Dysmature placenta; Vaccine exposure during pregnancy; This is an observational study case, reported by other health professional and initially received on 25-Mar-2020, concerning a 31-year-old pregnant, female subject of body weight 143 lbs, height 60 inches and body mass index (BMI) 27.9, enrolled in a prospective observational safety study.   The subject's past medical condition included bacterial vaginosis. The subject's current medical conditions included herpes simplex virus and increased body BMI. The subject's concomitant medication included Prenatal vitamins (unspecified vitamins and minerals) for pregnancy.  The subject's obstetrical history noted that the subject had four previous pregnancies which included three previous full-term live births with no birth defects and one previous stillbirth. The subject had no history of offspring with major congenital malformation (MCM). Also, 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 11-Feb-2019. The subject's estimated date of delivery (EDD) and corrected estimated date of delivery (CEDD) were reported as 18-Nov-2019. The type of pregnancy was singleton.   On 09-May-2019, the subject underwent non-stress test and no MCM was noted.  On 03-Jun-2019, the subject underwent spinal muscular atrophy, panorama test and cystic fibrosis mutation analysis. There was no MCMs noted.  On 06-Jun-2019, the subject underwent ultrasound. No MCM was noted.  On 29-Jul-2019, the subject underwent non-stress test. No MCM was noted.  On 30-Aug-2019 and 05-Sep-2019, the subject underwent ultrasound. No MCM was noted.  On 27-Sep-2019 and 04-Oct-2019, the subject underwent non-stress test and ultrasound. No MCM was noted.  On 10-Oct-2019, at approximately 34 weeks of gestation (calculated by LMP), the subject was administered Flucelvax QIV (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent, dose: 0.5 mL, batch number: 261218, route of administration, anatomical location and expiration date: not reported] (explicitly coded as ''Vaccine exposure during pregnancy'') for an influenza immunisation.   On an unspecified date, after vaccination, the subject developed dysmature placenta which was reported as pregnancy complication.  On 10-Oct-2019, 18-Oct-2019, 25-Oct-2019 and 08-Nov-2019, the subject underwent ultrasound and no MCM was noted.  At gestational age of 39.1 weeks (as reported), the subject delivered a live birth, male neonate via Caesarean section. The characteristics of the neonate included birth weight of 3265 grams, head circumference 31.8 cm and length: 50.8 cm. Appearance, pulse, grimace, activity, and respiration (APGAR) scores were 8 (one minute) and 9 (five minutes). No date for APGAR score at 10 minutes was provided. No MCM was identified at birth.  At the time of this report, the outcome of dysmature placenta was not reported.  Per company, the event of dysmature placenta was considered serious due criterion of medical significance.  The reporter did not provide causality assessment to Flucelvax QIV.  Company comment:The subject was administered Flucelvax QIV at approximately 34 weeks of gestational age (explicitly considered as vaccine exposure during pregnancy).  On an unknown date after vaccination, the subject developed placental disorder (reported as dysmature placenta). Chronology seems unclear. Causality may have been confounded by medical history of increased body BMI. Considering all the above mentioned, causal relationship between the suspect product and the event of vaccine exposure during pregnancy is assessed as not related based on company's conventions, while for placental disorder is assessed as unlikely related. (defaults to "related" in the safety database for reporting purposes).; Sender's Comments: The subject was administered Flucelvax QIV at approximately 34 weeks of gestational age (explicitly considered as vaccine exposure during pregnancy).  On an unknown date after vaccination, the subject developed placental disorder (reported as dysmature placenta). Chronology seems unclear. Causality may have been confounded by medical history of increased body BMI. Considering all the above mentioned, causal relationship between the suspect product and the event of vaccine exposure during pregnancy is assessed as not related based on company's conventions, while for placental disorder is assessed as unlikely related. (defaults to "related" in the safety database for reporting purposes).