Correlation between 25-hydroxy vitamin D levels and COVID-19 severity in pregnant women: a cross-sectional study.

Objective: To evaluate the relationship between 25-hydroxy vitamin D (25(OH)D) levels and disease severity in hospitalized COVID-19 positive pregnant women.

Methods: The COVID-19 (+) pregnant women (confirmed by PCR test) were classified as asymptomatic, mild symptomatic, and severe disease according to their symptoms and laboratory results. Severe COVID-19 criteria were respiratory symptoms and/or findings. The following laboratory results were considered as poor prognostic factors: the number of lymphocytes <800/µl and/or CRP value >10 times the upper limit of the normal range and/or ferritin value >500 ng/ml and/or D-Dimer value >1000 µg/l. The patients were divided into two groups; asymptomatic or mild symptomatic group (Group 1), and severe disease and/or poor prognostic factor group (Group 2). The 25(OH)D levels were compared between groups. ROC curve analysis was used to analyze the cutoff value for vitamin D to predict the severity of COVID-19.

Results: 25(OH)D levels were found to be statistically significantly lower in group 2 (15.5 (10.25) ng/ml in Group 1, 13 (12) ng/ml in Group 2,  = .010). The 25(OH)D level under 14.5 ng/ml was associated with severe COVID-19 and/or poor prognostic factors ( = .010). The risk of severe COVID-19 and/or having poor prognostic factors was 1.87 times higher among pregnant women who had 25(OH)D levels below 14.5 ng/ml. This value was found to have 54.1% sensitivity and 61.3% specificity in predicting severe COVID-19 and/or poor prognostic laboratory findings in pregnant women.

Conclusion: There is a relationship between vitamin D status and the severity of COVID-19 in pregnant women. During the pandemic period, vitamin D supplementation for pregnant women should gain more importance.