Perinatal factors impacting echocardiographic left ventricular measurement in small for gestational age infants: a prospective cohort study
BMC Pediatrics volume 23, Article number: 393 (2023)
Infants born small for gestational age (SGA) have an increased risk of developing various cardiovascular complications. While many influencing factors can be adjusted or adapt over time, congenital factors also have a significant role. This study, therefore, seeks to explore the effect of perinatal factors on the left ventricular (LV) parameters in SGA infants, as assessed immediately after birth.
Methods and materials
This single-center prospective cohort study, conducted between 2014 and 2018, involved healthy SGA newborns born > 35 weeks’ gestation, delivered at New York-Presbyterian Brooklyn Methodist Hospital, and a gestational age (GA)-matched control group of appropriate for gestational age (AGA) infants. Data analysis was performed using multivariate linear regression in STATA.
The study enrolled 528 neonates, 114 SGA and 414 AGA. SGA infants exhibited a mean GA of 38.05 weeks (vs. 38.54), higher male representation (69.3% vs. 51.5%), lower birth weight (BW) (2318g vs 3381g), lower Apgar scores at birth, and a higher rate of neonatal intensive care unit admission compared to AGA infants (41.2% vs.18.9%; p<0.001). Furthermore, SGA infants were more likely to be born to nulliparous women (63.16% vs. 38.16%; p<0.001), with lower body mass index (BMI) (29.8 vs. 31.7; p=0.004), a lower prevalence of gestational maternal diabetes (GDM) (14.9 % vs. 35.5%; p<0.001), and a higher prevalence of preeclampsia (18.4 % vs. 6.52%; p<0.001). BW was identified as the most significant predictor affecting most LV parameters in this study (p<0.001), except shortening fraction, asymmetric interventricular septal hypertrophy and Inter-ventricular septal thickness/LV posterior wall ratio (IVS/LVPW). Lower GA (coefficient = -0.09, p=0.002), insulin use in GDM (coefficient = 0.39, p=0.014), and low APGAR scores at 1 minute (coefficient = -0.07, p<0.001) were significant predictors of IVS during diastole (R-squared [R2]=0.24). High maternal BMI is marginally associated with LVPW during systole (R2=0.27, coefficient = 0.01, p=0.050), while male sex was a significant predictor of LV internal dimension during diastole (R2=0.29, p=0.033).
This study highlights the significant influence of perinatal factors on LV parameters in SGA infants, with BW being the most influential factor. Although LV morphology alone may not predict future cardiovascular risk in the SGA population, further research is needed to develop effective strategies for long-term cardiovascular health management in this population.
Small for gestational age (SGA) infants have been shown to be at an increased risk of perinatal morbidity and mortality. To our interest, several observational studies have found a link between numerous heart pathologies and SGA compared to appropriate for gestational age (AGA) during fetal life, infancy, and adolescence [1,2,3]. A longitudinal study conducted in Finland found that young adults who were born SGA had higher blood pressure, impaired glucose metabolism, and increased carotid intima-media thickness (IMT) compared to individuals who were born with normal birth weight (BW) . Another Chinese study found that children born prematurely with intrauterine growth restriction (IUGR) have increased systemic arterial stiffness and mean blood pressure .
The increased risk of cardiovascular disease (CVD) in SGA individuals is thought to be related to fetal programming, a concept that describes how the developing fetus responds to environmental cues and adapts its physiology to cope with anticipated postnatal conditions . Adverse conditions during fetal development can result in permanent changes in the structure and function of organs, including the cardiovascular system, leading to an increased risk of CVD . Several mechanisms have been proposed to explain the association between SGA and CVD, including impaired angiogenesis and vasculogenesis, altered structure and function of the heart, and changes in the metabolic and endocrine systems . Many cardiac parameters have been studied over the years using echocardiography (echo) to assess heart function and reveal pathological diseases such as cardiomyopathy . The left ventricle (LV) is the engine that powers the human body's systemic circulation, and echo is used to estimate the LV mass (LVmass) and the LVmass to volume ratio (LVmass/vol) to predict pathologies like LV hypertrophy . A prospective, population-based, longitudinal cohort study found that being born prematurely or with a very low BW is associated with differences in cardiovascular structure and function in adulthood when assessed at the ages of 26-30, including smaller LV, LV end-diastolic volume, LV end-systolic volume, stroke volume, and cardiac output .
Echo is a key tool used to assess these structural and functional changes in the heart, particularly parameters of the LV . Recognizing that LV morphology, as assessed by echo, can undergo modifications due to various factors throughout life, the specific alterations in LV morphology in SGA infants and the precise perinatal factors contribuSting to these changes are not yet fully understood. This knowledge gap necessitates further investigation to provide more understanding of the cardiac health trajectory in SGA infants.
