Swelling at the injection site; Redness; Pain; Maternal exposure during pregnancy; This spontaneous prospective pregnancy case was reported by a physician and describes the occurrence of INJECTION SITE SWELLING (Swelling at the injection site), INJECTION SITE ERYTHEMA (Redness), INJECTION SITE PAIN (Pain) and MATERNAL EXPOSURE DURING PREGNANCY (Maternal exposure during pregnancy) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 037k2014) for COVID-19 vaccination.     Concurrent medical conditions included Allergy to animal (Cats).   On 23-Dec-2020, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. The patient's last menstrual period was on 08-Nov-2020 and the estimated date of delivery was 15-Aug-2021. On 23-Dec-2020, the patient experienced INJECTION SITE PAIN (Pain) and MATERNAL EXPOSURE DURING PREGNANCY (Maternal exposure during pregnancy). On 24-Dec-2020, the patient experienced INJECTION SITE SWELLING (Swelling at the injection site) and INJECTION SITE ERYTHEMA (Redness). The patient received mRNA-1273 (Moderna COVID-19 Vaccine) beginning around the  sixth week of the pregnancy. The delivery occurred on an unknown date, which was reported as Unknown. For neonate 1, The outcome was reported as Intrauterine Fetal Death. On 23-Dec-2020, MATERNAL EXPOSURE DURING PREGNANCY (Maternal exposure during pregnancy) had resolved. At the time of the report, INJECTION SITE SWELLING (Swelling at the injection site), INJECTION SITE ERYTHEMA (Redness) and INJECTION SITE PAIN (Pain) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 17-Dec-2020, Pregnancy test: positive (Positive) Positive.   The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Concomitant medication list was not provided.  Treatment information was not provided.  Company comment: This case concerns female patient of unknown age, who was vaccine with the first dose of Moderna vaccine mRNA-1273 during pregnancy. Additionally patient experienced non-serious, expected events of injection site pain, injection site erythema and injection site swelling.  Injection site pain occurred at the day of vaccination and injection site erythema and swelling on the next day. All events were assessed as possibly related due to temporal association, company causality for pregnancy is not applicable.   Most recent FOLLOW-UP information incorporated above includes: On 24-Dec-2020: Upon internal review on 28-Jan-2022, significant data updated. Pregnancy details, event coding, event MAH causality  were updated; Sender's Comments: This case concerns female patient of unknown age, who was vaccine with the first dose of Moderna vaccine mRNA-1273 during pregnancy. Additionally patient experienced non-serious, expected events of injection site pain, injection site erythema and injection site swelling.  Injection site pain occurred at the day of vaccination and injection site erythema and swelling on the next day. All events were assessed as possibly related due to temporal association, company causality for pregnancy is not applicable.