Maternal cardiovascular function in pregnancies complicated by intrauterine growth restriction

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

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

Blood Pressure Monitoring and Perinatal Outcomes in Normotensive Women with Gestational Diabetes Mellitus

Alterations in ambulatory blood pressure detected by monitoring (ABPM) have been associated with perinatal complications in hypertensive pregnant women. Aim: To establish the relationships between the blood pressure (BP) profiles detected by ABPM and adverse perinatal outcomes in normotensive women with gestational diabetes mellitus (GDM). Methods: A prospective study of normotensive women in whom 24 h ABPM was performed at 28–32 weeks of pregnancy. The obstetric and perinatal outcomes were evaluated. Results: Two hundred patients were included. Thirty-seven women with GDM and obesity had significantly higher mean systolic BP (SBP) and nocturnal SBP and diastolic BP (DBP) compared to women with only GDM (n = 86). Nocturnal SBP (OR = 1.077; p = 0.015) and obesity (OR = 1.131; p = 0.035) were risk factors for the development of hypertensive disorders of pregnancy (HDPs). Mothers of newborns with neonatal complications (n = 27) had higher nocturnal SBP (103.8 vs. 100 mmHg; p = 0.047) and DBP (62.7 vs. 59.4; p = 0.016). Women who delivered preterm (n = 10) had higher BP and a non-dipper pattern (p = 0.005). Conclusions: Nocturnal SBP was a predictor of HDPs in normotensive women with obesity or GDM. Alterations in ABPM in these patients were associated with poor obstetric and perinatal outcomes.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Multivariable evaluation of maternal hemodynamic profile in pregnancy complicated by fetal growth restriction: prospective study

OBJECTIVE

To evaluate the association between fetal growth restriction (FGR) and maternal hemodynamic parameters using multivariable analysis, adjusting for major confounding factors, such as hypertensive disorders of pregnancy (pre-eclampsia and gestational hypertension).

METHODS

A prospective cohort study was conducted between January 2013 and April 2016. Two cohorts of patients were recruited, between 24 and 39 weeks of gestation, in a high-risk outpatient setting. These cohorts comprised 49 appropriate-for-gestational-age singleton fetuses and 93 that were FGR (abdominal circumference (AC) at recruitment in the second half of pregnancy ≤ 10th percentile with a previous normal AC at 20-22 weeks). Maternal echocardiography was performed at the time of enrolment and included hemodynamic parameters of systolic and diastolic function and cardiac remodeling indices. Data were analyzed using a multivariable generalized linear model to estimate the association of FGR with maternal hemodynamic parameters after adjusting for significant confounding factors.

RESULTS

In the multivariable analysis, after adjustment for hypertensive disorders of pregnancy and smoking, FGR was associated with a 14% increase in maternal total vascular resistance, 16% reduction in cardiac output, 13% reduction in left ventricular mass and 11% reduction in heart rate; similar results were observed for the corresponding indexed parameters. Hypertensive disorders of pregnancy in the absence of FGR were associated with a 25% increase in total vascular resistance, 16% increase in left ventricular mass and 14% reduction in diastolic function; similar results were observed for the corresponding indexed parameters.

CONCLUSION

FGR is significantly and independently associated with several maternal hemodynamic parameters, even after adjustment for major confounding factors, such as hypertensive disorders of pregnancy. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Association between thyroid-stimulating hormone and maternal hemodynamics in hypertensive disorders of pregnancy: an observational study

Background

Hypertensive disorders of pregnancy (HDP) are characterized by hemodynamic disturbances. Altered thyroid function is a risk factor for poor outcomes of pregnancy. However, the associations between thyroid function biomarkers and maternal hemodynamics during pregnancy in HDP remain unclear.

Methods

From January 2016 to January 2018, pregnant women diagnosed with HDP admitted to the Nanjing Maternity and Child Health Care Hospital were prospectively enrolled in the third trimester. Normally distributed variables were expressed as mean ± standard deviation and skewed variables were expressed as median (25th percentile, 75th percentile). Correlations between thyroid-stimulating hormone (TSH) or free thyroxine (FT4) and maternal hemodynamic parameters were assessed by Pearson’s correlation coefficient and 95% confidence interval (95%CI). Bonferroni’s correction for multiple correlations was performed. Logistic regression models with odd ratio (OR) and 95%CI were applied to confirm the associations.

