Reflux; Pregnant (4 Weeks); This spontaneous prospective pregnancy case was reported by a consumer and describes the occurrence of GASTROOESOPHAGEAL REFLUX DISEASE (Reflux) and MATERNAL EXPOSURE DURING PREGNANCY (Pregnant (4 Weeks)) in a 39-year-old female patient (gravida 2, para 2) who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 030A21A) for COVID-19 vaccination.     The patient's past medical history included COVID-19 on 25-Jan-2021, Alcohol use (alcohol use 4-5 drinks per week; stopped 21-Mar-2021) in August 1999, Pregnancy (Induction at 37 weeks; live birth; baby's lungs were not ready; 3 day NICU stay for infant for surfactant administration and jaundice. Conceived after three months of treatment with letrazole/Femara.) on 16-Aug-2019, Pre-eclampsia (postpartum (hospital re-admission at day 5 postpartum)) in August 2019 and Gestational hypertension (prior pregnancy; diagnosed at 32 weeks). Previously administered products included for Product used for unknown indication: Femara (Previous pregnancy was conceived after three months of treatment with  letrazole/Femara). Past adverse reactions to the above products included No adverse event with Femara. Concurrent medical conditions included Drug allergy (Benadryl (suspected)), Pregnancy with advanced maternal age (40 years at week 13), Headache, Back pain, Acid reflux (esophageal) (Began daily Pepcid treatment in March 2021) since 20-Nov-2020, Obesity and Hypertension (Chronic hypertension before the pregnancy. Better during pregnancy, returned following childbirth) since 27-Sep-2019. Concomitant products included FAMOTIDINE (PEPCID [FAMOTIDINE]) for Acid reflux (esophageal), LABETALOL for Hypertension, ONDANSETRON (ZOFRAN [ONDANSETRON]) from 26-Apr-2021 to an unknown date for Nausea, PARACETAMOL (TYLENOL) for Pain, ASPIRIN [ACETYLSALICYLIC ACID] from 22-Mar-2021 to an unknown date for Pre-eclampsia, MINERALS NOS, VITAMINS NOS (PRENATAL VITAMINS [MINERALS NOS;VITAMINS NOS]) from 21-Mar-2021 to an unknown date for an unknown indication.    On 16-Mar-2021 at 11:00 AM, 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 28-Feb-2021 and the estimated date of delivery was 05-Dec-2021. On 16-Mar-2021, the patient experienced MATERNAL EXPOSURE DURING PREGNANCY (Pregnant (4 Weeks)). On 24-Mar-2021, the patient experienced GASTROOESOPHAGEAL REFLUX DISEASE (Reflux). The patient received mRNA-1273 (Moderna COVID-19 Vaccine) beginning around the  second week of the pregnancy. The patient had a vaginal delivery which occurred on an unknown date, which was reported as Full-term. For neonate 1, The outcome was reported as Term Birth NOS. On 17/Nov/2021 patient had Postpartum preeclampsia 5 days. Readmitted to hospital for 48 hours magnesium sulfate when blood pressure would not come down with labetalol or Procardia Patient delivered female baby with Weight-0.45 kg,Length-50.8 cm,Head circumference-35 cm. Baby was born at 37 weeks. On 16-Mar-2021, MATERNAL EXPOSURE DURING PREGNANCY (Pregnant (4 Weeks)) had resolved. At the time of the report, GASTROOESOPHAGEAL REFLUX DISEASE (Reflux) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 25-Jan-2021, SARS-CoV-2 antibody test: positive (Positive) Positive. On 26-Apr-2021, Ultrasound scan vagina: normal (normal) Normal. In May 2021, Electrocardiogram: normal (normal) Normal. On 28-May-2021, Prenatal screening test: normal (normal) No chromosomal abnormalities detected. On 28-May-2021, Ultrasound antenatal screen: normal (normal) Normal. In July 2021, Echocardiogram: normal (normal) Normal. In July 2021, Ultrasound antenatal screen: normal (normal) Normal. In July 2021, Ultrasound scan: normal (normal) Weekly ultrasounds (size, biophysical profile) - all normal until 37 weeks 16/Nov/2021 (passed subsequent NST). In September 2021, Glucose tolerance test: normal (normal) 3 hour test,Normal. In October 2021, Prenatal screening test: normal (normal) Weekly NSTs - all normal.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.       The patient's estimated date of conception was 9-Mar-2021. On 21-Mar-2021, the pregnancy test was positive.  Patient became pregnant around mid-March 2021. This was a planned pregnancy. At the time that patient received  first vaccine and was not aware that patient was pregnant as it was too early in the pregnancy for an at-home test to have been accurate. Age, diet and weight were other related causes reported for event Reflux  On 28-May-2021, she had a glucose tolerance test and a 24 hour urine test. On 23-Jun-2021, the patient had a maternal serum alpha-fetoprotein (AFP) done. Results of testing were not provided.  Heart burn is another reported indication for Pepcid.  No treatment medications were reported.   This case was linked to MOD-2021-249624 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 01-Feb-2022: Upon internal review on 10-Feb-22, significant corrections were performed. Event onset date, stop date, outcome for maternal exposure during pregnancy, event start date for Acid reflux, LMP in patient tab, and rechallenge for suspect product was updated.