This study aims to investigate the relationship between perinatal factors and echocardiographic LV parameters in SGA infants, measured postnatally, to provide a more comprehensive understanding of the of the potential factors that might be associated LV parameters.
Materials and methods
Study design and setting
This investigation was a single-center, prospective cohort study aimed at identifying factors influencing echocardiographic estimates of LV function in SGA infants compared to AGA infants. The study was carried out at the labor ward and neonatal intensive care unit (NICU) of NewYork-Presbyterian Brooklyn Methodist Hospital (NYPBMH) between 2014 and 2018. As part of this study, comprehensive echo evaluations were conducted on all newborns within the time frame of 48 to 72 hours following delivery and before hospital discharge. This specific period was chosen to assess the cardiac function and characteristics of the infants. The study was conducted in adherence to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines  and the Helsinki declaration. Ethical approval was obtained from the hospital's institutional review board. Data confidentiality was ensured by assigning unique identification numbers to each participant and securing data in a locked repository.
SGA newborns who appeared healthy and were delivered at the NYPBMH were included in this study. SGA status was determined using Fenton growth charts . SGA was defined as a birth weight below the 10th percentile of gestational age using Fenton growth charts . All SGA infants underwent echo examination per unit protocol to assess for congenital heart disease. The SGA cohort was matched with a control group of AGA infants born during the same period, who had undergone echocardiography before hospital discharge for murmur evaluation. Infants with signifcant cardiac pathologies were excluded, though those with asymptomatic and insignificant benign pathologies (e.g., hemodynamically insignificant or restrictive patent ductus arteriosus, patent foramen ovale) were included. Neonates were excluded if echo was not performed for any reason, if data was lost during follow-up, if they were large for gestational age (LGA), or if they had congenital malformations, perinatal depression, low 5-minute APGAR score (<5), genetic diagnosis, heart disease, hypoxic respiratory failure, severe sepsis/shock requiring vasopressors or inotropes, or if they were born before the 35th week of gestation.
The independent variables in this study, believed to influence LV cardiac function, were classified as categorical or continuous variables. Categorical variables included NICU status, sex, gravidity, parity, gestational diabetes mellitus (GDM), preeclampsia, ethnicity, mode of delivery. Continuous independent variables encompassed gestational age (GA), BW, height, head circumference (HC), Ponderal Index (PI) = (Weight in grams) / (Length in centimeters)3, maternal age, maternal body mass index (BMI), and APGAR scores at one and five minutes. GDM was diagnosed based on the diagnostic criteria established by the American Diabetes Association, which oral glucose tolerance test with specific plasma glucose thresholds for fasting, 1-hour, and 3-hour measurements . Relevant maternal medical history was obtained from the hospital's electronic medical records, while neonatal information was collected after birth. The target LV cardiac parameters in this study included LVmass, LVmass/vol, inter-ventricular septal thickness during diastole (IVSd) and systole (IVSs), LV internal dimension during diastole (LVIDd) and systole (LVIDs), LV posterior wall thickness at end of diastole (LVPWd) and systole (LVPWs), IVSd/LPVWd ratio, shortening fraction (FS). The only categorical variable among these was asymmetric interventricular septal hypertrophy (ASH), defined as an IVS/LVPW ratio > 1.3. Two-dimensional (2D) Echo evaluation was performed using a Philips 5500 ECHO machine, with a focus on LV dimensions. LV morphology was assessed using the 2D method for structural evaluation and the M-mode method for functional assessment. Echocardiography in this study was performed by a single board-certified cardiologist.
Data were organized using Microsoft Excel and presented in tables. Raw data were presented as frequencies and percentages or means and Standard Error (SE) as appropriate. Differences in baseline characteristics between categorical variables were analyzed using the chi-square test of independence, and the two-sample t-test was used for continuous variables. Statistical significance was set at p<0.05.
To explore the relationship between the continuous LV cardiac variables and the independent variables of interest, a linear regression model was employed. This model allows for the examination of the nature and strength of the relationship between these variables. Initially, each independent variable was fitted individually (univariate analysis) to evaluate potential significance. Subsequently, significant variables were combined in a multivariate linear regression model, eliminating collinear variables based on correlation matrix (>0.9), variance inflation factors (>10), or clinical relevance. For the multivariate linear regression analysis, we included all enrolled infants, encompassing both the SGA and AGA groups, in order to examine the combined effects of various factors on the outcome variable. As part of sensitivity analysis, a repeat of the same multivariate linear regression analysis will be done on SGA and AGA groups separately. The results of the multivariate linear regression were reported, including coefficients, standard errors, p-values, R-squared (R2) and adjusted (adj) R2. Given the binary nature of ASH, binary logistic regression was employed. All statistical analyses, tables, and graphs were generated using Stata software (version 16.0, StataCorp LLC, College Station, TX).