Results

A total of 163 third-trimester pregnant women with HDP with a mean gestational age of 35.62 ± 2.83 weeks were recruited. The infant birth weight of patients with elevated TSH levels was lower than that of patients with normal TSH levels (2635 ± 867 g vs. 3037 ± 673 g, p = 0.002). Reduced cardiac output (CO) was defined as CO < 3.5 L/min. The infant birth weight of patients with reduced CO was lower than that of patients with normal CO (2250 ± 510 g vs. 2890 ± 774 g, p = 0.002). TSH levels were significantly and negatively correlated with CO (r = − 0.260, 95%CI: − 0.392- -0.103, p < 0.001). FT4 levels were not significantly correlated with any of the maternal hemodynamic parameters (all p > 0.05). TSH level (OR = 1.371, 95%CI: 1.086–1.733, p = 0.008) was confirmed associated with reduced CO in the logistic regression analysis.

Conclusions

Elevated TSH levels are associated with reduced CO in HDP during the third trimester.

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.

Endothelial dysfunction and vascular stiffness in women with previous pregnancy complicated by early or late pre-eclampsia

OBJECTIVES

Pre-eclampsia (PE) is associated with an increased cardiovascular risk later in life. The persistence of endothelial dysfunction after delivery may represent the link between PE and cardiovascular disease. We aimed to evaluate endothelial function and arterial stiffness after delivery of pregnancy complicated by early-onset (EO) or late-onset (LO) PE and their correlation with gestational age and mean uterine artery pulsatility index at PE diagnosis and birth-weight percentile.

METHODS

The study included 30 women with previous EO-PE, 30 with previous LO-PE and 30 controls with no previous PE. Participants were examined at between 6 months and 4 years after delivery. All included women were free from cardiovascular risk factors and drugs. Data on demographic and clinical characteristics during pregnancy were collected retrospectively from obstetrical charts. Endothelial function and arterial stiffness were assessed by peripheral arterial tonometry and pulse-wave analysis.

RESULTS

All vascular parameters were significantly different, indicating circulatory impairment, in women with previous EO-PE. Women with previous LO-PE had higher vascular rigidity than did controls and all had normal values of reactive hyperemia index, although they were significantly lower when compared with those of controls. On multivariate analysis, gestational age and mean uterine artery pulsatility index at the time of PE diagnosis, and birth-weight percentile were all statistically related to the vascular indices studied, after correcting for confounding parameters.

CONCLUSIONS

Women with previous pregnancy complicated by PE, in particular those with early-onset disease, showed persistent microcirculatory dysfunction, as suggested by a significant reduction in reactive hyperemia index value, and increased arterial stiffness. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Maternal cardiac deceleration capacity: a novel insight into maternal autonomic function in pregnancies complicated by hypertensive disorders and intrauterine growth restriction

OBJECTIVE

To explore maternal cardiac deceleration capacity (DC), a marker of autonomic function derived from electrocardiographic (ECG) signals, in pregnancies complicated by intrauterine growth restriction (IUGR) and hypertensive disorders of pregnancy (HDP) associated to IUGR (HDP-IUGR) or to appropriate for gestational age fetal growth (HDP-AGAf).

METHODS

Prospective single center case-control study conducted at Buzzi Children's Hospital, Milan. Maternal ECGs were analyzed by Phase Rectified Signal Averaging (PRSA) method to obtain cardiac DC in women with: HDP-IUGR, HDP-AGAf, severe-IUGR, mild-IUGR and uncomplicated pregnancies. IUGR was defined as abdominal circumference <5th centile; severe-IUGR was associated with umbilical artery Doppler pulsatility index >2 standard deviations. Non-parametric tests were adopted.

RESULTS

269 women were recruited. Women with HDP-IUGR (n=35) showed significantly higher cardiac DC compared both to controls (n=141) (p=0.003) and women with HDP-AGAf (n=18) (p=0.01). Women with severe-IUGR (n=14) showed significantly higher DC than controls (p=0.01). Women with mild-IUGR (n=61) as well as women with HDP-AGAf showed no differences in DC compared to controls (both p=0.3).

