center observational study on 55 term singleton pregnant women with spontaneous labor. All women recruited underwent serial bedside measurements of the main hemodynamic parameters using a non-invasive ultrasound system (USCOM-1A). Total vascular resistances (TVR), heart rate (HR), stroke volume (SV), cardiac output (CO) and arterial blood pressure were measured before epidural administration (T0), after 5 min 5 (T1) from epidural bolus and at the end of the first stage of labor (T2). FHR was continuously recorded through computerized cardiotocography before and after the procedure.

RESULTS

The starting CO was significantly higher in a subgroup of women with low TVR than in women with high-TVR group. After the bolus of epidural analgesia in the low-TVR group there was a significant reduction in CO and then increased again at the end of the first stage, in the high-TVR group the CO increased insignificantly after the anesthesia bolus, while it increased significantly in the remaining part of the first stage of labor. On the other hand, CO was inversely correlated with the number of decelerations detected on cCTG in the 1 hour after the epidural bolus while the short-term variation was significantly lower in the group with high-TVR.

CONCLUSION

Maternal hemodynamic status at the onset of labor can make a difference in fetal response to the administration of epidural analgesia.

Maternal peripheral vascular resistance at mid gestation in chronic hypertension as a predictor of fetal growth restriction

We aimed at analyzing the relationship between maternal hemodynamics as expressed by Peripheral Vascular Resistance (PVR) at mid gestation and fetal growth at delivery in chronic hypertension. 152 chronic hypertensive patients were submitted to echocardiography noting PVR at 22-24 weeks' gestation and were followed until delivery noting birthweight centile and the diagnosis of fetal growth restriction (FGR). The logarithmic correlation analysis showed that PVR at mid gestation was strongly related to birthweight at delivery (r = -0.72; p < .001). Moreover, PVR was predictive of both a birthweight <10th centile (PVR >1466 Sensitivity 75.0%, Specificity 93.4%, AUC 0.83, p < .001) and FGR (PVR > 1355 Sensitivity 84.2%, Specificity 93.2%, AUC 0.88, p < .001). This study highlights the importance of maternal hemodynamics as expressed by PVR at mid gestation for the identification of chronic hypertensive patients at risk for developing fetal growth restriction. This observation might open new areas of intervention to treat patients with altered hemodynamics (PVR > 1355 dyne s cm^-5).

Distinction between SGA and FGR by means of fetal umbilical vein flow and maternal hemodynamics

OBJECTIVES

To improve identification of fetal growth restriction (FGR) by means of umbilical venous flow (QUV) and maternal hemodynamics, including systemic vascular resistance (SVR) and cardiac output (CO), in order to distinguish between FGR and SGA.

METHODS

We enrolled 68 pregnancies (36 SGA, 8 early FGR and 24 late FGR) who underwent a complete fetal hemodynamic examination including QUV and a noninvasive maternal hemodynamics assessment by means of USCOM.

RESULTS

In comparison with SGA, QUV and corrected for estimated fetal weight QUV (cQUV) were significantly lower in early and late-FGR. In addition, maternal CO was lower in early and late-FGR, while SVR was lower only in early-onset FGR. According to ROC analysis, cQUV centile (AUC 0.92, 0.72) was the best parameter for the prediction of SGA before and after 32 weeks, followed by SVR and CO. For all parameters, the prediction was always better in the case of early-onset FGR <32 weeks.

CONCLUSIONS

UV flow and maternal hemodynamics examination are useful tools to accurately discern between SGA and FGR.

Fetal Umbilical Vein Flow in the Classification of Fetuses with Growth Restriction

Objectives: To assess umbilical vein (UV) blood flow in fetal growth restriction (FGR) and in pregnancy with small for gestational age (SGA) fetus. To evaluate the predictive capacity of UV blood flow (QUV) in the discrimination of SGA fetuses from FGR before and after 32 weeks of pregnancy. Methods: Sixty-five women with a recent diagnosis of FGR or SGA fetuses were enrolled and underwent a complete fetal Doppler examination comprehending QUV. We collected SGA (n = 34), early-FGR (n = 9), and late-FGR (n = 22) fetuses. Results: UV diameter was lower in early and late-FGR compared to SGA, while time-averaged maximum velocity (TAMXV) was lower only in early-FGR. UV blood flow (QUV) and QUV corrected for estimated fetal weight (cQUV) were significantly lower in early-FGR and late-FGR compared to SGA. The receiver operating characteristic (ROC) curves analysis of cQUV showed a significant predictive capacity for SGA diagnosis before and after 32 weeks. Conclusions: The evaluation of UV blood flow allows distinguishing SGA fetuses from FGR. The assessment of UV flow should be taken into consideration in future research of new parameters to differentiate SGA from FGR.

Hemodynamic maladaptation and left ventricular dysfunction in chronic hypertensive patients at the beginning of gestation and pregnancy complications: a case control study

OBJECTIVE

The aim of this study was to evaluate early pregnancy differences in maternal hemodynamics, cardiac geometry and function, between chronic hypertensive (CH) patients with and without the development of feto-maternal complications later in pregnancy.

