Low birth weight/ birth weight 2466 grams; Foetal exposure during pregnancy; This is a serious spontaneous case, initially received from other health professional on 31-May-2019, concerning a female neonate patient. The patient's mother was 27-year-old with obstetrical history of one previous pregnancy reported with a full-term live birth and no birth defects. The historical condition of the patient's mother included bacterical vaginosis (since an unspecified date). The historical drug of patient's mother included Metrogel for bacterical vaginosis (from 10-Aug-2018 to 17-Aug-2018). The current condition of the patient's mother included rheumatoid arthritis. The concomitant medications of the patient's mother included ferrous sulfate for anemia, prenatal vitamins (minerals NOS, vitamins NOS) for pregnancy. The mother's last menstrual period (LMP) date was 15-Jun-2018. The patient's mother did not use tobacco, alcohol or illicit drugs during pregnancy. On 28-Aug-2018 and 04-Sep-2018, the patient's mother underwent ultrasound and no major congenital malformations were noted. On 02-Oct-2018, at gestational age of 15-weeks and 4 days, the foetus was exposed to Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, cell-culture-derived, route of administration: transplacental, batch number: 252664, dose, anatomical location and expiry date: not reported] (explicitly coded as foetal exposure during pregnancy) for an unknown indication.   On the same day, the patient's mother underwent cystic fibrosis mutation analysis and spinal muscular atrophy screening with no major congenital malformations noted.  On 17-Nov-2018, 28-Feb-2019 and 20-Mar-2019, the patient's mother underwent ultrasound, and no major congenital malformation was noted.  On 12-Apr-2019, 6 month and 10 days after vaccination, the mother delivered a female neonate at 38.3 weeks gestation, by caesarean method. At the time of delivery, no pregnancy complications were reported. The neonate's birth weight was 2466 grams (explicitly coded as low birth weight), head circumference was 33 cm and body length 49.5 cm. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 8 (at one minute), 9 (at five minutes) and there was no data for 10 minutes. There was no major congenital malformation noted.    The outcome of the events was unknown.   The mother's estimated delivery date (EDD) and corrected EDD, both were reported as 24-Apr-2019.  This case is linked to (201903657), the corresponding maternal pregnancy report.; Reporter's Comments: A female neonate patient experienced low birth weight, diagnosed (at birth) 6 months 10 days after maternal receipt of Flucelvax QIVc at 15 weeks 4 days of gestation(considered as foetal exposure during pregnancy). The maternal gestational history included anaemia, bacterial vaginosis and treatment medications included ferrous sulfate, metrogel respectively. Despite the plausible temporal relationship, the event low birth weight assessed as not related as the maternal gestational history provide more plausible explanation rather than suspect vaccine. Hence, causality assessed as not related. The event foetal exposure during pregnancy assessed as not related considering the intended use of the vaccine. The company assessed this case as serious (medically significant).