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J. Perinat. Med. 33 (2005) 336–339 • Copyright
by Walter de Gruyter • Berlin • New York. DOI 10.1515/JPM.2005.060

Nomogram of the fetal gastric size development in normal

pregnancy

Kumral Kepkep, Yildiz A. Tuncay*, Gökhan Introduction

Göynümer and Gamze Yetim
Fetal stomach is the widest part of gastrointestinal sys-
SSK Göztepe Educational Hospital, Clinic of
tem. Fetal digestive tract plays a major role in the amni-
Gynecology and Obstetrics, Istanbul, Turkey
otic fluid circulation. Amniotic fluid swallowed by the
fetus initially enters the stomach and is subsequently
absorbed or transferred to the intestine and then returned
Abstract
to the amniotic fluid by the fetal micturition. Therefore,
Objective To construct an ultrasonographic nomogram abnormal conditions of the digestive tract may alter both
of the fetal gastric size with gestational age in normal amniotic fluid volume and gastiric volume. When filled
singleton pregnancy. with amniotic fluid, the fetal stomach appears as an
Patients and methods Out of 17 000 outpatient preg- echolucent organ on ultrasonography in the left upper
nant women who were admitted to our hospital, a total quadrant of the fetal abdomen w6x. The earliest sonogra-
of 250 fetal measurements were randomly collected from phic visualization of the fetal stomach is possible at
routine ultrasonographic examinations performed in 9 weeks of gestation and measurements of gastric size
women with normal singleton pregnancies between 13 are possible after 10 weeks’ gestation. The characteristic
and 39 weeks of gestation without medical or obstetric anatomy of the stomach, including the greater curvature,
complications. None of the fetuses had detectable fetal the lesser curvature, the fundus, the body, and pylorus,
malformations. The ultrasound plane which provided the may be detected at about 14 weeks’ gestation w2, 3x.
largest stomach area including the pylorus on a trans- The stomach is investigated routinely by ultrasonog-
verse and oblique section was used for definition and raphy. However, not only sonographic visualization of the
measurement of gastric longitudinal dimensions. The fetal stomach with normal configuration and localization,
transverse section at the center of the gastric corpus was but also the motility of fetal swallowing must be evalu-
used for transverse and anteroposterior dimensions. ated w4, 7x. Gastric size was identified as a potential
Biparietal diameter, abdominal circumference were also marker for congenital malformations of the fetal digestive
measured. tract and the motility of the gastrointestinal tract w12x.
Results The fetal gastric longitudinal, anteroposterior Several studies investigated the developmental profile
and transverse dimensions were significantly correlated of the stomach in the human fetus at advanced stages
with gestational age (r values 0.74, 0.71, and 0.49, of gestation and documented growth charts for fetal
respectively). There was a significant correlation meas- stomach dimensions throughout pregnancy. They report-
urements between gastric size and AC. The correlation ed that the fetal stomach dimensions and volume
coefficents for gastric dimensions with gestational age increase linearly with gestational age w3, 8, 12x.
was larger than those with AC (rs0.732, 0.702 and We aim to construct an ultrasonographic nomogram of
0.489, respectively). The ratio of fetal gastric anteropos- gastric size in the developing human fetus between 13
terior dimension to fetal AC was a constant parameter and 39 weeks of gestation and to evaluate the usefulness
calculated as 1/3. of the standard in assessing growth of fetal gastric size
Conclusion Fetal stomach dimensions in normal preg- in normal pregnancy.
nancy correlate with gestational age and nomogram of
fetal gastric development appears to be useful in assess-
ment of normal fetal growth. Patients and methods
Keywords: Human fetal stomach; ultrasonography; fetal Of 17 000 pregnant women admitted to our hospital for routine
gastric size. antenatal control from May, 2002 to January, 2003, 250 cases
with normal singleton pregnancies between 13 and 39 weeks’
*Corresponding author: gestation were randomly assigned to receive ultrasonographic
¸
Yildız Ayhan Tuncay, MD visualization of the fetal stomach. None of the fetuses had sig-
F Kerim Gökay cad. nificant oligohydramnios, polyhydramnios, macrosomia, growth
Ortabahar sok. No: 2/25
restriction or detectable fetal malformations. The mothers had
Göztepe/Istanbul/Turkey 34730
Tel.: q90 216 566 48 48 no medical or obstetric complications (e.g., hypo- and hyper-
Fax: q90 216 566 82 19 thyroidism, diabetes mellitus, hypertension) and the pregnancies
E-mail: ertuncaytr@yahoo.com were uneventful. The gestational age was estimated from last

