Foetal exposure during pregnancy; Low birth weight of 2160 g; This observational study case was received on 14-Sep-2020 from other health professional and concerned a female neonate subject. The neonate's mother was 28-year-old, female pregnant subject, of body weight 117.5 lbs, height 62 inches and body mass index (BMI) 21.5 enrolled in, a prospective observational safety study.  The neonate's mother's current medical conditions included dichorionic diatomic twin pregnancy. The neonate's mother's concomitant medications included Prenatal (unspecified vitamins and minerals) for pregnancy.  The neonate's mother had no previous pregnancies. 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 or alcohol during pregnancy.  The neonate's mother's last menstrual period (LMP) date was 22-Dec-2019. The mother's estimated date of delivery (EDD) and corrected estimated date of delivery (CEDD) were reported as 27-Sep-2020. The type of pregnancy was multiple, twin pregnancy.  On 18-Feb-2020, at approximately 8 weeks of gestation (calculated per LMP), the neonate's mother was vaccinated with Afluria QIV (Flu Vaccine Egg Split QIV) [Influenza vaccine; dose, route of administration, anatomical location: not reported] (explicitly coded as Foetal exposure during pregnancy') for an influenza immunisation. The batch number reported was P100126099.  On the same day, the ultrasound revealed no MCM and dichorionic diatomic twin pregnancy was confirmed.  On 18-Mar-2020, 14-Apr-2020, 06-May-2020, 03-Jun-2020 and 01-Jul-2020, the ultrasound revealed no MCM.  at gestational age of 37 weeks (as reported), mother vaginally delivered two live birth female neonates. The characteristics of the first neonate included birth weight: 2160 grams, body length: 45.7 cm and head circumference: 31.5 cm. The appearance, pulse, grimace, activity, and respiration (APGAR) scores at one minute was 8, at five minutes was 9 and at 10 minutes no data was provided. No MCM was identified at birth.   The outcome of the event 'low birth weight baby' was not reported.  The reporter did not provide causality assessment to Afluria QIV.  The event of 'low birth weight baby' was considered to be medically significant by a Physician within Seqirus's Pharmacovigilance and Risk Management Department.  This case is linked to case number 202004473 (corresponding mother case) and 202004475 (corresponding twin case).  Company comment: The neonate's mother was vaccinated with the suspect product, Afluria QIV (explicitly coded as Foetal exposure during pregnancy'). Reportedly, six months and 19 days after vaccination, the mother vaginally delivered two female neonates. The one neonate's birth weight was low (2160 g). Chronology is unsuggestive. Causality was highly confounded by twin pregnancy. No information regarding neonate's mother medical history was provided. Considering all the above mentioned, causal relationship between the suspect product and the event of low birth weight baby is assessed as not related. Foetal exposure during pregnancy is not related per company's conventions.; Sender's Comments: The neonate's mother was vaccinated with the suspect product, Afluria QIV (explicitly coded as Foetal exposure during pregnancy'). Reportedly, six months and 19 days after vaccination, the mother vaginally delivered two female neonates. The one neonate's birth weight was low (2160 g). Chronology is unsuggestive. Causality was highly confounded by twin pregnancy. No information regarding neonate's mother medical history was provided. Considering all the above mentioned, causal relationship between the suspect product and the event of low birth weight baby is assessed as not related. Foetal exposure during pregnancy is not related per company's conventions.