An understanding of the factors associated with the COVID-19 vaccine uptake in pregnant women is paramount to persuade women to get vaccinated against COVID-19. We estimated the vaccination rate of pregnant women against COVID-19 and evaluated psychosocial factors associated with vaccine uptake among them. We conducted a cross-sectional study with a convenience sample. In particular, we investigated socio-demographic data of pregnant women (e.g., age, marital status, and educational level), COVID-19 related variables (e.g., previous COVID-19 diagnosis and worry about the side effects of COVID-19 vaccines), and stress due to COVID-19 (e.g., danger and contamination fears, fears about economic consequences, xenophobia, compulsive checking and reassurance seeking, and traumatic stress symptoms about COVID-19) as possible predictors of COVID-19 vaccine uptake. Among pregnant women, 58.6% had received a COVID-19 vaccine. The most important reasons that pregnant women were not vaccinated were doubts about the safety and effectiveness of the COVID-19 vaccines (31.4%), fear that COVID-19 vaccines could be harmful to the fetus (29.4%), and fear of adverse side effects of COVID-19 vaccines (29.4%). Increased danger and contamination fears, increased fears about economic consequences, and higher levels of trust in COVID-19 vaccines were related with vaccine uptake. On the other hand, increased compulsive checking and reassurance seeking and increased worry about the adverse side effects of COVID-19 vaccines reduced the likelihood of pregnant women being vaccinated. An understanding of the psychosocial factors associated with increased COVID-19 vaccine uptake in pregnant women could be helpful for policy makers and healthcare professionals in their efforts to persuade women to get vaccinated against COVID-19. There is a need for targeted educational campaigns to increase knowledge about COVID-19 vaccines and reduce vaccine hesitancy in pregnancy.