Size and shape of the four-chamber view of the fetal heart in fetuses with an estimated fetal weight less than the tenth centile

Practical Evaluation of the Fetal Cardiac Function

The fetal heart adapts dynamically to nutrient and oxygen needs from all fetal organs. These continuous changes make it difficult to define normal/abnormal cardiac function based only on the evaluation of a few cycles. Many signs of fetal cardiac dysfunction have been suggested; however, very few can stand as true manifestations of cardiac deterioration, and none has emerged as a single reliable marker of cardiac dysfunction. It is the combination of abnormal findings that provides a more accurate assessment of the status of the fetal heart function.

Subclinical myocardial dysfunction among fetal growth restriction neonates: a case-control study

OBJECTIVES

To evaluate cardiac structural and functional changes in neonates with fetal growth restriction (FGR) compared to appropriate-for-gestational-age (AGA) neonates using conventional echocardiography, tissue Doppler imaging (TDI), and speckle tracking echocardiography.

METHOD

This case-control study included 85 FGR neonates and 75 non-FGR, weight adequate for gestational age neonates. Among these, 37 were symmetric FGR and 48 were asymmetric FGR. All the biophysical profiles of these newborns were assessed. An echocardiographic test was performed to evaluate cardiac dimension, Left ventricular ejection fraction (LV EF), Mitral valve Doppler flow velocities, myocardial performance index, tissue annular velocities, and LV global longitudinal strain (GLS).

RESULTS

Although LVEF was found to be within the normal range, mean EF was reduced among neonates with FGR than non-FGR controls (EF: 66.14 ± 3.85% vs 69.46 ± 3.58%; p < 0.001, in FGR and non-FGR, respectively). Furthermore, LV E/E' a measure of LV diastolic function was altered among both types of FGR neonates. Similarly, LV GLS was reduced among FGR neonates (LV GLS: -20.69 ± 2.7% vs -19.06 ± 2.9%; p < 0.001 in non-FGR and FGR, respectively).

CONCLUSION

FGR neonates exhibit significant alterations in cardiac geometry compared to AGA controls. FGR neonates also demonstrated a significant reduction in LV EF, FS, and LV global longitudinal strain, depicting failure to adapt to the increased cardiac workload after birth.

Umbilical Vein Flows and Cardiac Size, Shape, and Ventricular Contractility in Fetuses With Estimated Weight Less-Than 10th Centile

OBJECTIVES

In a cohort of patients with estimated fetal weights (EFWs) <10th centile, we aimed 1) to compare the prevalence of abnormalities of fetal 4-chamber view (4CV) cardiac size, shape, and ventricular contractility in fetal growth restricted (FGR) and small-for-gestational-age (SGA) fetuses and 2) to compare umbilical vein flow (UVF) measurements to standard Doppler surveillance in predicting abnormalities of cardiac function.

METHODS

Prospective observational cohort study of fetuses with EFW <10th percentile. Measurements of size and shape used were 4CV transverse width, 4CV cardiac area, 4CV global sphericity index, and right-to-left ventricular mid-chamber width ratio. Variables of contractility used were fractional shortening change at the mid-ventricle chamber, global longitudinal strain, fractional area change, and left ventricular cardiac output. The UVF and standard Doppler surveillance including umbilical artery (UA), middle cerebral artery, and cerebroplacental ratio (CPR) were collected. Control data were from previously published studies.

RESULTS

A total of 95 fetuses with EFWs <10th centile were included in the study. The rates of abnormalities of cardiac size and shape and ventricular contractility were all significantly elevated compared with normally grown control fetuses but similar between FGR and SGA fetuses. In a subset of 76 patients with UVF data, evaluation UVF identified more patients with any abnormality of contractility compared with UA (37.9 vs 17.2%, P = .02).

CONCLUSIONS

The addition of UVF doubled the detection rate of ventricular contractility abnormalities. The addition of UVF should be considered in the surveillance of FGR and SGA fetuses to further stratify the severity of hypoxemia and to identify those at greater risk for future cardiovascular dysfunction.

Fetuses with deceleration of growth improve their growth following maternal rest

OBJECTIVE

The purpose of this study was to determine if fetuses with deceleration of growth velocity resulting in an EFW <10th percentile increase their growth above the 10th percentile following 2 weeks of maternal rest in the left lateral recumbent position.

METHODS

This was a retrospective observational study of 265 fetuses with the prenatal diagnosis of an EFW <10th percentile. Fetuses were classified by four definitions of abnormal growth velocity: (1) a growth velocity less than 20 g/day, (2) 30 percentile decrease in the EFW, (3) 50 percentile decrease in the EFW, and (4) abnormal growth trajectory. Once the fetuses were identified with an EFW <10th percentile the patient was requested to begin 2 weeks of rest in the left lateral recumbent position during her waking hours following which the EFW was reassessed 2 week later to determine the effect of maternal rest on the EFW.

RESULTS

Irrespective of the four types of decreased growth velocity described in the methods section, there was as significant increase (p < 0.001) in the EFW following 2 weeks of maternal rest as follows: (1) growth less than 20 g/day (75%); (2) decrease of 30 or more EFW percentiles (79%); (3) decrease of 50 or more EFW percentiles (64%); and abnormal growth trajectory (77%).

CONCLUSIONS

This suggests an important role of increased maternal cardiac output as the result of resting in the left lateral recumbent position that may be associated with improved fetal growth. These observations should be the basis for future prospective randomized trials to test this hypothesis.

Association of Amniotic Fluid Volume and Fetal Cardiac and Cerebrovascular Parameters in Fetal Growth Restriction

OBJECTIVES

To investigate the prevalence of oligohydramnios, brain sparing, and cardiac dysfunction among a cohort of fetal growth restriction (FGR).