Selection and inclusion process
Figure 1 depicts the process of selection and inclusion in our prospective cohort study. During the study period, 908 neonates were admitted to the hospital. Because of the pathologies described in Fig. 1, 81 neonates were excluded, and 174 neonates were found to be LGA and were appropriately excluded, leaving 653 neonates eligible for our study. 125 neonates were excluded because their echocardiograms were either not performed or were not reported. Our study ultimately included 528 neonates, including 114 SGA and 414 AGA neonates.
Table 1 summarizes the differences in baseline characteristics between SGA and AGA in various categorical variables. The table shows that a significantly higher proportion of SGA infants required admission to the NICU compared to AGA infants (41.23% vs. 17.87%; p<0.001). Additionally, SGA infants had a higher percentage of males (69.30% vs. 51.45%; p=0.001) and a lower prevalence of maternal diabetes (14.91% vs. 35.51%; p<0.001) and higher preeclampsia (18.42% vs. 6.52%; p<0.001) compared to AGA infants. In terms of parity, SGA infants had a significantly higher proportion of nulliparous mothers (63.16% vs. 38.16%; p<0.001) and a lower proportion of multiparous mothers (34.21% vs. 58.21%) compared to AGA infants. There was no significant difference in mode of delivery between the two groups. Regarding maternal ethnicity, the largest proportion of SGA infants was born to White and African American mothers (39.47%), while White mothers accounted for the majority of AGA infants (43.24%). Despite these trends, the difference in ethnicity between the two groups was not statistically significant (p=0.070).
Table 2 shows the differences in baseline characteristics SGA and AGA in several continuous variables. The mean GA for SGA babies was lower than AGA babies (38.05 weeks vs 38.69 weeks, p<0.001), however, the difference is clinically insignificant. BW, height, head circumference, and chest circumference were all significantly lower in SGA babies compared to AGA babies (p<0.001). PI was also significantly lower in SGA babies (2.44 g/cm3 vs 2.79 g/cm3, p<0.001). Maternal BMI was also significantly higher in AGA babies than SGA babies (29.82 kg/m2 vs 31.68 kg/m2, p=0.004). In terms of neonatal outcomes, SGA babies had a significantly lower APGAR score at 1 minute (7.73 vs 8.29, p=0.001) and a significantly lower APGAR score at 5 minutes (8.53 vs 8.83, p<0.001). There were no significant differences in maternal systolic and diastolic blood pressure or mean blood pressure between the two groups.
LV dependent variables comparison between SGA and AGA infants
Table 3 presents a summary of LV dependent variables in SGA and AGA infants. The results indicate that SGA infants have significantly lower mean values for IVSd (3.47 ± 0.63 mm vs. 4.00 ± 0.78 mm, p<0.001), IVSs (4.51 ± 0.81 mm vs. 5.34 ± 1.05 mm, p<0.001), LVIDd (16.82 ± 2.06 mm vs. 18.57 ± 2.11 mm, p<0.001), LVIDs (10.95 ± 1.47 mm vs. 11.93 ± 1.62 mm, p<0.001), LVPWd (3.09 ± 0.61 mm vs. 3.48 ± 0.61 mm, p<0.001), LVPWs (4.20 ± 0.59 mm vs. 4.82 ± 0.70 mm, p<0.001), LVmass (7.50 ± 2.35 g vs. 10.27 ± 3.26 g, p<0.001), and Lvmass/Vol (44.82 ± 11.02 g/m2 vs. 49.49 ± 12.15 g/m2, p<0.001) compared to AGA infants. There was also a significant difference in the mean values for FS between SGA and AGA infants (34.48 ± 4.10% vs. 35.56 ± 4.51%, p=0.021).
Table 4 shows a subgroup analysis of our SGA population based on growth restriction status. We had 70 symmetric IUGR neonates and 44 asymmetric IUGR neonates. Our analysis reveals no statistically significant differences in the LV cardiac parameters measured. The comparison of demographic findings between the symmetric IUGR and asymmetric IUGR groups revealed no significant differences, except for head circumference (symmetric IUGR 30.9±0.20 cm vs asymmetric IUGR 33.1±0.20 cm, p<0.001) and APGAR score at 1 minute (symmetric IUGR 8.1±0.19 vs asymmetric IUGR 7.1±0.38, p=0.014). The p-values for NICU (p=0.381), sex (p=0.143), gravida (p=0.232), parity (p=0.970), GDM (p=0.837), preeclampsia (p=0.683), ethnicity (p=0.113), mode of delivery (p=0.552), insulin (p=0.208), GA (p=0.403), BW (p=0.739), height (p=0.080), chest circumference (p=0.886), ponderal index (p=0.141), maternal age (p=0.719), and maternal BMI (p=0.325) were non-significant.