CONCLUSIONS

Women with pregnancy complicated by severe placental failure, such as HDP-IUGR and severe IUGR, show significant autonomic alterations, as indicated by elevated cardiac DC. On the contrary, pregnancy complications such as HDP-AGAf and mild IUGR show no impact on maternal autonomic balance. We present a new approach to explore maternal autonomic cardiovascular regulation that might reflect the severity of placental vascular insufficiency.

Differences in cardiovascular function comparing prior preeclamptics with nulliparous controls

OBJECTIVE

The objective of the current study was to evaluate cardiovascular function; including blood pressure, cardiac output, pulse wave velocity and vascular compliance in nonpregnant nulliparous women compared to women with a history of preterm preeclampsia.

STUDY DESIGN

This was a case control study. Blood pressure was measured using the Finapres Pro. Baseline cardiac output was determined by echocardiography. Pulse wave velocity was estimated using simultaneous electrocardiographic tracings and ultrasound determined arterial flow waveforms and calculated as estimated distance divided by the time interval between EKG r-wave peak and ultrasound derived peak popliteal artery flow. During volume challenge, 500mL of lactated Ringers solution was infused through an indwelling antecubital catheter over 10min. Cardiac output and blood pressure during and 15min after the infusion were estimated using the Finapres Pro.

MAIN OUTCOME MEASURES

Indices of arterial stiffness and vascular compliance.

RESULTS

Previous preeclamptics exhibited a significant increase in pulse pressure and cardiac output in response to volume challenge when compared with nulliparous controls. Prior preeclamptics had a strong positive correlation between blood pressure indices (r=0.50-0.68, p⩽0.01) and pulse pressure (r=0.58, P=0.008) with pulse wave velocity that was not evident in control women.

CONCLUSIONS

In women with prior preterm preeclampsia a relationship between blood pressure, intravascular volume and arterial stiffness, is evident in the nonpregnant state and in the absence of hypertension or overt cardiovascular disease. This supports an overarching hypothesis that nonpregnant physiology is an important contributor to pregnancy adaptations.

Maternal cardiac function, uteroplacental Doppler flow parameters and pregnancy outcome: a systematic review

OBJECTIVE

To investigate the existing evidence for a link between maternal cardiac function, abnormal uteroplacental flow and poor perinatal outcome in women with and without known cardiac disease.

METHODS

PubMed and EMBASE databases were searched systematically for studies relating cardiac functional parameters and uteroplacental Doppler flow with pregnancy outcome in women with pre-existing congenital cardiac disease and women without known cardiac disease. Only studies based on echocardiography were included.

RESULTS

From 1732 citations, 10 articles were included. In women with known congenital heart disease, a relationship was found between abnormal uteroplacental Doppler flow patterns and cardiac function before and during pregnancy. Conversely, women without a history of congenital heart disease, but with abnormal uterine artery resistance and pregnancy complications, more often showed global left ventricular diastolic dysfunction (33%; P = 0.0001), impaired myocardial relaxation (72%; P < 0.0001) and left ventricular systolic dysfunction (17%; P = 0.006), even up to 1 year postpartum.

CONCLUSION

There is increasing evidence for an association between pre-existing subclinical cardiac dysfunction, poor placentation (reflected by uteroplacental Doppler flow abnormalities) and poor pregnancy outcome. It may be postulated that pre-existing suboptimal cardiac performance, as a result of either congenital heart disease or a subclinical latent condition, is one of the common denominators of poor placentation, leading to poor pregnancy outcome.

Maternal tissue blood flow and oxygen saturation in pre-eclampsia and intrauterine growth restriction

OBJECTIVE

To investigate the hypothesis that impaired maternal tissue perfusion occurs in pre-eclampsia and intrauterine growth restriction (IUGR) and this correlates with maternal tissue oxygenation.

STUDY DESIGN

Strain gauge plethysmography was used to compare maternal calf blood flow during the third trimester in 16 women with pre-eclampsia, 6 women with IUGR and 16 normal pregnant controls. A Mediaid iPOX pulse oximeter was used to measure maternal tissue oxygenation in the three groups and these were compared with tissue blood flow.

