A total of 563 participants were included in the final analysis among which 414 were in the control group (babies with AGA) and 149 were in the intervention group (babies with LGA). Table 1 demonstrates and compares the various neonatal and maternal variables between LGA and AGA infants. Results show that most of the participant in both groups were males (AGA = 51.45% and LGA = 61.7%). The mode of delivery was dominantly C-sections (66%) while in the AGA group, vaginal and c-section deliveries were equally distributed (50%). Among the AGA (33.5%) were admitted to neonatal intensive care unit (NICU), while in LGA there was a higher number of babies that were admitted to NICU (74.6%). The analysis of the APGAR scores at 1 minute and 5 minutes showed statistically insignificant results (p=0.081 and p=0.125 respectively). ASH was more prominent in LGA infants (42.3%) as compared to AGA infants (28.0%). The table also demonstrates some descriptive biometric characteristics of the infants such as GA, BW, height, head circumference, chest circumference, and ponderal index (PI). On comparing the GA of LGA and AGA infants, it was found that it was almost similar in LGA infants (38.30 ± 1.20) and AGA infants (38.69 ± 1.48). The BW was expectedly significantly higher in LGA than AGA infants (4337.46 ± 404.45 and 3381.05 ± 445.77 respectively). Similarly, the other measurements such as height, head circumference, and chest circumference. were significantly increased in LGA infants compared to AGA infants. The PI is another important factor that was measured. PI is the ratio of body weight to height and is calculated as weight/height3 (Cole et al., 1997). The mean PI in LGA infants was calculated as 3.11 ± 0.38 compared to the mean PI of AGA infants which was calculated as 2.79 ± 0.34.
As for the maternal variables, in the AGA group, the white ethnicity was ranked most with 51.6% of all AGA infants being white. However, in the LGA group, most infants were of black ethnicity with 41.7% (not much higher than the white ethnicity with 40.9%). Most of the participants in the AGA group had non-diabetic mothers (63.8%) while in the LGA group there was almost an equal number of diabetic and non-diabetic mothers (50.3% vs 49.7%). Preeclampsia was not evident in the mothers of both AGA and LGA infants (93.4 and 86.6 respectively). The maternal BMI of LGA infants (35.74 ± 7.49) was significantly higher than that of AGA infants (31.68 ± 6.03). Finally, gravida yielded statistically insignificant results (p=0.47). The details of the neonatal and maternal factors can be seen in Table 1.
Table 1. Neonatal and Maternal variables of LGA and AGA infants
Variable
|
LGA
|
AGA
|
Total
|
P-value
|
f*
|
%
|
f
|
%
|
Neonatal Variables
|
Mode of Delivery
|
|
|
|
|
|
|
|
Vaginal
|
50
|
33.56
|
204
|
49.64
|
254
|
0.001
|
|
C-Section
|
99
|
66.44
|
207
|
50.36
|
306
|
NICU Admission
|
|
|
|
|
|
|
|
No
|
29
|
25.44
|
147
|
66.52
|
176
|
<0.001
|
|
Yes
|
85
|
74.56
|
74
|
33.48
|
159
|
Sex
|
|
|
|
|
|
|
|
Male
|
92
|
61.74
|
213
|
51.45
|
305
|
0.031
|
|
Female
|
57
|
38.26
|
201
|
48.55
|
258
|
APGAR 1
|
|
|
|
|
|
|
|
Low
|
22
|
14.97
|
40
|
9.71
|
62
|
0.081
|
|
Normal
|
125
|
85.03
|
372
|
90.29
|
497
|
APGAR 5
|
|
|
|
|
|
|
|
Low
|
4
|
2.72
|
4
|
0.97
|
8
|
0.125
|
|
Normal
|
143
|
97.28
|
408
|
99.03
|
551
|
Asymmetric Septal Hypertrophy
|
|
|
|
|
|
|
|
