This solicited pregnancy report received from a consumer concerned a male neonate of unspecified age, race and ethnic origin. The patient's mother was enrolled in a non-company sponsored study C-VIPER: COVID 19 Vaccines International Pregnancy Exposure Registry number: "PRIVATE"). The patient's weight was 3.44 kilograms, and height was 54 centimeters. No birth defects, genetic or inherited disorders have been diagnosed since birth. The mother had no relevant medical history. Concomitant medications included prenatal vitamins, levothyroxine, vitamin D and Select-OB Plus DHA Prenatal Supplement Plus DHA. Maternal obstetrical history included one previous pregnancy, resulting in a miscarriage. The mother had no history of tobacco or recreational drug use, however reported alcohol use during the first three months of current pregnancy. Maternal first day of the last menstrual period (LMP) was calculated to be 23-Apr-2021. The estimated delivery date (EDD) was reported to be 28-Jan-2022. Type of pregnancy was reported as singleton. The patient's mother previously received two doses of Comirnaty (Pfizer BioNTech Covid-19 vaccine) (dose number in series 1) (form of admin, route of admin, and batch number: ER8737 and ER8735, expiry: unknown) dose was not reported, 1 total administered on 03-APR-2021 and 24-APR-2021 for Covid-19 immunisation. At gestational age 31 weeks and three days, The patient's mother received Covid-19 vaccine ad26.cov2.s (dose number in series 2) (suspension for injection, route of admin not reported, batch number: 213D21A, expiry: unknown) dose was not reported, 1 total administered on 29-NOV-2021 for Covid-19 immunization. Maternal concomitant medications included calcium carbonate/colecalciferol for drug used for unknown indication, fish oil for drug used for unknown indication, levothyroxine sodium for drug used for unknown indication, and minerals NOS/vitamins NOS for drug used for unknown indication. On 29-NOV-2021, the patient experienced fetal exposure during pregnancy. On FEB-2022, Laboratory data included: Hearing test (NR: not provided) Not reported. at gestational age 41 weeks and one day, the mother delivered vaginally a live, full-term, male neonate. The mother spent two days in the hospital for the delivery. The neonate's birth weight was 3440 grams, body length 54 cm. On an unspecified date, the patient experienced pyloric stenosis (dose number in series 2). On 05-Mar-2022, the baby was hospitalized due to pyloric stenosis. On 06-Mar-2022, the baby underwent surgery for pyloric stenosis. At the time of the initial report on 14-Mar-2022, baby's weight was 4200 grams, body length 58 cm. The action taken with Covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from fetal exposure during pregnancy on 05-FEB-2022, and the outcome of pyloric stenosis was not reported. The reporter considered the causality between Covid-19 vaccine ad26.cov2.s, and pyloric stenosis as unassessable. The reporter did not provide a causality assessment between Covid-19 vaccine ad26.cov2.s, and fetal exposure during pregnancy. Company causality between Covid-19 vaccine ad26.cov2.s, and pyloric stenosis was related, and between Covid-19 vaccine ad26.cov2.s, and fetal exposure during pregnancy was not related. This report was serious (Hospitalization Caused / Prolonged, Congenital Anomaly/Birth Defect, and Other Medically Important Condition). This parent/child case is linked to 20220118594. Sender's Comments: V0: 20220350441-Covid-19 vaccine ad26.cov2.s-Pyloric stenosis. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s). Therefore, this event(s) is considered related. 20220350441-Covid-19 vaccine ad26.cov2.s-fetal exposure during pregnancy. The event(s) has a compatible/suggestive temporal relationship, is unlabeled, and has unknown scientific plausibility. There are other factors more likely to be associated with the event(s) than the drug. Specifically: SPECIAL SITUATIONS. Therefore, this event(s) is considered not related.