Subchorionic hematoma; Benign gestational trombocytopenia; Vaccine exposure during pregnancy; This is an observational study case form, received from other health professional on 12-Nov-2020 and concerned a 32-year-old, pregnant female subject of body weight: 134 lbs, height: 66.5 inches and body mass index (BMI): 21.3, enrolled, a prospective observational safety study on pregnancy outcomes in women immunized with Afluria QIV, a seasonal quadrivalent vaccine, during pregnancy.   The subject's concurrent condition included penicillin allergy, attention deficit hyperactivity disorder, seasonal allergies, Rhesus antigen (Rh) negative and acne. The subject's concomitant medication included Zyrtec (cetirizine hydrochloride) for seasonal allergies, Clindamycin/benzoyl peroxide (benzoyl peroxide, clindamycin phosphate) and Sulfacetamide sodium sulfur, both used for acne, Prenatal unspecified vitamins and minerals used for pregnancy and Rhophylac (anti-d immunoglobulin) for Rh negative. The subject's past medications included Adderall (amfetamine aspartate, amfetamine sulfate, dexamfetamine saccharate, dexamfetamine sulfate) for attention deficit hyperactivity disorder.  The subject had no previous pregnancies. The subject had no history of offspring with major congenital malformation (MCM). The subject had no maternal or paternal history with MCM. The subject did not use tobacco, alcohol or illicit drugs during pregnancy.   The subject's last menstrual period (LMP) date was 01-Apr-2020, estimated delivery date (EDD) was reported as 06-Jan-2021 and corrected estimated date of delivery (CEDD) was reported as 14-Jan-2021. The type of pregnancy was singleton.   On 01-Jun-2020, ultrasound revealed no MCMs.  On 15-Jun-2020, ultrasound revealed no MCMs.  On 18-Aug-2020, ultrasound revealed no MCMs.  On 16-Oct-2020, at gestational age of 28 weeks (calculated per LMP), the subject was vaccinated with Afluria QIV (Flu Vaccine Egg Split QIV CSL) (influenza vaccine; dose, route of administration and  anatomical location: not reported) (explicitly coded as 'Vaccine exposure during pregnancy') for influenza immunisation. The batch number reported was P100253284.   On the same day, after receiving Afluria QIV, the subject developed benign gestational thrombocytopenia.  On an unspecified date in 2020, unknown amount of time after receiving Afluria QIV, pregnancy status was collected and the subject developed subchorionic hematoma.  At the time of initial reporting on 12-Nov-2020, the patient did not recover from the event of thrombocytopenia.  The outcome from the events of subchorionic hematoma was not reported.  The reporter did not provide a causality assessment to Afluria QIV.  The events 'thrombocytopenia' and 'subchorionic hematoma' were considered to be medically significant by a Physician within Seqirus's Department.  Company comment: A 32-year-old, pregnant subject was vaccinated with Afluria QIV at gestational age of 28 weeks. On the same day, after receiving Afluria QIV, the subject developed benign gestational thrombocytopenia. Chronology is implausible. Causality was confounded by concomitant medication, Zyrtec. Thrombocytopenia develops in 5% to 10% of women during pregnancy or in the immediate postpartum period. An unknown amount of time after receiving Afluria QIV, pregnancy status was collected and the subject developed subchorionic hematoma. With information presented, causality is assessed as not related for both events, due to biological/chronological implausibility. Vaccine exposure during pregnancy is assessed as not related per company's conventions.; Sender's Comments: A 32-year-old, pregnant subject was vaccinated with Afluria QIV at gestational age of 28 weeks. On the same day, after receiving Afluria QIV, the subject developed benign gestational thrombocytopenia. Chronology is implausible. Causality was confounded by concomitant medication, Zyrtec. Thrombocytopenia develops in 5% to 10% of women during pregnancy or in the immediate postpartum period. An unknown amount of time after receiving Afluria QIV, pregnancy status was collected and the subject developed subchorionic hematoma. With information presented, causality is assessed as not related for both events, due to biological/chronological implausibility. Vaccine exposure during pregnancy is assessed as not related per company's conventions.