Aim:The objective of this study was to describe the use of COVID-19-related medicines during pregnancy and their evolution between the early/late periods of the pandemic. Methods: Pregnant women who tested positive for SARS-CoV-2 from March 2020to July 2021 were included using the COVI-PREG registry. Exposure to the followingCOVID-19-related medicines was recorded: antibiotics, antivirals, hydroxychloro-quine, corticosteroids, anti-interleukin-6 and immunoglobulins. We described theprevalence of medicines used, by trimester of pregnancy, maternal COVID-19 sever-ity level and early/late period of the pandemic (before and after 1 July 2020).Findings: We included 1964 pregnant patients who tested positive for SARS-CoV-2.Overall, 10.4% (205/1964) received at least one COVID-19-related medicine includ-ing antibiotics (8.6%; 169/1694), corticosteroids (3.2%; 62/1964), antivirals (2.0%;39/1964), hydroxychloroquine (1.4%; 27/1964) and anti-interleukin-6 (0.3%;5/1964). The use of at least one COVID-19-related medicine was 3.1% (12/381) in asymptomatic individuals, 4.2% (52/1233) in outpatients, 19.7% (46/233) in in patients without oxygen, 72.1% (44/61) in those requiring standard oxygen, 95.7%(22/23) in those requiring high flow oxygen, 96.2% (25/26) in patients who required intubation and 57.1% (4/7) among patients who died. The proportion who received medicines to treat COVID-19 was higher before than after July 2020 (16.7%vs.Received: 12 July 2022 Revised: 23 September 2022 Accepted: 6 November 2022DOI: 10.1111/bcp.15611Br J Clin Pharmacol.2023;1–15.wileyonlinelibrary.com/journal/bcp© 2022 British Pharmacological Society.17.7%). Antibiotics, antivirals and hydroxychloroquine had lower rates of use during the late period. Conclusion: Medicine use in pregnancy increased with disease severity. The trend towards increased use of corticosteroids seems to be aligned with changing guidelines. Evidence is still needed regarding the effectiveness and safety ofCOVID-19-related medicines in pregnancy.