METHODS

To assess the prevalence of oligohydramnios amongst a large sample of FGR fetuses, we screened a database of ultrasounds of FGR pregnancies from our maternal-fetal medicine clinics (clinical cohort) for diminished amniotic fluid volume. Using a threshold of a maximum vertical pocket (MVP) of <2 cm for "oligohydramnios," and 2 to 3 cm as a "reduced fluid" group, trends of Doppler values and cardiac parameters were assessed from pregnancies in an ongoing research study (comprehensive cohort).

RESULTS

In the clinical cohort, oligohydramnios was identified in only 2/229 (0.8%) and reduced fluid in 19/229 (8%). In the comprehensive cohort, oligohydramnios was seen in 3/126 (2.3%) and reduced fluid in 14/126 (11.1%). A high rate of cardiac and Doppler abnormalities were observed in the oligohydramnios group of the comprehensive cohort. The patients with oligohydramnios had a distinctly different cardiac phenotype with small (2/3 with cardiac area <5th%) (P = 0.01) and round (3/3 with global sphericity index <5th%) (P = 0.02) hearts.

CONCLUSION

Oligohydramnios, when present with FGR, is accompanied by high rates of cerebral and cardiovascular abnormalities.

Maternal rest improves growth in small-for-gestational-age fetuses (<10th percentile)

BACKGROUND

Optimal management of fetuses diagnosed as small for gestational age based on an estimated fetal weight of <10th percentile represents a major clinical problem. The standard approach is to increase fetal surveillance with serial biometry and antepartum testing to assess fetal well-being and timing of delivery. Observational studies have indicated that maternal rest in the left lateral position improves maternal cardiac output and uterine blood flow. However, maternal bed rest has not been recommended based on the results of a randomized clinical trial that showed that maternal rest does not improve fetal growth in small-for-gestational-age fetuses. This study was conducted to revisit this question.

OBJECTIVE

This study aimed to determine whether maternal bed rest was associated with an increase in the fetal biometric parameters that reflect growth after the diagnosis of a small-for-gestational-age fetus.

STUDY DESIGN

A retrospective study was conducted on fetuses who were diagnosed as small for gestational age because of an estimated fetal weight of <10th percentile for gestational age. The mothers were asked to rest in the left lateral recumbent position. Fetal biometry was performed 2 weeks after the diagnosis. All fetuses before entry into the study had a previous ultrasound that demonstrated an estimated fetal weight of >10th percentile. To assess the response to bed rest, the change in fetal biometric parameters (estimated fetal weight, head circumference, abdominal circumference, and femur length) after the recommendation of bed rest was computed for 2 periods: (1) before the diagnosis of a weight of <10th percentile vs at the time of diagnosis of a weight of <10th percentile and (2) at the time of diagnosis of a weight of <10th percentile vs 2 weeks after maternal bed rest. For repeated measures, proportions were compared using the McNemar test, and percentile values were compared using the Bonferroni Multiple Comparison Test. A P value of <.05 was considered significant. To describe changes in the estimated fetal weight without bed rest, 2 control groups in which the mothers were not placed on bed rest after the diagnosis of a small-for-gestational-age fetus were included.

RESULTS

A total of 265 fetuses were observed before and after maternal bed rest. The following were observed in this study: (1) after 2 weeks of maternal rest, 199 of 265 fetuses (75%) had a fetal weight of >10th percentile; (2) the median fetal weight percentile increased from 6.8 (interquartile range, 4.4-8.4) to 18.0 (interquartile range, 9.5-29.5) after 2 weeks of bed rest; (3) similar trends were noted for the head circumference, abdominal circumference, and femur length. In the groups of patients who were not asked to be on bed rest, a reassignment to a weight of >10th percentile at a follow-up examination only occurred in 7 of 37 patients (19%) in the Texas-Michigan group and 13 of 111 patients (12%) in the Colorado group compared with the bed rest group (199/265 [75%]) (P<.001).

CONCLUSION

Patients who were prescribed 2 weeks of bed rest after the diagnosis of a fetal weight of <10th percentile had an increase in weight of >10th percentile in 199 of 265 fetuses (75%). This increase in fetal weight was significantly higher than that in the 2 control groups in which bed rest was not prescribed. This observation suggests that bed rest improves fetal growth in a subset of patients.

Role of global sphericity index in evaluation of fetal cardiac remodeling in late onset fetal growth restriction and small for gestational age fetuses

INTRODUCTION

Fetal growth restriction (FGR) fetuses develop cardiovascular remodeling and dysfunction and, in this process, heart first compensates by changing its shape from ellipsoid to spherical and then cardiac dysfunction follows. Our aim was to evaluate global sphericity index (GSI) after 32 weeks of gestation to evaluate this change in cardiac shape and correlate GSI changes associated with fetal growth abnormalities.

MATERIALS AND METHODS

This was a prospective study conducted at 32-38 weeks of gestation. Women were classified into three groups-Appropriate for gestational age (AGA), small for gestational age (SGA), late onset FGR (LO FGR) and GSI was measured and perinatal outcome studied.

RESULTS

Out of 217 women, 131 were of AGA, 31 were SGA, 55 were of late onset FGR. SGA and late onset FGR groups had low GSI compared to AGA group. There was no significant difference in mean GSI between late onset FGR and SGA groups. Neonatal morbidity, adverse perinatal outcomes did not significantly differ with GSI in SGA and late onset FGR groups.

CONCLUSION

This study showed that late gestation small fetuses develop early stages of cardiovascular remodeling as shown by GSI changes. These changes were independent of Doppler changes. This supports the concept that atleast a proportion of them are not constitutionally small but are true forms of FGR.

Comparison of the left and right ventricular size and systolic function of low-risk fetuses in the third trimester: Which is more dominant?

Objective

To quantify fetal cardiovascular parameters utilizing fetal-specific 2D speckle tracking technique and to explore the differences in size and systolic function of the left and right ventricles in low-risk pregnancy.