No
|
86
|
57.72
|
298
|
71.98
|
384
|
0.001
|
|
Yes
|
63
|
42.28
|
116
|
28.02
|
179
|
Gestational Age
|
38.30 ± 1.20
|
38.69 ± 1.48
|
|
0.01
|
Birth Weight
|
4337.46 ± 404.45
|
3381.05 ± 445.77
|
|
<0.001
|
Height
|
51.94 ± 2.24
|
49.50 ± 2.64
|
|
<0.001
|
Head Circumference
|
35.93 ± 1.40
|
34.31 ± 1.91
|
|
<0.001
|
Chest Circumference
|
36.26 ± 1.95
|
33.11 ± 2.01
|
|
<0.001
|
Ponderal Index
|
3.11 ± 0.38
|
2.79 ± 0.34
|
|
<0.001
|
Maternal Variables
|
Gravida
|
|
|
|
|
|
|
|
Primi
|
27
|
18.12
|
93
|
22.79
|
120
|
0.47
|
|
Multi
|
92
|
61.74
|
242
|
59.31
|
334
|
|
Grand
|
30
|
20.13
|
73
|
17.89
|
103
|
Parity
|
|
|
|
|
|
|
|
Nulli
|
27
|
18.12
|
158
|
38.44
|
185
|
<0.001
|
|
Multi
|
118
|
79.19
|
241
|
58.64
|
359
|
|
Grand
|
4
|
2.68
|
12
|
2.92
|
16
|
Diabetes
|
|
|
|
|
|
|
|
No
|
74
|
50.34
|
259
|
63.79
|
333
|
0.004
|
|
Yes
|
73
|
49.66
|
147
|
36.21
|
220
|
Preeclampsia
|
|
|
|
|
|
|
|
No
|
129
|
86.58
|
383
|
93.41
|
512
|
0.01
|
|
Yes
|
20
|
13.42
|
27
|
6.59
|
47
|
Ethnicity
|
|
|
|
|
|
|
|
White
|
52
|
40.94
|
179
|
51.59
|
231
|
<0.001
|
|
Black
|
53
|
41.73
|
114
|
32.85
|
167
|
|
Hispanic
|
14
|
11.02
|
8
|
2.31
|
22
|
|
Asian
|
1
|
0.79
|
15
|
4.32
|
16
|
|
Other
|
7
|
5.51
|
31
|
8.93
|
38
|
Maternal age
|
32.67 ± 5.63
|
31.55 ± 5.77
|
|
0.041
|
Maternal BMI
|
35.74 ± 7.49
|
31.68 ± 6.03
|
|
<0.001
|
*Values are expressed as frequencies and percentages or Mean ± SD.
Abbreviations: C-Section, Cesarean section; f, Frequency; %, percentage; DM, Diabetes Mellitus.
Table 2 shows a detailed description of cardiac variables that were collected for all the infants in our study. It compares the means and standard deviation of those cardiac variables for LGA infants and AGA infants. All the variables were statistically significant except the LVIDs (p=0.19). The mean thickness of the IVS was significantly increased in LGA infants as compared to AGA infants (5.1 vs 4.0 mm respectively in diastole and 6.4 vs 5.3 mm respectively in systole). The increased mean IVSs is due to the contraction of the muscle fibers that cause thickening of the IVS (Moore et al., 2021). Some variables like LVIDd and LVPWd were minimally elevated in LGA which might indicate clinical insignificance. The details of all the parameters can be found in the table below.
Table 2. Descriptive statistics of cardiac variables
Variable
|
LGA
|
AGA
|
Observations
|
P-value
|
Mean
|
SD
|
Mean
|
SD
|
LVmass
|
14.12
|
4.00
|
10.27
|
3.26
|
559
|
<0.001
|
LVmass/vol
|
58.89
|
14.80
|
49.49
|
12.15
|
549
|
<0.001
|
LVIDd
|
19.41
|
2.27
|
18.57
|
2.11
|
559
|
<0.001
|
LVIDs
|
12.14
|
1.84
|
11.93
|
1.62
|
559
|
0.19
|
IVSd
|
5.10
|
1.29
|
4.00
|
0.78
|
562
|
<0.001
|
IVSs
|
6.40
|
1.37
|
5.34
|
1.05
|
559
|
<0.001
|
LPWDd
|
4.05
|
0.73
|
3.48
|
0.61
|
559
|
<0.001
|
LVPWs
|
5.48
|
0.87
|
4.83
|
0.70
|
558
|
<0.001
|
IVS/LPW
|
1.28
|
0.39
|
1.17
|
0.28
|
557
|
<0.001
|
FS
|
37.49
|
5.20
|
35.56
|
4.51
|
559
|
<0.001
|
Abbreviations: IVS, thickness of Inter Ventricular Septum in diastole (IVSd) and systole (IVSs); LVID, cardiac left ventricular internal dimension during diastole (LVIDd) and systole (LVIDs); (LVPW), thickness of left ventricular posterior wall in diastole (LVPWd) and systole (LVPWs); FS, Fractional Shortening; LVmass/vol, LV mass to volume ratio; LGA, large for gestational age; AGA, appropriate for gestational age; SD, standard deviation.
