Pre-term birth; Foetal exposure during pregnancy; This is a serious spontaneous case, initially received from other health professional on 07-Jun-2019, concerning a female neonate patient.  The patient's mother was a 20-year-old female of height 61.5 inches, weight 94 pounds and body mass index (BMI) 17.5. The patient's mother had 1 previous pregnancy which was a preterm live birth with no birth defects. The patient's mother had no history of offspring with major congenital malformation. Also, the patient's mother had no maternal or paternal history with major congenital malformations.   The last menstrual period (LMP) date of the patient's mother was 23-Mar-2018. The type of pregnancy was singleton. The pregnancy status of the patient was collected, and no pregnancy complications were noted. The paternal age was reported as 32 years.   The patient's mother had not used tobacco or alcohol during her current pregnancy. The mother's historical conditions included yeast plus bacterial vaginosis. The mother's historical drugs included Metrogel (metronidazole) (from 30-Jul-2018 to 21-Dec-2018) for yeast plus bacterial vaginosis.  On 22-Aug-2018, the patient's mother had ultrasound and no major congenital malformation was noted. On 19-Sep-2018, the patient's mother had undergone quad screen test and no major congenital malformation was noted.  On 18-Oct-2018, at approximately 30 weeks of gestation, the patient's mother received Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, cell culture derived, batch number: 252664, route of administration, dose, anatomical location and expiry date: not reported] for an unknown indication and the foetus was exposed to Flucelvax QIVc via transplacental route (explicitly coded as foetal exposure during pregnancy).  On the same day, the patient's mother experienced anaemia.   On 11-Dec-2018, the patient's mother underwent ultrasound and no major congenital malformation was noted.  2 months and 3 days after vaccination, at gestational age of 33.1 weeks (reported as pre-term birth), the patient's mother delivered a normal live female neonate via vaginal method of delivery. The neonate's birth weight was 3374 grams, head circumference was 31.8 cm and body length were 45.1 cm. The APGAR scores were 8 (one minute) and 9 (five minutes). APGAR score was not reported at 10 minutes. There were no major congenital malformations (MCM) identified at birth.   The mother's estimated delivery date (EDD) and corrected EDD, both were reported as 07-Feb-2019.  This case is linked to 201903706 (mother case).; Reporter's Comments: A female neonate patient experienced preterm birth, 2 months 3 days after maternal receipt of Flucelvax QIVc at approximately 30 weeks of gestation (considered as foetal exposure during pregnancy). Considering the underlying maternal anaemia (risk factor) and previous obstetric history of preterm birth, which provide more plausible explanation, the event preterm birth assessed as not related to suspect vaccine. The event foetal exposure during pregnancy assessed as not related considering the intended use of the vaccine. The case will be further assessed upon receipt of follow-up information. The company assessed this case as serious (medically significant).