BORN WITHOUT HIS LEFT KIDNEY; FETAL STROKE; DRUG EXPOSURE IN UTERO; This spontaneous pregnancy report received from a parent concerned a male neonate. Initial information was processed along with the additional information received on 15-SEP-2021. The patient's height, and weight were not reported. No concurrent conditions were reported. The patient's parent's medical history allergic to ibuprofen and aspirin. The patient's parent received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 201A21A expiry: 21-SEP-2021) dose was not reported,1 total on left arm administered on 10-APR-2021 for prophylactic vaccination. No concomitant medications were reported.  On 10-APR-2021, the foetus experienced drug exposure in utero during second trimester. On 19-Jul-2021, foetus was diagnosed with a fetal stroke, the doctor had done Magnetic resonance imaging (MRI) and ultrasound to parent. The physicians said that it might be from the Janssen Covid-19 vaccine as it could cause blood clots. The patient was born with one kidney. In SEP-2021, the baby had undergone tests MRI and ultrasound on his brain to see if the stroke had caused any brain damage and observed movement and breathing. No results were yet released. Upon follow-up, on an unspecified date, the baby was still in the newborn intensive care unit but was improving and her son may be released from the NICU in the next week. The parent confirmed her son did have a fetal stroke and was born without his left kidney. The parent did not have access to her son's lab values but agreed to give access to contact treating physician. On unspecified date, the patient was hospitalized for born without his left kidney and fetal stroke. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from drug exposure in utero on 09-SEP-2021, and was recovering from born with one kidney, and fetal stroke. This report was serious (Hospitalization Caused / Prolonged, and Congenital Anomaly/Birth Defect). This parent/child case is linked to 20210921616.; Sender's Comments: V0: This spontaneous pregnancy report received from a parent (consumer) concerned a male neonate of unknown race and ethnicity who experienced a stroke during fetal life 101 days after in utero exposure to vaccination in the second trimester and was born without the left kidney 153 days after in-utero exposure to vaccination. The mother's medical, obstetric history, and concurrent conditions were not reported. The mother was allergic to ibuprofen and aspirin. No concomitant medications were reported. The neonate was diagnosed with a stroke during fetal life by maternal MRI and ultrasound. The treating physician felt the Janssen vaccine caused the stroke as it "could cause blood clots." After birth, the neonate showed movement and breathing and underwent an MRI and ultrasound of the brain; the scan results were not provided. At the time of this report, the neonate is being treated in the neonatal intensive care unit (NICU) and is recovering. Information regarding whether the patient's mother experienced thrombosis or thrombocytopenia during the pregnancy is not provided. As kidney development occurs during the first trimester and the vaccination was done in the second trimester, there is no temporal plausibility between vaccination and the event of renal aplasia. Given limited information (including maternal or fetal platelet count, anti-PF4 antibodies, etc.), a meaningful medical  assessment of the fetal stroke cannot be made. Information is limited in this case, and the occurrence of fetal stroke could represent the background incidence of such events in the general population. However, a relationship with Janssen Covid-19 vaccine cannot be ruled out and thus the relationship is considered indeterminate.