The multivariate linear regression analysis done to reveal the association between perinatal factors and LV parameters showed some interesting findings (Table 3). In the IVSd regression model (R2=0.34, Adjusted [Adj] R2=0.34), we observed that both GA and the APGAR score at 1 minute had statistically significant negative effects on IVSd. Specifically, GA had a significant negative impact with a coefficient of -0.140 (p<0.001), and the APGAR score at 1 minute also had a statistically significant negative effect, with a coefficient of -0.066 (p=0.004). However, Maternal insulin use during pregnancy and Birth weight both had a positive and significant effect on IVSd with a coefficient of 0.561 (p<0.001) and 0.001 (p<0.001) respectively. Similarly, BW was significantly associated positively with IVSs with a coefficient of 0.001 (p<0.001),
LVIDd regression results (R2=0.15, Adj R2=0.14) show that sex was found to be a significant predictor of LVIDd (p<0.001), with a negative coefficient of -0.776, indicating that male infants have a higher LVIDd than female infants. Similarly, in LVIDs regression model (R2=0.07, Adj R2=0.06), sex was found to be a significant predictor of LVIDs (p=0.001), with a negative coefficient of -0.464. GA was significantly associated with LVIDd (p=0.027) and LVIDs (p=0.014). Similarly, BW was associated with both LVIDd (p<0.001) and LVIDs (p=0.007). In the LVPWd (R2=0.23, Adj R2=0.23) and the LVPWs (R2=0.20, Adj R2=0.20) regression results, BW was the only positive associated perinatal factor (p<0.001). BW and Maternal BMI were found to be positively associated with FS (R2=0.04, Adj R2=0.04). These results were statistically significant (p=0.004 and p=0.009 respectively), with a positive coefficient of <0.001 and 0.093 respectively. This indicates that higher BW and maternal BMI are associated with an increase in FS.
The regression analysis for LVmass (R2=0.33, Adj R2=0.32) showed revealed that BW is a significant predictor of LVmass, with a positive coefficient of 0.004 (p<0.001), suggesting that higher BW is associated with an increase in LVmass. In the case of the LVmass/Vol regression model, the R-squared value was 0.08, and the adjusted R-squared value was 0.07. It showed a negative significant relationship between GA and LVmass/Vol (p=0.029). However, BW, was found to be a significant predictor with a positive association (p<0.001).
Regarding the univariate binary regression, neither ASH nor IVS/LVPW showed any significant associations with the independent variables included in the analysis, and therefore, the results of this analysis are not presented.
Table 3: Associations of Perinatal Factors with Left Ventricular Parameters
LV parameter
|
N
|
Variable
|
Coeff
|
SE
|
P-value
|
R2, Adj R2
|
IVSd
|
547
|
GA
|
-0.140
|
0.028
|
<0.001
|
0.34, 0.34
|
Birth weight
|
0.001
|
0.000
|
<0.001
|
APGAR1
|
-0.066
|
0.023
|
0.004
|
Insulin use
|
0.561
|
0.156
|
<0.001
|
*Other variables controlled for in this model: Maternal BMI.
|
IVSs
|
547
|
Birth weight
|
0.001
|
0.000
|
<0.001
|
0.25, 0.24
|
*Other variables controlled for in this model: NICU admission, GA, Birth weight, Category, PI, Maternal BMI, Diabetes, Diabetic control, Preeclampsia.