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Kepkep et al., Nomogram of the fetal gastric size 337

Figure 1 (a) Diagram representing the method of measurements of the fetal gastric size. (b) Ultrasonographic appearance of lon-
gitudinal (on left) and tranverse section (on right) of the fetal stomach.

menstrual period and ultrasonographic measurements of the (range, 1–5) and a median parity was 0.9"0.8 (range,
crown-rump length before 12 weeks. Biparietal diameter (BPD), 0–3). The gestational age was 13 to 39 weeks with a
abdominal circumference (AC) were also measured. The ultra- median of 26.14"6.5.
sonographic equipment was the Siemens Sonoline scanner with
Measurement of fetal gastric longitudinal dimension
a linear and convex array transducer of 3.5 MHz.
was significantly (Ps0.001) correlated with gestational
The fetal stomach, i.e., the largest area including the pyloric
site on a transverse or oblique section, was observed in the left
age (rs0.736) and AC (rs0.732). There were positive
upper quadrant of the fetal abdomen on routine ultrasonograph- correlations between fetal gastric transverse dimension
ic examination. The longitudinal dimension of the stomach was and gestational age (rs0.495) or AC (rs0.489),
measured. Transverse and anteroposterior dimensions were (P-0.01). Fetal gastric anteroposterior dimension was
measured at the transverse section of the gastric corpus center also significantly correlated (P-0.01) with gestational
(Figure 1a and 1b). In cases where the fetal stomach area was age (rs0.707) and AC (rs0.702). In addition to these cal-
visible, we measured the dimensions at least twice and recorded culations, we found a constant parameter of 1/3 as the
the largest measurement. In cases where the fetal stomach area ratio of fetal gastric anteroposterior dimension to fetal
was not immediately visible, we performed at least two more AC.
measurements at 15–30 min intervals and recorded the meas-
We constructed a nomogram for fetal gastric size
urements where applicable. When these repeat exams consis-
dimensions measurements "2 SD by gestational age
tently failed to visualize the fetal stomach even after the third
observation, we repeated ultrasonographic screening on another with (bi-weekly intervals; Table 1). The fetal gastric size
day. All measurements were performed by one observer. dimensions linearly increased with gestational age (Fig-
Statistical analyses were performed with SPSS for Windows ure 2).
(SPSS 10.0; SPSS Inc, Chicago, IL). Descriptive statistics are
reported as mean and "SD, and percentage; probability values
of -0.05 were considered to indicate a statistically significant
difference between means. Statistical comparisons were per- Discussion
formed by a one-way analysis of variance (ANOVA), followed by
Student t test. Pearson correlation coefficients were used for The developmental profile of the human fetal stomach
gastric size dimensions with gestational age and AC. was investigated using real-time ultrasonography.
Growth charts for fetal stomach dimensions have been
previously described and reported that the fetal stomach
Results is an index, reflecting the physical and pathological con-
dition in the digestive tracts. Some studies also reported
A total of 250 patients participated in our prospective prognostic significance of the absent fetal stomach in
study. The mean maternal age was 25.74"4.1 years ultrasonography w1, 2, 5, 7, 8x. Fetuses with persistently
(range, 18–40 years). The mean gravidity was 2.0"0.9 nonvisualized stomachs have an increased incidence of

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338 Kepkep et al., Nomogram of the fetal gastric size

Table 1 Nomogram of fetal gastric size dimension including mean"SD according gestational age.

Gestational n Longitudinal Transverse Anteroposterior

age dimension (mm) dimension (mm) dimension (mm)

13–15 10 6.0"2.5 3.9"2.2 3.5"1.9

16–18 20 10.6"4.8 6.1"3.4 8.7"6.3
19–21 36 11.9"5.5 8.3"5.2 10.8"4.9
22–24 48 16.6"9.4 9.1"5.0 12.5"7.2
25–27 32 19.6"12.4 8.5"4.1 15.8"11.2
28–30 43 22.3"15.4 12.8"14.4 20.9"13.3
31–33 16 26.3"18.5 10.8"6.4 19.3"16.9
34–36 34 26.7"16.5 12.5"6.9 23.4"16.9
37–39 11 30.8"12.4 12.1"2.2 26.8"1.9

