This is a serious observational study case, initially received from other health professional on 26-Mar-2019, concerning a 35-year-old, adult, female pregnant subject of height: 66 inches, body weight: 260 lbs and body mass index (BMI): 42, enrolled in a prospective observational safety study. The subject had no maternal and paternal history of major congenital malformations. The subject had no history of offspring with major congenital malformations. The subject had 2 previous pregnancies and no birth defects were reported. The subject's last menstrual period (LMP) date was 07-Apr-2018. The type of pregnancy was singleton. The subject did not use tobacco, alcohol or illicit drugs during pregnancy. The subject's current conditions included anxiety, hypertension and cardiomyopathy. The subject's concomitant medication included Prenatal vitamins for pregnancy and ZOLOFT for anxiety. On 02-Jul-2018, the subject had undergone spinal muscular atrophy, cystic fibrosis mutation and urine drug screening and no major congenital malformations were noted. On 09-Jul-2018, the subject had undergone ultrasound scan and subchorionic hematoma with no major congenital malformations were noted. On 06-Aug-2018, the subject had undergone ultrasound scan and subchorionic hematoma was resolved with no major congenital malformations. On the same day, the subject had undergone Q natal test and no major congenital malformations were noted. On 29-Aug-2018, the subject had undergone ultrasound scan and low-lying placenta with no major congenital malformations were noted. On the same day, the subject had undergone maternal serum alpha-fetoprotein (MSAFP/ serum markers) and no major congenital malformations were noted. On 26-Oct-2018, at gestation age of 28 weeks, the subject was administered Influenza Vaccine (batch number: 252664, dose, route of administration, anatomical location and expiry date: not reported) (explicitly coded as vaccine exposure during pregnancy) for an unknown indication. On 04-Dec-2018, 1 months and 8 days after vaccination, the subject experienced bronchitis. The subject was treated with ZITHROMAX (dose: 250 mg, frequency: as directed, from 04-Dec-2018 to 05-Dec-2018) orally. On 19-Dec-2018, 08-Jan-2019, 10-Jan-2019 and 22-Jan-2019, the subject had undergone ultrasound scan and no major congenital malformations were noted. The mother gave a live birth to a neonate of an unspecified gender at 38.9 weeks gestation vaginally. No major congenital malformations were identified at birth. The subject's pregnancy complication included dysmature placenta (placental disorder). The outcome of the event bronchitis was recovered on 05-Dec-2018 and the outcome of the event placental disorder was not reported. The subject's estimated delivery date (EDD) was 13-Jan-2019. The subject's corrected estimated delivery date (CEDD) was 12-Feb-2019. Reporter's Comments: A 35-year-old pregnant subject experienced bronchitis, 1 month 8 days after receipt of Flu Vaccine Cell Subunit QIV (at 28 weeks of gestation) (considered as vaccine exposure during pregnancy). Considering the infective aetiology (suspected bacterial) of the event bronchitis, the causal role of inactivated study vaccine is ruled out. Hence, sponsor assessed the causality as not related. The patient was diagnosed with dysmature placenta, unspecified period post vaccination. Despite lack of onset latency, the gestational history of the patient (low lying placenta and subchorionic hematoma) prior to vaccination, provide more plausible explanation of the event dysmature placenta rather than study vaccine. Hence, causality assessed as not related. The event vaccine exposure during pregnancy, assessed as not related considering the intended use of the vaccine. The company assessed the case as serious (medically significant).