Neonate's birth weight was 4196 grams/large for gestational age; Foetal exposure during pregnancy; This is a serious spontaneous case reported by other health professional and initially received on 31-May-2019 and follow-up 1 received on 04-Jun-2019 (being processed together), concerning a male neonate patient.  The patient's mother of age 25-year-old with body weight: 189 lbs, height: 68 inches and body mass index (BMI): 28.7, had one previous pregnancy, which included full term live birth. The patient's mother had no history of offspring with major congenital malformation. The maternal history of the patient's mother included wildervanck syndrome in sister. The patient's mother had no paternal history with major congenital malformations. The patient's mother did not have a prior history of use of tobacco, alcohol or illicit drugs during pregnancy. The concomitant medications of the patient's mother included Prenatal vitamins (minerals nos, vitamins nos) for pregnancy.  The patient's mother's last menstrual period (LMP) date was 19-Jun-2018. The type of pregnancy was singleton. The pregnancy status of the patient's mother was collected and there were no complications noted.  On 14-Aug-2018, the patient's mother underwent spinal muscular atrophy screening and cystic fibrosis mutation analysis with no congenital malformations noted. On 11-Sep-2018, the patient's mother underwent ultrasound scan and no congenital malformations were noted.  On 16-Oct-2018, the patient's mother (gestation period: 17 weeks) was administered Flucelvax QIVc (influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 252664, dose, route of administration, expiry date and anatomical location: not reported) for an unknown indication. The patient was exposed to Flucelvax QIVc via transplacental route (explicitly coded as foetal exposure during pregnancy).    On the same day, the patient's mother underwent ultrasound scan and no congenital malformations were noted. On 25-Oct-2018, the patient's mother underwent quad screen test (prenatal test), and no major congenital malformation was noted. On 26-Mar-2019, the patient's mother started treatment with Colace (docusate sodium) (dose: 1 unit, route: oral, frequency: twice daily, stop date: ongoing) for stool softener.  at 40 weeks of gestational age, the patient's mother gave a live birth to a male neonate by vaginal method. The characteristics of the neonate included birth weight: 4196 grams (explicitly coded as large for gestational age), head circumference: 35.6 cm, body length: 54.6 cm, appearance, pulse, grimace, activity, and respiration (APGAR) scores at one minute: 9, five minutes: 9 and ten minutes: no data was provided. The neonate had no major congenital malformations identified at birth.  The patient's mother estimated delivery date (EDD) was reported as 26-Mar-2019.  This case was linked to case 201903678 (mother case).; Reporter's Comments: A male neonate patient experienced large for gestational age (LGA), diagnosed at birth (40 weeks of gestation) after maternal receipt of Flucelvax QIVc (considered as foetal exposure during pregnancy) at 17 weeks of gestation. The known aetiologies of LGA includes genetic, increased maternal weight gain during pregnancy and maternal gestational diabetes. Considering the lack of biological evidence associated with suspect vaccine, the event large for gestational age, causality assessed as not related. The maternal BMI 28.7 is considered as known risk factor. The event foetal exposure during pregnancy assessed as not related considering the intended use of the vaccine.  The company assessed the case as serious (medically significant).