Background: COVID-19 caused some worries among pregnant women. Worries during pregnancy can affect women’s well-being. We investigated worry and well-being and associated factors among pregnant women during the COVID-19 epidemic.Methods: This descriptive cross-sectional study was conducted on 484 pregnant women using an online questionnaire. Sampling was performed in a period between May 5 and Aug 5, 2020. Inclusion criteria were having a single healthy fetus and having no significant psychological disorder. We collected the data using the Persian versions of the World Health Organization's well-being Index (WHO-5 well-being index) and the Cambridge worry scale.Results: The mean total scores of the WHO-5 well-being index and the rate of WHO-5 score < 50 were 64.9 ± 29.0 and 24.4%, respectively. Predictors of women’s worry are the increased level of fear of COVID-19, a low family income, employment situation, nulliparity, and having no close family member with chronic disease (p < 0.05). The results of logistic regression analysis on well-being scores showed that the worry about fetus health (OR = 1.081, p = 0.005), women’s own health and relationships (OR = 1.055, p = 0.047), and having an infected person with COVID-19 among relatives (OR = 2.095, p = 0.039) could predict the well-being in pregnant women. The mean score of worry about fetus health in the current study was lower than that of the previous study (p = 0.024). The mean score of socio-economic worry in the current study was higher than that of the previous cross-sectional study (p = 0.025). The result indicates that the percentage of participants with a low level of well-being did not differ by the two periods under study (chi-square = 0.099, p = 0.753) (table 7). Conclusions: The percentage of women experiencing a low well-being state was relatively high. This result is worthy of attention by health care providers and policy makers. To decrease women’s socio economic concerns, governments and charities should expand programs providing financial support to pregnant women in low-income families. Providing care and support to pregnant women should have high priority during the COVID-19 pandemic.