RESULTS

Maternal tissue blood flow was significantly reduced in pre-eclampsia compared to the two other groups (p=0.003). Blood flow was significantly reduced in pre-eclampsia compared to IUGR (p=0.03). However there was no difference in blood flow between normal pregnancy and IUGR groups (p=0.76). No significant difference was noted in maternal tissue oxygenation between the normal pregnancy, pre-eclampsia and IUGR groups (mean±S.E.M. [97.13±0.4, 96.69±0.33, 97.83±0.47 respectively], p=0.26). No correlation was noted between blood flow and tissue oxygenation in the three groups of women.

CONCLUSION

We have demonstrated that reduced maternal resting tissue blood flow present in women with pre-eclampsia is not seen in women with IUGR and the reduction in blood flow in pre-eclampsia is not associated with changes in maternal tissue oxygenation.

Left ventricular midwall mechanics at 24 weeks' gestation in high-risk normotensive pregnant women: relationship to placenta-related complications of pregnancy

OBJECTIVES

Most studies during pregnancy have assessed maternal left ventricular (LV) function by load-dependent indices, assessing only chamber function. The aim of this study was to assess afterload-adjusted LV myocardial and chamber systolic function at 24 weeks' gestation and 6 months postpartum in high-risk normotensive pregnant women.

METHODS

A group of 118 high-risk women with bilateral notching of the uterine arteries underwent an echocardiographic examination to evaluate midwall mechanics (midwall shortening (mFS%) and stress-corrected midwall shortening (SCmFS%)) of the LV at 24 weeks' gestation and 6 months postpartum. Patients were followed until delivery and pregnancies were classified retrospectively as uneventful (uncomplicated outcome) or complicated. A control group of 54 low-risk women with uneventful pregnancies without bilateral notching was also enrolled.

RESULTS

The pregnancy was uneventful in 74 (62.7%) women, whereas 44 (37.3%) developed complications. At 24 weeks' gestation, mFS% and SCmFS% were greater in the uncomplicated-outcome compared with the complicated-outcome group (25.9 ± 4.8 vs 18.8 ± 5.0%, P < 0.001 and 107.9 ± 18.4 vs 77.9 ± 20.7%, P < 0.001, respectively). At 6 months postpartum, SCmFS% remained greater in the uncomplicated-outcome compared with the complicated-outcome group (100.4 ± 21.6 vs 87.8 ± 19.1, P < 0.05). In the uncomplicated-outcome group, SCmFS% was higher during pregnancy than it was postpartum, whereas in the complicated-outcome group, it was lower during pregnancy than it was postpartum (P < 0.05).

CONCLUSIONS

Maternal cardiac midwall mechanics appear to be enhanced (SCmFS% increased compared with controls) during pregnancy compared with postpartum in high-risk patients with uncomplicated pregnancy, whereas midwall mechanics are depressed both during pregnancy and postpartum in patients with pregnancy complications.

Maternal cardiac function in complicated twin pregnancy: a longitudinal study

OBJECTIVE

To evaluate longitudinally a cohort of twin pregnancies and to assess whether the occurrence of adverse pregnancy outcome may be related to specific maternal cardiac findings.

METHODS

Women with twin pregnancies were enrolled prospectively and underwent serial maternal echocardiography at 20-23 weeks, 26-29 weeks and 30-33 weeks of gestation. Patients were excluded if delivery took place prior to 34 weeks. Cardiac findings were compared between patients with uneventful pregnancy outcome and those who developed one of the following complications: pre-eclampsia or gestational hypertension; small-for-gestational age (SGA) neonates (birth weight of one or both twins < 5(th) centile for gestational age).