Methods

A prospective cohort study was performed in 453 low-risk single fetuses (28+0–39+6 weeks) to evaluate ventricular size [i.e., end-diastolic length (EDL), end-systolic length (ESL), end-diastolic diameter (ED), end-systolic diameter (ES), end-diastolic area, end-systolic area, end-diastolic volume (EDV), and end-systolic volume (ESV)] and systolic function [i.e., ejection fraction (EF), stroke volume (SV), cardiac output (CO), cardiac output per kilogram (CO/KG), and stroke volume per kilogram (SV/KG)].

Results

This study showed that (1) the reproducibility of the interobserver and intraobserver measurements was good to excellent (ICC 0.626–0.936); (2) with advancing gestation, fetal ventricular size and systolic function increased, whereas right ventricular (RV) EF decreased and left ventricular (LV) EF was not significantly changed; (3) LV length was longer than RV length in diastole (2.24 vs. 1.96 cm, P &lt; 0.001) and systole (1.72 vs. 1.52 cm, P &lt; 0.001); (4) LV ED-S1 and ES-S1 were shorter than the RV ED-S1 and ES-S1 (12.87 vs. 13.43 mm, P &lt; 0.001; 5.09 vs. 5.61 mm, P &lt; 0.001); (5) there were no differences between the LV and RV in EDA or EDV; (6) the mean EDV ratio of right-to-left ventricle was 1.076 (95% CI, 1.038–1.114), and the mean ESV ratio was 1.628 (95% CI, 1.555–1.701); (7) the EF, CO and SV of the LV were greater than the RV (EF: 62.69% vs. 46.09%, P &lt; 0.001; CO: 167.85 vs. 128.69 ml, P &lt; 0.001; SV: 1.18 vs. 0.88 ml, P &lt; 0.001); (8) SV and CO increased with ED-S1 and EDL, but EF was not significantly changed.

Conclusion

Low-risk fetal cardiovascular physiology is characterized by a larger RV volume (especially after 32 weeks) and greater LV outputs (EF, CO, SV, SV/KG and CO/KG).

Umbilical Venous Volume Flow in Late-Onset Fetal Growth Restriction

OBJECTIVES

Umbilical vein flow (UVF) is reduced in fetal growth restriction (FGR). We compared absolute and size-adjusted UVF (estimated fetal weight [EFW] and abdominal circumference [AC]) and rates of abnormal UVF parameters (<10th percentile) among FGR fetuses meeting Delphi criteria (FGR-D) against small for gestational age (SGA) fetuses and appropriate for gestational age (AGA) controls.

METHODS

Absolute UVF, UVF/EFW, and UVF/AC were compared between 73 FGR pregnancies (35 FGR-D, 38 SGA) and 108 AGA controls. Rates of abnormal UVF were compared to abnormal umbilical artery pulsatility index (UAPI). Independent samples t-tests, Mann-Whitney U, odds ratio (OR), chi-squared, and Fisher's exact tests were used as appropriate.

RESULTS

Mean absolute UVF was significantly decreased in FGR-D compared to AGA (P = .0147), but not between SGA and AGA fetuses. The incidence of both abnormal absolute UVF and UVF/AC values (<10th centile) was higher among late-onset FGR fetuses versus AGA fetuses (UVF: OR 2.7, confidence interval [CI] 1.37-5.4; UVF/AC: OR 2.73, CI 1.37-5.4). UVF was more frequently abnormal than UAPI and in only two fetuses were both Doppler values abnormal.

CONCLUSION

Absolute UVF is altered in late-onset FGR, and most pronounced among FGR-D. UVF may provide additional insight into fetal compromise in those affected by growth restriction.

Cardiac Size, Shape, and Ventricular Contractility in Fetuses at Sea Level With an Estimated Weight Less-than 10th Centile

OBJECTIVES

To investigate cardiac size, shape, and ventricular contractility in fetuses with estimated fetal weight (EFW) <10th centile at sea level (Houston).

METHODS

A prospective ultrasound study examined 37 fetuses with EFW <10th centile at sea level. High-frequency cine clips were used to evaluate the 4-chamber view including end-diastolic measurements and global sphericity index. The size, shape, and contractility of both ventricles were analyzed with speckle tracking methods. Z scores were calculated using the mean ± standard deviation (SD) derived from normal controls. Measurements were abnormal if their Z score values were <-1.65 or >+1.65. The proportion of small fetuses with abnormal parameters was compared to normal reference ranges. Results were compared to a similar published study of small fetuses at higher altitude in Denver.

RESULTS

About one-third of Houston fetuses with EFW <10th centile had enlarged globular shaped 4-chamber hearts with increased right ventricle (RV) area, RV basal-apical length, RV base width, and left ventricle (LV) basal-apical length measurements. Bilateral ventricular hypertrophy was often present. An increased proportion of Houston fetuses had increased ventricular contractility. However, decreased ventricular contractility was more prevalent for higher altitude fetuses.

CONCLUSIONS

Third trimester fetuses at sea level, with an EFW <10th centile, were often associated with enlarged and globular-shaped hearts. They had increased global and longitudinal ventricular contractility as compared to controls. Higher altitude fetuses also had enlarged globular-shaped hearts but with a greater proportion of cases having decreased ventricular contractility as compared to the sea level cohort.

