Dysmature placenta; Vaccine exposure during pregnancy; This is a serious observational study case initially received on 20-Sep-2019, concerning a 20-year-old adult female, pregnant subject (Ethnicity: Not reported), of body weight 265 lbs, height 65 inches and body mass index (BMI) 44.1, enrolled, a safety study.  The subject's obstetrical history noted that the subject had one previous spontaneous abortion. 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 01-Mar-2018. The subject's estimated date of delivery (EDD) was reported as 04-Jan-2019. The type of pregnancy was singleton.   The subject's historical condition was chlamydia, while current conditions were anaemia, hypertension, nausea and vomiting. The subject's historical drug included azithromycin. The subject's concomitant medications included prenatal vitamins (unspecified vitamins) for pregnancy, Zofran (ondansetron) for nausea and vomiting, ferrous sulfate for anaemia and labetalol for hypertension.  On 14-May-2018, the subject underwent ultrasound and no MCM was noted.   On 23-Jul-2018, the subject underwent quadscreen and ultrasound, there was no MCM noted.  On 15-Oct-2018, at approximately 32 weeks of gestation, the subject was administered Flu Vaccine Cell Subunit QIV NVD [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 252664, dose: 0.5 mL, route of administration, anatomical location, batch number and expiration date: not reported] (explicitly coded as vaccine exposure during pregnancy) for an influenza immunisation.   On the same day, the subject underwent ultrasound and no MCM was noted.  On an unknown date, the subject experienced dysmature placenta, reported as pregnancy complication.  On 29-Oct-2018 and 05-Nov-2019, ultrasound was performed, and no MCM was noted.  On 14-Nov-2018 and 19-Nov-2018, the subject underwent non-stress test and no MCM was noted.  On 06-Dec-2018, the subject underwent ultrasound and no MCM was noted.  On 11-Dec-2018 and 19-Dec-2018, the subject underwent non-stress test and no MCM was noted.  On 26-Dec-2018, at gestational age of 38.7 weeks, the subject delivered a live birth, male neonate via Caesarean section. The characteristics of the neonate included birth weight: 3147 grams, head circumference: 33 cm, length: 52 cm and appearance, pulse, grimace, activity, and respiration (APGAR) scores were 8 (one minute) and 9 (five minutes). There was no APGAR score data for 10 minutes reported. No MCM was identified at birth.   The outcome for the event of dysmature placenta was not reported.  Company comment: A 20-year-old adult female, pregnant subject experienced placental disorder associated with Flu Vaccine Cell Subunit QIV NVD. The product was given in 32nd week of gestation. Onset date of the event was unknown. Chronology needs more clarification. The subject's obstetrical history noted that the subject had one previous spontaneous abortion. Concomitant drugs ondansetron and labetalol may have contributed in development of this event. Having in mind provided information, causality is assessed as not related to the product. The event of exposure during pregnancy was assessed as unrelated per company's conventions.; Reporter's Comments: A 20-year-old adult female, pregnant subject experienced placental disorder associated with Flu Vaccine Cell Subunit QIV NVD. The product was given in 32nd week of gestation. Onset date of the event was unknown. Chronology needs more clarification. The subject's obstetrical history noted that the subject had one previous spontaneous abortion. Concomitant drugs ondansetron and labetalol may have contributed in development of this event. Having in mind provided information, causality is assessed as not related to the product. The event of exposure during pregnancy was assessed as unrelated per company's conventions.