Foetal exposure during pregnancy; Preterm birth at 35.4 gestational weeks; This is an observational study case, initially received from other health professional on 06-Apr-2020, concerning a female, neonate subject whose mother was 25-year-old female subject (Ethnicity: not reported) of body weight: 176 lbs, height: 69 inches and body mass index (BMI) 26, enrolled in, a prospective observational study on pregnancy outcomes in women immunized with Flucelvax, seasonal cell culture influenza trivalent (TIVc) or quadrivalent (QIVc) vaccine during pregnancy.  The subject's mother's current condition included increased BMI.  The subject's mother's concomitant medication included Prenatal vitamins (unspecified vitamins and minerals) for pregnancy.  The subject's mother's obstetrical history included three previous pregnancies with one full term live birth and two spontaneous abortions. The subject's mother did not have a history of offspring with major congenital malformation (MCM). The subject's mother had no maternal or paternal history with MCMs. The subject's mother did not use tobacco, alcohol or illicit drugs during pregnancy.  The subject's mother last menstrual period (LMP) date was 17-May-2019, the estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were reported as 21-Feb-2020. The type of pregnancy was singleton. The subject's father was a 25-year-old.  On 21-Jun-2019, the subject's mother underwent spinal muscular atrophy and cystic fibrosis mutation analysis and no MCM was noted.   On 23-Jul-2019, the subject's mother underwent ultrasound scan and no MCM was noted.   On 06-Aug-2019, the subject's mother underwent panorama test and no MCM was noted.   On 10-Sep-2019, the subject's mother underwent ultrasound scan and no MCM was noted.   On 08-Oct-2019, at approximately 20 weeks of gestation (calculated per LMP), the subject's mother was administered Flucelvax QIV (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent; dose: 0.5 ml, batch number: 261218, route of administration, anatomical location and expiry date: not reported] (explicitly coded as 'Foetal exposure during pregnancy') for influenza immunisation.   On 08-Nov-2019, the subject's mother underwent ultrasound scan and no MCM was noted.   at 35.4 weeks of gestation (as reported), the mother delivered live birth female neonate, by caesarean method of delivery. The neonate's birth weight was 2600 grams, head circumference and body length were not reported. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 9 at one minute and 9 at five minutes. APGAR score was not reported for 10 minutes. There was no major congenital malformation identified at birth.   At the time of this report, the outcome of event premature birth' was not reported.   The event of premature birth' was assessed as serious due to the criterion of medical significance, per company.   The reporter did not provide causality assessment.  This case is linked to 202002773 (the corresponding mother's case).  Company comment: A pregnant subject experienced premature delivery, 3 months and 10 days after receiving Flucelvax QIV. Chronology is unsuggestive. The subject's medical history included increased BMI. Causal role of the suspect vaccine cannot be excluded and is assessed as unlikely related (defaults to "related" in the safety database for reporting purposes). Vaccine exposure during pregnancy assessed as not related per company's conventions.; Sender's Comments: A pregnant subject experienced premature delivery, 3 months and 10 days after receiving Flucelvax QIV. Chronology is unsuggestive. The subject's medical history included increased BMI. Causal role of the suspect vaccine cannot be excluded and is assessed as unlikely related (defaults to "related" in the safety database for reporting purposes). Vaccine exposure during pregnancy assessed as not related per company's conventions.