|
LVIDd
|
547
|
Sex
|
-0.776
|
0.177
|
<0.001
|
0.15, 0.14
|
GA
|
0.149
|
0.067
|
0.027
|
Birth weight
|
0.001
|
0.000
|
<0.001
|
APGAR1
|
0.100
|
0.054
|
0.062
|
*Other variables controlled for in this model: Maternal BMI, Preeclampsia, Mean BP.
|
LVIDs
|
555
|
Sex
|
-0.464
|
0.142
|
0.001
|
0.07, 0.06
|
GA
|
0.133
|
0.054
|
0.014
|
Birth weight
|
0.000
|
0.000
|
0.007
|
*Other variables controlled for in this model: Preeclampsia.
|
LVPWd
|
547
|
Birth weight
|
0.001
|
0.000
|
<0.001
|
0.23, 0.23
|
*Other variables controlled for in this model: GA, Maternal BMI, Preeclampsia, Insulin use.
|
LVPWs
|
552
|
Birth weight
|
0.001
|
0.000
|
<0.001
|
0.20, 0.20
|
*Other controlled for variables in this model: GA, Maternal BMI, Preeclampsia.
|
FS
|
554
|
Birth weight
|
<0.001
|
<0.001
|
0.009
|
0.04, 0.04
|
Maternal BMI
|
0.093
|
0.032
|
0.004
|
*Other variables controlled for in this model: MOD.
|
LVmass
|
552
|
Birth weight
|
0.004
|
0.000
|
<0.001
|
0.33, 0.32
|
Parity
|
0.223
|
0.119
|
0.063
|
*Other variables controlled for in this model: Sex, GA, Maternal BMI, Preeclampsia.
|
LVmass/Vol
|
538
|
GA
|
-0.920
|
0.410
|
0.029
|
0.13, 0.12
|
Birth weight
|
0.008
|
0.001
|
<0.001
|
*Other variables controlled for in this model: Maternal BMI, Insulin use.
|
Abbreviations: LVmass, Left Ventricular mass; LVmass/Vol, LVmass to Volume ratio; IVSd, Inter-Ventricular Septal thickness during diastole; IVSs, Inter-Ventricular Septal thickness during systole; LVIDd, LV Internal Dimension during diastole; LVIDs, LV Internal Dimension during systole; LVPWd, LV Posterior Wall thickness at end of diastole; LVPWs, LV Posterior Wall thickness at end of systole; IVS/LVPW, Inter-Ventricular Septal thickness to LV Posterior Wall thickness ratio in diastole; FS, Shortening Fraction; SD, Standard Deviation; RMSE, Root Mean Square Error; Coeff, Coefficient; GA, Gestational Age; BMI, Body Mass Index; BP, Blood Pressure; MOD, Mode Of Delivery; Adj, Adjusted.
The multivariate linear regression that was performed to determine the association between perinatal factors and cardiac variables between LGA and AGA infants are shown in table 4. The data showed no significant association between any of the perinatal variables and LV mass in both LGA and AGA infants except BW. There was a positive relationship between LVmass and BW as the coefficient was 0.003, meaning that for each unit increase in BW the LV mass increases by 0.003. This result was statistically significant (p<0.001). Finally, there was also an association between pre-eclampsia and LV mass in AGA infants (coeff – 1.222, p=0.045). The same could not be said for the LGA group as there was no statistical significance. Details about the rest of the perinatal variables and their association with LV mass can be seen in Table 3.
Similarly, there was a positive association between BW in AGA infants and LV mass to volume ratio with a coefficient of 0.005 (p<0.001). However, there was no statistical significance observed in the LGA group (p=0.06). The remaining perinatal factors (Maternal BMI and insulin-controlled DM) had no statistical significance in either group. Analysis shows that the thickness of interventricular septum was significantly affected by perinatal factors. However, there were some discrepancies between their effects on the IVS during diastole and systole. For instance, during diastole the IVS thickness had a statistically significant positive association with perinatal factors such as BW (p<0.001), and insulin-controlled DM (p=0.02) in the AGA group. It also had a statistically significant negative association with apgar score at 1 minute (p<0.001) in the same group. In the LGA group, there was a positive association between IVS thickness during diastole and BW (p<0.001), and insulin-controlled DM (p=0.003). On the contrary, the thickness of IVS during systole had a statistically significant positive association with only BW (p<0.001) in both groups.