Patterns of Brain Sparing in a Fetal Growth Restriction Cohort

Objective: Our objective was to compare differences in Doppler blood flow in four fetal intracranial blood vessels in fetuses with late-onset fetal growth restriction (FGR) vs. those with small for gestational age (SGA). Methods: Fetuses with estimated fetal weight (EFW) <10th percentile were divided into SGA (n = 30) and FGR (n = 51) via Delphi criteria and had Doppler waveforms obtained from the middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), and vertebral artery (VA). A pulsatility index (PI) <5th centile was considered “abnormal”. Outcomes included birth metrics and neonatal intensive care unit (NICU) admission. Results: There were more abnormal cerebral vessel PIs in the FGR group versus the SGA group (36 vs. 4; p = 0.055). In FGR, ACA + MCA vessel abnormalities outnumbered PCA + VA abnormalities. All 8 fetuses with abnormal VA PIs had at least one other abnormal vessel. Fetuses with abnormal VA PIs had lower BW (1712 vs. 2500 g; p < 0.0001), delivered earlier (35.22 vs. 37.89 wks; p = 0.0052), and had more admissions to the NICU (71.43% vs. 24.44%; p = 0.023). Conclusions: There were more anterior vessels showing vasodilation than posterior vessels, but when the VA was abnormal, the fetuses were more severely affected clinically than those showing normal VA PIs.

3D Fractional Limb Volume Identifies Reduced Subcutaneous and Lean Mass in Fetal Growth Restriction

OBJECTIVES

Fetal 2D and 3D fractional limb volume (FLV) measurements by ultrasound can detect fetal lean and subcutaneous mass and possibly percent body fat. Our objectives were to 1) compare FLV measurements in fetuses with fetal growth restriction (FGR) versus small for gestational age (SGA) defined by the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG)-supported international Delphi consensus and 2) correlate FLV findings with birth metrics. We hypothesize that FLV measurements will be significantly smaller in FGR versus SGA fetuses and will correlate closer with Ponderal index (PIx) in the neonate than abdominal circumference (AC).

METHODS

Patients were categorized as FGR or SGA as defined by ISUOG. Total thigh volume (TTV), volumes of lean mass (LMV), and fat mass volume (FMV) were calculated from 3D acquisitions. Measurements were compared between groups and correlated with birthweight (BW) and PIx (BW/crown-heal length).

RESULTS

The FGR group (n = 37) delivered earlier (37/2 versus 38/0; P = .0847), were lighter (2.2 kg versus 2.6 kg; P = .0003) and had lower PIx (0.023 versus 0.025; P = .0013) than SGAs (n = 22). FGRs had reduced TTV (40.6 versus 48.4 cm³ ; P = .0164), FMV (20.8 versus 25.3 cm³ ; P = .0413), and LMV (19.8 versus 23.1 cm³ ; P = .0387). AC had the highest area under the curve (0.69) for FGR. FMV was more strongly associated with PIx than the AC (P = .0032).

CONCLUSIONS

The AC and FLV measurements were significantly reduced in FGR fetuses compared to SGAs. While the AC outperformed FLV in predicting FGR, the FLV correlated best with PIx, which holds investigative promise.

Post-COVID-19 fetal cardiac evaluation in moderate infection group of pregnant women

PURPOSE

To determine the long-term fetal cardiac effects of the SARS-CoV-2 infection in pregnant women recovered from moderate COVID-19 with fetal echocardiography (ECHO).

METHODS

Forty-five pregnant women that recovered from moderate COVID-19 (CRG) 4 weeks after the infection confirmation, were compared with 45 gestational and maternal age-matched control groups (CG) in terms of demographic features fetal cardiac morphological (sphericity index, cardiothoracic ratio), and functional (myocardial performance index, mitral E/A, tricuspid E/A, mitral and tricuspid annular plane systolic excursion) parameters.

RESULTS

There was no difference in demographic features between the groups. Fetal cardiac morphologic parameters were found to be similar between the two groups. When the fetal cardiac functional assessment of the two groups was compared, only mitral E/A ratio results were found to be statistically significantly lower in the CRG than in the control group (p = 0.030).

CONCLUSION

The fetal heart does not seem to be negatively affected by COVID-19 after recovery from moderate infection. These results about the fetal effect of SARS-CoV-2 may improve our limited knowledge of the utility of fetal ECHO in pregnant women who recovered from COVID-19.

Differences in body composition and growth persist postnatally in fetuses diagnosed with severe compared to mild fetal growth restriction

BACKGROUND

Fetal growth restriction (FGR) is most commonly diagnosed in pregnancy if the estimated fetal weight (EFW) is <  10th%. Those with abnormal Doppler velocimetry, indicating placental insufficiency and pathological FGR, demonstrate reduced fat and lean mass compared to both normally growing fetuses and FGR fetuses with normal Dopplers. The aim of this study was to determine how severity of FGR and abnormal Doppler velocimetry impacts neonatal body composition. Among a cohort of fetuses with an EFW <  10th%, we hypothesized that those with abnormal Dopplers and/or EFW <  3rd% would have persistent reductions in lean body mass and fat mass extending into the neonatal period compared to fetuses not meeting those criteria.

METHODS

A prospective cohort of FGR fetuses with an estimated fetal weight (EFW) <  10th% was categorized as severe (EFW <  3rd% and/or abnormal Dopplers; FGR-S) versus mild (EFW 3-10th% ; FGR-M). Air Displacement Plethysmography and anthropometrics were performed at birth and/or within the first 6-8 weeks of life.

RESULTS

FGR-S versus FGR-M were born one week earlier (P = 0.0024), were shorter (P = 0.0033), lighter (P = 0.0001) with smaller weight-for-age Z-scores (P = 0.0004), had smaller head circumference (P = 0.0004) and lower fat mass (P = 0.01) at birth. At approximately 6-8 weeks postmenstrual age, weight, head circumference, and fat mass were similar but FGR-S neonates were shorter (P = 0.0049) with lower lean mass (P = 0.0258).

CONCLUSION

Doppler velocimetry abnormalities in fetuses with an EFW <  10th% identified neonates who were smaller at birth and demonstrated catch-up growth by 6-8 weeks of life that favored fat mass accretion over lean mass and linear growth.

Doppler velocimetry discordance between paired umbilical artery vessels and clinical implications in fetal growth restriction

BACKGROUND

Studies revealing a discrepancy in umbilical artery Dopplers between the two umbilical arteries in normally-grown fetuses necessitates further evaluation of the paired umbilical arteries in the setting of fetal growth restriction as this is a critical component in the surveillance of this population.