Main analysis results
The findings of the study, which used multivariate linear regression analysis, are presented in Table 5. In the IVSd regression model (R2=0.24, Adj R2=0.23), GA had a negative and significant effect, with a coefficient of -0.09 (p=0.002). APGAR score at 1 minute had also statistically significant negative effect on IVSd, with a coefficient of -0.07 (p<0.001). Maternal insulin use during pregnancy had a positive and significant effect on IVSd with a coefficient of 0.39 (p=0.014). As for BW, it was significantly associated positively with IVSd and IVSs (p<0.001).
Table 5 also shows LVIDd regression results (R2=0.29, Adj R2=0.27). Sex was found to be a significant predictor of LVIDd (p=0.033), with a negative coefficient of -0.62, indicating that male infants have a higher LVIDd than female infants. In LVIDs regression model (R2=0.18, Adj R2=0.16), BW was the only significant variable in it (p<0.001). BW was significantly associated with LVIDd (p<0.001), LVIDs (p=0.005) and LVPWd (p<0.001). Maternal BMI was found to be marginally significant (p=0.05), with a positive coefficient of 0.01, indicating that higher maternal BMI is associated with an increase in LVPWs (R2=0.27, Adj R2=0.25). LVPWs was also significantly associated with BW (p<0.001).
The regression model for LVmass had an R2 of 0.32 and Adj R2 of 0.30, and BW was found to be a significant predictor of LVmass (p<0.001), with a positive coefficient, indicating that a higher BW is associated with an increase in LVmass. As for LVmass/Vol regression model (R2=0.08, Adj R2=0.07), no significant relationships were observed between variables assessed and LVmass/Vol other than that of BW (p<0.001). No significant relationships were observed between either neonatal or maternal factors and FS. In the univariate binary regression, ASH and IVS/LVPW showed no significant associations with the included independent variables; thus, the results of that analysis are not presented.
Table 6 presents a comprehensive analysis of the associations between perinatal factors and LV parameters, examining SGA and AGA infants separately. The findings reveal significant associations in several instances. Specifically, in the SGA group, a significant association was observed between IVSd and BW (p=0.002). Similarly, significant associations were found between LVIDd and the Ponderal Index (p=0.038). Conversely, LVIDs exhibited a significant association with Birth Weight (p=0.020). Furthermore, Birth Weight demonstrated a significant association with LVPWd (p=0.001), while Maternal BMI exhibited a significant association with LVPWs (p=0.010). However, no significant associations were identified between FS and any of the examined variables. Additionally, BW demonstrated a significant association with LVmass (p<0.001), whereas LVmass/Vol exhibited a significant association with Maternal BMI (p=0.045). As for the AGA group, IVSd showed a significant association with GA (p=0.002), BW (p<0.001), APGAR at 1 minute (p<0.001) and maternal insulin use during pregnancy (p=0.035). Similarly, IVSs exhibited a significant association with Birth Weight (p=0.005). For LVIDd, significant associations were found with Sex (p=0.008) and Birth Weight (p=0.007), whereas LVIDs showed significant associations with Sex (p=0.040) and BW (p=0.039). Furthermore, Birth Weight demonstrated significant associations with LVPWd (p<0.001), LVPWs (p<0.001), LVmass (p<0.001) and LVmass/Vol (p=0.001).
In this prospective cohort study, a total of 528 neonates were enrolled, including 114 classified as SGA. The study findings indicate that SGA infants exhibit smaller LV dimensions and mass compared to their AGA counterparts. However, despite the statistically significant differences, both groups demonstrated similar FS values within the normal range, suggesting that the systolic function of the LV remains unaffected by the reduced LV size and mass in SGA infants. The mean LVmass/Vol ratio was 48.48 (SGA=44.82 ± 11.02 g/m2 vs. AGA=49.49 ± 12.15 g/m2), with no significant associations observed between the assessed variables and LVmass/Vol, except for BW. GA and maternal insulin use were identified as significant predictors of IVSd, while BW and APGAR scores were significant predictors of IVSs. Overall, this study provides valuable insights into the differences in neonatal outcomes and cardiac characteristics between SGA and AGA infants.
