Foetal exposure during pregnancy; Preterm birth; This is an observational study case, initially received from other health professional on 27-Nov-2019, concerning a female neonate whose mother was a 27-year-old, pregnant female subject of body weight: 160 lbs, height: 63 inches and body mass index (BMI): 28.3, 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 subject's father was a 26-year-old.  The subject's mother medical history included increased BMI. The mother's concomitant medications included Prenatal (ascorbic acid, betacarotene, calcium carbonate, colecalciferol, cyanocobalamin, dl-alpha tocopheryl acetate, ferrous fumarate, folic acid, nicotinamide, pyridoxine hydrochloride, riboflavin, thiamine mononitrate, zinc oxide) for pregnancy.  The subject's mother had no previously pregnancies. The subject's mother had no history of offspring with major congenital malformation (MCM) and no relevant maternal and paternal medical history. The mother did not use tobacco, alcohol or illicit drugs during pregnancy.   The subject's mother last menstrual period (LMP) date was 08-Feb-2019. The type of pregnancy was singleton. The subject's mother estimated delivery date (EDD) was reported as 15-Nov-2019 and corrected estimated date of delivery (CEDD) was reported as 17-Nov-2019.   On 12-Apr-2019, the mother underwent ultrasound scan and MCM was noted.   On 03-May-2019, the mother underwent first trimester screen and no MCM was noted.   On 18-Oct-2019, approximately at 36 weeks of gestation, the subject's mother was administered Flu Vaccine Cell Subunit QIV NVD (Flucelvax QIV) [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 261226, dose: 0.5 ml, route of administration, anatomical location and expiration date: not reported] (explicitly coded as Foetal exposure during pregnancy') for an influenza immunization.  four days after vaccination, at gestational age of 36.3 weeks, the subject's mother vaginally delivered a normal, female neonate of body weight 2991 grams, head circumference 34.9 cm and body length 48.3 cm. 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 MCM identified at birth.  The event of 'premature birth' is considered serious due to criterion of medically significance, per company.  The reporter did not provide causality assessment.  This case is linked to cases 201907041 (mother case).  Company comment: Subject's mother received Flucelvax at approximately 36 weeks of gestation. Four days after vaccination, at gestational age of 36.3 weeks, a neonate was delivered, which was reported as preterm birth. Causality assessment is confounded by subject's increased BMI (28.3) and use of concomitant medications. Nevertheless, causal involvement of vaccine is not excluded, therefore the event of preterm birth is assessed as possibly related to Flucelvax. Foetal exposure is assessed as unrelated to the suspect product per company's conventions.; Sender's Comments: Subject's mother received Flucelvax at approximately 36 weeks of gestation. Four days after vaccination, at gestational age of 36.3 weeks, a neonate was delivered, which was reported as preterm birth. Causality assessment is confounded by subject's increased BMI (28.3) and use of concomitant medications. Nevertheless, causal involvement of vaccine is not excluded, therefore the event of preterm birth is assessed as possibly related to Flucelvax. Foetal exposure is assessed as unrelated to the suspect product per company's conventions.