Objectives: to assess the effect-related inflammatory and coagulation biomarkers in pregnancy and their connection with the coronavirus disease of 2019 (COVID-19). Methods: A prospective case-control study was carried out among normal third-trimester pregnant women admitted to the labor room of Dr. Soetomo General Academic Hospital between January until June 2021. Two classified groups of patients were established in accordance with the result of the RT-PCR test. Demographic, clinical and laboratory results data of the two groups were collected and compared. Results: Platelet-to-lymphocyte ratio (PLR) was shown to be the only significant biomarkers found in the expectant with COVID-19, which was 35.8% higher compared to the ones free of COVID-19 [212.25 (157.57-269.37) vs 156.29 (128.55-195.3), p=0.048]. Logistic regression analysis of PLR between groups showed that the level of PLR was an independent factor in pregnant women with COVID-19 (OR 4.483, 95%CI 1.262-15.926). The ROC analysis showed that the PLR cut-off among the expectant was 171.335, with both sensitivity and specificity were 66.7% (p=0.021). The result shows no significant differences in leukocyte count, absolute neutrophils – lymphocyte count and percentage, neutrophil-to-lymphocyte ratio (NLR) and D-Dimer level between pregnant women infected with COVID-19 and free of the virus (p>0.05). Conclusion: Intriguingly, physiological adaptation during the course of the third trimester of pregnancy found no difference in most inflammation and coagulation markers, both in the condition of infected COVID-19 or not. The evidence from this single-centre study supports the viewpoint that elevated PLR was associated with independent biomarkers and thereby might be helpful to detect expectant with COVID-19.