Polyhydramnios; Vaccine fetal exposure during pregnancy; This is an observational study case, initially received from other health professional on 30-Jan-2020, concerning a foetal subject of unknown gender, whose mother was 31-year-old, pregnant, female subject of body weight: 196 lbs, height: 63 inches and body mass index (BMI): 34.7 enrolled in a prospective observational safety study.  The mother's medical history included history of gestational hypertension and gestational diabetes mellitus and high body mass index.  The mother's concomitant medications included Prenatal vitamins (unspecified vitamins and minerals) for pregnancy, Claritin (Loratadine) for allergies, glyburide and metformin, both used for gestational diabetes mellitus.  The mother's last menstrual period (LMP) date was 03-Apr-2019. The type of pregnancy was singleton. The mother's estimated delivery date (EDD) was 08-Jan-2020 and corrected estimated delivery date (CEDD) was 13-Jan -2020. The subject's mother did not consume alcohol, tobacco and illicit drugs during pregnancy. The father's age was not provided. The pregnancy was complicated by A2 gestational diabetes mellitus and allergies.  On 02-Jul-2019, the subject's mother underwent first sequential and nuchal translucency. No MCM was noted.  On 30-Jul-2019, the subject's mother underwent second sequential and no MCM was noted.  On 29-Aug-2019, the subject's mother underwent targeted ultrasound and no MCM was noted.  On 24-Oct-2019, the subject's mother underwent growth on biophysical profile (BPP) ultrasound and no MCM was noted.  On 08-Nov-2019, at gestational age of 31 weeks, the subject's 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] for influenza immunisation (explicitly coded as 'Foetal exposure during pregnancy').  On an unknown date, the pregnancy status was collected and polyhydramnios was noted in fetus.  At the time of initial report, the outcome of polyhydramnios was not reported.  The event of polyhydramnios was considered serious due to the criterion of medical significance.  This reporter did not provide the causality assessment to Afluria QIV.  This case is linked to case 202001580 (the corresponding mother case).  Company Comment: Polyhydramnios was noted in fetus associated with the suspect product, Afluria QIV. Foetal exposure during pregnancy occurred at approximately 27 weeks of gestation. Chronology is very unclear. Pregnant state may provide alternative aetiology for the event. Foetal exposure during pregnancy is assessed as not related per company's conventions. Limited and unclear reported information concerning the event polyhydramnios precludes thorough causality assessment, therefore causality for the event is unassessable.; Sender's Comments: Polyhydramnios was noted in fetus associated with the suspect product, Afluria QIV. Foetal exposure during pregnancy occurred at approximately 27 weeks of gestation. Chronology is very unclear. Pregnant state may provide alternative aetiology for the event. Foetal exposure during pregnancy is assessed as not related per company's conventions. Limited and unclear reported information concerning the event polyhydramnios precludes thorough causality assessment, therefore causality for the event is unassessable.