The association between perinatal factors and the LVIDd and LVIDs were also analyzed. Sex was the most interesting finding as the results showed that there is a strong association between being a male and having an increased LVIDd in AGA and LGA infants (p=0.002 and p=0.025 respectively). Similarly, there was a strong association between being a male and having an increased LVIDs in AGA and LGA infants (p=0.03 and p=0.041). BW was also found to be statistically correlated with LVIDd and LVIDs only in the AGA group (p<0.001). APGAR score at 1 minute had a positive association with LVIDd in AGA infants (coeff=0.161 and p=0.014). Finally, preeclampsia had a negative correlation with LVIDs in LGA infants (coeff=-1.146 and p=0.013).
Once again, BW was positively correlated with LVPW during diastole in AGA and LGA infants (p<0.001 and p=0.003). Similarly, it was also positively correlated with LVPW during systole in AGA and LGA infants (p<0.001 and p=0.011). In addition, there was a statistically significant positive association between maternal BMI and shortening fraction in LGA infants (p=0.025). Shortening fraction was not found to be positively correlated with any other perinatal factors.
The final variable that was analyzed is the IVS/LVPW ratio. It is used to determine if the heart is symmetric in size or not. The cutoff for this value is used to determine ASH. Analysis unveiled that the only positively correlated with IVS/LVPW in LGA infants was insulin-controlled DM (coeff=0.236, p=0.03). The rest of the variables were statistically insignificant. Details are listed in Table 4.
Table 4. Results of the multivariate regression to investigate the association between cardiac parameters (dependent variables) and perinatal factors (independent variables) for AGA and LGA infants.
Cardiac Parameter
|
AGA
|
LGA
|
Observations
|
Variable
|
Coefficient
|
SE
|
P-value
|
Observations
|
Variable
|
Coefficient
|
SE
|
P-value
|
LV mass
|
405
|
sex
|
-0.499
|
0.301
|
0.098
|
147
|
sex
|
-0.119
|
0.658
|
0.857
|
BW
|
0.003
|
<0.001
|
<0.001
|
BW
|
0.003
|
0.001
|
<0.001
|
Preeclampsia
|
1.222
|
0.608
|
0.045
|
Preeclampsia
|
0.326
|
0.986
|
0.742
|
*Other variables controlled for in these models: Parity, Maternal BMI.
|
LV mass/vol
|
398
|
BW
|
0.005
|
0.001
|
<0.001
|
140
|
BW
|
0.006
|
0.003
|
0.060
|
*Other variables controlled for in these models: Maternal BMI, Insulin use.
|
|
|
ivs_d
|
402
|
BW
|
<0.001
|
<0.001
|
<0.001
|
145
|
BW
|
0.001
|
<0.001
|
<0.001
|
APGAR1
|
-0.095
|
0.024
|
<0.001
|
APGAR1
|
-0.002
|
0.053
|
0.965
|
DM (Insulin)
|
0.399
|
0.171
|
0.020
|
DM (Insulin)
|
1.015
|
0.330
|
0.003
|
*Other variables controlled for in these models: Maternal BMI.
|
|
|
ivs_s
|
401
|
BW
|
0.001
|
<0.001
|
<0.001
|
146
|
BW
|
0.001
|
<0.001
|
<0.001
|
preeclampsia
|
0.175
|
0.209
|
0.403
|
preeclampsia
|
0.546
|
0.322
|
0.093
|
*Other variables controlled for in these models: Maternal BMI, DM, Insulin use.
|
lvid_d
|
402
|
sex
|
-0.644
|
0.202
|
0.002
|
145
|
sex
|
-0.833
|
0.369
|
0.025
|
BW
|
0.002
|
<0.001
|
<0.001
|
BW
|
<0.001
|
<0.001
|
0.576
|
APGAR1
|
0.161
|
0.066
|
0.014
|
APGAR1
|
-0.044
|
0.092
|
0.638
|
preeclampsia
|
0.700
|
0.426
|
0.101
|
preeclampsia
|
-1.101
|
0.571
|
0.056
|
*Other variables controlled for in these models: Maternal BMI, meanbp.
