PATTERNS OF FETAL GROWTH IN AN ASIAN INDIAN COHORT
Barbara V Parilla, MD, Colin McCulloch, BA, Suela Sulo, MSc,
Leticia Curran RDMS, Diana McSherry, PhD
Division of Maternal- Fetal Medicine and the James R. & Helen D. Russell Institute for Research &
Innovation, Advocate Lutheran General Hospital, Park Ridge, Illinois and Digisonics, Inc, Houston Texas
Abstract:
Objective :To evaluate the fetal growth pattern in a cohort of Indian Asian women using
standard growth curves. Our hypothesis is that a much higher percent of these fetuses
are labeled as small for gestational age (SGA) than would be expected from a normally
distributed population. We also reviewed the outcomes of neonates that were
designated as SGA fetuses to see if there was any associated neonatal morbidity.
GA (wks)
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Method: Our ultrasound database was queried for Asian Indian patients referred to our
Maternal-Fetal Medicine practice for evaluation of fetal growth over the last 2 years. The
primary outcome was percent of fetuses with AC or overall estimated fetal weight <10%.
Data abstracted included indication for the US, all the individual US parameters, EFW,
and the corresponding percentiles. Neonatal data included GA at delivery, birth weight,
length, head circumference, and AC when available. NICU admission, indication, and
length of stay were also recorded. This study was approved by our facility’s IRB.
Results: 207 patients and all their US reports were reviewed; 48/207 (23%) of these
fetuses had an AC reported as <10% using Hadlock. The AC measurement on average
was 2 cm below the expected mean in the third trimester. The EFW was reported as
< 10% in 44/207 (21%) of this cohort, with the AC as the main contributing factor. Of the
48 neonates identified as SGA prenatally, 9 were admitted to the NICU: 2 neonates had
congenital heart disease, one set of twins at 33 weeks, 1 infant with a pneumothorax,
and 2 with hypoglycemia, one of which was SGA. The total number of SGA neonates
(BW < 2500g) born to this cohort of Asian Indian women was 22/207 (10.6%) which
would be expected in a normally distributed population.
Conclusion: Fetal size, particularly the AC measurement, is smaller than expected in
this Indian Asian cohort, with the majority of these neonates appropriate for gestational
age at birth. A tailored fetal growth curve should be utilized in this population.
Introduction:
Research into the developmental origins of health and disease has focused attention on
fetal development as a determinant of future health. Size and body proportions at birth
predict short and long-term outcomes, from infant mortality through childhood growth
and cognitive ability to diseases in adult life such as type 2 diabetes and cardiovascular
disease. Indian neonates are among the smallest in the world; mean full-term birth
weight is 2.6 to 2.9 kg compared with 3.5 to 3.7 kg for white populations in high income
countries. Asian Indian women are frequently referred to our Maternal-Fetal Medicine
practice to evaluate their fetuses for possible growth restriction. Most commonly, this is
due to a lagging abdominal circumference (AC).
Results:
Table 1. Pune reference table at one week intervals
Figure 1. Comparison of Pune and Hadlock curves
The Pune curves are not superimposable on modified Hadlock curves, suggesting the
growth patterns are different.
A lagging fetal AC frequently leads to serial ultrasounds to assess fetal growth, and also
results in increased antenatal fetal surveillance. Non-stress testing and biophysical
profiles can have false positive results, which can lead to preterm delivery and
iatrogenic prematurity. The purpose of this study was to evaluate the fetal growth
pattern in this cohort of women using our commonly used growth curves (Hadlock
1984). Our hypothesis is that a much higher percent of these fetuses are labeled as
growth restricted or small for gestational age (SGA) than would be expected from a
normally distributed population. In addition, we reviewed the outcomes of neonates that
were designated as growth restricted fetuses to see if there was any associated
neonatal morbidity. Lastly, we compared our standardized fetal curves (Hadlock 1984)
with recently published fetal biometric data of a rural Indian Cohort (Pune study) to see
if there was a better correlation between the fetal biometry of the rural Indian cohort,
and our neonatal outcome.