OBJECTIVE

Umbilical artery Doppler sampling in fetal growth restriction is typically assessed in 1 umbilical artery in a free loop of cord. Although discrepancies of >20% between the 2 umbilical arteries occur in 1 of 3 normal pregnancies, this has not been assessed in fetal growth restriction. Our objectives were to determine the frequency of discordant Doppler pulsatility indices between paired umbilical arteries in a fetal growth restriction cohort and to determine if sampling of 1 or both arteries alters surveillance or timing of delivery.

STUDY DESIGN

A cohort of 425 growth-restricted fetuses between 25 and 39 weeks of gestation had umbilical artery Doppler pulsatility indices determined from both umbilical arteries in a midsegment of the cord to determine: (1) the discrepancy percentage between paired umbilical artery pulsatility indices and (2) the frequency of both arteries being normal, abnormal, or discordant (pulsatility index < and >95th percentile). To determine what sampling method increased the detection of an abnormal Doppler index, 3 sampling methods were compared: (1) average pulsatility index from both umbilical arteries, (2) pulsatility index from 1 umbilical artery chosen randomly, and (3) highest pulsatility index of the 2 umbilical arteries.

RESULTS

The mean percentage difference between umbilical artery pulsatility indices was 11.7%, and in 15.8% of cases, it exceeded 20%. Both umbilical artery pulsatility indices were normal in 71.1% (302/425), abnormal in 12.2% (52/425), and discordant in 16.7% (71/425) of cases (P<.0001). Of the 3 sampling methods, the pulsatility index was abnormal in: (1) 19.2% (82/425) of cases when averaged from both umbilical arteries, (2) 22.1% (94/425) of cases when choosing 1 umbilical artery at random, and (3) 28.9% (123/425) of cases when the highest umbilical artery pulsatility index was used (P=.003).

CONCLUSION

In this large fetal growth restriction cohort, the overall discrepancy between the 2 umbilical artery pulsatility indices was 11.7%. Among fetuses with at least 1 abnormal umbilical artery pulsatility index, 71 of 123 (57.7%) had 1 normal pulsatility index and 1 abnormal. Thus, the number of arteries sampled and the sampling method used may alter clinical decision-making, including frequency of surveillance and timing of delivery.

Comparative evaluation of echocardiography indices during the transition to extrauterine life between small and appropriate for gestational age infants

OBJECTIVES

To study changes in heart function and hemodynamics during the transitional period in small for gestational (SGA) infants and appropriate (AGA) healthier counterparts.

DESIGN

A hospital based prospective observational study was performed at a perinatal center. Echocardiograms were performed on the first postnatal day and again at 48 h age. Term SGA infants were compared with those AGA newborns matched for the GA and mode of delivery.

RESULTS

Eighteen SGA infants were compared with 18 AGA infants [gestation 38 ± 1.5 vs. 38 ± 1.2 weeks, p > 0.05 and birthweight 2331 ± 345 vs. 3332 ± 405 grams, p < 0.05, respectively]. Maternal weight and body mass index was higher among non-affected pregnancies, 61% infants were born vaginally, and no differences in cord blood pH at birth were noted. SGA infants had higher systolic and mean blood pressure at both time points, lower indices of right ventricular (RV) performance [TAPSE (tricuspid annular peak systolic excursion) 7.4 ± 2.8 vs. 9.3 ± 0.7 on day 1, 7.2 ± 2.8 vs. 9.2 ± 0.5 on day 2, p = 0.001], lower pulmonary acceleration time (PAAT) suggestive of elevated pulmonary vascular resistance [56.4 ± 10.5 vs. 65.7 ± 13.2 on day 1, 61.4 ± 12.5 vs. 71.5 ± 15.7 on day 2, p = 0.01] and higher left ventricular (LV) ejection fraction [62.1 ± 7.8 vs. 54.9 ± 5.5 on day 1, 61.9 ± 7.6 vs. 55.8 ± 4.9 on day 2, p = 0.003].

CONCLUSIONS

SGA infants had evidence of higher pulmonary vascular resistance, and lower RV performance during the postnatal transition. The relevance and impact of these changes to hemodynamic disease states during the postnatal transition requires prospective investigation.

Second-trimester cardiovascular biometries in growth-restricted fetuses; a multicenter cohort study

BACKGROUND

Intrauterine growth restriction is associated with an increased risk of cardiovascular changes neonatally. However, the underlying pathways are poorly understood, and it is not clear whether the dysfunction is already present in the fetus.

OBJECTIVE

This study aimed to investigate fetal cardiac dimensions assessed from images at the second trimester anatomy scan from fetuses classified postnatally as small for gestational age and intrauterine growth restricted and compare them with appropriate for gestational age fetuses.

STUDY DESIGN

This was a substudy from The Copenhagen Baby Heart Study, a prospective, multicenter cohort study including fetuses from the second trimester of pregnancy in Copenhagen from April 2016 to October 2018. The mothers were recruited at the second trimester anatomy scan that included extended cardiovascular image documentation followed by consecutively measured heart biometries by 2 investigators blinded for the pregnancy outcome. The fetuses were classified postnatally as small for gestational age and intrauterine growth restricted according to the International Society of Ultrasound in Obstetrics and Gynecology 2020 guidelines using birthweight and with a retrospective assessment of Doppler flow. The mean differences in the cardiovascular biometries were adjusted for gestational age at the time of the second trimester scan and the abdominal circumference. The z-scores were calculated, and the comparisons were Bonferroni corrected (significance level of P<.005). Receiver operating characteristic curves were computed after performing backward regression on several maternal characteristics and biomarkers.

