Increased periconceptual maternal glycated haemoglobin in diabetic mothers reduces fetal long axis cardiac function

Fetal Interventricular Septum Volume Evaluated by Three-Dimensional Ultrasound Using Spatiotemporal Image Correlation and Virtual Organ Computer-Aided Analysis in Fetuses From Pre-Gestational Diabetes Mellitus Pregnant Women

BACKGROUND

To assess the interventricular septum (IVS) volume of fetuses from pre-gestational diabetes mellitus (DM) pregnant women by 3-dimensional ultrasound using spatiotemporal image correlation (STIC) and virtual organ computer-aided analysis (VOCAL) methods.

METHODS

This was a prospective cross-sectional study of 45 fetuses from pre-gestational DM and 45 fetuses from healthy pregnant women (controls). Only singleton pregnancies between 20 and 34 + 6 weeks of gestation were included. The fetal IVS volumes were obtained off-line using STIC and VOCAL methods. To analyze differences among variables, the Student’s t-test and Mann-Whitney U test were used. The correlation among continuous variables was determine using Spearman’s correlation test (r).

RESULTS

The median of fetal IVS volume was significantly higher in pre-gestational DM than in healthy pregnant women (0.3 cm³ vs. 0.2 cm³, p = 0.032). A strong positive correlation was observed between fetal IVS volume and gestational age at the time of ultrasound examination (r = 0.75, R² = 0.48, p < 0.0001) and between fetal IVS volume and estimated fetal weight (r = 0.63, R² = 0.37, p < 0.0001). No significant correlation was noted between fetal IVS volume and glycated hemoglobin levels (r = −0.16, R² = 0.01, p = 0.540) in the pre-gestational DM pregnant women.

CONCLUSIONS

Significant differences were observed in fetal IVS volumes between pre-gestational and healthy mothers, with higher values in the fetuses of pre-gestational DM pregnant women.

Effect of maternal diabetes on fetal heart function on echocardiography: systematic review and meta-analysis

OBJECTIVE

Maternal diabetes in pregnancy is associated with structural anomalies of the fetal heart, as well as hypertrophy and functional impairment. This systematic review and meta-analysis aimed to estimate the effect of maternal diabetes on fetal cardiac function as measured by prenatal echocardiography.

METHODS

We performed a search of the EMBASE, PubMed and The Cochrane Library databases, from inception to 4 July 2019, for studies evaluating fetal cardiac function using echocardiography in pregnancies affected by diabetes compared with uncomplicated pregnancies. Outcome measures were cardiac hypertrophy and diastolic, systolic and overall cardiac function as assessed by various ultrasound parameters. The quality of the studies was assessed using the Newcastle-Ottawa Scale. Data on interventricular septal (IVS) thickness, myocardial performance index (MPI) and E/A ratio were pooled for the meta-analysis using random-effects models. For pregnancies with diabetes, results were reported overall and according to whether diabetes was pregestational (PDM) or gestational (GDM). Results were also stratified according to the trimester in which fetal cardiac assessment was performed.

RESULTS

Thirty-nine studies were included, comprising data for 2276 controls and 1925 women with pregnancy affected by diabetes mellitus (DM). Of these, 1120 had GDM, 671 had PDM and in 134 cases diabetes type was not specified. Fetal cardiac hypertrophy was more prevalent in diabetic pregnancies than in non-diabetic controls in 21/26 studies, and impaired diastolic function was observed in diabetic pregnancies in 22/28 studies. The association between DM and systolic function was inconsistent, with 10/25 studies reporting no difference between cases and controls, although more recent studies measuring cardiac deformation, i.e. strain, did show decreased systolic function in diabetic pregnancies. Of the studies measuring overall fetal cardiac function, the majority (14/21) found significant impairment in diabetic pregnancies. Results were similar when stratified according to GDM or PDM. These effects were already present in the first trimester, but were most profound in the third trimester. Meta-analysis of studies performed in the third trimester showed, compared with controls, increased IVS thickness in both PDM (mean difference, 0.75 mm (95% CI, 0.56-0.94 mm)) and GDM (mean difference, 0.65 mm (95% CI, 0.39-0.91 mm)) pregnancies, decreased E/A ratio in PDM pregnancies (mean difference, -0.09 (95% CI, -0.15 to -0.03)), no difference in E/A ratio in GDM pregnancies (mean difference, -0.01 (95% CI, -0.02 to 0.01)) and no difference in MPI in either PDM (mean difference, 0.04 (95% CI, -0.01 to 0.09)) or GDM (mean difference, 0.03 (95% CI, -0.01 to 0.06)) pregnancies.

