Blood in her stool / Little tiny blood clot comes out of stool; liver started hurting; gut(stomach) pain/ stomach pain worsened; mesentery are swollen and she has inflammation there; Enlarged a spleen; Heart palpitation; Chest pain; started having loose bowel/ Loose bowel worsened; Lymph nodes are swollen and she has inflammation there; abnormal T wave on ECG; inflammation; Nursing mother received the vaccine/ She is not sure if her inflammation is affecting her baby; This spontaneous case was reported by a consumer and describes the occurrence of HAEMATOCHEZIA (Blood in her stool / Little tiny blood clot comes out of stool) in a 36-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 032H21A and 001J21-2A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Inflammatory arthritis, Egg allergy and Dairy intolerance.   On 20-Dec-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 17-Jan-2022, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 17-Jan-2022, the patient experienced MATERNAL EXPOSURE DURING BREAST FEEDING (Nursing mother received the vaccine/ She is not sure if her inflammation is affecting her baby). On an unknown date, the patient experienced HAEMATOCHEZIA (Blood in her stool / Little tiny blood clot comes out of stool) (seriousness criterion medically significant), HEPATIC PAIN (liver started hurting), ABDOMINAL PAIN UPPER (gut(stomach) pain/ stomach pain worsened), ABDOMINAL LYMPHADENOPATHY (mesentery are swollen and she has inflammation there), SPLENOMEGALY (Enlarged a spleen), PALPITATIONS (Heart palpitation), CHEST PAIN (Chest pain), DIARRHOEA (started having loose bowel/ Loose bowel worsened), LYMPHADENITIS (Lymph nodes are swollen and she has inflammation there), ELECTROCARDIOGRAM ABNORMAL (abnormal T wave on ECG) and INFLAMMATION (inflammation). On 17-Jan-2022, MATERNAL EXPOSURE DURING BREAST FEEDING (Nursing mother received the vaccine/ She is not sure if her inflammation is affecting her baby) had resolved. At the time of the report, HAEMATOCHEZIA (Blood in her stool / Little tiny blood clot comes out of stool), HEPATIC PAIN (liver started hurting), ABDOMINAL PAIN UPPER (gut(stomach) pain/ stomach pain worsened), ABDOMINAL LYMPHADENOPATHY (mesentery are swollen and she has inflammation there), SPLENOMEGALY (Enlarged a spleen), PALPITATIONS (Heart palpitation), CHEST PAIN (Chest pain), DIARRHOEA (started having loose bowel/ Loose bowel worsened) and LYMPHADENITIS (Lymph nodes are swollen and she has inflammation there) had not resolved and ELECTROCARDIOGRAM ABNORMAL (abnormal T wave on ECG) and INFLAMMATION (inflammation) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 19-Sep-2019, SARS-CoV-2 test: yes (Positive) Covid-19 positive test Yes. In 2022, Computerised tomogram: abnormal (abnormal) Lymph nodes were swollen, mesentery were swollen, and had inflammation there.. In 2022, Electrocardiogram: abnormal (abnormal) Abnormal T wave on ECG. In 2022, Hepatic enzyme: slightly elevated (High) slightly elevated but not concerning.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   Patient had a history relating to mentioned AE and both Acute and Chronic illnesses at the time of vaccination. No concomitant medications were reported. It was reported that the patient had side effects but did not have medical proof or name for them. Two weeks after both doses, she had blood in her stool and a little tiny blood clot came out but there had not been any finding in accordance with that. After the second vaccine, her liver was hurting, her enzymes were slightly elevated but not concerning so they just monitored it. She started having loose bowel and gut(stomach) pain, which got worsened. Her platelet after the first vaccine were normal and they felt she could get the second dose. She was not sure if her inflammation was affecting her baby. She had not been diagnosed. She was supposed to get a colonoscopy in a week. No treatment medications were reported. CC: This is a Spontaneous case, concerning a 36-year-old female patient, currently Breastfeeding, with no relevant medical history reported, who experienced the serious unexpected adverse event of Haematochezia (serious criteria Medically Significant), that occurred in an unknown day after the administration of the first dose of mRNA-1273 vaccine. Additionally, the special situation of Maternal Exposure During Breast Feeding and other non-serious adverse events were reported. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report. Event assessed as serious due to Important Medical Event.   This case was linked to MOD-2022-506803, MOD-2022-506778 (Parent-Child Link).   See case MOD-2022-506803,MOD-2022-506778 for details regarding the child case.; Sender's Comments: This is a Spontaneous case, concerning a 36-year-old female patient, currently Breastfeeding, with no relevant medical history reported, who experienced the serious unexpected adverse event of Haematochezia (serious criteria Medically Significant), that occurred in an unknown day after the administration of the first dose of mRNA-1273 vaccine. Additionally, the special situation of Maternal Exposure During Breast Feeding and other non-serious adverse events were reported. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report. Event assessed as serious due to Important Medical Event.