**1. Introduction**

Originating in the province of Wuhan (China) in December 2019, the coronavirus known as SARS-CoV-2 became a worldwide public concern, as warned by the World Health Organization, for its ability to cause severe respiratory tract infections. COVID-19, a disease caused by such etiologic agent, presents fever, cough, expectoration, headache, myalgia or fatigue, and diarrhea as the most common symptoms, and may progress to Severe Acute Respiratory Syndrome (SARS) [1]. This respiratory complication signals the potential of the pathogen to cause respiratory failure, the risks of which can be lethal and exacerbated by the presence of comorbidities, such as hypertension, diabetes mellitus, and cardiovascular diseases [2].

COVID-19 has already infected 122,813,796 people and caused the death of 2,709,640, according to weekly epidemiological data provided by the World Health Organization on March 20, 2021 [3]. Also, according to the 55th Epidemiological Report released by the Brazilian Department of Health, Brazil has the second highest number of accumulated cases worldwide (11,950,459), as well as the number of accumulated deaths (292,752) [4].

Pregnant women are part of this worrying scenario. They are commonly in contact with healthcare professionals and attend medical facilities, representing one of the groups most physiologically susceptible to cardiorespiratory complications, such as hypoxia, and changes in lung volume and functional capacity, especially when they show common signs and symptoms of COVID-19 that make diagnosis difficult, such as dyspnea [5].

In Brazil, a review conducted from January 1 to March 20, 2021 (from the Epidemiological Week – EW 01/2021 to 11/2021), shows that of the 353,277 cases hospitalized due to SARS, about 2,746 individuals were pregnant women, and 1,491 pregnant women (54.3%) were affected by COVID-19. The Southeast region corresponds to the Brazilian region with the highest number of pregnant women affected by SARS (1,063 cases or 38.7%), followed by the Northeast region (519 cases or 18.9%). The most representative states in these regions are São Paulo, Ceará, Minas Gerais, and Rio de Janeiro. The most affected age group was 20–29 years (40.9%), followed by pregnant women aged 30–39 years (40.2%), with the third trimester of pregnancy being the period with the highest concentration of cases [4].

Pregnant women with SARS are at risk of death mainly because of progressive respiratory failure and severe sepsis due to the physiological susceptibility to infections during pregnancy [5]. Thus, SARS evolved to death in 3.6% of the 9,500 pregnant women covered by the Special Epidemiological Report of EW 11/2021, of which 90.2% were confirmed to have been infected with COVID-19. Also, the highest number of cases was in the Southeast and North regions (36.4 and 25.8%, respectively), affecting a larger number of pregnant women aged 30–39 years, corresponding to 42.1% [4, 6].

Given the worrisome healthcare scenario described, this study aims to describe the clinical outcomes of SARS due to SARS-CoV-2 in Brazilian pregnant women and to compare the morbidity and mortality rates due to other causes in this group, stratified by the variables: gestational age and age group.

### **2. Methodology**

This is an observational analytical study based on documents, whose data were collected in the database of the Brazilian Department of Health, precisely in the

*Analysis of the Factors That Influence the Clinical Outcome of Severe Acute Respiratory… DOI: http://dx.doi.org/10.5772/intechopen.99915*

2020 Special Epidemiological Report No. 40 (https://www.gov.br/saude/pt-br/a ssuntos/media/pdf/2020/dezembro/11/boletim\_epidemiologico\_covid\_40-1.pdf). The proposed document has a consolidated report on the number of cases and deaths from COVID-19 in specific groups, including pregnant women affected by SARS, the object of analysis in this study. The information contained in the Report included data accumulated up to Epidemiological Week - EW 49 (11/29/2020 to 12/05/2020).

The study variables were the age group and gestational age of the pregnant women, stratified by cases and deaths in two groups: SARS caused by COVID-19 and SARS caused by other etiologic agents, such as the influenza virus, other viruses of the respiratory system, and unidentified cases. This grouping of cases caused by etiological agents is done by the Brazilian Department of Health itself. The age of the pregnant women was divided into five age groups (10–19 years, 20–29 years, 30–39 years, 40–49 years, and 50–59 years), and gestational age into four categories (first, second, third trimester, and unidentified). Cases under investigation were not included in the specified sample.

Initially, a descriptive analysis was performed to present the absolute and relative frequency of cases and deaths at the age and gestational age strata of pregnant women distributed in the two groups: SARS caused by COVID-19 and SARS caused by other etiologic agents. To learn the severity degree of the disease by the study categories (age group and gestational age), the lethality coefficient was calculated according to the following formula:

$$L(\%) = Number\ of\ deaths\ SARS\ caused\ by\ COVID19$$

$$\frac{Number\ of\ deaths\ SARS\ caused\ by\ COVID19}{Number\ of\ diagonals\ cases\ of\ SARS\ caused\ COVID19} \times 100.\tag{1}$$

The rates of cases and deaths in the referred categories were compared using the binomial test at the level of 5%, with the aid of BioEstat 5.3 software. Sample 1 size, total number of confirmed SARS cases due to COVID-19, and number of successful cases in each stratum analyzed were considered. The same was employed for sample 2 with cases of SARS caused by other agents. The same procedure was carried out for deaths.

The research respected the ethical aspects of research with human beings, described in the Resolution of the National Health Council 510/16, on the guidelines and regulatory standards for research in human and social sciences. It provides for the waiver of consideration by an Ethics Committee when using data available in the public domain [7]. The ethical criteria of the Declaration of Helsinki and international standards were observed.