Our finding indicted that BW serves as the most reliable predictor of LV dimension, as it was significantly associated with LVmass, LVmass/Vol, LVIDd, LVIDs, IVSd, IVSs, LVPWd, and LVPWs, all demonstrating a positive coefficient. This suggests that a higher BW corresponds with an increase in these parameters. These association could potentially indicate that the size of the LV chamber is directly proportional to the weight of infants, a relationship previously observed in literature . A prior single-center cross-sectional study on 20 SGA children at 24 months revealed that SGA babies had early and mild cardiovascular dysfunction compared to AGA controls, with these changes closely associated with BW . Additionally, that same group have demonstrated that breastfeeding significantly benefits the cardiovascular system . Moreover, in a study of 62 asymmetric IUGR newborns, 39 symmetric IUGR neonates, and a control group of 50 AGA, it was observed that, aside from LVPW in diastole, all LV dimensions were smaller in asymmetric IUGR newborns compared to symmetric IUGR neonates . A similar study used 2D Echo to measure the valve diameters of 376 infants born < 32 weeks gestation and weighing < 2,000 g to give reference values for cardiac valve annulus diameters . They demonstrated a modest relationship between BW and valve diameter, with good intraobserver and interobserver agreement . Another research group tracked SGA newborns for three months using echocardiography on postnatal day five, as well as at one and three months, and found reduced ventricular diameters, ventricular wall thicknesses, and LVmass, but no differences in systolic and diastolic functioning .
Our hypothesis posits that the alterations observed are not merely confined to the neonate period but potentially extend into later stages of life. In a study involving a cohort of 64 extremely low BW children aged 11, there were notable differences in LV end-diastolic dimension, LV end-systolic dimension, aorta dimension, and left atrial (LA) dimension , when compared to a control group of 36 healthy children . Another study examining 81 children born as extremely low BW (ELBW) infants with a median BW of 890 g found no patients with diastolic or systolic problems, but there were statistical differences in right ventricle dimension in diastole, LV inner dimension in diastole, and the LA . Additionally, ELBW children exhibited significantly elevated heart rates and higher nocturnal blood pressure levels .
The impact of GA on the IVSd reveals a noteworthy finding. GA demonstrated a significant negative effect on IVSd, as indicated by a coefficient of -0.09. Unlike BW, GA displayed an inverse relationship with IVS thickness. This suggests that neonates born prematurely may not necessarily exhibit the manifestations of low birth weight or small size, as prematurity itself is an indication of their condition. Furthermore, premature delivery before the completion of nephrogenesis and IUGR contribute to the development of chronic kidney disease and subsequently lead to CVD . In the case of SGA fetuses and fetuses with IUGR, the myocardial performance index was significantly elevated compared to appropriately grown fetuses, implying impaired cardiac function . Significant distinctions between term and preterm neonates were observed in various cardiac parameters, such as interventricular septum and left systolic/diastolic ventricle diameters, LVPWD in systole (p<0.01), FS and ejection fraction, and basal LV and right ventricular lateral wall measurements in the Ew .
Furthermore, APGAR at 1 minute was significantly associated with IVSd (p<0.001), with a negative coefficient indicating that a lower APGAR at 1 minute is associated with increased thickness of IVSd. A low APGAR score is a known risk factor for poor prenatal outcome, which may be related to cardiac effects. The utilization of the 1-minute Apgar score in this study was based on its significance in assessing the initial condition of newborns and its ability to reflect the effects of intrauterine stress factors during birth, whereas the 5-minute Apgar score primarily reflects the efficacy of resuscitative measures performed during the first few minutes of life. This observation is supported by one study showing that the incidence of perinatal complications is higher in infants with Apgar scores less than 7 . This association is explained by the possibility that a low APGAR score indicates fetal distress, premature birth, meconium-stained amniotic fluid, placental abruption, fetal edema, maternal use of certain medications during pregnancy, such as beta-blockers, and certain medical conditions, such as maternal hypotension, anemia, or infections [26,27,28,29]. Our analysis also revealed a significant difference (p=0.014) in the APGAR score at 1 minute between symmetric and asymmetric IUGR groups. This finding suggests that asymmetric IUGR neonates experienced significantly more stress during their time in the uterus compared to symmetric IUGR neonates.
The sex of the infant was also found to be a significant predictor of LVIDd (p=0.033), with a negative coefficient of -0.62, indicating that male infants have a higher LVIDd than female infants. Males appear to have larger LV dimensions than females. According to one research paper, men had significantly higher LV mass, volume, and dimension compared to women, even after adjusting for body size differences . Another study found that men had larger LV end-diastolic and end-systolic volumes compared to women .
