Statistical analysis
The normality of the variables was analyzed by Kolmogorov-Smirnov test and Shapiro-Wilk test. For the variables that were approximately to normal distribution descriptive statistics such as mean, standard deviation and the range values were calculated. For non-normal data median values were compared. Comparison of two group means were tested using student independent test. Categorical variables were expressed in terms of frequency and percent values. Logistic regression was used to calculate crude odds ratios and adjusted odds ratios and their 95% confidence intervals for each comorbidity as well as cardiovascular, obstetric, fetal, delivery, and other events. We performed univariable analysis at first, and multivariable logistic regression analysis was performed for the variables with P < 0.1. For all analyses, statistical significance was assigned based on a p-value <0.05. All statistical analyses were conducted using SPSS (IBM-SPSS Statistics v22.0, Inc. Chicago, IL) and R version 4.0.4 (R Foundation for Statistical Computing, Vienna, Austria, 2021).