TACHYCARDIA; SWELLING OF LEGS; SUBCHORIONIC HEMORRHAGE; COLLAPSE; SYNCOPE; MILD CHILLS; FEELING UNWELL; HEADACHE; MATERNAL EXPOSURE DURING PREGNANCY; This solicited pregnancy report received from a consumer concerned a 29-year-old female an unspecified race and ethnic origin. The patient was enrolled in a non-company sponsored study. The patient's weight was 73.469 kilograms, and height was 175 centimeters. The patient's past medical history included: miscarriage, suspected Covid-19, tobacco user, and e-cigarette smoker and no use of alcohol, and concurrent conditions included: multigravida. The patient was gravida 4, para 0. The first day of the last menstrual period (LMP) was calculated to be 18-FEB-2021. The estimated delivery date (EDD) was reported to be 25-NOV-2021. Type of pregnancy was reported as singleton.  The patient initiated treatment with Covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin not reported, batch number: 041A21A expiry: Unknown) dose was not reported, administered on 09-APR-2021 for Covid-19 immunization (maternal exposure during pregnancy). Concomitant medications included enoxaparin sodium, famotidine, labetalol, minerals nos/vitamins nos, and paracetamol. On 10-MAY-2021, the patient experienced mild chills, headache, and was feeling unwell. On the same day, the patient experienced syncope and collapse. On 21-MAY-2021, the patient underwent prenatal ultrasound, which showed sub-chorionic hemorrhage. On 01-JUN-2021, the patient experienced tachycardia and was hospitalized for unspecified days. Reportedly, resting heart rate before pregnancy and vaccine was below 60 beats per minute (bpm). Average resting heart rate in MAY-2021 to JUN-2021 was 145 bpm, with medications lowering the average resting heart rate to 125 bpm. On 15-JUN-2021, patient developed swelling of legs which was controlled by compressions.  The action taken with Covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from mild chills, feeling unwell, and headache on 17-MAY-2021, had not recovered from tachycardia, syncope, collapse, and swelling of legs, and the outcome of subchorionic hemorrhage and maternal exposure during pregnancy was not reported. The reporter considered the causality between covid-19 vaccine ad26.cov2.s, and tachycardia, syncope, and collapse as related. The reporter did not provide a causality assessment between covid-19 vaccine ad26.cov2.s, and subchorionic hemorrhage, maternal exposure during pregnancy, swelling of legs, mild chills, feeling unwell, and headache. Company causality between covid-19 vaccine ad26.cov2.s, and subchorionic hemorrhage, maternal exposure during pregnancy, and swelling of legs was not related, and between covid-19 vaccine ad26.cov2.s, and tachycardia, syncope, collapse, mild chills, feeling unwell, and headache was related.  This report was serious (Hospitalization Caused / Prolonged, and Other Medically Important Condition).; Sender's Comments: V0: 20211119623-covid-19 vaccine ad26.cov2.s-Tachycardia, Syncope, Collapse . This event(s) is considered related. 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). 20211119623-Covid-19 vaccine ad26.cov2.s-subchorionic hemorrhage. This event(s) is considered not related. 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: MEDICAL HISTORY 20211119623-covid-19 vaccine ad26.cov2.s-Maternal exposure during pregnancy. This event(s) is considered not related. 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