Background: Coronaviruses have been the cause of 3 major outbreaks during the last 2 decades. Information on coronavirus diseases in pregnant women is limited, and even less is known about seriously ill pregnant women. Data are also lacking regarding the real burden of coronavirus disease 2019 (COVID-19) infection in pregnant women from low/middle-income countries. The aim of this study was to determine the characteristics and clinical course of COVID-19 in pregnant/puerperal women admitted to ICUs in Turkey. Methods: This was a national, multicenter, retrospective study. The study population comprised all SARS-CoV-2-infected pregnant/puerperal women admitted to participating ICUs between 1 March 2020 and 1 January 2022. Data regarding demographics, comorbidities, illness severity, therapies, extrapulmonary organ injuries, non-COVID-19 infections, and maternal and fetal/neonatal outcomes were recorded. LASSO logistic regression and multiple logistic regression analyses were used to identify predictive variables in terms of ICU mortality. Results: A total of 597 patients (341 pregnant women, 255 puerperal women) from 59 ICUs in 44 hospitals were included and of these patients, 87.1% were unvaccinated. The primary reason for ICU admission was acute hypoxemic respiratory failure in 522 (87.4%), acute hypoxemic respiratory failure plus shock in 14 (2.3%), ischemic cerebrovascular accident (CVA) in 5 (0.8%), preeclampsia/eclampsia/HELLP syndrome in 6 (1.0%), and post-caesarean follow-up in 36 (6.0%). Nonsurvivors were sicker than survivors upon ICU admission, with higher APACHE II (p < 0.001) and SOFA scores (p < 0.001). A total of 181 (30.3%) women died and 280 (46.6%) had received invasive mechanical ventilation (IMV). Myocardial injury, the highest SOFA score during ICU stay, LDH levels on admission, the highest levels of AST during ICU stay, average daily dose of corticosteroids, IMV, prophylactic dose anticoagulation (compared with therapeutic dose anticoagulation), PaO2/FiO2 ratio <100, pulmonary embolism, and shock were identified as predictors of mortality. Rates of premature birth (46.4%), cesarean section (53.7%), fetal distress (15.3%), stillbirth (6.5%), and low birth weight (19.4%) were high. Rates of neonatal death (8%) and respiratory distress syndrome (21%) were also high among live-born infants. Conclusions: Severe/critical COVID-19 infection during the pregnancy/puerperal period was associated with high maternal mortality and fetal/neonatal complication rates in Turkey.