During the Pfizer vaccine tests, 23 women volunteers involved in the study became pregnant, and the only one who suffered a pregnancy loss had not received the actual vaccine, but a placebo.Getting COVID-19, on the other hand, can have potentially serious impact on pregnancy and the mother’s health. Learn more about coronavirus and pregnancy. Johns Hopkins Medicine encourages women to reach out to their medical providers to discuss other questions they have about COVID-19 as it relates to fertility or pregnancy.