Polyhydramnios; Large for gestational age (LGA); Fetal exposure during pregnancy; This is an observational study case, initially received from other health professional on 24-Feb-2020, concerning a foetus subject, whose mother was a 39-year-old female, of body weight 219 lbs, height 62 inches and body mass index (BMI) 40.1, enrolled in, a prospective observational safety study.  The mother's medical history included increased BMI, advanced maternal age pregnancy, gastroesophageal reflux disease and gestational diabetes.  The subject's mother's concomitant medications included metformin for gestational diabetes, Concept DHA (ascorbic acid, biotin, calcium pantothenate, copper sulfate, cyanocobalamin, ferrous fumarate, fish oil, folic acid, magnesium sulfate, nicotinic acid, polysaccharide-iron complex, pyridoxine hydrochloride, riboflavin, thiamine mononitrate, zinc acetate) for pregnancy, omeprazole for gastroesophageal reflux disease, butalbital-acetaminophen for headaches, ferrous sulfate for anemia and promethazine for nausea  The mother had two previous pregnancies with two full term live births. The subject's mother had no maternal or paternal history with major congenital malformations (MCMs). The mother did not use tobacco, alcohol or illicit drugs during pregnancy.   The mother's last menstrual period (LMP) was on 16-Apr-2019 and type of pregnancy was singleton. The estimated delivery date (EDD) was reported as 21-Jan-2020 and corrected estimated date of delivery (CEDD) of subject's mother was not reported. The paternal age was not reported. The pregnancy was complicated by headache, anemia and nausea.  On 25-Jun-2019, the subject's mother underwent non-invasive prenatal testing and no MCM was noted.   On 09-Jul-2019, the subject's mother underwent nuchal translucency ultrasound and no MCM was noted.   On 09-Aug-2019, the subject's mother underwent maternal serum alpha-fetoprotein screening (MSAFP)/ serum markers and no MCM was noted.  At approximately 26 weeks of gestation, the mother was administered Afluria QIV (Flu Vaccine Egg Split QIV CSL) [influenza vaccine, batch number: P100112488, dose, route of administration, anatomical location and expiration date: not reported] (explicitly coded as Foetal exposure during pregnancy') for an influenza immunization.   On an unknown date in 2019, polyhydramnios was noted. Also, it was noted that the subject was large for gestational age, however, further details were not provided.     On 31-Dec-2019, at 37 weeks of gestation, the mother vaginally delivered a live, male neonate of birth weight 3310 grams. The neonate's head circumference and body length were not reported. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 8 (one minute) and 9 (five minutes). APGAR score was not reported for 10 minutes. There was no MCM identified at birth.   At the time of initial reporting, the outcome of the events large for gestational age' and polyhydramnios' was not reported.   The events of polyhydramnios' and large for gestational age' were considered serious due to the criterion of medical significance, per company.   The reporter did not provide causality assessment to Afluria QIV.  This case is linked to the case 201905998 (the corresponding mother case).  Company comment: Reportedly, large for dates baby and polyhydroamnios were noted on an unknown date in 2019. A subject's mother was administered Afluria QIV at approximately 26 weeks of gestation. Chronology needs more clarification. However, birth weight on delivery was 3310 grams. Causality was highly confounded by mother's medical history of gestational diabetes, BMI increased and advanced maternal age, however causal role of the suspect vaccine cannot be totally excluded and is assessed as unlikely related (defaults to "related" in the safety database for reporting purposes). Foetal exposure during pregnancy is assessed as unrelated per company's conventions.; Sender's Comments: Reportedly, large for dates baby and polyhydroamnios were noted on an unknown date in 2019. A subject's mother was administered Afluria QIV at approximately 26 weeks of gestation. Chronology needs more clarification. However, birth weight on delivery was 3310 grams. Causality was highly confounded by mother's medical history of gestational diabetes, BMI increased and advanced maternal age, however causal role of the suspect vaccine cannot be totally excluded and is assessed as unlikely related (defaults to "related" in the safety database for reporting purposes). Foetal exposure during pregnancy is assessed as unrelated per company's conventions.