GA (wks)
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
10%
3.8
4.93
6.06
7.19
8.31
9.42
10.53
11.62
12.7
13.76
14.81
15.84
16.84
17.83
18.78
19.71
20.6
21.46
22.29
23.1
23.89
24.66
25.41
26.16
26.9
27.64
28.38
29.12
29.86
30.6
31.34
10%
0.34
0.65
0.96
1.27
1.58
1.89
2.19
2.5
2.8
3.1
3.4
3.69
3.97
4.25
4.51
4.76
5
5.22
5.43
5.63
5.82
6
6.17
6.34
6.5
6.66
6.82
6.98
7.14
7.3
7.45
AC (cm)
50%
5
6.12
7.24
8.36
9.47
10.59
11.69
12.8
13.9
14.99
16.08
17.15
18.21
19.24
20.26
21.24
22.2
23.12
24.02
24.89
25.74
26.57
27.38
28.19
29
29.8
30.61
31.41
32.22
33.02
33.83
FL (cm)
50%
0.64
0.95
1.26
1.57
1.88
2.19
2.49
2.8
3.1
3.4
3.7
3.99
4.27
4.54
4.81
5.06
5.3
5.52
5.73
5.93
6.12
6.3
6.47
6.64
6.8
6.96
7.12
7.27
7.42
7.57
7.72
90%
6.3
7.41
8.51
9.62
10.73
11.85
12.96
14.08
15.2
16.33
17.45
18.57
19.68
20.77
21.84
22.89
23.9
24.88
25.83
26.75
27.65
28.53
29.39
30.25
31.1
31.95
32.79
33.64
34.48
35.33
36.17
GA (wks)
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
GA (wks)
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
90%
0.94
1.25
1.56
1.87
2.18
2.49
2.79
3.1
3.4
3.7
4
4.29
4.57
4.84
5.11
5.36
5.6
5.82
6.04
6.23
6.42
6.6
6.77
6.94
7.1
7.26
7.41
7.56
7.71
7.85
7.99
10%
1.13
1.52
1.9
2.28
2.66
3.03
3.4
3.75
4.1
4.44
4.76
5.07
5.37
5.65
5.92
6.17
6.4
6.61
6.81
6.99
7.16
7.31
7.45
7.58
7.7
7.81
7.92
8.01
8.1
8.17
8.24
10%
4.34
5.79
7.23
8.66
10.08
11.48
12.85
14.19
15.5
16.77
17.99
19.17
20.29
21.36
22.37
23.32
24.2
25.01
25.75
26.43
27.06
27.63
28.16
28.65
29.1
29.52
29.91
30.26
30.58
30.86
31.11
BPD (cm)
50%
1.43
1.81
2.19
2.57
2.95
3.32
3.69
4.05
4.4
4.75
5.08
5.41
5.72
6.01
6.29
6.56
6.8
7.02
7.22
7.41
7.57
7.73
7.86
7.99
8.1
8.2
8.3
8.38
8.45
8.51
8.56
HC (cm)
50%
5.54
6.98
8.42
9.85
11.27
12.67
14.04
15.39
16.7
17.98
19.21
20.4
21.54
22.63
23.65
24.61
25.5
26.32
27.07
27.76
28.38
28.96
29.48
29.96
30.4
30.8
31.17
31.5
31.79
32.04
32.25
Methods:



This was a retrospective cohort study of Asian Indian patients referred to our
Maternal-Fetal Medicine practice for evaluation of fetal growth between January
2012 and April 2014. Our ultrasound database (Digisonics, Inc) was queried for
Asian Indian ethnicity. Because this demographic information is not reliably
recorded, we also chose to review the names and if needed photo ID’s of all
patients referred to our practice from two obstetricians in particular that care for
this population, for possible inclusion.
Table 2. Small for gestational age based on different criteria
90%
6.74
8.18
9.62
11.04
12.46
13.86
15.23
16.58
17.9
19.18
20.43
21.63
22.78
23.88
24.92
25.89
26.8
27.64
28.4
29.1
29.75
30.33
30.87
31.35
31.8
32.21
32.57
32.9
33.19
33.43
33.63
207 patients and all their US reports were reviewed. The most common indications for
the ultrasound examination were fibroids (50), advanced maternal age (39), screening
for fetal growth/ malformation (31), and gestational diabetes (7).
The mean maternal age was 32.7±5.2 (21-47). Nulliparous women made up 19.8% of
this cohort. 48/207 (23%) of these fetuses had an AC reported as <10% using the
equations of Hadlock. The AC measurement on average was 2 cm below the expected
mean in the third trimester. In addition, the EFW was reported as <10% in 44/207
(21%) of this cohort, with the AC as the main contributing factor.
180 patients (87%) delivered at term with a mean birth weight of 2920±2415 gm, and a
mean birth length of 47.6±8 cm. Of the 48 neonates identified as SGA prenatally, 9 were
admitted to the NICU.
The total number of SGA neonates (BW < 2500g) born to this cohort of Asian Indian
women was 22/207 (10.6%) which would be expected in a normally distributed
population.
Complete outcome data was available in 45/48 fetuses with an AC reported as <10%
using Hadlock’s formula. 19/45 (42%) of those neonates were labeled small for
gestational age (SGA) based on their birth weight. The remaining 26/45 (58%) neonates
were considered appropriate for gestational age (AGA).
SECONDARY ANALYSIS
We then went back to the US reports of those fetuses with an AC<10% based on
Hadlock’s formula, and compared those percentiles with those generated from the
Pune study, which reported fetal biometry in a rural Indian cohort (n=653) but only the
10th, 50th, and 90th percentile for 20, 28, and 36 weeks’ gestation were reported.
If data from a target study has the same growth pattern as the Hadlock standard, all the
data points will be superimposable on the same modified curve as the Hadlock mean for
that measurement. The Pune data did not fall on the same curves for these
measurements (Figure 1); thus the growth pattern in the Pune study is different than for
the Hadlock data.
Since the data points did not fall on the same modified curves, we could not use this
approach to fill in other points for the Pune data. Therefore, spline curves were
generated using the Pune data. Initial 12 week values from Hadlock Table III are
included for reference, but they do not influence the calculated data at gestational ages
within the Pune data range (Figure 2).