|
Lvid_s
|
407
|
sex
|
-0.345
|
0.159
|
0.030
|
148
|
sex
|
-0.635
|
0.308
|
0.041
|
BW
|
0.001
|
<0.001
|
<0.001
|
BW
|
<0.001
|
<0.001
|
0.913
|
preeclampsia
|
0.170
|
0.319
|
0.596
|
preeclampsia
|
-1.146
|
0.456
|
0.013
|
*Other variables controlled for in these models: None
|
lvpwd
|
402
|
BW
|
0.001
|
<0.001
|
<0.001
|
145
|
BW
|
<0.001
|
<0.001
|
0.003
|
DM (Insulin)
|
0.257
|
0.137
|
0.061
|
DM (Insulin)
|
-0.031
|
0.201
|
0.877
|
*Other variables controlled for in these models: Maternal BMI, Preeclampsia
|
lvpws
|
405
|
BW
|
0.001
|
<0.001
|
<0.001
|
147
|
BW
|
<0.001
|
<0.001
|
0.011
|
*Other variables controlled for in these models: Maternal BMI, Preeclampsia.
|
FS
|
406
|
BW
|
<0.001
|
0.001
|
0.423
|
148
|
BW
|
<0.001
|
0.001
|
0.968
|
Maternal BMI
|
0.065
|
0.038
|
0.086
|
Maternal BMI
|
0.135
|
0.059
|
0.025
|
*Other variables controlled for in these models: MOD.
|
IVS/LVPW
|
|
DM (Insulin)
|
0.025
|
0.066
|
0.703
|
145
|
DM (Insulin)
|
0.236
|
0.107
|
0.030
|
preeclampsia
|
0.078
|
0.059
|
0.185
|
preeclampsia
|
0.178
|
0.096
|
0.066
|
*Other variables controlled for in these models: Birth weight
|
Abbreviations: LV mass, Left Ventricular mass; LVmass/Vol, Left Ventricular mass to Volume ratio; IVS_d, Inter-Ventricular Septal thickness during diastole; IVS_s, Inter-Ventricular Septal thickness during systole; LVID_d, Left Ventricular Internal Dimension during diastole; LVID_s, Left Ventricular Internal Dimension during systole; LVPWd, Left Ventricular Posterior Wall thickness at end of diastole; LVPWs, Left Ventricular Posterior Wall thickness at end of systole; FS, Shortening Fraction; SE, Standard Error; GA, Gestational Age; BW, Birth Weight; BMI, Body Mass Index; DM, Diabetes Mellitus; DM (insulin), Diabetes Mellitus controlled by insulin medication ; APGAR 1, APGAR score at 1 minute ; meanBP, mean Blood Pressure; MOD, Mode Of Delivery.
The analysis of ASH yielded the most interesting results. It was observed that the odds of developing ASH in LGA infants were the same as AGA infants (OR=1, p<0.001). Additionally, the odds of developing ASH decreased with an increase in GA (OR=0.79, p<0.001). The remaining variables can be referred to in Table 5.
Table 5. Results of binary logistic regression showing the association between ASH (dependent variable) and perinatal factors (independent variable) in infants.
ASH
|
Observations: 553
|
Variable
|
Odds Ratio
|
SE
|
z-value
|
P-value
|
GA
|
0.79
|
0.06
|
-3.40
|
<0.001
|
BW
|
1.00
|
0.00
|
3.30
|
<0.001
|
APGAR1
|
0.90
|
0.05
|
-1.87
|
0.06
|
meanbp
|
1.02
|
0.01
|
1.71
|
0.09
|
Intercept
|
446.41
|
1267.73
|
2.15
|
0.03
|
Abbreviations: ASH, Asymmetric Septal Hypertrophy; SE, Standard Error; GA, Gestational Age; BW, Birth Weight; APGAR1, APGAR score at 1 minute; meanbp, mean blood pressure.