Maternal insulin consumption during pregnancy has been shown in our study to have a substantial effect on IVSd (R2=0.24), with a coefficient of 0.39 (p=0.014). Cardiovascular abnormalities are among the most prevalent in diabetes mothers' babies, accounting for 3%-9% of diabetic pregnancies and being 2.5-10 times more common than in normal pregnancies . If the mother has gestational diabetes and develops insulin resistance in the third trimester, the relative risk for serious cardiovascular problems is highest . The incidence of complications was observed to be 3.4% with maternal HbA1c levels less than 8.5% and 22.4% with HbA1c levels greater than 8.5% . Infants born to mothers who had HbA1c levels above 10% in late pregnancy are more likely to suffer neonatal problems . Hypertrophic cardiomyopathy (HCM) is thought to arise as a result of both prenatal hyperinsulinemia and the typically elevated expression and affinity of insulin receptors, resulting in the proliferation and hypertrophy of cardiac myocytes [34, 35]. A case report of cardiac hypertrophy in an exceptionally low BW newborn who received insulin therapy after developing chronic hyperglycemia due to parenteral nourishment supports the concept that iatrogenic hyperinsulinemia plays a role in the development of HCM . Fetal hyperinsulinemia and insulin-like growth factor-I (IGF-1) have also been linked to morphological fetal heart abnormalities. IGF-1 stimulates cardiomyocyte hypertrophy, resulting in reduced myocardial compliance and functional impairment [37, 38]. Nonetheless, the usage of insulin may be an indication of poor glycemic control, which may be a potential confounder in this scenario that leads to IVSd enlargement .
We also found that maternal BMI was marginally significant in our study (p=0.050), with a positive coefficient of 0.01, indicating that higher maternal BMI might be associated with an increase in LVPWs. Maternal obesity has been linked to changes in the structure and function of the heart, resulting in cardiac abnormalities . The current obesity pandemic among women of childbearing age increases the risk of cardiovascular disease and cardiomyopathies . Pregnancy induces metabolic changes, which are more pronounced in obese women, such as increased body weight, circulation lipids, glucose, and inflammatory markers. Epidemiological studies show that maternal obesity increases the risk of cardiovascular disease and premature mortality in adult and elderly children . Little is known about cardiac development and function in children born to obese mothers, although research indicates that neonates' LV mass increases in proportion to maternal gestational weight growth .
Overall, these findings elucidate the connections between perinatal factors such as BW, GA and maternal health conditions, and their influence on specific measures of LV structure and function. This study enhances our comprehension of the baseline cardiac characteristics seen in SGA neonates, taking into account these perinatal influences.
There are several limitations to this study that must be considered when interpreting the findings. Several factors may have an impact on the generalizability of this study. To begin, the study was conducted in a single hospital. Because the study population was unique to this hospital, the results may not be representative of other populations . The study's small sample size may have limited statistical power, resulting in the failure to detect significant differences between groups. The small sample size may have also introduced bias into the study, affecting its external validity . The generalizability is also influenced by exclusion criteria, which may limit the findings' applicability to neonates with specific pathologies. Furthermore, the study's ability to reflect the long-term outcomes of SGA infants' LV function and the overall cardiovascular risk is limited by the lack of long-term follow-up of the participants after their discharge from the hospital. The study was also not blinded, which could lead to bias in measurements and interpretation of the findings . We also didn't include information about potential confounding variables like maternal smoking, which is a known risk factor for low BW and cardiac dysfunction . Finally, echo was used exclusively to evaluate LV function. While echo is a common tool for assessing LV function, it is not without limitations . It is also important to note that our study did not employ advanced imaging techniques for assessing LV morphology. A potential limitation of this study is that the echocardiographic evaluations were conducted by a single cardiologist, which may introduce limitations in assessing interobserver variability.
This prospective cohort study compared the neonatal maternal data and multiple LV dimension parameters of SGA and AGA infants. All LV dimension parameters were found to be significantly related to BW, implying that a higher BW is associated with an increase in LV dimensions. We also discovered that low APGAR scores at 1 minute were linked to higher IVSd, implying that low APGAR scores may be linked to increased cardiac thickness. Furthermore, we discovered that IVSd is significantly thickened in neonates born to moms who took insulin to control their diabetes during pregnancy, and that male infants had a greater LVIDd than female infants. The changes seen during the neonatal period may have long-term consequences. As a result, it is critical to closely monitor and manage neonates with low BW and low APGAR scores to avoid long-term complications. Further research is needed to explore the long-term implications of these findings and develop appropriate interventions to minimize the risk of adverse cardiac outcomes in neonates.
Availability of data and materials
The data used for the analysis in this work are available upon reasonable request from the corresponding author.
- Adj R2 :
Appropriate for gestational age
Adjusted relative risk
Asymmetric interventricular septal hypertrophy
Body mass index
Extremely low birth weight
Insulin-like growth factor-I
Intrauterine growth restriction
Inter-ventricular septal thickness during diastole
Inter-ventricular septal thickness during systole
Large for gestational age
LV internal dimension during diastole
LV internal dimension during systole
Left ventricular mass
Left ventricular mass to volume ratio
LV posterior wall thickness at end of diastole
LV posterior wall thickness at end of systole
Neonatal intensive care unit
- R2 :
Root mean square error
Small for gestational age
Graupner O, et al. Myocardial deformation analysis in late-onset small-for-gestational-age and growth-restricted fetuses using two-dimensional speckle tracking echocardiography: a prospective cohort study. J Perinat Med. 2022;50(3):305–12.
