Discussion
Diabetes is the most common endocrine disorder during pregnancy.
Fetal-maternal morbidity is significantly reduced if diabetes is
diagnosed and precautions are taken. In this study, we evaluated fetal
EFT, which is a candidate to be a new marker to determine maternal
diabetes status in pregnancy. Unlike other studies in the literature, we
took one step further by separately evaluating fetal EFT in pregnancies
with both PGDM and GDM. Cut off values of EFT for the diagnosis of
diabetes risk were also identified.
It is known that epicardial adipose tissue has important paracrine and
metabolic effects. EFT is closely related to excess fat tissue in the
body. However, the main reason for EFT to be a reliable marker is that
EFT is not affected by changes in subcutaneous and muscle
tissues12. Previous studies in adults revealed that
increase in EFT is an important diabetic marker and may be a determinant
in terms of morbidities that may occur due to
diabetes22. Furthermore, a close relationship was
found between EFT and metabolic syndrome, obesity and insulin
resistance8.
Some recent studies investigated whether use of EFT as a marker in
adults could be beneficial for pregnant women and their fetuses. In the
study by Jackson et al., EFT of fetuses was compared between diabetic
and non-diabetic pregnant women16. They found that
fetal EFT was statistically significantly higher in diabetic pregnant
women (EFT mean=1.43mm). However, in their studies, diabetic pregnancies
were not grouped and evaluated as PGDM and GDM. Similarly, we found that
EFT of fetuses was higher in diabetic pregnant women compared to
non-diabetic pregnancies. Unlike to other studies, we also demonstrated
that fetal EFT was significantly higher in pregnancies with PGDM
compared to those with GDM.
In our study, we found that maternal age and values of HbA1C, AC and DVP
were significantly higher in PGDM and GDM groups. Although maternal age
was not significantly different between GDM and control groups, pregnant
women with PGDM were significantly older than both GDM and control
groups. We’ve also oberved a statistically significant correlation
between fetal EFT and maternal age. Most of the previous studies did not
explore any significant relationship between fetal EFT and maternal
age15,17,18. Only in the study of Akkurt et al.,
maternal age was found to be greater in diabetic pregnant women as in
our study6. The reason for higher maternal age in
pregnant women with PGDM may be explained by the desire of women with
existing diabetes to postpone their pregnancy to a later age. Another
explanation is that these women with PGDM are more likely suffer from
comorbidities which increase the risk of failure to conceive.
Since diagnosis of PGDM was established at the first trimester of
pregnancy in our study population, OGTT was performed to GDM and control
groups. We found that fetal EFT was significantly positively correlated
with every parameter of OGTT values (fasting, 1st hour
and 2nd hour). Although this correlation was weak for
FPG level, it was strong for 1st hour and
2nd hour glucose levels after OGTT. Similarly, Yavuz
et al. compared and correlated fetal EFT values and blood glucose
measurements obtained during a 75-gr OGTT18. In their
study, fetal EFT had a significantly weak and moderate correlation with
1st hour and 2nd hour glucose level
after controlling for maternal age, gestational age, body mass index and
abdominal circumference. However, when only GDM pregnancies were
included, fetal EFT was positively and moderately related to 2-h glucose
values18. Furthermore, we also explored that there was
a significant and moderate positive correlation between fetal EFT values
and maternal HbA1c levels. Confirming our results, Aydin et al. observed
a strong positive correlation between fetal EFT and maternal HbA1C
values17. In this study, fetal EFT was found to be
significantly associated with adverse perinatal outcomes of diabetes
including macrosomia and polyhydramnios. Fetal EFT was significantly
positively correlated with fetal AC and DVP of amniotic fluid volume.
Akkurt et al. were also demonstrated a higher fetal EFT in pregnancies
with GDM compared to normal pregnancies6. Unlike from
our study, Aydin et al. were determined a positive correlation between
fetal EFT and DVP values instead of AC values17.
However, they compared fetal EFT values only between GDM and control
groups. Among all three groups in our study, HbA1c, AC and DVP values
were significantly higher in PGDM group followed by GDM group. These
findings provide strong evidence that high EFT value is a fetal
reflection of poorly controlled maternal glucose level.
In this study, we investigated the diagnostic value of fetal EFT on
diabetic pregnancies and determined cut-off EFT values for both PGDM and
GDM. Until recently, there are two studies in the literature that
calculate which values of fetal EFT can be used as cut-offs for diabetes
in pregnancy. The first of these was done by Akkurt et al. in
20186. The recommended equation of the mentioned study
for calculation of EFT in pregnant women with diabetes was EFT = 0.05 x
gestational age + 0.07 (R2 = 0.70). In our study, we did not calculate
the equation related to the gestational week. Instead, we evaluated EFT
of all pregnant women in the same week to ensure standardization.
Another study in the literature was performed by Aydin et al. in
202015. They conducted a study to determine the
relationship between fetal EFT and weight. Aydin et al. stated that a
cut-off fetal EFT value above 1.38 mm was predictive for diagnosis of
fetuses with large for gestational age with a sensitivity of 94.4% and
a specificity of 97.6%15. All patients in that study
were evaluated at 22 weeks of gestation, but diabetic pregnancies were
not grouped as PGDM and GDM. In the present study, cut-off EFT values
for pregnant women with PGDM and GDM were 1.30 mm (sensitivity 97.3%,
specificity 98.2%) and 1.27 mm (sensitivity 94%, specificity 95%),
respectively. Both EFT cut-off values of our study were found to be
lower than the values calculated by Aydin et al. and Akkurt et
al.6,17 We believed that the reason for this
difference is related to patient selection criteria and classification
of study population rather than measurement technique of fetal EFT.