CONCLUSIONS

The findings of this review show that maternal diabetes is associated with fetal cardiac hypertrophy, diastolic dysfunction and overall impaired myocardial performance on prenatal ultrasound, irrespective of whether diabetes is pregestational or gestational. Further studies are needed to demonstrate the relationship with long-term outcomes. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Reference ranges for the fetal mitral, tricuspid, and interventricular septum annular plane systolic excursions (mitral annular plane systolic excursion, tricuspid annular plane systolic excursion, and septum annular plane systolic excursion) between 20 and 36 + 6 weeks of gestation

Objectives This study aimed to establish reference ranges for fetal mitral, tricuspid, and interventricular septum annular plane systolic excursions (MAPSE, TAPSE, and SAPSE) in normal pregnant women between 20 and 36 + 6 weeks of gestation. Methods This prospective and cross-sectional study included 360 low-risk singleton pregnancies between 20 and 36 + 6 weeks of gestation. MAPSE, TAPSE, and SAPSE were measured by M-mode in real time in an apical or basal four-chamber view through placing the cursor at the atrioventricular junction, marked by the valve rings at the tricuspid, mitral, and basal septum, respectively. A regression analysis was done to determine the appropriate polynomial equation model for both measurements and standard deviation (SD) values in relation to gestational age (GA). The intra- and inter-observer reproducibility was evaluated using the concordance correlation coefficient (CCC) and limits of agreement (LoA). Results There was a significant positive correlation between MAPSE (r=0.705, p<0.0001), TAPSE (r=0.804, p<0.0001), and SAPSE (r=0.690, p<0.0001) and GA. The mean of each parameter ranged as follows: 2.87-5.56 mm, MAPSE; 3.98-8.07 mm, TAPSE; and 2.34-4.21 mm, SAPSE. Poor/moderate intra- and inter-observer reliability (CCC between 0.70 and 0.90) and poor/moderate agreement of all the tested parameters were evaluated (LoA between 10 and 50%). Conclusions Reference values were established for the fetal MAPSE, TAPSE, and SAPSE between 20 and 36 + 6 weeks of gestation in low-risk pregnant women. These parameters showed poor/moderate reproducibility.

Main Patterns of Fetal Cardiac Remodeling

The heart is a central organ in the fetal adaptation to an adverse environment. Fetal cardiac changes may persist postnatally and increase the risk of cardiovascular disease in adulthood. Knowledge about fetal cardiac structural as well as functional remodeling has radically improved over the last few years. As it occurs in postnatal life, the fetal heart remodels - changing its structure and shape - to adapt to an insult. Several conditions have been reported to be associated with fetal cardiac remodeling including intrauterine growth restriction, diabetes, exposure to antiretroviral drugs, conception by assisted reproductive technologies, pulmonary stenosis, and other congenital heart diseases. Here we summarized the main observable patterns of cardiac remodeling, i.e., globular shape, hypertrophy without dilation, and hypertrophy with cardiomegaly. We discuss the potential pathophysiology behind different types of remodeling. Defining precisely the distinct patterns of fetal cardiac remodeling is critical for advancing in the understanding of fetal cardiovascular programming and its consequences on adult health, and potentially for the design of preventive strategies that might have an impact on long-term cardiovascular health.