RESULTS

We included 8278 fetuses, with 625 (7.6%) of them being small for gestational age and 289 (3.5%) being intrauterine growth restricted. Both small for gestational age and intrauterine growth restricted fetuses had smaller heart biometries, including the diameter at the location of the aortic valve (P<.005), the ascending aorta in the 3-vessel view (P<.005), and at the location of the pulmonary valve (P<.005). The intrauterine growth restricted group had significantly smaller hearts with respect to length and width (P<.005) and smaller right and left ventricles (P<.005). After adjusting for the abdominal circumference, the differences in the aortic valve and the pulmonary valve remained significant in the intrauterine growth restricted group. Achievement of an optimal receiver operating characteristic curve included the following parameters: head circumference, abdominal circumference, femur length, gestational age, pregnancy associated plasma protein-A multiples of median, nullipara, spontaneous conception, smoking, body mass index <18.5, heart width, and pulmonary valve with an area under the curve of 0.91 (0.88-0.93) for intrauterine growth restricted cases.

CONCLUSION

Intrauterine growth restricted fetuses had smaller prenatal cardiovascular biometries, even when adjusting for abdominal circumference. Our findings support that growth restriction is already associated with altered cardiac growth at an early stage of pregnancy. The heart biometries alone did perform well as a screening test, but combined with other factors, it increased the sensitivity and specificity for intrauterine growth restriction.

Assessment of the Size and Shape of the 4-Chamber View and the Right and Left Ventricles using Fetal Speckle Tracking in Normal Fetuses at 17-24 Gestational Weeks

INTRODUCTION

The aim of the study was to establish normal reference values obtained by fetal speckle tracking analysis of the fetal heart between 17-24 weeks of gestation among Thai fetuses and compare the nomograms with previous studies.

METHODS

The 4-chamber view of the fetal heart in 79 normal fetuses was analyzed by speckle tracking analysis to determine the best-fit regression model. The 95% reference intervals and Z-score equations of fetal cardiac parameters were computed.

RESULTS

The end-diastolic length, width, area, and circumference of the 4-chamber view (4CV) as well as the ventricular end-diastolic length, 24-segment widths, and area were all increased as a function of gestational age (GA) and 5 fetal biometric parameters. In contrast, the global sphericity index (SI), 24-segment SI, and right ventricle/left ventricle width and area ratios did not change with GA or fetal biometric measurements. There were few differences in Z-score reference ranges of fetal cardiac measurements between the current study and previous studies conducted in different patient populations.

CONCLUSION

Our study provided z-score and corresponding centile calculators, 5th and 95th centile reference tables, and corresponding graphs for evaluating the size and shape of the 4CV and the right and left ventricles using 6 independent variables between 17 and 24 weeks of gestation. These results provide normal reference ranges for future studies of fetuses with pathologies that may alter the size and shape of the 4-chamber view and ventricles.

Is Cardiomegaly an Indication of "Heart-Sparing Effect" in Small Fetuses?

INTRODUCTION

This study aimed to test the hypothesis that cardiac size is maintained in small fetuses presenting with cardiomegaly.

MATERIALS AND METHODS

We identified singleton fetuses with estimated fetal weight <10th centile and with cardiomegaly without another more likely cardiac or extra-cardiac cause. We used Z-scores for cardiac and thoracic circumferences normalized for gestational age (GA), biparietal diameter (BPD), head circumference (HC), and femur length (FL), obtained from 188 normally grown fetuses.

RESULTS

When comparing chest size, small fetuses had significantly lower thoracic circumferences median Z-scores (IQR) for GA = -4.82 (-6.15 to -3.51), BPD = -2.42 (-4.04 to -1.48), HC = -2.72 (-4.53 to -1.90), and FL = -1.60 (-2.87 to -0.71); p < 0.001 for all. When comparing heart size, small fetuses showed lower cardiac circumferences median Z-scores (IQR) for GA = -1.59 (-2.79 to -0.16); p < 0.001, similar cardiac circumferences Z-scores for BPD = 0.29 (-0.65 to 1.28); p = 0.284 and HC = 0.11 (-1.13 to 0.96); p = 0.953, and higher cardiac circumferences Z-scores for FL = 0.94 (-0.05 to 2.13); p < 0.001.

CONCLUSIONS

Our results show that in small fetuses with cardiomegaly, the heart maintains normal dimensions when normalized to cranial diameters and higher dimensions when normalized to long bones. This provides insight into cardiac adaptation to adverse intrauterine environment.

Fetal-TAPSE for Surveillance of Cardiac Function in Growth-Restricted Fetuses With a Portosystemic Shunt

OBJECTIVES

Congenital portosystemic shunt (CPSS) in a growth-restricted fetus may lead to cardiac overload and ultimately hemodynamic imbalance. The aim of the study was to describe the application of tricuspid annular plane systolic excursion (TAPSE) for surveillance of cardiac function in growth-restricted fetuses diagnosed with CPSS.

METHODS

The study group consisted of 7 fetuses with growth restriction diagnosed with CPSS between 2018 and 2020. Patients were followed longitudinally every 2 weeks. Sonographic fetal-TAPSE (f-TAPSE) was performed every 2 weeks. At each visit, the following parameters were recorded: estimated fetal weight, biophysical profile, nonstress test, Doppler flow indices, and fetal cardiothoracic index. Postnatal laboratory and imaging tests were retrieved from the medical files.

RESULTS

Mean gestational age at diagnosis of CPSS was 32 + 1 weeks. Cardiomegaly was observed in all cases. All portosystemic shunts were classified as intrahepatic. Values of f-TAPSE were above the 95th percentile in 6/7 fetuses at presentation and throughout follow-up. Gestational age at delivery ranged between 36 + 5 and 38 + 5 weeks. Postnatally, spontaneous closure of the shunt was noted in 2 infants. Transient hyperammonemia was diagnosed in 2 neonates, with no signs of the characteristic complication.

