Marginal umbilical cord insertion; Birth weight (g): 4593/Large for gestational age; Fetal exposure during pregnancy; This is a serious spontaneous case, initially received from other health professional on 18-Jun-2019, concerning a male neonate patient.  The patient's mother was a 31-year-old female of body weight 213.8 lbs, height 59 inches and body mass index (BMI): 43.2. The patient's mother had 3 previous pregnancies in which two were full term live births and the one was ectopic pregnancy with no birth defects. The patient's mother had no history of offspring with major congenital malformations. The patient's mother had no paternal history with major congenital malformations. The patient's mother had congenital heart defect. The mother's concomitant medication included Prenatal vitamins (minerals nos, vitamins nos) as supplement.  The last menstrual period (LMP) date of the patient's mother was 24-Aug-2018. The type of pregnancy was singleton. The patient's mother had not used tobacco, alcohol or illicit drugs during her current pregnancy.   On 04-Oct-2018, approximately at 6 weeks gestation, the foetus was exposed to Afluria Quadrivalent [influenza vaccine, route of administration: transplacental, batch number: YF40408, dose, anatomical location, and expiry date: not reported] (explicitly coded as fetal exposure during pregnancy) for an unknown indication.   On 15-Oct-2018, 11 days after the vaccine administration, the patient's mother experienced constipation and was treated with Colace (docusate sodium, dose: 1 tablet, prn, orally from 15-Oct-2018 to ongoing).  On 26-Oct-2018, the patient's mother underwent ultrasound and no major congenital malformation was noted.  On 16-Nov-2018, the patient's mother underwent sequential 1 (prenatal test), nuchal translucency test and inheritest core and no major congenital malformations were noted.  On 13-Dec-2018, patient's mother underwent sequential 2 (prenatal test) and no major congenital malformation was noted.  On 22-Mar-2019, 5 months and 18 days after vaccination, the patient's mother experienced polyhydramnios. On 05-Apr-2019, 6 months and 1 day after vaccination, the patient's mother experienced anemia and was treated with iron (dose: 325 mg, qd, oral, from 05-Apr-2019 to ongoing). On 26-Apr-2019, 6 months and 22 days after vaccination, the patient's mother was found to be positive for group B Streptococcus.  On 28-May-2019, 7 months and 24 days after vaccination, live normal neonate was delivered at 39.6 gestational week by caesarean method. The male neonate (patient) weighed 4593 grams (explicitly coded as large for gestational age), body length and head circumference were not reported. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 9 (at one minute) and 9 (at five minutes). The pregnancy complication noted at the time of birth was marginal umbilical cord insertion. No major congenital malformations (MCMs) were identified at birth.  The mother's estimated delivery date (EDD) and corrected EDD, both were reported as 31-May-2019.  The outcome of the events was not reported.  This case is linked to 201903600 (the corresponding mother case).; Reporter's Comments: A male neonate patient was delivered at 39.6 weeks with large for gestational age weight (4593 grams) and found to have marginal umbilical cord insertion, after foetal exposure to vaccine during 6th week of gestation. Considering no known biological mechanism, the events were considered as not related to suspect vaccine. progressive age of the mother (31 years). BMI 43.2 can be considered as confounding factors. The decision to administer a vaccine during pregnancy is related to medical decision making by the mother and her physician and is not related to any property of the medication. The event of exposure during pregnancy was assessed as not related considering the intended use of the vaccine.   The company assessed the case as serious (medically significant).