Bilateral hydronephrosis of kidneys/Left kidney hydronephrosis; This spontaneous case was reported by a consumer and describes the occurrence of CONGENITAL HYDRONEPHROSIS (Bilateral hydronephrosis of kidneys/Left kidney hydronephrosis) in a male foetus of an unknown age exposed to mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 041L20A and 025L20A) , while the mother received the product for COVID-19 vaccination.    MEDICAL HISTORY (Parent): The mother's past medical history included Vaccine exposure during pregnancy from 06-Jan-2021 to 04-Feb-2021, High risk pregnancy (at 23 weeks; put on partial bedrest on 16-Feb-2021 due to short cervix), Retained placenta in May 2021, Postpartum hemorrhage in May 2021, In vitro fertilization (first IVF cycle worked) in September 2020 and Embryo transfer in September 2020. Concurrent medical conditions included Rheumatoid arthritis (as a child; currently doing well since age 16) since 1990, Uveitis (both eyes; chronic, remains the same) since 1994 and Glaucoma both eyes (chronic, remains the same).    MEDICAL HISTORY (Patient): Concomitant product exposures included BRIMONIDINE TARTRATE (ALPHAGAN) and BIMATOPROST (LUMIGAN) for Glaucoma, MINERALS NOS, VITAMINS NOS (PRENATAL VITAMINS [MINERALS NOS;VITAMINS NOS]) from 01-Sep-2020 to an unknown date for Pregnancy, PREDNISONE for Uveitis.   On 06-Jan-2021 at 9:00 AM, the mother received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 04-Feb-2021 at 1:00 PM, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. The mother's last menstrual period was on 06-Sep-2020 and the estimated date of delivery was 13-Jun-2021. On 16-Feb-2021, the foetus was diagnosed with CONGENITAL HYDRONEPHROSIS (Bilateral hydronephrosis of kidneys/Left kidney hydronephrosis) (seriousness criteria hospitalization and medically significant). The patient was hospitalized on 07-May-2021 due to CONGENITAL HYDRONEPHROSIS. The Foetus was exposed to mRNA-1273 (Moderna COVID-19 Vaccine) beginning around the  seventeenth week of the pregnancy. The vaginal delivery occurred on 07-May-2021, which was reported as Premature. For neonate 1, the birth weight was 2440 grams (5lbs 6oz). The outcome was reported as Pre-Term Birth NOS. Live, pre-term birth at 34 weeks gestation. Length: 45.01 cm Head circumference: 31 cm. At the time of the report, CONGENITAL HYDRONEPHROSIS (Bilateral hydronephrosis of kidneys/Left kidney hydronephrosis) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 08-Dec-2020, Ultrasound antenatal screen: Found hydronephrosis on baby. On 03-Feb-2021, Ultrasound antenatal screen: Found hydronephrosis on the kidneys. On 16-Feb-2021, Ultrasound antenatal screen: Found hydronephrosis on the kidneys. On 06-Apr-2021, Ultrasound antenatal screen: Found hydronephrosis on baby. On 04-May-2021, Ultrasound antenatal screen: Found hydronephrosis on baby.         A perinatal complication for the infant was reported as bilateral hydronephrosis of the kidneys. The patient received care in the neonatal intensive care unit (NICU) for 13 days. Abnormalities on delivery and at one month post-partum were reported as left kidney hydronephrosis for which the infant has been seen by a pediatric urologist.  No treatment information was provided.  Company Comment: This spontaneous case concerns a male fetus exposed to mRNA-1273 around the 17th and 21st week of the pregnancy with the first and the second dose respectively. The unexpected and serious (due to hospitalization and medically significant) event of CONGENITAL HYDRONEPHROSIS was diagnosed with an antenatal ultrasound performed 12 days after de second dose of vaccination. The vaginal delivery occurred as a pre-term birth at 34 weeks gestation with retained placenta and postpartum hemorrhage. The patient was hospitalized after delivery due to congenital bilateral hydronephrosis of the kidneys. The patient received care in the neonatal intensive care unit for 13 days. Abnormalities on delivery and at one-month post-partum were reported as left kidney hydronephrosis for which the infant has been seen by a pediatric urologist. No treatment information was provided. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.   This case was linked to MOD-2021-003424 (Parent-Child Link).   See case MOD-2021-003424 for details regarding the Parent case.  Most recent FOLLOW-UP information incorporated above includes: On 19-Jul-2021: Upon internal review on 27Jul-2022, significant correction was performed. The company comment was updated; Sender's Comments: This spontaneous case concerns a male fetus exposed to mRNA-1273 around the 17th and 21st week of the pregnancy with the first and the second dose respectively. The unexpected and serious (due to hospitalization and medically significant) event of CONGENITAL HYDRONEPHROSIS was diagnosed with an antenatal ultrasound performed 12 days after de second dose of vaccination. The vaginal delivery occurred as a pre-term birth at 34 weeks gestation with retained placenta and postpartum hemorrhage. The patient was hospitalized after delivery due to congenital bilateral hydronephrosis of the kidneys. The patient received care in the neonatal intensive care unit for 13 days. Abnormalities on delivery and at one-month post-partum were reported as left kidney hydronephrosis for which the infant has been seen by a pediatric urologist. No treatment information was provided. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report.