Foetal exposure during pregnancy; Birth weight 4255 g; This is an observational study case from, initially received from other health professional on 20-May-2020, concerning a male neonate, whose mother was 31-year-old, pregnant, female subject of body weight 187.5 lbs, height 66.5 inches and body mass index (BMI) 29.9, enrolled in, a prospective observational safety study.  The subject's mother's medical history included BMI high, mild bipolar disorder, anxiety, depression, attention deficit hyperactivity disorder (ADHD), nausea and decreased levels of vitamin D3.  The subject's mother's concomitant medications included Unisom (doxylamine succinate) and vitamin B6, both for nausea, sertraline hydrochloride for anxiety, Prenatal vitamins (unspecified vitamins and minerals) for pregnancy and Vitamin D3 (colecalciferol) for decreased levels of vitamin D3.  The subject's mother's obstetrical history included three previous pregnancies, with one full term live birth and two elective abortions. The subject's mother had no maternal or paternal history with major congenital malformations (MCMs). The subject's mother had history of offspring with MCMs including fetal leukemia and tumor lysis syndrome (decreased shortly after birth, as reported). The subject's mother did not use tobacco, alcohol or illicit drugs during pregnancy.  The subject's mother's last menstrual period (LMP) date was 02-Aug-2019, the estimated delivery date (EDD) was reported as 08-May-2020 and corrected estimated date of delivery (CEDD) was not reported. The type of pregnancy was singleton.  The subject's father's age was not provided.  On 02-Oct-2019, the subject's mother underwent ultrasound and no MCMs were noted.  On 09-Oct-2019, at gestational age of nine weeks (calculated per LMP), the subject's mother was administered Afluria QIV (Flu Vaccine Egg Split QIV CSL) [influenza vaccine; batch number: P100123038, dose, anatomical location, route of administration and expiration date: not reported] (explicitly coded as Foetal exposure during pregnancy') for influenza immunization.  On the same day, the subject's mother underwent prenatal blood work and no MCMs were noted.  On 15-Oct-2019, the subject's mother underwent gonorrhoea (GC) and chlamydia cultures test and no MCMs were noted.  On 01-Nov-2019, the subject's mother underwent first trimester screen and no MCMs were noted.  On 04-Dec-2019, the subject's mother underwent maternal serum alpha-fetoprotein (MSAFP/serum markers) and no MCMs were noted.  On 20-Dec-2019, the subject's mother underwent anatomic scan and no MCMs were noted.  On 17-Jan-2020, 3 months 8 days after vaccination, the subject's mother developed gastroesophageal reflux disease (GERD) and started treatment for it with Pepcid (famotidine) at the dose of one tablet, twice a day, administered orally.   at gestational age of 39.9 weeks (reported as), the subject's mother vaginally delivered a live birth male neonate. The birth weight of neonate was 4255 g. Head circumference was 36.2 cm and length were 52.7 cm.  Appearance, pulse, grimace, activity and respiration (APGAR) score at one minute was 7 and at five minutes was 9. APGAR score for 10 minutes was not provided.  No pregnancy complications were noted. No MCM was identified at birth.  At the time of this report, the outcome of the event large for dates baby' was not reported.  The event of large for dates baby' was assessed as serious due to criterion of medical significance, per company.  The reporter did not provide causality assessment.  This case is linked to the case 202001664, the corresponding mother case.  Company Comment: A male neonate subject was large for dates baby (according to birth weight of 4255 g) after foetal exposure to Flucelvax QIVc. Vaccine was administered at gestation age of 9 weeks. Baby was born 6 months 28 days later. The subject's mother's medical history included BMI high, mild bipolar disorder, anxiety, depression, attention deficit hyperactivity disorder (ADHD), nausea and decreased levels of vitamin D3. The subject's mother's concomitant medications included Unisom (doxylamine succinate) and vitamin B6, both for nausea, sertraline hydrochloride for anxiety, Prenatal vitamins (unspecified vitamins and minerals) for pregnancy and Vitamin D3 (colecalciferol) for decreased levels of vitamin D3. Causal role of the suspect vaccine is assessed as not related, due to presented confounders and unsuggestive chronology. Foetal exposure during pregnancy is assessed as not related per company's conventions.; Sender's Comments: A male neonate subject was large for dates baby (according to birth weight of 4255 g) after foetal exposure to Flucelvax QIVc. Vaccine was administered at gestation age of 9 weeks. Baby was born 6 months 28 days later. The subject's mother's medical history included BMI high, mild bipolar disorder, anxiety, depression, attention deficit hyperactivity disorder (ADHD), nausea and decreased levels of vitamin D3. The subject's mother's concomitant medications included Unisom (doxylamine succinate) and vitamin B6, both for nausea, sertraline hydrochloride for anxiety, Prenatal vitamins (unspecified vitamins and minerals) for pregnancy and Vitamin D3 (colecalciferol) for decreased levels of vitamin D3. Causal role of the suspect vaccine is assessed as not related, due to presented confounders and unsuggestive chronology. Foetal exposure during pregnancy is assessed as not related per company's conventions.