Epigenetic Down-Regulation of Sirt 1 via DNA Methylation and Oxidative Stress Signaling Contributes to the Gestational Diabetes Mellitus-Induced Fetal Programming of Heart Ischemia-Sensitive Phenotype in Late Life

Rationale: The incidence of gestational diabetes mellitus (GDM) is increasing worldwide. However, whether and how GDM exposure induces fetal programming of adult cardiac dysfunctional phenotype, especially the underlying epigenetic molecular mechanisms and theranostics remain unclear. To address this problem, we developed a late GDM rat model.

Methods: Pregnant rats were made diabetic on day 12 of gestation by streptozotocin (STZ). Experiments were conducted in 6 weeks old offspring.

Results: There were significant increases in ischemia-induced cardiac infarction and gender-dependent left ventricular (LV) dysfunction in male offspring in GDM group as compared to controls. Exposure to GDM enhanced ROS level and caused a global DNA methylation in offspring cardiomyocytes. GDM attenuated cardiac Sirt 1 protein and p-Akt/Akt levels, but enhanced autophagy-related proteins expression (Atg 5 and LC3 II/LC3 I) as compared to controls. Ex-vivo treatment of DNA methylation inhibitor, 5-Aza directly inhibited Dnmt3A and enhanced Sirt 1 protein expression in fetal hearts. Furthermore, treatment with antioxidant, N-acetyl-cysteine (NAC) in offspring reversed GDM-mediated DNA hypermethylation, Sirt1 repression and autophagy-related gene protein overexpression in the hearts, and rescued GDM-induced deterioration in heart ischemic injury and LV dysfunction.

Conclusion: Our data indicated that exposure to GDM induced offspring cardiac oxidative stress and DNA hypermethylation, resulting in an epigenetic down-regulation of Sirt1 gene and aberrant development of heart ischemia-sensitive phenotype, which suggests that Sirt 1-mediated signaling is the potential therapeutic target for the heart ischemic disease in offspring.

Maternal arterial stiffness and fetal cardiovascular physiology in diabetic pregnancy

OBJECTIVES

In mothers with pregestational or gestational diabetes, abnormal arterial stiffness (stiffer arteries) has been reported. The impact of abnormal maternal arterial stiffness on placental and fetal cardiovascular physiology is unknown. The purpose of this study was to determine the impact of maternal diabetes on maternal arterial stiffness and the association with fetal cardiovascular physiology as measured by fetal echocardiography.

METHODS

Between December 2013 and January 2017 a prospective study was conducted on diabetic (but otherwise healthy) and non-diabetic, healthy pregnant mothers aged 18-40 years at 20-28 weeks' gestation who had a normal fetal cardiac echocardiogram and obstetric ultrasound. Clinical data were collected by means of a patient questionnaire and measurement of blood pressure, height, weight, arterial augmentation index (AIx) and placental and fetal cardiovascular parameters were collected by fetal echocardiography. Descriptive statistics were calculated. Comparisons were made using parametric and non-parametric tests between controls and diabetic mothers.

RESULTS

Twenty-three healthy pregnant controls and 43 diabetic pregnant women (22 with pregestational and 21 with gestational diabetes) were included in the study. Maternal AIx was higher in those with diabetes than in healthy controls (12.4 ± 10.6% vs 4.6 ± 7.9%; P = 0.003). Fetal aortic valve (AoV) velocity time integral (VTI) was higher in fetuses whose mothers had diabetes than in those with non-diabetic mothers (7.7 ± 1.9 cm vs 6.3 ± 3.0 cm; P = 0.022). Left ventricular (LV) myocardial performance index (MPI) was lower in diabetic pregnancies than in controls (0.40 ± 0.09 vs 0.46 ± 0.11; P = 0.021). Umbilical artery (UA) resistance index (RI) was lower in diabetic pregnancies with glycated hemoglobin (HbA1c) levels ≥ 6.5% than in those with HbA1c levels < 6.5% (0.69 ± 0.06, n = 15 vs 0.76 ± 0.08, n = 21; P = 0.009) but not at higher HbA1C cut-offs. No correlation between AIx and AoV-VTI, LV-MPI or UA-RI was found.