RESULTS

A group of 28 twin gestations was obtained for analysis, including eight complicated cases. At each visit, mean ± SD cardiac output (CO) was significantly higher in uncomplicated than complicated twin pregnancies (6.55 ± 0.82 vs 4.99 ± 0.67 L/min, P < 0.001 at 20-23 weeks; 7.31 ± 0.74 vs 5.66 ± 1.17 L/min, P < 0.001 at 26-29 weeks; 7.50 ± 0.89 vs 5.32 ± 0.74 L/min, P < 0.001 at 30-33 weeks), as was stroke volume (83.4 ± 12.2 vs 64.5 ± 9.2 mL, P = 0.001 at 20-23 weeks; 84.4 ± 15.6 vs 64.5 ± 12.0 mL, P = 0.003 at 26-29 weeks; 85.0 ± 19.2 vs 65.6 ± 10.7 mL, P = 0.013 at 30-33 weeks), whereas total vascular resistance (TVR) was lower (1005 ± 137 vs 1406 ± 159 dynes × s/cm(5) , P < 0.001 at 20-23 weeks; 924 ± 100 vs 1249 ± 231 dynes × s/cm(5) , P < 0.001 at 26-29 weeks; 929 ± 96 vs 1400 ± 244 dynes × s/cm(5) , P < 0.001 at 30-33 weeks). Moreover, CO, blood pressure (BP), heart rate (HR) and TVR remained stable throughout the assessed pregnancy interval in women developing a complication, whereas significant changes (rise in CO, HR and BP; fall in TVR) were noted in the uncomplicated group.

CONCLUSIONS

Maternal cardiac function in twin pregnancies complicated by pre-eclampsia or SGA neonates apparently does not undergo the profound longitudinal changes that occur in uneventful twin pregnancies.

Maternal cardiac function in normal twin pregnancy: a longitudinal study

OBJECTIVE

To investigate maternal cardiac function in a cohort of uncomplicated twin gestations assessed longitudinally.

METHODS

Women with twin pregnancies were enrolled prospectively and underwent serial maternal echocardiography at 20-23 weeks, 26-29 weeks and 30-33 weeks of gestation. Patients were excluded if any of these complications occurred after recruitment: delivery < 34 weeks; pre-eclampsia or gestational hypertension; small-for-gestational age neonates (birth weight of one or both twins < 5(th) centile for gestational age). Cardiac findings were compared with those obtained at the same gestational age periods in a group of singleton gestations.

RESULTS

A group of 20 uncomplicated twin gestations was obtained for analysis and 10 singleton pregnancies were then selected as controls. At each visit, mean ± SD cardiac output (CO) was significantly higher in twins than in singletons (6.55 ± 0.82 vs 5.62 ± 0.82 L/min, P = 0.007 at 20-23 weeks; 7.31 ± 0.74 vs 6.39 ± 0.74 L/min, P = 0.003 at 26-29 weeks; 7.50 ± 0.89 vs 6.68 ± 0.65 L/min, P = 0.015 at 30-33 weeks), whereas total vascular resistance (TVR) was lower (1005 ± 137 vs 1179 ± 199 dynes × s/cm(5) , P = 0.009 at 20-23 weeks; 924 ± 100 vs 1070 ± 138 dynes × s/cm(5), P = 0.003 at 26-29 weeks; 929 ± 96 vs 1031 ± 122 dynes × s/cm(5), P = 0.018 at 30-33 weeks). In both twins and singletons, CO showed a significant increase while TVR decreased significantly throughout the assessed pregnancy time period.

CONCLUSION

In twin gestation, maternal cardiac function apparently undergoes more profound changes compared with in singleton gestation, as testified by higher CO and lower TVR values at each stage of pregnancy starting from the mid-trimester.

Relationship between cardiovascular function and fetal growth restriction in women with pre-eclampsia

OBJECTIVE

To investigate the relationship between cardiovascular function in women with pre-eclampsia and fetal growth restriction (FGR) using impedance cardiography.

METHOD

This retrospective study was performed with 639 participants allocated to one of 4 groups, a pre-eclampsia (PE) with FGR group, a PE without FGR group, a pregnancy-induced hypertension (PIH) without FGR group, and normal pregnancy (NP) group. Hemodynamic monitoring was performed noninvasively using impedance cardiography.

RESULTS

Mean arterial pressure and peripheral resistance were significantly higher, and cardiac output and maternal systolic function were significantly lower, in the 2 PE groups than in the PIH and NP groups, and these differences were the greatest between the NP and the PE with FGR groups.

CONCLUSION

Impedance cardiography allowed to observe a gradual increase in peripheral resistance and cardiac output from the NP group to the PIH, the PE without FGR, and the PE with FGR groups. The most reduced systolic function and cardiac output and the most increased peripheral resistance was observed in the PE with FGR group.