Malpresentation, breech; Foetal exposure during pregnancy; Neonate's birth weight was 4230 g; This is an observational study case, initially reported by other health professional on 20-Feb-2020, concerning a male, neonate subject whose mother was 29-year-old, female, of body weight 140 lbs, height 64.8 inches and body mass index (BMI) 23.4, enrolled in, a prospective observational safety study.   The subject's mother's medical history included hypothyroidism, nausea, vomiting and asymptomatic bacteriuria in pregnancy.  The subject's mother's concomitant medications included TDAP (diphtheria vaccine toxoid, pertussis vaccine acellular, tetanus vaccine toxoid) as vaccine, ondansetron for nausea and vomiting, levothyroxine for hypothyroidism, amoxicillin for asymptomatic bacteriuria in pregnancy, unspecified vitamins as obstetrical (OB) supplement and azelaic acid for an unknown indication.  The subject's mother's obstetrical history noted that the mother had no previous pregnancies. The subject's mother had no history of offspring with major congenital malformation (MCM). The mother's great grandfather had malignant tumour of colon, while mother's mother, grandmother and aunt all had thyroid gland disorder. The subject's father had polycystic kidney disease (adult type). The subject's mother did not use tobacco, alcohol or illicit drugs during pregnancy.   The subject's mother last menstrual period (LMP) date was 06-May-2019, while the estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were both reported as 10-Feb-2020. The type of pregnancy was singleton. The subject's father was a 31-year-old.  On 03-Jul-2019, the subject's mother underwent initial ultrasound. No MCMs were noted.  On 31-Jul-2019, the subject's mother underwent nuchal translucency and first trimester screen. No MCMs were noted.  at approximately 20 weeks of gestation, the subject's mother was administered Flucelvax QIVc (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number reported as 261200, dose: 0.5 mL, route of administration, anatomical location and expiration date: not reported] (explicitly coded as 'Foetal exposure during pregnancy') for an influenza immunisation.   On the same day, the subject's mother underwent anatomy ultrasound and no MCMs were noted.  On an unspecified date, it was noted that the subject was in breech position in uterus.  On 15-Feb-2020, at approximately 40.7 weeks of gestation, the mother delivered a live male neonate via caesarean method. The neonate's birth weight was 4230 grams, body length and head circumference were not reported. The appearance, pulse, grimace, activity, and respiration (APGAR) score at one minute was 6, at five minutes was 9 and no data was provided at ten minutes. No MCMs were identified at the time of birth.   At the time of initial reporting, the outcome for the events of 'breech presentation' and 'high birthweight baby' was not reported.  The events of 'breech presentation' and 'high birthweight baby' were considered as serious due to criterion of medical significance, per company.  The causality assessment was not provided.  This case is linked to the case 202001886, the corresponding mother case.  Company comment: Reportedly, breech presentation and large for dates baby were associated with Flucelvax QIV. The patient's mother was vaccinated at approximately 20 weeks of gestation. The event of breech presentation was noted on an unspecified date and large for dates baby was noted on delivery. Chronology needs more clarification. Most breech presentations seem to be chance occurrences and in up to 15% of cases, it may be due to foetal or uterine causes. Foetal exposure during pregnancy and breech presentation are assessed as not related. Considering usuggestive chronology and highly confounded causality by medical history of hypothyroidism, causal role of the suspect vaccine is assessed as not related for the event large for dates baby.; Sender's Comments: Reportedly, breech presentation and large for dates baby were associated with Flucelvax QIV. The patient's mother was vaccinated at approximately 20 weeks of gestation. The event of breech presentation was noted on an unspecified date and large for dates baby was noted on delivery. Chronology needs more clarification. Most breech presentations seem to be chance occurrences and in up to 15% of cases, it may be due to foetal or uterine causes. Foetal exposure during pregnancy and breech presentation are assessed as not related. Considering usuggestive chronology and highly confounded causality by medical history of hypothyroidism, causal role of the suspect vaccine is assessed as not related for the event large for dates baby.