CONCLUSIONS

Arterial stiffness is higher in pregnant women with diabetes than in controls. Fetuses of diabetic mothers show altered cardiovascular parameters, with higher AoV-VTI and lower LV-MPI, which are markers of myocardial function. Placental function assessed by UA-RI was normal despite differences between groups. Arterial stiffness did not correlate with placental or fetal cardiovascular variables. Instead, the findings are likely to represent a shared response to the environment of abnormal glucose metabolism. The clinical significance of these findings is yet to be determined. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Recent Advances in Placenta-Heart Interactions

Congenital heart defects (CHD) occur in ∼1 in every 100 live births. In addition, an estimated 10% of fetal loss is due to severe forms of CHD. This makes heart defects the most frequently occurring birth defect and single cause of in utero fatality in humans. There is considerable evidence that CHD is heritable, indicating a strong contribution from genetic risk factors. There are also known external environmental exposures that are significantly associated with risk for CHD. Hence, the majority of CHD cases have long been considered to be multifactorial, or generally caused by the confluence of several risk factors potentially from genetic, epigenetic, and environmental sources. Consequently, a specific cause can be very difficult to ascertain, although patterns of associations are very important to prevention. While highly protective of the fetus, the in utero environment is not immune to insult. As the conduit between the mother and fetus, the placenta plays an essential role in maintaining fetal health. Since it is not a fully-formed organ at the onset of pregnancy, the development of the placenta must keep pace with the growth of the fetus in order to fulfill its critical role during pregnancy. In fact, the placenta and the fetal heart actually develop in parallel, a phenomenon known as the placenta–heart axis. This leaves the developing heart particularly vulnerable to early placental insufficiency. Both organs share several developmental pathways, so they also share a common vulnerability to genetic defects. In this article we explore the coordinated development of the placenta and fetal heart and the implications for placental involvement in the etiology and pathogenesis of CHD.

Fetal myocardial deformation in maternal diabetes mellitus and obesity

OBJECTIVE

Experimental evidence suggests that changes in the fetal myocardium result from intrauterine effects of maternal diabetes mellitus and obesity. The aim of this study was to assess fetal cardiac function using two-dimensional speckle-tracking echocardiography to determine the effects of maternal diabetes and obesity on the fetal myocardium.

METHODS

Comparative cross-sectional evaluation of myocardial function in fetuses of mothers with diabetes mellitus (FDM) or obesity (FO) and normal gestational age-matched control fetuses (FC) was performed using two-dimensional speckle-tracking echocardiography at two centers.

RESULTS

In total, 178 fetuses (82 FDM, 26 FO and 70 FC) met the enrolment criteria. Mean gestational age at assessment was similar among groups: 25.3 ± 5.1 weeks for FDM, 25.0 ± 4.6 weeks for FO and 25.1 ± 4.9 weeks for FC. Mean maternal body mass index was significantly higher in FDM and FO groups compared with the FC group. Statistically significant differences in fetal cardiac function were detected between FDM and FC for global longitudinal strain (mean ± SD, -21.4 ± 6.5% vs -27.0 ± 5.2%; P < 0.001), global circumferential strain (mean ± SD, -22.6 ± 6.5% vs -26.2 ± 6.8%; P = 0.002), average longitudinal systolic strain rate (median, -1.4 (interquartile range (IQR), -1.7 to -1.1)/s vs -1.6 (IQR, -2.0 to -1.4)/s; P = 0.001) and average circumferential systolic strain rate (median, -1.4 (IQR, -1.9 to -1.1)/s vs -1.6 (IQR, -2.1 to -1.3)/s; P = 0.006). Cases of non-obese FDM also had abnormal strain parameters compared with FC. Global longitudinal strain (mean ± SD, -21.1 ± 7.5%) and average circumferential systolic strain rate (median, -1.3 (IQR, -1.8 to -1.1)/s) were significantly lower in FO compared with FC.

