Foetal exposure during pregnancy; Polyhydramnios; This is an observational study case, initially received from other health professional on 09-Jun-2020, concerning a male foetus whose mother was 31-year-old, female, pregnant subject of body weight: 225 lbs, height: 65 inches and body mass index (BMI): 37.4, enrolled in, a prospective observational safety study on pregnancy outcomes in women immunized with seasonal cell culture influenza trivalent (TIVc) or quadrivalent (QIVc) vaccine during pregnancy.  The foetus mother's medical history included high BMI and headache.   The foetus mother's concomitant medications included Prenatal vitamins (unspecified vitamins and minerals) for pregnancy and Tylenol (paracetamol) for headache.  The foetus mother's obstetrical history included one previous pregnancy with one full term live birth. The foetus mother had no history of offspring with major congenital malformation (MCM). The subject's mother had no maternal and paternal medical history with MCM. The foetus mother did not use tobacco, illicit drug or alcohol during pregnancy.  The foetus mother's last menstrual period (LMP) date was 05-May-2019. The foetus mother's estimated delivery date (EDD) was on 09-Feb-2020 and corrected estimated date of delivery (CEDD) was on 01-Feb-2020. The type of pregnancy was singleton. The foetus father was a 29-year-old.  On 01-Aug-2019, the foetus mother underwent panorama test and no MCMs were noted.  On 06-Aug-2019, the foetus mother underwent ultrasound and no MCMs were noted.  On 23-Oct-2019, approximately at gestational age of 24 weeks (calculated per LMP), the foetus mother was administered with Flucelvax QIV (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent; dose: 0.5 ml, batch number reported as 262218 (Seqirus batch number: possibly 261218, unable to map definitively), route of administration, anatomical location and expiration date: not reported] (explicitly coded as Foetal exposure during pregnancy') for influenza immunisation.   On 24-Oct-2019, one day after vaccination, the subject's mother developed anaemia and was treated with ferrous sulfate, at dose of 325 mg, three times a day.  On 10-Nov-2019, 13-Dec-2019, 03-Jan-2020 and 16-Jan-2020, the foetus mother underwent ultrasound and no MCMs were noted.  On 31-Jan-2020, the pregnancy status was collected, and polyhydramnios was noted.  At gestational age of 39.9 weeks (as reported), the foetus mother vaginally delivered live birth male neonate. The neonate's birth weight was 3410 grams, head circumference was 34.3 cm and length were 53.3 cm. The appearance, pulse, grimace, activity, and respiration (APGAR) scores at one minute was 8, at five minutes was 9, while at ten minutes was not provided. No pregnancy complications were noted. No MCMs were identified at the time of birth.   On the same day, the outcome of the event polyhydramnios was resolved. Also, the foetus mother recovered from anaemia and treatment with ferrous sulphate was finished.  The event of polyhydramnios' was considered as serious due to criterion of medical significance, per company.  The reporter did not provide causality assessment to Flucelvax QIV.  This case is linked to case number 202002643 (the corresponding mother case).  Company Comment: A male foetus experienced foetal exposure to the suspect product Flucelvax QIVc. Foetus mother was administered Flucelvax QIVc at approximately 24 weeks of gestation. The event of polyhydramnios was noted 3 months 8 days after vaccination. The foetus mother's medical history included high BMI and headache treated with Tylenol (paracetamol). Causal role of the suspect product is assessed as not related, due to biological implausibility and unsuggestive chronology. Foetal exposure during pregnancy is assessed as not related per company conventions.; Sender's Comments: A male foetus experienced foetal exposure to the suspect product Flucelvax QIVc. Foetus mother was administered Flucelvax QIVc at approximately 24 weeks of gestation. The event of polyhydramnios was noted 3 months 8 days after vaccination. The foetus mother's medical history included high BMI and headache treated with Tylenol (paracetamol). Causal role of the suspect product is assessed as not related, due to biological implausibility and unsuggestive chronology. Foetal exposure during pregnancy is assessed as not related per company conventions.