The spline curves fit the published Pune data very well, so we used these to generate a
Pune reference table at one week intervals (Table 1).
Only 6/19 (32%) neonates designated as SGA by birth weight had fetal AC
measurements <10% using the generated Pune table. Table 2 displays the different
criteria used for SGA in those neonates with complete outcome data.
Conclusions:
1.
In our study, fetal size, particularly the AC measurement, was smaller than
expected using the Hadlock curves in our Indian Asian cohort, with the majority
of these neonates appropriate for gestational age at birth.
2.
The Hadlock curves appear to overestimate an AC<10%, while the generated
Pune tables appear to underestimate SGA neonates based on an AC<10%.
3.
Our findings highlight the need for a tailored fetal growth curve to be utilized in
this population, in order to decrease unnecessary fetal testing and avoid
iatrogenic prematurity.
4.
Prospective, short and long term outcome data is needed in order to formulate
the best recommendations for pregnancy nutrition and weight gain in different
populations.
5.
The smaller fetal measurements obtained in the Pune cohort likely represents
both genetic variability and suboptimal nutrition. We are currently prospectively
collecting fetal measurements in our Indian Asian patients to generate a new,
more accurate assessment of fetal growth in this population.
References:
The fetal biometric data was abstracted from the obstetric ultrasound reports
viewed directly from our ultrasound database. Neonatal outcome data was
abstracted from the neonatal electronic medical record (EMR), which is linked to
the mother’s EMR in our system. The primary outcome was percent of fetuses
with AC or overall estimated fetal weight (EFW) <10%. Data abstracted included
maternal age, gravity, parity, indication for the US, all the individual US
parameters, EFW, and the corresponding percentiles. Neonatal data included
gestational age at delivery, birth weight, length, head circumference, and AC if
available. NICU admission, indication, and length of stay were also recorded.
This study was approved by the Advocate Health Care IRB.
Statistical analysis was performed using Microsoft Excel and SPSS for Windows,
version 22 (Chicago, IL). Descriptive statistics for continuous data (mean ±
standard deviation, and range) and categorical data (number and %) was
calculated on all patient characteristics. Spline curves were generated using a
Digisonics application.
90%
1.83
2.21
2.59
2.97
3.35
3.72
4.09
4.45
4.8
5.14
5.48
5.8
6.11
6.41
6.69
6.95
7.2
7.43
7.64
7.83
8.01
8.18
8.33
8.47
8.6
8.72
8.83
8.93
9.02
9.1
9.16
1. Pylipow M. Early postnatal weight gain, intellectual performance, and body mass index at 7 years of age in term
infants with intrauterine growth restriction. J Pediatr - 01-FEB-2009; 154(2): 201-6
SGA by birth weight
19
SGA by Hadlock
prenatal
SGA by Pune
prenatal
45
6
2. Tarry-Adkins JL. Mechanisms of early life programming: current knowledge and future directions. Am J Clin Nutr 01-DEC-2011; 94(6 Suppl): 1765S-1771S
3. Steculorum SM. Perinatal programming of metabolic diseases: role of insulin in the development of hypothalamic
neurocircuits. Endocrinol Metab Clin North Am - 01-MAR-2013; 42(1): 149-64
4. Practice Bulletin. Antepartum Fetal Surveillance. ACOG. Obstet Gynecol VOL. 124, NO.1, July 2014
5. Signore C, Freeman RK, Spong CY. Antenatal Testing – A Reevaluation: Executive Summary of a Eunice Kennedy
Shriver National Institute of Child Health and Human Development Workshop. Obstet Gynecol. Mar 2009; 113(3): 687–
701. doi: 10.1097/AOG.0b013e318197bd8a
6. Kinare AS, Chinchwadkar MC, Natekar AS, Coyaji KJ, Wills AK, Joglekar CV, et al. Patterns of Fetal Growth in a
Rural Indian Cohort and Comparison With a Western European Population.J Ultrasound Med 2010; 29:215-223.
Figure 2. Spline fit curves generated from Pune data
Spline curves were generated using the Pune data. The curves fit the published Pune
data very well. BPD is the 1st plot, HC is 2nd, AC is 3rd and FL is last.
7. Hadlock FP, Deter RL, Harris RB, Park SK. Estimating fetal age: computer-assisted analysis of multiple fetal growth
parameters. Radiology 1984; 152:497-501.
8. Olsen IE, Groveman SA, Lawson ML, Clark RH, Zemel BS. New Intrauterine Growth Curves Based on United
Stated Data. Pediatrics 2010; Vol 125 No.2:e214-e224. (DOI:10.1542/peds.2009-0913)
9. Saloman LJ, Bernard JP, Ville Y. Estimation of fetal weight: reference range at 20-36 weeks’ gestation and
comparison with actual birthweight reference range. Ultrasound Obstet Gynecol 2007; 29:550-555.
10. Mathai M, Thomas S, Peedocayil A, Regi A, Jasper P, Joseph R. Growth pattern of the Indian fetus. Int J
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