CONCLUSIONS

Unfavorable changes occur in the fetal myocardium in response to both maternal diabetes mellitus and obesity. The long-term prognostic implications of these changes require further study. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Early nutrition, epigenetics, and cardiovascular disease

PURPOSE OF REVIEW

Here, we provide a summary of the current knowledge on the impact of early life nutrition on cardiovascular diseases that have emerged from studies in humans and experimental animal models. The involvement of epigenetic mechanisms in the Developmental Origins of Health and Disease will be discussed in relation to the implications for the heart and the cardiovascular system.

RECENT FINDINGS

Environmental cues, such as parental diet and a suboptimal in utero environment can shape growth and development, causing long-lasting cardiometabolic perturbations. Increasing evidence suggest that these effects are mediated at the epigenomic level, and can be passed onto future generations. In the last decade, epigenetic mechanisms (DNA methylation, histone modifications) and RNA-based mechanisms (microRNAs, piRNAs, and tRNAs) have therefore emerged as potential candidates for mediating inheritance of cardiometabolic diseases.

SUMMARY

The burden of obesity and associated cardiometabolic diseases is believed to arise through interaction between an individual's genetics and the environment. Moreover, the risk of developing poor cardiometabolic health in adulthood is defined by early life exposure to pathological cues and can be inherited by future generations, initiating a vicious cycle of transmission of disease. Elucidating the molecular triggers of such a process will help tackle and prevent the uncontrolled rise in obesity and cardiometabolic disease.

Ultrasound assessment of fetal cardiac function

Introduction: Fetal heart evaluation with US is feasible and reproducible, although challenging due to the smallness of the heart, the high heart rate and limited access to the fetus. However, some cardiac parameters have already shown a strong correlation with outcomes and may soon be incorporated into clinical practice. Materials and Methods: Cardiac function assessment has proven utility in the differential diagnosis of cardiomyopathies or prediction of perinatal mortality in congenital heart disease. In addition, some cardiac parameters with high sensitivity such as MPI or annular peak velocities have shown promising results in monitoring and predicting outcome in intrauterine growth restriction or congenital diaphragmatic hernia. Conclusion: Cardiac function can be adequately evaluated in most fetuses when appropriate expertise, equipment and time are available. Fetal cardiac function assessment is a promising tool that may soon be incorporated into clinical practice to diagnose, monitor or predict outcome in some fetal conditions. Thus, more research is warranted to further define specific protocols for each fetal condition that may affect cardiac function.

Longitudinal annular displacement by M-mode (MAPSE and TAPSE) in twin-to-twin transfusion syndrome before and after laser surgery

OBJECTIVE

To evaluate mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE) in fetuses with twin-to-twin transfusion syndrome (TTTS) before and after laser therapy.

METHODS

A prospective study in 24 fetal pairs with TTTS evaluated 24 h before and within 48 h after fetoscopy and 13 gestational age-matched normal monochorionic fetal pairs. MAPSE and TAPSE were measured in an apical or basal four-chamber view by placing the M-mode cursor at the lateral valve ring.

RESULTS

Mean preoperative MAPSE (controls 3.6 ± 1.3 mm vs. donors 2.7 ± 0.8 mm vs. recipients 2.8 mm ± 0.9; P < 0.001) and TAPSE (controls 4.4 ± 1.5 mm vs. donors 3.3 ± 1 mm vs. recipients 3.6  ± 1.1 mm; P < 0.001) values were significantly reduced in both TTTS fetuses. When subdividing according to TTTS stages, changes were significant in both stage I-II and III-IV subgroups, although differences were more pronounced in the latter. All observations remained unchanged 48 h post-fetoscopy.

CONCLUSION

Both recipient and donor fetuses had decreased global longitudinal motion, even in early TTTS stages.

