Vaccine fetal exposure during pregnancy; Birth weight of 4054 g; This observational study case was received from other health professional on 19-Feb-2021 and concerned a male neonate whose mother was a 25-year-old pregnant, female subject, of body weight 217 lbs, height 62 inches and body mass index (BMI) 39.7, enrolled in, a prospective observational safety study.  The maternal concurrent conditions included high BMI, acid reflux, asthma and bipolar affective disorder. The maternal concomitant medications included Albuterol (salbutamol), Xopenex (levosalbutamol hydrochloride), Qvar (beclometasone dipropionate), Singulair (montelukast sodium) and Symbicort (budesonide, formoterol fumarate), all used for asthma, Prenatal vitamins (unspecified minerals and vitamins) for pregnancy, Protonix (omeprazole) for acid reflux, Prozac (fluoxetine hydrochloride) and Seroquel (quetiapine fumarate), both used for bipolar disorder.   The maternal obstetrical history noted that the subject had no previous pregnancies. The neonate's mother had no maternal or paternal history major congenital malformation (MCM). The neonate's mother did not use alcohol, tobacco or illicit drugs during pregnancy. The father's age was not reported.  The neonate's mother last menstrual period (LMP) date was 26-Jun-2019, estimated delivery date (EDD) was reported as 07-May-2020, while corrected estimated date of delivery (CEDD) was not reported. The type of pregnancy was singleton.   On 12-Sep-2019, ultrasound revealed no MCM.  On 21-Nov-2019, ultrasound revealed no MCM.  On 30-Dec-2019, at 21 weeks of gestation (calculated per LMP), the neonate's mother 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 'fetal exposure during pregnancy') for influenza immunisation. The batch number was P100112488.  On the same day, 20-week anatomy ultrasound revealed no MCM.  At 39.6 weeks of gestation (as reported), the neonate's mother vaginally delivered a male neonate. The neonate's birth weight was 4054 g, head circumference and length were not reported. APGAR (appearance, pulse, grimace, activity and respiration) scores at one minute, at five minutes and at ten minutes were not reported. No MCM was identified at birth. No pregnancy complications were noted.  The outcome of the event 'high birthweight baby' was not reported.  The reporter did not provide a causality assessment.  The event of 'high birthweight baby' was considered to be medically significant by a physician within Seqirus's Pharmacovigilance and Risk Management Department.  This case is linked to 202001960 (the corresponding mother case).  Company comment: A male neonate was delivered as large for dates baby, after foetal exposure to Afluria QIV vaccine at 21 weeks of gestation. The neonate's birth weight was 4054 g. Per some sources, the range of normal is between 2.5 and 4.5 kilograms. The maternal concurrent conditions included high BMI, which may have contributed to development of the event. Considering all the above mentioned, causality between suspect product and the event large for dates baby is assessed as not related, due to mentioned confounder, chronological and biological implausibility. Foetal exposure during pregnancy assessed as not related per company's conventions.; Sender's Comments: A male neonate was delivered as large for dates baby, after foetal exposure to Afluria QIV vaccine at 21 weeks of gestation. The neonate's birth weight was 4054 g. Per some sources, the range of normal is between 2.5 and 4.5 kilograms. The maternal concurrent conditions included high BMI, which may have contributed to development of the event. Considering all the above mentioned, causality between suspect product and the event large for dates baby is assessed as not related, due to mentioned confounder, chronological and biological implausibility. Foetal exposure during pregnancy assessed as not related per company's conventions.