gestational diabetes after the vaccine; At the beginning of June: rash in both legs. It never went away until two weeks after she gave birth; At the beginning of May: rash in stomach and left arm; Face swelled up; Throat swelled up; Rash in left arm; Pregnant and got first dose of the vaccine; This spontaneous retrospective pregnancy case was reported by a consumer and describes the occurrence of GESTATIONAL DIABETES (gestational diabetes after the vaccine) in a 34-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 018B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Gestational diabetes (Gestational diabetes started with Jun and was on insulin.).    On 06-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. The patient's last menstrual period was on an unknown date and the estimated date of delivery was 31-Aug-2021. On 06-Apr-2021, the patient experienced MATERNAL EXPOSURE DURING PREGNANCY (Pregnant and got first dose of the vaccine). On 09-Apr-2021, the patient experienced SWELLING FACE (Face swelled up), PHARYNGEAL SWELLING (Throat swelled up) and RASH (Rash in left arm). In May 2021, the patient experienced RASH (At the beginning of May: rash in stomach and left arm). In June 2021, the patient experienced GESTATIONAL DIABETES (gestational diabetes after the vaccine) (seriousness criterion medically significant) and RASH (At the beginning of June: rash in both legs. It never went away until two weeks after she gave birth). The delivery occurred  on 31-Aug-2021, which was reported as Normal Pregnancy Outcome. For neonate 1, The outcome was reported as Delivered NOS. On 06-Apr-2021, MATERNAL EXPOSURE DURING PREGNANCY (Pregnant and got first dose of the vaccine) had resolved. In 2021, RASH (At the beginning of June: rash in both legs. It never went away until two weeks after she gave birth) had resolved. At the time of the report, GESTATIONAL DIABETES (gestational diabetes after the vaccine), SWELLING FACE (Face swelled up) and PHARYNGEAL SWELLING (Throat swelled up) outcome was unknown and RASH (Rash in left arm) and RASH (At the beginning of May: rash in stomach and left arm) had resolved.        mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was temporarily withheld on an unknown date.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   No concomitants were reported . Patient did not get second dose.  Treated with steroid shot and round of steroid shot. For rash in both legs. Patient does not remember treatment maybe 3 doses of steroids in Jul-2021  This case concerns a 34-year-old female patient with no previous relevant medical history, who experienced Maternal exposure during pregnancy and the unexpected serious event of Gestacional diabetes and non serious multiple events of Rash after Spikevax (mRNA- 1273 vaccine / Moderna COVID-19 Vaccine). The patient received first dose of Spikevax at aproximately 14 week of pregnancy. The multiple events of rash occurred at 4 days, aproximatedly 1 month and 2 months after the dose of Spikevax and were treated with glucocorticoids. The event Gestational diabetes occured approximately 1 month and 24 days after the first dose of Spikevax with requirement of insulin.  The delivery occurred 21 weeks after the first dose, which was reported as normal pregnancy outcome. Trement with glucocorticoids remains a confounder for the event Gestacional diabetes. The benefit-risk relationship of Spikevax vaccine is not affected by this report; Sender's Comments: This case concerns a 34-year-old female patient with no previous relevant medical history, who experienced Maternal exposure during pregnancy and the unexpected serious event of Gestacional diabetes and non serious multiple events of Rash after Spikevax (mRNA- 1273 vaccine / Moderna COVID-19 Vaccine). The patient received first dose of Spikevax at aproximately 14 week of pregnancy. The multiple events of rash occurred at 4 days, aproximatedly 1 month and 2 months after the dose of Spikevax and were treated with glucocorticoids. The event Gestational diabetes occured approximately 1 month and 24 days after the first dose of Spikevax with requirement of insulin.  The delivery occurred 21 weeks after the first dose, which was reported as normal pregnancy outcome. Trement with glucocorticoids remains a confounder for the event Gestacional diabetes. The benefit-risk relationship of Spikevax vaccine is not affected by this report