Speckle tracking and myocardial tissue imaging in infant of diabetic mother with gestational and pregestational diabetes

The aim of this study was to evaluate the myocardial changes in infants of diabetic mother either with gestational or pregestational diabetes and its relation to maternal diabetic control. The study included 45 infants of diabetic mother (IDMs) and 45 healthy newborn as a control group. IDMs were then categorized into 2 subgroups: twenty infants of mother with pregestational diabetes and twenty-five infants of mothers with gestational diabetes. The studied groups underwent measurement of the maternal and neonatal glycated Hb % (HbA1c), conventional echocardiography, tissue Doppler imaging (TDI) and two-dimensional speckle tracking imaging (STI). The weight, the rate of complications, and the rate of cesarean section were significantly higher in the IDMs group than in the control group. Significant positive correlation was present between the levels of HbA1c of IDMs and HbA1c of their mothers (P < 0.05). A significant deterioration of both systolic and diastolic functions measured by both conventional echocardiography and TDI was present in IDMs with both pre-gestational and gestational diabetes compared with the control group. Also, the septal/posterior wall ratio (SW/PW) was significantly higher in pregestational (1.86 ± 0.3) and gestational (2 ± 0.4) groups than in the control group (1 ± 0.06). Two-dimensional STI showed that the cardiac torsion was significantly impaired in pre-gestational (9.66 ± 2.5) and gestational (8.66 ± 3.9) groups when compared with the control group (5.4 ± 2.4) [P < 0.0001]. It also showed that the global strain was significantly impaired in pre-gestational (-10.4 ± 3.2) and gestational (-13.1 ± 4.7) groups when compared with the control group (-19 ± 2) [P < 0.0001]. However, no significant differences were present among the two patients' subgroups in echocardiographic data except for a significant decrease of E'/A' ratio and S wave at tricuspid annulus derived by TDI and impaired global strain derived by STI in infants of mothers with pre-gestational DM than those with gestational DM [P = 0.02]. SW/PW and cardiac torsion were significantly higher in infant of diabetic mother than the normal newborn and on the contrary systolic function and global strain were significantly lower in IDMs especially in infants of mother with pre-gestational diabetes. All the previous TDI findings did not show any significant correlation to neither maternal nor fetal HbA1c. Also, there was no significant correlation between cardiac torsion and the rest of TDI data neither in IDMs group nor in the control group. TDI and two-dimensional STI were efficient and sensitive tools able to early detect cardiac dysfunction in IDMs even in the absence of morphologic cardiac changes.

Evaluation of the regional ventricular systolic function by two-dimensional strain echocardiography in gestational diabetes mellitus (GDM) fetuses with good glycemic control

OBJECTIVE

The aim is to quantitatively assess regional ventricular systolic function by two-dimensional strain (2DS) echocardiography in gestational diabetes mellitus (GDM) fetuses with good glycemic control.

METHODS

We studied 60 consecutive normal fetuses and 35 fetuses of GDM mothers with good glycemic control by echocardiography. M-mode and two-dimensional echocardiography were used to measure ejection fraction and wall dimensions of left ventricle and right ventricle. Both left and right ventricle peak systolic myocardial strain values were obtained by 2DS echocardiography.

RESULTS

Compared with normal fetuses, the thickness of the interventricular septum (IVS) and the thickness of right ventricular wall were significantly increased in GDM fetuses (p < 0.05). Compared with those of normal fetuses, the peak systolic myocardial strain decreased significantly in the apical segments of the IVS and the apical segments of the left ventricular lateral wall in GDM fetuses (p < 0.05), as well as the apical and middle segments of right ventricular wall in GDM fetuses (p < 0.05). Peak negative 2DS values in 60 normal fetuses increased with the gestational age, showing a significant linear correlation(r = -0.625, p < 0.001). The average ventricular strain was not correlated to ventricular wall thickness (r = 0.127, p = 0.394).

CONCLUSIONS

2DS is a feasible approach to assess regional ventricular systolic function in the fetal hearts and it can be used to examine cardiac systolic function in GDM fetuses with good glycemic control.