Grudzień A, et al. Longitudinal assessment of cardiac function in extremely low birth weight children at 7 and 11 years of age: implications for adult medicine. Kardiol Pol. 2021;79(5):539–45.
Olander RFW, et al. Differences in cardiac geometry in relation to body size among neonates with abnormal prenatal growth and body size at birth. Ultrasound Obstet Gynecol. 2020;56(6):864–71.
Kajantie E, et al. Size at birth as a predictor of mortality in adulthood: a follow-up of 350 000 person-years. Int J Epidemiol. 2005;34(3):655–63.
Cheung YF, et al. Relation of arterial stiffness with gestational age and birth weight. Archives of Disease in Childhood. 2004;89(3):217–21.
Barker DJ. Fetal programming of coronary heart disease. Trends Endocrinol Metab. 2002;13(9):364–8.
Palinski W. Effect of maternal cardiovascular conditions and risk factors on offspring cardiovascular disease. Circulation. 2014;129(20):2066–77.
Kumar VHS. Cardiovascular Morbidities in Adults Born Preterm: Getting to the Heart of the Matter! Children. 2022;9(12):1843.
Wood MJ, Picard MH. Utility of echocardiography in the evaluation of individuals with cardiomyopathy. Heart. 2004;90(6):707–12.
Foppa M, Duncan BB, Rohde LE. Echocardiography-based left ventricular mass estimation. How should we define hypertrophy? Cardiovasc Ultrasound. 2005;3:17. Published 2005 Jun 17. https://doi.org/10.1186/1476-7120-3-17.
Harris SL, et al. Cardiovascular Outcomes in Young Adulthood in a Population-Based Very Low Birth Weight Cohort. J Pediatr. 2020;225:74-79.e3.
Schubert U, et al. Transition from fetal to neonatal life: Changes in cardiac function assessed by speckle-tracking echocardiography. Early Human Development. 2013;89(10):803–8.
von Elm E, et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. J Clin Epidemiol. 2008;61(4):344–9.
Fenton TR. A new growth chart for preterm babies: Babson and Benda’s chart updated with recent data and a new format. BMC Pediatr. 2003;3:13.
Rani PR. Begum, Screening and Diagnosis of Gestational Diabetes Mellitus, Where Do We Stand. J Clin Diagn Res. 2016;10(4):Qe01-4.
Abushaban L, et al. Normal reference ranges for left ventricular dimensions in preterm infants. Ann Pediatr Cardiol. 2014;7(3):180–6.
Castagno M, et al. Small-for-gestational-age birth is linked to cardiovascular dysfunction in early childhood. Am Heart J. 2019;217:84–93.
Cinar B, et al. Left ventricular dimensions, systolic functions, and mass in term neonates with symmetric and asymmetric intrauterine growth restriction. Cardiol Young. 2015;25(2):301–7.
van Ark AE, et al. Cardiac Valve Annulus Diameters in Extremely Preterm Infants: A Cross-Sectional Echocardiographic Study. Neonatology. 2018;114(3):198–204.
Gürses D, Seyhan B. Evaluation of cardiac systolic and diastolic functions in small for gestational age babies during the first months of life: a prospective follow-up study. Cardiol Young. 2013;23(4):597–605.
Kwinta P, et al. From a regional cohort of extremely low birth weight infants: cardiac function at the age of 7 years. Neonatology. 2013;103(4):287–92.
Grillo MA, Mariani G, Ferraris JR. Prematurity and Low Birth Weight in Neonates as a Risk Factor for Obesity, Hypertension, and Chronic Kidney Disease in Pediatric and Adult Age. Front Med (Lausanne). 2021;8: 769734.
Hassan WA, et al. Cardiac function in early onset small for gestational age and growth restricted fetuses. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2013;171(2):262–5.
Ciccone MM, et al. Different functional cardiac characteristics observed in term/preterm neonates by echocardiography and tissue doppler imaging. Early Human Development. 2011;87(8):555–8.
Bonds DR, et al. Fetal weight/placental weight ratio and perinatal outcome. Am J Obstet Gynecol. 1984;149(2):195–200.
Gutbir Y, et al. Low Apgar score in term newborns and long-term infectious morbidity: a population-based cohort study with up to 18 years of follow-up. Eur J Pediatr. 2020;179(6):959–71.
Christensen J, et al. Apgar-score in children prenatally exposed to antiepileptic drugs: a population-based cohort study. BMJ Open. 2015;5(9): e007425.
