Foetal exposure during pregnancy; Pre-term birth at 36.6 weeks of gestational age; This observational study case was received from other health professional  on 09-Mar-2021, concerning a male neonate, whoes mother was a 35-year-old female, pregnant subject of body weight 108 lbs, height 62 inches and body mass index (BMI) 19.8.   The maternal medical history included advanced maternal age. The maternal concomitant medications included Prenatal vitamins (unspecified vitamins and mineral) for healthy pregnancy.  The maternal obstetrical history included three previous pregnancies with one full term live birth and two elective abortions. The neonate's mother had no history of offspring with major congenital malformation (MCM). The neonate's mother had no maternal or paternal medical history with MCM. The neonate's mother did not use tobacco, alcohol or illicit drugs during pregnancy.  The maternal last menstrual period (LMP) date was 23-Jun-2020. Estimated delivery date (EDD) was reported as 30-Mar-2021 and corrected estimated date of delivery (CEDD) was not reported. The type of pregnancy was singleton.  On 02-Sep-2020, at approximately ten weeks of gestation (calculated per LMP), the neonate's mother was vaccinated with Afluria QIV (Flu Vaccine Egg Split QIV CSL) (influenza vaccine; dose, route of administration and  anatomical location: not reported) (explicitly coded as 'Fetal exposure during pregnancy') for influenza immunisation. The batch number reported was P100239705.  On an unknown date in Sep-2020, an unknown amount of time after receiving Afluria Quadrivalent, the neonate's mother had low potassium.  On 18-Sep-2020, panorama test revealed no MCMs.    On 19-Sep-2020, first trimester screen revealed no MCMs.    On 21-Sep-2020, the neonate's mother started treatment for low potassium with potassium chlorate, at a dose of 20 mcg, three times a day, administered orally.   On 03-Nov-2020, amniocentesis revealed no MCMs.  On 06-Nov-2020, the neonate's mother finished the treatment with potassium chloride.  At gestational age of 36.6 weeks (as reported), the mother delivered premature live male neonate via vaginal method of delivery. The birth weight of the neonate was 2781 g, head circumference 32 cm and length 49.5 cm. Appearance, pulse, grimace, activity and respiration (APGAR) score at one minute was 9, at five minutes was 9 and at ten minutes was not reported. There were no MCMs identified at birth.  The outcome of event 'premature birth' was not reported.  The reporter did not provide a causality assessment.  The event of 'premature birth' was considered to be medically significant by a Physician within Seqirus's.  The case is linked to the case 202007475 (corresponding mother case).  Company comment:The neonate was born as premature baby approximately 6 months after foetal exposure to the suspect product, Afluria QIV. Chronology is implausible. The maternal medical history of advanced maternal age confounds causality for the event. Causality between the suspect product and the event premature baby is assessed as not related due to biological and chronological implausibility and presented confounder. Foetal exposure during pregnancy is assessed as not related per company's conventions.; Sender's Comments: The neonate was born as premature baby approximately 6 months after foetal exposure to the suspect product, Afluria QIV. Chronology is implausible. The maternal medical history of advanced maternal age confounds causality for the event. Causality between the suspect product and the event premature baby is assessed as not related due to biological and chronological implausibility and presented confounder. Foetal exposure during pregnancy is assessed as not related per company's conventions.