No. The concern has come from the claim that the spike protein made by the body after getting an mRNA vaccine is similar to Syncitin 1, which is a protein in the placenta, and antibodies would attack the placenta. However, they are not similar enough. There has not been a higher rate of birth defects or abortions in people with COVID-19. There were also some people in the Pfizer and Moderna trials have gotten pregnant. There were few adverse effects for pregnant people in the study and all occurred in the placebo group.