ARRHYTHMIA; FOETAL EXPOSURE DURING PREGNANCY; This solicited pregnancy report received from a consumer concerned a male neonate. The patient's mother was enrolled in a non-company sponsored study.  The neonate's birth weight was 7 pounds and 10 ounces, body length 21 inches. At the time of the this report, on 13-APR-2022, baby's weight was 13 pounds and 12 ounces, body length 25 inches. The patient's weight was 3.46 kilograms, and height was 53 centimeters. The patient's other pre-existing medical conditions included: The patient (baby) had no birth defects, genetic or inherited disorders have been diagnosed since birth. Maternal obstetrical history included three previous pregnancies, of which one resulted in a live newborn and two ended with miscarriage. The mother had no history of exposure to drugs for recreational use, tobacco use, or alcoholic beverage. The body Mass Index (BMI) of mother was 21.13. The last menstrual period (LMP) was 17-MAR-2021. The estimated delivery date (EDD) was reported to be 22-Dec-2021. On 11-APR-2021, at gestational age 3 weeks 4 days, the mother of the neonate received treatment with covid-19 vaccine ad26.cov2.s (suspension for injection, mother's route of admin was unknown and transplacental for baby, batch number and expiry was not reported) dose was not reported, 1 total for covid-19 immunisation which is foetal exposure during pregnancy. The batch number was not reported and has been requested. Concomitant medications included prenatal vitamins (minerals nos/vitamins nos). At gestational age 39 weeks and three days, the mother delivered vaginally a live, full-term, male neonate. Labor was induced due to fetal arrhythmia.  On an unspecified date in DEC-2021, Laboratory data included: Cardiac function test (NR: not provided) not reported, and Hearing test (NR: not provided) not reported. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from foetal exposure during pregnancy on 18-DEC-2021, and the outcome of arrhythmia was not reported. The reporter considered the causality between covid-19 vaccine ad26.cov2.s, and arrhythmia as not related. The reporter did not provide a causality assessment between covid-19 vaccine ad26.cov2.s, and foetal exposure during pregnancy. Company causality between covid-19 vaccine ad26.cov2.s, and foetal exposure during pregnancy and arrhythmia was not related.  This report was serious (Other Medically Important Condition). This parent/child case is linked to 20210755629.; Sender's Comments: V0: 20220445189 - covid-19 vaccine ad26.cov2.s Fetal arrhythmia. The event(s) shows an incompatible temporal relationship. Therefore, this event(s) is considered not related. (Considering date of vaccination-17-Mar-2021 and mother was delivered on 18-Dec-2021; where labor was induced due to Fetal arrhythmia; Temporality considered as NOT suggestive)  20220445189 - 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.