Oligohydramnios; Foetal exposure during pregnancy; This is an observational study case, initially received from other health professional on 12-Dec-2019 with additional information received on 16-Dec-2019  (being processed together), concerning a male neonate whose mother was a 21-year-old subject of body weight: 160 lbs, height: 61.2 inches and body mass index (BMI): 30,  enrolled in a prospective observational safety study.  The subject's mother current conditions included obesity (body mass index 30) and iron deficiency.  The subject's mother concomitant medications Prenatal vitamins (minerals nos, vitamins nos) for OB (obstetrical care) and Fusion plus (ascorbic acid, biotin, cyanocobalamin, ferrous fumarate, folic acid, lactobacillus casei, nicotinic acid, pantothenic acid, polysaccharide-iron complex, pyridoxine hydrochloride, riboflavin, thiamine hydrochloride) for iron deficiency.  The subject's mother did not have previous pregnancies. The subject's mother did not have any history of offspring with major congenital malformation (MCM) and no paternal or maternal history with MCMs. The mother did not use tobacco, alcohol or illicit drugs during pregnancy. The paternal age was 24-year-old.  The mother's last menstrual period (LMP) date was on 20-Feb-2019, estimated delivery date (EDD) and corrected EDD (CEDD) was 27-Nov-2019. The pregnancy was singleton.   On 17-May-2019, nuchal translucency and first trimester screen were performed, no major MCMs was noted.  On 19-May-2019, second trimester screen and maternal serum alpha fetoprotein (MSAFP, serum markers) were performed, no major MCMs was noted.  On 09-Jul-2019, anatomy ultrasound was performed, no major MCMs was noted.  On 20-Sep-2019, at approximately 30 weeks of gestation, the subject received Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, dose: 0.5 ml, batch number: 261200, route of administration, expiry date and anatomical location: not reported] (explicitly coded as Foetal exposure during pregnancy') for influenza immunisation.  On 24-Sep-2019, the subject's mother developed yeast/vaginal itching, and was treated with metronidazole and fluconazole.  On an unspecified date in 2019, the oligohydramnios was noted.  At 39.5 weeks of gestational age, the subject's mother delivered live male neonate via caesarean method of delivery (per reporter failure to descend, oligohydramnios and arrest of dilation'). Neonate's birth weight was 3402 grams, body length and head circumference were not reported and the appearance, pulse, grimace, activity and respiration (APGAR) score one minute: 9, five minutes: 9 and ten minutes: not reported. There was no MCM identified at birth.  The event of oligohydramnios was assessed as serious due to medically significance per the company.   This case is linked with case 201907304 corresponding mother case.  Company comment: The subject's mother received vaccine at approximately 30 weeks of gestation. Oligohydramnios may also develop in a third trimester of pregnancy, however it is unknown when this adverse event was initially noted. Causality assessment is confounded by mother's obesity. Based on the currently available information the causal relationship between Flucelvax and oligohydramnios is considered unassessable. Foetal exposure during pregnancy is unrelated to Flucelvax.; Sender's Comments: The subject's mother received vaccine at approximately 30 weeks of gestation. Oligohydramnios may also develop in a third trimester of pregnancy, however it is unknown when this adverse event was initially noted. Causality assessment is confounded by mother's obesity. Based on the currently available information the causal relationship between Flucelvax and oligohydramnios is considered unassessable. Foetal exposure during pregnancy is unrelated to Flucelvax.