The effect of pregestational diabetes on fetal heart function

Pregestational diabetes affects nearly 2% of all pregnancies. Moreover, Type 2 diabetes in child-bearing women is on the rise because of the childhood obesity epidemic. Pregestational diabetes can affect the fetal heart in several ways. First, the risk of fetal congenital heart disease is markedly increased; second, fetal hypertrophic cardiomyopathy may occur even with good glycemic control; third, studies have shown impaired function of the hearts of some infants and fetuses of diabetic pregnancies, which can occur with and without septal hypertrophy. Small-for-gestational-age infants of diabetic mothers may have diminished cardiovascular health in the long term. This review mainly discusses methods to detect fetal diabetic cardiomyopathy prenatally. The focus is on the noninvasive diagnostic markers that can serve as an outcome measure for future therapeutic trials, which are still lacking. There is some experimental research on treatment strategies to prevent fetal heart disease in diabetic pregnancies but little clinical data.

Hemoglobin A1c in pregestational diabetic gravidas and the risk of congenital heart disease in the fetus

This study aimed to determine whether poor glycemic control in early pregnancy is associated with an increased risk of congenital heart disease (CHD) for infants of women with preexisting diabetes. A retrospective review examined two tertiary care centers of diabetic pregnancies that recorded early hemoglobin A1c (HbA1c) values (<20 weeks). The incidence of prenatally diagnosed CHD was calculated and stratified by HbA1c level. Poor glycemic control was defined as an HbA1c level of 8.5 % or higher. Fetal echocardiography was used to identify fetuses that resulted in infants with suspected CHD. Neonatal echocardiograms and pathology reports were reviewed for confirmation of the diagnosis. Of 535 patients, 30 (5.6 %) delivered an infant with confirmed CHD. Among the patients with poor glycemic control, 8.3 % (n = 17) delivered an infant with CHD, whereas 3.9 % (n = 13) of those with an HbA1c level lower than 8.5 % delivered an infant with CHD (p = 0.03). Poor glycemic control in early pregnancy is associated with an increased risk of CHD in offspring. The incidence of CHD in patients with adequate glycemic control still is sufficiently high to justify routine fetal echocardiography for all gravidas with preexisting diabetes regardless of HbA1c level.

Diagnosis and management of heart failure in the fetus

Heart failure can be defined as the inability of the heart to sufficiently support the circulation. In the fetus, heart failure can be caused by a myriad of factors that include fetal shunting abnormalities, genetic cardiomyopathies, extracardiac malformations, arrhythmias and structural congenital heart disease. With advances in ultrasound has come the ability to characterize many complex conditions, previously poorly understood. Fetal echocardiography provides the tools necessary to evaluate and understand the various physiologies that contribute to heart failure in the fetus. In this review, we will explore the different mechanisms of heart failure in this unique patient population and highlight the role of fetal echocardiography in the current management of these conditions.

Fetal cardiac function: technical considerations and potential research and clinical applications

Fetal echocardiography was initially used to detect structural anomalies but has more recently also been proposed to assess fetal cardiac function. This review summarizes technical issues and limitations in fetal cardiac function evaluation, as well as its potential research and clinical applications. Functional echocardiography has been demonstrated to select high-risk populations and to be associated with outcome in several fetal conditions including intrauterine growth restriction, twin-to-twin transfusion syndrome, maternal diabetes, and congenital diaphragmatic hernia. Fetal heart evaluation is challenging due to the smallness and high heart rate of the fetus and restricted access to the fetus far from the transducer. Due to these limitations and differences in cardiac function which are related to fetal maturation, cardiovascular parameters should be validated in the fetus and used with caution. Despite these precautions, in expert hands and with appropriate ultrasound equipment, evaluation of cardiac function is feasible in most fetuses. Functional fetal echocardiography is a promising tool that may soon be incorporated into clinical practice. Research is warranted to further refine the contribution of fetal cardiac assessment to the diagnosis, monitoring, or prediction of outcomes in various fetal conditions.