Gudayu TW. Proportion and factors associated with low fifth minute Apgar score among singleton newborn babies in Gondar University referral hospital. North West Ethiopia Afr Health Sci. 2017;17(1):1–6.
Masood M, et al. Association of Apgar Score With Meconium Staining of Amniotic Fluid in Labor. Cureus. 2021;13(1): e12744.
Gardin JM, et al. Relationship of cardiovascular risk factors to echocardiographic left ventricular mass in healthy young black and white adult men and women. The CARDIA study. Coronary Artery Risk Development in Young Adults. Circulation. 1995;92(3):380–7.
Al-Biltagi M, El Razaky O, El Amrousy D. Cardiac changes in infants of diabetic mothers. World J Diabetes. 2021;12(8):1233–47.
Narchi H, Kulaylat N. Heart disease in infants of diabetic mothers. Images Paediatr Cardiol. 2000;2(2):17–23.
Nold JL, Georgieff MK. Infants of diabetic mothers. Pediatr Clin North Am. 2004;51(3):619–37, viii.
Breitweser JA, et al. Cardiac septal hypertrophy in hyperinsulinemic infants. J Pediatr. 1980;96(3 Pt 2):535–9.
Buchanan TA, Kitzmiller JL. Metabolic interactions of diabetes and pregnancy. Annu Rev Med. 1994;45:245–60.
Salvatori G, et al. Cardiac hypertrophy and insulin therapy in a pre-term newborn: is there a relationship? Italian Journal of Pediatrics. 2022;48(1):24.
El-Ganzoury MM, et al. Infants of diabetic mothers: echocardiographic measurements and cord blood IGF-I and IGFBP-1. Pediatric Diabetes. 2012;13(2):189–96.
Zielinsky P, et al. Natural history of myocardial hypertrophy and its association with hyperinsulinism in infants of diabetic mothers. Arq Bras Cardiol. 1997;69(6):389–94.
Feghali MN, Umans JG, Catalano PM. Drugs to Control Diabetes During Pregnancy. Clin Perinatol. 2019;46(2):257–72.
Liu Y, et al. Global birth prevalence of congenital heart defects 1970–2017: updated systematic review and meta-analysis of 260 studies. International journal of epidemiology. 2019;48(2):455–63.
Wang J, et al. Association of Maternal Gestational Weight Gain With Left Ventricle Geometry and Function in Offspring at 4 Years of Age: A Prospective Birth Cohort Study. Frontiers in pediatrics. 2021;9:722385–722385.
Eriksson JG, et al. Long-term consequences of maternal overweight in pregnancy on offspring later health: findings from the Helsinki Birth Cohort Study. Annals of medicine. 2014;46(6):434–8.
Guzzardi MA, et al. Maternal obesity and cardiac development in the offspring: study in human neonates and minipigs. JACC: Cardiovascular Imaging. 2018;11(12):1750–5.
He Z, et al. Clinical Trial Generalizability Assessment in the Big Data Era: A Review. Clin Transl Sci. 2020;13(4):675–84.
Faber J, Fonseca LM. How sample size influences research outcomes. Dental Press J Orthod. 2014;19(4):27–9.
Karanicolas PJ, Farrokhyar F, Bhandari M. Practical tips for surgical research: blinding: who, what, when, why, how? Can J Surg. 2010;53(5):345–8.
Jaddoe VW, et al. Active and passive maternal smoking during pregnancy and the risks of low birthweight and preterm birth: the Generation R Study. Paediatr Perinat Epidemiol. 2008;22(2):162–71.
Potter E, Marwick TH. Assessment of Left Ventricular Function by Echocardiography: The Case for Routinely Adding Global Longitudinal Strain to Ejection Fraction. JACC Cardiovasc Imaging. 2018;11(2 Pt 1):260–74.
Open access funding provided by Qatar National Library.
The publication of this article was funded by Qatar National Library. This research did not receive any other grants from funding agencies in the public, commercial, or not-for-profit sectors.
Ethics approval and consent to participate
Data collection and analysis were conducted in accordance with the Helsinki Declaration, and ethical approval was obtained from the Institutional Review Board (IRB) of NewYork-Presbyterian Brooklyn Methodist Hospital. Since echocardiography, a minimal risk procedure, was performed based on clinical indications and data collection was retrospective, obtaining consent from the neonates' legal guardians was deemed unnecessary by NewYork-Presbyterian Brooklyn Methodist Hospital’s IRB. All methods were performed in accordance with the relevant guidelines and regulations.
Consent for publication
The authors declare no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Elmakaty, I., Amarah, A., Henry, M. et al. Perinatal factors impacting echocardiographic left ventricular measurement in small for gestational age infants: a prospective cohort study. BMC Pediatr 23, 393 (2023). https://doi.org/10.1186/s12887-023-04204-w