Foetal exposure during pregnancy; Birth weight 2381 g; Pre-term birth / Birth at 36.9 weeks of gestation; This observational study case, initially received on 18-Feb-2021 from other health professional and concerned a male neonate, whose mother was 22-year-old pregnant, female subject of body weight: 160 Ibs, height: 63 inches and body mass index (BMI) 28.3, enrolled in, a prospective observational safety study.   The maternal concurrent conditions included sickle cell trait, BMI high and nausea.  The maternal concomitant medications included Prenatal vitamins (unspecified vitamins and minerals) for pregnancy, ondansetron, vitamin B6 and Unisom (doxylamine succinate) for nausea.  The maternal obstetrical history included two previous pregnancies with one preterm live birth and one spontaneous abortion. The neonate's mother had no maternal or paternal history with major congenital malformations (MCMs) and had no history of offspring with MCM. The neonate's mother did not use tobacco, alcohol or illicit drugs during pregnancy.  The maternal last menstrual period (LMP) date was reported as 08-Jul-2019, the estimated delivery date (EDD) was reported as 13-Apr-2020 and corrected estimated date of delivery (CEDD) was reported as 21-Apr-2020. The type of pregnancy was singleton. The paternal age was not reported.  On 04-Oct-2019, at approximately 12 weeks of gestation (calculated per LMP), the neonate's mother was vaccinated with Afluria QIV (Flu Vaccine Egg Split QIV CSL) (influenza vaccine, route of administration, anatomical location: not reported) (explicitly coded as 'Foetal exposure during pregnancy') for an influenza immunisation. The batch number reported was P100112488.  On the same day, the nuchal translucency, prenatal panel, first sequential and hemoglobinopathy (maternal sickle cell trait) revealed no MCMs.  At gestational age of 36.9 weeks (reported as), the mother delivered live birth, male neonate via caesarean delivery method. The neonate's birth weight was 2381 g, his head circumference and length were not reported. Appearance, pulse, grimace, activity and respiration (APGAR) scores at one, five and ten minutes were not reported. There were no MCMs identified at birth. No pregnancy complications were noted at delivery.   The outcome of the events 'low birth weight' and 'premature birth' was not reported.  The reporter did not provide causality assessment.  The events 'low birth weight' and 'premature birth' were considered to be medically significant by a Physician within Seqirus's Pharmacovigilance and Risk Management Department.  The case is linked to the case 201905820 (the corresponding mother case).  Company comment: The neonate subject experienced low birth baby weight and was born as premature baby approximately six months after foetal exposure to the suspect product, Afluria QIV. Chronology is implausible. The subject's mother medical history of high body mass index, two previous pregnancies with one preterm live birth and one spontaneous abortion confounds causality for the events. Causality between suspect product and the events low birth weight baby and premature baby is assessed as not related due to biological and chronological implausibility and presented confounders. Foetal exposure during pregnancy is assessed as not related per company's conventions.; Sender's Comments: The neonate subject experienced low birth baby weight and was born as premature baby approximately six months after foetal exposure to the suspect product, Afluria QIV. Chronology is implausible. The subject's mother medical history of high body mass index, two previous pregnancies with one preterm live birth and one spontaneous abortion confounds causality for the events. Causality between suspect product and the events low birth weight baby and premature baby is assessed as not related due to biological and chronological implausibility and presented confounders. Foetal exposure during pregnancy is assessed as not related per company's conventions.