ObjectiveTo assess the levels of adherence among pregnant women to the basic COVID-19 preventive measures, and to analyze the effect of risk perception and sociodemographic and clinical factors on adherence.MethodA multicenter, cross-sectional study was conducted at the obstetrics clinics of 50 primary care centers selected using a multistage sampling method. An online-administered, structured questionnaire was used to collect self-reported levels of adherence to four basic preventive measures against COVID-19, along with perceived COVID-19 severity, infectiousness, and harmfulness to the baby, besides sociodemographic and clinical data including obstetrical and other medical history.ResultsA total of 2460 pregnant women were included with a mean (SD) age of 30.21 (6.11) years. Levels of self-reported compliance were highest for hand hygiene (95.7%), followed by social distancing (92.3%), masking (90.0%), and avoidance of contact with a COVID-19 infected person (70.3%). Perceived COVID-19 severity and infectiousness, and harmfulness to the baby were observed in 89.2%, 70.7%, and 85.0% of the participants, respectively, and were variably associated with compliance to preventive measures. Analysis of sociodemographic factors highlighted the significance of education and economic status in determining adherence to preventive measures, which represents a potential inequity in the risk of COVID-19 infection.ConclusionThis study highlights the importance of patients’ education to enable functional perception of COVID-19 that promotes self-efficacy, besides investigating the specific social determinants of health to tackle inequalities in terms of prevention efficiency and the subsequent health outcomes.