CONCLUSIONS

In growth-restricted fetuses diagnosed concomitantly with CPSS, f-TAPSE offers a practical sonographic tool for assessment of cardiac function and may serve as an additional clinical marker for follow-up. The appearance of cardiomegaly in growth-restricted fetuses should prompt a dedicated sonographic evaluation of the fetal portal system.

Cardiac Measurements of Size and Shape in Fetuses With Absent or Reversed End-Diastolic Velocity of the Umbilical Artery and Perinatal Survival and Severe Growth Restriction Before 34 Weeks' Gestation

OBJECTIVES

The purpose of this study was to evaluate the end-diastolic size and shape of the 4-chamber view as well as the right ventricle (RV) and left ventricle (LV) in growth-restricted fetuses before 34 weeks' gestation with absent or reversed end-diastolic velocity of the umbilical artery and compare the results between those with perinatal deaths and those who survived the neonatal period.

METHODS

Forty-nine fetuses with growth restriction and absent or reversed end-diastolic velocity of the umbilical artery were studied. The size, shape, and sphericity index of the 4-chamber view, RV, and LV were assessed. The number and percentage of fetuses with z score values of less than -1.65 and greater than 1.65 were computed.

RESULTS

Of the 49 fetuses, there were 13 perinatal deaths (27%) and 36 (63%) neonatal survivors. Measurements that were unique for neonatal survivors were an increased RV apical transverse width and decreased measurements of the following: LV and RV widths, LV and RV areas, as well as RV sphericity indices.

CONCLUSIONS

Fetuses with a smaller RV and LV size and area and those with a globular-shaped RV were at significantly lower risk for perinatal death.

Applications of Advanced Ultrasound Technology in Obstetrics

Over the years, there have been several improvements in ultrasound technologies including high-resolution ultrasonography, linear transducer, radiant flow, three-/four-dimensional (3D/4D) ultrasound, speckle tracking of the fetal heart, and artificial intelligence. The aims of this review are to evaluate the use of these advanced technologies in obstetrics in the midst of new guidelines on and new techniques of obstetric ultrasonography. In particular, whether these technologies can improve the diagnostic capability, functional analysis, workflow, and ergonomics of obstetric ultrasound examinations will be discussed.

Reference Ranges for Pulsed-Wave Doppler of the Fetal Cardiac Inflow and Outflow Tracts from 13 to 36 Weeks' Gestation

BACKGROUND

Doppler assessment of ventricular filling and outflow tract velocities is an integral part of fetal echocardiography, to assess diastolic function, systolic function, and outflow tract obstruction. There is a paucity of prospective data from a large sample of normal fetuses in the published literature. The authors report reference ranges for pulsed-wave Doppler flow of the mitral valve, tricuspid valve, aortic valve, and pulmonary valve, as well as heart rate, in a large number of fetuses prospectively examined at a single tertiary fetal cardiology center.

METHODS

The study population comprised 7,885 fetuses at 13 to 36 weeks' gestation with no detectable abnormalities from pregnancies resulting in normal live births. Prospective pulsed-wave Doppler blood flow measurements were taken of the mitral, tricuspid, aortic, and pulmonary valves. The fetal heart rate was recorded at the time of each assessment. Regression analysis, with polynomial terms to assess for linear and nonlinear contributors, was used to establish the relationship between each measurement and gestational age.

RESULTS

The measurement for each cardiac Doppler measurement was expressed as a Z score (difference between observed and expected values divided by the fitted SD corrected for gestational age) and percentile. Analysis included calculation of gestation-specific SDs. Regression equations are provided for the cardiac inflow and outflow tracts.

CONCLUSIONS

This study establishes reference ranges for fetal cardiac Doppler measurements and heart rate between 13 to 36 weeks' gestation that may be useful in clinical practice.

Fetal speckle-tracking echocardiography: a comparison between two-dimensional and electronic spatio-temporal image correlation (e-STIC) technique

BACKGROUND

Speckle tracking technology has been applied to assess ventricular deformation throughout the cardiac cycle. An electronic four dimensional probe that allows rapid acquisition of electronic spatio-temporal image correlation volumes (eSTIC) has been recently introduced.

OBJECTIVES

The aim of our study was to investigate whether e-STIC acquisition improves deformation analyses reproducibility.

STUDY DESIGN

We recruited fetuses between 20 and 40 weeks of gestation. We obtained a 2D video clip and an e-STIC volume of a four-chamber view. We focused on left ventricular global strain (LV-GS) and left ventricular ejection fraction (LV-FE). Intraobserver, interobserver and intermethod agreement were assessed by means of intraclass correlation coefficient (ICC) and illustrated by Bland-Altman plots. Systematic differences between measurements were assessed using a paired t-test.

RESULTS

The mean difference between LV-GS values obtained with e-STIC and 2D analysis was -0.10 (95% CI -2.28, 2.08). No systematic differences were found between the two techniques for LV-GS values (p-value = .927). The mean difference between LV-FE values obtained with e-STIC and 2D analysis was 7.55 (95% CI 4.16, 10.95; p-value <.001). The inter-rater reliability of LV-GS was moderate-to-substantial for both e-STIC and 2D. The inter-rater reliability of LV-FE obtained via e-STIC was superior to that obtained via 2D analysis. The intra-rater reliability of LV-GS obtained with e-STIC was superior to that obtained with 2D analysis (ICC 0.857; 95% IC 0.761-0.917). The intra-rater reliability of LV-FE obtained via e-STIC was superior to that obtained via 2D analysis (ICC 0.647; IC 0.51-0.783).

CONCLUSIONS

e-STIC seems to be a better technique than 2D analysis for intra-rater reliability of LV-GS. 4D acquisition might improve intrinsic limitations of speckle tracking echocardiography.