Myocardial hypertrophy and dysfunction in maternal diabetes

Diabetes in pregnancy, both pre-gestational and gestational, is a frequent cause of fetal myocardial hypertrophy, partly due to fetal hyperinsulinism. In fetal life, cardiac function may be impaired, especially during diastole, as a result of decreased left ventricular distensibility and altered left atrial dynamics secondary to myocardial hypertrophy. In neonates, the hypertrophy is a transient disorder, with spontaneous regression of the increased myocardial thickness during the first months of life. Nevertheless, cardiac hypertrophy may be associated with neonatal cardiomegaly and respiratory distress secondary to poor left ventricular compliance. The development of a number of new echocardiographic parameters discussed in this article, and primarily based on the pathophysiological consequences of myocardial hypertrophy, highlight an area of research priority: the assessment of diastolic function in fetuses of diabetic mothers with (and without) myocardial hypertrophy. A score for grading the severity of fetal diastolic dysfunction in these fetuses is proposed.

Fetal cardiac effects of maternal hyperglycemia during pregnancy

Maternal diabetes mellitus is associated with increased teratogenesis, which can occur in pregestational type 1 and type 2 diabetes. Cardiac defects and with neural tube defects are the most common malformations observed in fetuses of pregestational diabetic mothers. The exact mechanism by which diabetes exerts its teratogenic effects and induces embryonic malformations is unclear. Whereas the sequelae of maternal pregestational diabetes, such as modulating insulin levels, altered fat levels, and increased reactive oxygen species, may play a role in fetal damage during diabetic pregnancy, hyperglycemia is thought to be the primary teratogen, causing particularly adverse effects on cardiovascular development. Fetal cardiac defects are associated with raised maternal glycosylated hemoglobin levels and are up to five times more likely in infants of mothers with pregestational diabetes compared with those without diabetes. The resulting anomalies are varied and include transposition of the great arteries, mitral and pulmonary atresia, double outlet of the right ventricle, tetralogy of Fallot, and fetal cardiomyopathy.A wide variety of rodent models have been used to study diabetic teratogenesis. Both genetic and chemically induced models of type 1 and 2 diabetes have been used to examine the effects of hyperglycemia on fetal development. Factors such as genetic background as well as confounding variables such as obesity appear to influence the severity of fetal abnormalities in mice. In this review, we will summarize recent data on fetal cardiac effects from human pregestational diabetic mothers, as well as the most relevant findings in rodent models of diabetic cardiac teratogenesis.

Intrapartum fetal ECG and diabetes

AIM

The objective of this study was to determine the prevalence and types of ST-segment changes of the fetal electrocardiogram (FECG) during labour in term fetuses born to mothers with diabetes mellitus (DM) or gestational diabetes.

METHODS

This was a retrospective case-control study involving populations from two multi centre trials: the Swedish Randomized Control Trial and the European Union ST-analysis (EU-STAN) trial. ST-segment changes were assessed in 104/309 cases and 207/468 controls from the Swedish and EU-STAN trials, respectively.

RESULTS

ST depression was present on the FECG in 22.1% of fetuses of mothers with DM compared to 12% of controls OR = 2.6, 95% CI = 1.4-4.7, p = 0.002 after adjusting for trial, birth weight, and nulliparity. ST elevation was present in 47.1% of DM patients and 41.2% of controls (OR = 1.4, 95% CI = 0.9-2.3, p = 0.18).

CONCLUSION

ST depression on the FECG was significantly more prevalent in the fetuses of mothers with DM, probably not indicating hypoxia but an altered ability of the myocardium to respond to the stress of labour. Further studies into the mechanism of fetal compromise during diabetic labour, are required.

Maternal diabetes and the fetal heart

Maternal diabetes mellitus significantly affects the fetal heart and fetal-placental circulation in both structure and function. The influence of pre-conceptional diabetes begins during embryonic development in the first trimester, with altered cardiac morphogenesis and placental development. It continues to have an influence on the fetal circulation through the second and third trimesters and into the perinatal and neonatal period.