Foetal exposure during pregnancy; Birth weight 4167 g; This observational study case initially received on 18-Feb-2021 from other health professional and concerned a female neonate whose mother was 27-year-old pregnant, female subject of body weight 220 ibs, height 67 inches and body mass index (BMI) 34.5, enrolled in, a prospective observational safety study.   The maternal concurrent conditions included Rh-negative, BMI high and bilateral sciatic nerve pain. The maternal concomitant medications included Prenatal vitamin (unspecified vitamins and minerals) for pregnancy and cyclobenzaprine for sciatic nerve pain.  The maternal obstetrical history included two previous pregnancies with two spontaneous abortions. The neonate's mother had no maternal or paternal history with major congenital malformations (MCMs) and had no history of offspring with MCMs. The neonate's mother did not use tobacco, alcohol or illicit drugs during pregnancy.  The maternal last menstrual period (LMP) date was reported as 31-Aug-2019. The maternal estimated delivery date (EDD) was reported as 06-Jun-2020 and corrected estimated data of delivery (CEDD) was reported as 12-Jun-2020. The type of pregnancy was singleton.  On 25-Oct-2019, the ultrasound revealed no MCMs.  On 26-Nov-2019, the nuchal translucency revealed thickened nuchal fold. No MCMs were noted. The non-invasive prenatal testing (NIPT) revealed no MCMs.  On 26-Dec-2019, the maternal serum alpha-fetoprotein screening (MSAFP)/serum markers revealed no MCMs.  On 27-Jan-2020, at approximately 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, anatomical location and route of administration: not reported) (explicitly coded as 'Foetal exposure during pregnancy') for influenza immunisation. The batch number reported was P100112488.  On the same day, the 20-week anatomy ultrasound revealed no MCMs.  On 24-Feb-2020, 28 days after vaccination, the neonate's mother experienced acid reflux and started treatment with Pepcid (famotidine) at dose of 20 mg, every day, orally.  At 41 weeks of gestation (as reported), the mother delivered live birth, female neonate via vaginal delivery method. The neonate's birth weight was 4167 g, body length, head circumference and 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 on delivery.  The outcome of event 'high birthweight baby' was not reported.  The reporter did not provide a causality assessment.  The event 'high birthweight baby' was considered to be medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.  The case is linked to 202002688, the corresponding mother case.  Company comment: A female neonate was exposed to the suspect product, Afluria QIV. The neonate's mother was vaccinated with Afluria QIV at approximately 21 weeks of gestation. Neonate's weight on birth was 4167 grams. Causality between suspect product and event of large for dates baby is assessed as not related due to biological implausibility. Per some sources, the range of normal is between 2.5 and 4.5 kilograms. Foetal exposure during pregnancy is assessed as not related per company's conventions.; Sender's Comments: A female neonate was exposed to the suspect product, Afluria QIV. The neonate's mother was vaccinated with Afluria QIV at approximately 21 weeks of gestation. Neonate's weight on birth was 4167 grams. Causality between suspect product and event of large for dates baby is assessed as not related due to biological implausibility. Per some sources, the range of normal is between 2.5 and 4.5 kilograms. Foetal exposure during pregnancy is assessed as not related per company's conventions.