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.