Discussion:
Main Findings:
Our research is consistent with what has been previously published in
non-pregnant populations infected with COVID-19. In our report, pregnant
patients with transaminitis were generally sicker and more likely to
require oxygen supplementation, intubation and ICU admission. A large
meta-analysis found that ICU admission was predicted by elevations in
ALT, AST, leukocyte count, lactate dehydrogenase (LDH) and
procalcitonin.5 LDH was also seen in other studies of
non-pregnant patients to be elevated with severe COVID-19 infections,
serving as a predictor of poorer outcomes.6,7 While we
did not evaluate the predictive value of LDH in this study, it would be
an interesting follow-up to explore the predictive power of LDH in
pregnant populations. Current studies also find that elevations in ALT
and AST were more likely to be found in patients with severe COVID-19
infection compared to mild cases, suggesting that impaired hepatic
function is likely representative of a sicker
patient.6
Few studies have looked at liver injury in pregnant patients with
COVID-19. In one study, a preeclampsia-like syndrome induced by COVID-19
was described in pregnant patients with severe COVID pneumonia, causing
an elevation of liver enzymes to twice the normal
concentrations.8 Another study examining clinical
characteristics of 118 pregnant patients in Wuhan, China found 66.7% of
patients with severe COVID-19 to have elevated AST compared to 16.5% of
those without severe disease. In addition, they found 44.4% of patients
with severe COVID-19 to have elevated ALT compared to 20.2% of those
without severe disease.9 In contrast, another study in
Wuhan looked specifically at characteristics of pregnant patients with
COVID-19 and liver injury and found no correlation with severity of
COVID-19.10 Specifically, they found 29.7% of the
patients to have transaminitis and found no changes in this group of
patients in regard to the maternal or neonatal outcomes. The only
significant finding was elevated inflammatory markers of procalcitonin
and IL-6 in the transaminitis group, suggesting that pregnant women with
COVID-19 and liver injury have worse inflammation when compared to those
without liver injury. Although not all outcome findings were consistent,
both our study and prior studies suggest the importance of identifying
transaminitis in pregnant patients infected with COVID-19, either to
identify potential worse outcomes or inflammation.
There are many theories proposing how COVID-19 may cause transaminitis.
These include the possibility of direct insult of hepatocytes by the
virus or by drug toxicity from interventions given to treat
COVID-19.11,12 In contrast, other studies believe it
is through activation of the ACE2 on cholangiocytes which indirectly
affect hepatocytes.13 Earlier studies on other viruses
suggest that transaminitis may not be due to direct viral insult, but
rather due to the activation of the body’s own innate immune response as
is likely the case with Influenza A and H1N1.12 While
the exact etiology of the damage remains unknown, 2-11% of patients
with COVID-19 are found to have coinciding liver abnormalities and
14-53% of cases are noted to have elevated AST and
ALT.11 Additionally, patients admitted to the ICU
typically incur higher rates of liver dysfunction and elevated
transaminases when compared to patients who did not not require as high
a level of care.11,15 Finally, patients with abnormal
liver function have been seen to have longer length hospital stays,
which has significant clinical implications.16
Strengths:
A strength of this study is that it adds another perspective to limited
previous data on pregnant patients with COVID-19 and associated
transaminitis.
Limitations:
The main limitations of our study include small sample size and the
single-center location, which may limit generalizability. Additionally,
patients who were less than 23 weeks of gestation were seen in the
emergency department and not all were routinely tested for COVID-19. In
addition, hepatic function panels were not routinely done in all
admitted patients, which further limited our data and the number of
patients who were included in the study. Finally, our hospital is a
transfer center and thus not all of the patients deliver at our
institution and delivery information could not be consistently obtained
from other institutions, thus limiting our neonatal outcome data.