Effects of SARS-CoV-2 Variants on Maternal Infection and Severity: A Single-Center Experience

Background and aims Pregnant women are one of the vulnerable groups affected by COVID-19. With the mutation of the virus, the severity of the disease in this vulnerable group may vary in different waves of COVID-19 subtypes. The aim of this study is to define the demographic, clinical, laboratory, and mortality results of pregnant COVID-19 patients according to three time frames (March to December 2020, January to June 2021, and July to November 2021). Materials and methods The data of patients admitted to the ICU between March 23, 2020, and November 30, 2021, were retrospectively scanned. Pregnant patients with SARS-CoV-2 PCR test positivity or pregnant patients with COVID-19 who have a negative PCR test but symptoms of COVID-19 and radiological findings consistent with COVID-19 on thorax CT who need intensive care were included in the study. The patients were divided into three groups according to the dates when the Ministry of Health of the Republic of Turkey reported the variants of COVID-19 in Turkey. The nonvariant type was dominant in the first period (March to December 2020), alpha and beta variants were dominant in the second period (January to June 2021), and the delta variant appeared in the last period (July to November 2021). Demographic, clinical, and laboratory findings at the first admission to the ICU and mortality rates of the patients were recorded. Results PCR test was performed in all 109 patients, of whom 101 were PCR test positive. In other eight patients, despite the negative PCR test, thorax CT findings were typical of COVID-19 pneumonia, and other bacterial and viral agents were also excluded. The mean age of the patients was 30.53 years, the mean APACHE II score was 9.68, and the mean gestational age was 28.55 weeks. Around 72.5% of the patients were in the third trimester. Of the 101 PCR-positive patients, 20.2% were delta variants, 16.5% alpha or beta variants, and 63.3% were of unknown variants. Five of the patients were vaccinated. The most common symptom was dyspnea (94.5%), and the most common comorbidity was hypothyroidism (9.17%). Invasive mechanical ventilation (IMV) was needed in 44.95% of pregnant patients. The distribution of pregnant patients admitted to the ICU according to the periods March to December 2020, January to June 2021, and July to November 2021 was 16.5%, 21.1%, and 62.4%, respectively (p<0.001). Two groups of patients were compared: those that survived versus those that deceased. Variables predicting mortality were APACHE score, IMV requirement, length of stay in the ICU, prone positioning, Anakinra treatment, and ECMO (extracorporeal membrane oxygenator) requirement, which were significantly higher in the deceased group than in the living group (p<0.001, p<0.001, p=0.001, p<0.001, p<0.001, and p=0.001, respectively). There was no significant difference between the patients' age, gestational age, variants, treatments other than Anakinra, and the number of patients admitted to the ICU in the three periods (p=0.667, p=0.174, p=0.904, and p=0.605, respectively). In the multiple logistic regression analysis for mortality, high APACHE II score and IMV requirement were found as risk factors for mortality. Conclusion In the last period of delta variant predominance, pregnant COVID-19 patients were admitted to the ICU significantly more frequently than in the first two periods. Mechanical ventilation requirement and high APACHE II score were determined as risk factors for mortality.