Influence of birth weight on fetal cardiac indices at 35-37 weeks' gestation

OBJECTIVE

Echocardiographic studies have reported that fetuses with low birth weight, compared to those with normal birth weight, have globular hearts and reduced cardiac function. Dichotomizing continuous variables, such as birth weight, may be helpful in describing pathology in small studies but can prevent us from identifying physiological responses in relation to change in size. The aim of this study was to explore associations between fetal cardiac morphology and function and birth weight, as a continuous variable, as well as uterine artery (UtA) pulsatility index (PI), as an indirect measure of placental perfusion, and the cerebroplacental ratio (CPR), as an indirect measure of fetal oxygenation.

METHODS

This was a prospective study of 1498 women with singleton pregnancy undergoing routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation. Pregnancies complicated by pregestational or gestational diabetes mellitus, chronic hypertension, pregnancy-induced hypertension or pre-eclampsia were excluded from the analysis. Conventional and more advanced echocardiographic modalities, such as speckle tracking, were used to assess fetal cardiac function in the right and left ventricles. The morphology of the fetal heart was assessed by calculating the right and left sphericity indices. In addition, the PI of the UtA, umbilical artery (UA) and fetal middle cerebral artery (MCA) was determined and the CPR was calculated by dividing MCA-PI by UA-PI. Multiple linear regression models were used to assess determinants of fetal echocardiographic parameters.

RESULTS

The study population included 146 (9.7%) small-for-gestational-age (SGA) fetuses with birth weight < 10^th percentile and 68 (4.5%) with fetal growth restriction (FGR). In the SGA and FGR groups, compared to the non-SGA and non-FGR fetuses, respectively, there was a more globular right ventricle and reduced left and right ventricular systolic function, and, from the left ventricular diastolic functional indices, the E/A ratio was increased. There was a linear association of right ventricular sphericity index, indices of left and right ventricular systolic function and E/A ratio with birth-weight Z-score. There were no significant associations between cardiac morphological and functional indices and UtA-PI Z-score or CPR Z-score.

CONCLUSIONS

This screening study at 35-37 weeks' gestation has demonstrated that birth weight is a determinant of fetal cardiac morphology and function but UtA-PI and CPR, as indirect measures of placental perfusion and fetal oxygenation, are not. This suggests that the differences in fetal cardiac indices between small and appropriately grown fetuses may be part of a normal physiological response to change in fetal size rather than part of a pathological adaptation to abnormal placental perfusion and fetal oxygenation. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Assessment of ventricular contractility in fetuses with an estimated fetal weight less than the tenth centile

OBJECTIVE

To determine whether abnormal global, transverse, and longitudinal ventricular contractility of the heart in fetuses with an estimated fetal weight <10th centile is present, irrespective of Doppler studies of the umbilical artery and cerebroplacental ratio.

STUDY DESIGN

This was a retrospective study of 50 fetuses with an estimated fetal weight <10th centile that were classified based on Doppler results from the pulsatility indices of the umbilical artery and middle cerebral artery, and the calculated cerebroplacental ratio (pulsatility indices of the umbilical artery/middle cerebral artery). Right and left ventricular measurements were categorized into 3 groups: (1) global ventricular contractility (fractional area change), (2) transverse ventricular contractility (24-segment transverse fractional shortening), and (3) basal-apical longitudinal contractility (longitudinal strain, longitudinal displacement fractional shortening, and basal lateral and septal wall annular plane systolic excursion). Z scores for the above measurements were computed for fetuses with an estimated fetal weight <10th centile using the mean and standard deviation derived from normal controls. Ventricular contractility measurements were considered abnormal if their Z score values were <5th centile (z score <-1.65) or >95th centile (Z score >1.65), depending on the specific ventricular measurement.

RESULTS

The average gestational age at the time of the examination was 32 weeks 4 days (standard deviation 3 weeks 4 days). None of the 50 study fetuses demonstrated absent or reverse flow of the umbilical artery Doppler waveform. Eighty-eight percent (44/50) of fetuses had one or more abnormal measurements of cardiac contractility of 1 or both ventricles. Analysis of right ventricular contractility demonstrated 78% (39/50) to have 1 or more abnormal measurements, which were grouped as follows: global contractility 38% (19/50), transverse contractility 66% (33/50); and longitudinal contractility 48% (24/50). Analysis of left ventricular contractility demonstrated 1 or more abnormal measurements in 58% (29/50) that were grouped as follows: global contractility 38% (19/50); transverse contractility 40% (20/50); and longitudinal contractility 40% (20/50). Of the 50 study fetuses, 25 had normal pulsatility index of the umbilical artery and cerebroplacental ratios, 80% of whom had 1 or more abnormalities of right ventricular contractility and 56% of whom had 1 or more abnormalities of left ventricular contractility. Abnormal ventricular contractility for these fetuses was present in all 3 groups of measurements; global, transverse, and longitudinal. Those with an isolated abnormal pulsatility index of the umbilical artery (n=11) had abnormalities of transverse contractility of the right ventricular and global contractility in the left ventricle. When an isolated cerebroplacental ratio abnormality was present, the right ventricle demonstrated abnormal global, transverse, and longitudinal contractility, with the left ventricle only demonstrating abnormalities in transverse contractility. When both the pulsatility index of the umbilical artery and cerebroplacental ratio were abnormal (3/50), transverse and longitudinal contractility measurements were abnormal for both ventricles, as well as abnormal global contractility of the left ventricle.

CONCLUSIONS

High rates of abnormal ventricular contractility were present in fetuses with an estimated fetal weight <10th centile, irrespective of the Doppler findings of the pulsatility index of the umbilical artery, and/or cerebroplacental ratio. Abnormalities of ventricular contractility were more prevalent in transverse measurements than global or longitudinal measurements. Abnormal transverse contractility was more common in the right than the left ventricle. Fetuses with estimated fetal weight less than the 10th centile may be considered to undergo assessment of ventricular contractility, even when Doppler measurements of the pulsatility index of the umbilical artery, and cerebroplacental ratio are normal.