METHODS

We performed a case-control study on nulliparous CH treated patients. From a group of CH patients referred to our outpatient clinic at 4-6 weeks for a clinical evaluation the first consecutive 30 patients with subsequent complications (superimposed PE, abruptio placentae, uncontrolled severe hypertension with delivery <34 weeks, HELLP syndrome, FGR, perinatal death) were enrolled; the first 2 CH women with uneventful pregnancy referred after the case were enrolled as controls for a total of 60 patients. All patients were shifted to alpha-methyl dopa at the beginning of pregnancy and were submitted to an echocardiographic evaluation to assess the maternal hemodynamics, cardiac geometry, diastolic and systolic function.

RESULTS

Patients developing complications had a lower early pregnancy heart rate (73 ± 11 vs. 82 ± 11 bpm), cardiac output (5.23 ± 1.2 vs. 6.5 ± 1.3 L/min, p<.01) and cardiac index (3.0 ± 0.7 vs. 3.6 ± 0.7 L/min/m², p<.01); higher total vascular resistance (1554 ± 305 vs. 1248 ± 243 d.s.cm^-5, p<.01) and total vascular resistance index (2666 ± 519 vs. 2335 ± 431, d.s.cm^-5/m², p<.01); higher left ventricular mass index (42.1 ± 8.6 vs. 36.9 ± 8.3 g/m², p<.01) and relative wall thickness (0.40 ± 0.05 vs. 0.36 ± 0.05, p<.01) of the left ventricle, resulting in a higher prevalence of altered cardiac geometry vs. uneventful CH controls. Diastolic and systolic dysfunction were also present with a higher E/e' ratio (10.50 ± 3.56 vs. 7.22 ± 1.91, p<.01) and a lower stress corrected midwall mechanics (89 ± 21 vs. 100 ± 22, p=.02) of the left ventricle.

CONCLUSION

CH treated patients developing maternal and/or fetal complications show early pregnancy altered cardiac geometry, diastolic and systolic dysfunction, and impaired hemodynamics with a high resistance circulation.

Pregnancy complications in chronic hypertensive patients are linked to pre-pregnancy maternal cardiac function and structure

BACKGROUND

Chronic hypertension complicates around 3% of all pregnancies and is associated with an increased risk for pregnancy complications such as superimposed preeclampsia, fetal growth restriction, preterm delivery, and stillbirth, reaching a rate of complications of up to 25-28%.

OBJECTIVE

We performed an echocardiographic study to evaluate pre-pregnancy cardiac geometry and function, along with the hemodynamic features of treated chronic hypertension patients, searching for a possible correlation with the development of feto-maternal complications and with pre-pregnancy therapy.

MATERIALS AND METHODS

This was a prospective observational cohort study of 192 consecutive patients receiving treatment for chronic hypertension (calcium channel blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, α1-adrenoceptor antagonists, and/or diuretics). Patients underwent echocardiography before pregnancy, assessing left ventricular morphology and function, cardiac output, and total vascular resistance. Pre-pregnancy therapy was noted, patients were shifted to α-methyldopa right before pregnancy, and were followed until delivery, noting major early (<34weeks' gestation) and late (≥34 weeks' gestation) complications. Comparisons among the 3 groups (ie, those with no complications, early complications, and late complications) were performed with 1-way analysis of variance with Student-Newman-Keuls correction for multiple comparisons. The Mann-Whitney U test was used for non-normally distributed data. Comparison of proportions was used as appropriate. Receiver operating characteristic curve analysis was used to identify cutoff values of diastolic dysfunction in this population using the E/e' ratio, and separate cutoff of values for total vascular resistance for the prediction of early and late complications of pregnancy. Binary univariate and multivariate logistic regression as well as Cox proportional hazards regression were used to evaluate the possible correlation among angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and/or calcium channel blocker pre-pregnancy therapy, cardiovascular features, and the risk for subsequent early and late complications of pregnancy.

RESULTS

Of 192 patients, 141 had no complications, and 51 had a complicated pregnancy (24 had early complications and 27 had late complications). Concentric geometry was more frequent in those women with early versus late and no complications (50% vs 13.5% and 11.1%, respectively; P < .05), whereas eccentric hypertrophy was more represented in women with late versus early and no complications (32% versus 12.5% and 1.4%, respectively; P < .05). The receiver operating characteristic curve showed an E/e' ratio value >7.65 (sensitivity, 59.6%; specificity, 68.6%) as a predictor of subsequent complications of pregnancy, whereas total vascular resistance <1048 (sensitivity, 83.7%; specificity, 55.6%) was predictive for late complications and total vascular resistance >1498 (sensitivity, 87.5%; specificity, 78.0%) for the early complications of pregnancy. Univariate analysis showed that the following parameters were predictive for complications of pregnancy: altered geometry of the left ventricle (odds ratio, 5.94; 95% confidence interval, 2.90-12.19), diastolic dysfunction (odds ratio, 3.22; 95% confidence interval, 1.63-6.37), altered total vascular resistance (odds ratio, 3.52; 95% confidence interval, 1.78-6.97), and pre-pregnancy therapy without calcium channel blockers/angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (odds ratio, 2.73; 95% confidence interval, 1.37-5.42). These parameters, except for altered total vascular resistance, were independent predictors in the multivariate analysis corrected for body mass index, heart rate, parity, and mean arterial pressure.

CONCLUSION

Chronic hypertension patients with pre-pregnancy cardiac remodeling and dysfunction more often develop early and late complications of pregnancy. Pre-pregnancy therapy for chronic hypertension patients with calcium channel blockers and/or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers may positively influence cardiac profiles and the outcome of a future pregnancy with a reduced rate of complications.

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.

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.

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.