structural defects and amniotic fluid (AF) abnormalities. between 18 and 39 weeks’ gestation and constructed a
Brumfield et al. w2x reported 26 fetuses with a persistent growth chart for a standardized fetal stomach dimension
nonvisualized stomach that had structural anamolies in throughout pregnancy. They found that the fetal gastric
65% and a 29% survival rate. 35% of fetuses with no area was significantly correlated with gastric volume
structural defect had abnormal AF volume, and the over- (rs0.91) and gestational age (rs0.74). However, the cor-
all perinatal survival was only 50%. However, no accept- relation coefficient for gastric area with gestational age
ed standards exist for fetal gastric size to evaluate was smaller than those for the BPD (rs0.97) and abdom-
congenital abnormalities of the gastrointestinal tracts inal transverse area (rs0.97). In our study there was also
w12x. a positive correlation between the fetal gastric dimension
We constructed a nomogram for a standardized fetal and gestational age and AC. In addition, the correlation
gastric size dimensions throughout pregnancy. In our coefficient for all gastric dimensions with gestational age
study, there was a significant correlation between fetal were larger than those for the AC. Sase et al. w12x sug-
gastric size dimensions and gestational age or AC. In gested that the gastric area ratio, defined as the ratio of
other words, fetal gastric size dimensions increased lin- the fetal gastric area divided by the area of the fetal
early from 13 to 39 weeks’ gestation as the AC increases abdominal transverse section, is a preferable method to
with gesatational age (P-0.01). Goldstein et al. w3x evaluate the gastric size of the fetus because the gastric
reported a nomogram including mean and "SD values area ratio is constant during pregnancy. Moreover, they
of fetal gastric size dimensions (longitudinal, transverse reported that the standard deviation of the normal gastric
and anteroposterior) by gestational age in 152 fetuses measurements increases markedly with advanced ges-
between 9 to 40 weeks of gestation. Similar to our find- tational age thus limiting the ability to use abnormalities
ing, they found a positive correlation between fetal gas- of stomach size in cases with congenital digestive tract
tric dimensions and gestational age. anomalies, particularly in mid to late gestation.
Sase et al. w12x collected a total of 386 fetal gastric In the study of Nagata et al. w9x, measurements of the
measurements from routine ultrasonographic examina- fetal gastric maximal longitudinal and anteroposterior
tions of women with normal singleton pregnancies dimensions were obtained by real-time ultrasound imag-

Figure 2 Correlation between fetal gastric size dimensions and gestational age.

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Kepkep et al., Nomogram of the fetal gastric size 339

ing in 618 cases between 16 and 41 weeks of gestation. ratio of fetal gastric anteroposterior dimension to fetal
They found 4 phases of gastric function in the developing AC. We suggest that this ratio may be a new parameter
human fetus, divided by 3 critical points of gestational in assessing the fetal stomach.
age. The fetal gastric dimensions increased linearly from In conclusion, the fetal gastric size in normal pregnan-
16–17 to 26–27 weeks’ gestation (phase 1), are constant cy increases linearly with gestational age and AC. A
from 26–27 to 32–33 weeks’ gestation (phase 2), nomogram of fetal gastric growth appears to be useful
increase again from 32–33 to 36–37 weeks’ gestation in the assessment of the normal developing fetus. The
(phase 3), and finally decreased term (phase 4). We found ratio of 1/3 describing the ratio between fetal gastric
a linear correlation between fetal gastric size and ges- anteroposterior dimension to fetal AC is a new constant
tational age regardless of these developmental intervals. for evaluating fetal stomach in normal pregnancy and
We believe that the changes in fetal stomach size might identification of congenital structural defects.
be due to gastric motility, and therefore, these develop-
mental intervals were not assessed.
Previous studies reported that non-visualization of the Acknowledgement
fetal stomach by ultrasonography is a potential marker
for congenital malformations of the fetal digestive tract This report was presented as a poster presentation at the ‘‘14th
and other associated structural defects, and a poor out- World Congress on Ultrasound in Obstetrics and Gynecology,’’
come. McKenna et al. w5x investigated fetuses from August 31–September 4, 2004, in Stockholm, Sweden.
19 weeks of gestation to term using ultrasonography and
emphasized the prognostic significance of non-visuali-
zation of fetal stomach. They reported that there are References
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When we constructed our nomogram of fetal gastric
size dimensions in the developing human fetus, we cal- Received December 6, 2004. Revised February 17, 2005.
culated a constant of 1/3 at each gestational age as the Accepted April 1, 2005.

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