This is a serious observational study case initially received on 23-May-2019, concerning a 23-year-old, adult female, pregnant subject of body weight 224.2 lbs, height 65.5 inches and body mass index (BMI) 36.7, enrolled in, a prospective observational safety study on pregnancy outcomes in women immunized with AFLURIA QIV, a seasonal quadrivalent vaccine, during pregnancy. The subject did not have previous pregnancy. Also, the subject had no maternal or paternal history with major congenital malformations. The subject did not have a prior history of use of tobacco, alcohol or illicit drugs during pregnancy. The subject's concomitant medication included prenatal vitamin plus calcium carbonate. The subject's last menstrual period (LMP) date was 17-Aug-2018. The type of pregnancy was singleton. On an unspecified date, the pregnancy status was collected and there were no complications noted. On 16-Oct-2018, at gestational age of 08 weeks, the subject was administered Flu Vaccine Egg Split QIV CSL (influenza vaccine, batch number: YF41608, dose, route of administration, anatomical location and expiry date: not reported) (explicitly coded as vaccine exposure during pregnancy) for an unknown indication. On the same day (16-Oct-2018), the subject underwent ultrasound scan and no major congenital malformations were noted. On 14-Nov-2018, the subject underwent nuchal translucency test and sequential (trimester) 1 screening, but no major congenital malformations were noted. On 12-Dec-2018, the subject underwent sequential (trimester) 2 screening and no major congenital malformations were noted. On 27-Feb-2019, 4 months and 11 days after vaccination, the subject experienced anaemia. The subject was treated with iron (start date: 01-Mar-2019, dose: 325 mg, frequency: qd, route: oral and stop date: 27-Mar- 2019). On 27-Mar-2019, 5 months and 11 days after vaccination, the subject developed gestational diabetes. The subject was treated with Humulin-NPH (insulin human injection, isophane, start date: 17-Apr-2018, dose: 6 units, frequency: qd, route of administration: subcutaneous and stop date: reported as ongoing). On 22-Apr-2019, 6 months and 6 days after vaccination, the subject was found to be positive for Group B Streptococcus infection. The outcome of the events gestational diabetes mellitus and group B streptococcus infection was not recovered (reported as ongoing) and anaemia was recovered on 27-Mar-2019. 7 months and 3 days after vaccination, at gestational age of 39.3 weeks, the subject delivered a male neonate by caesarean method of delivery. The neonate birth weight was 3827 grams. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 8 (one minute), 9 (five minutes) and no data was provided at ten minutes. There was no major congenital malformation noted. The subject's estimated date of delivery (EDD) was reported as 24-May-2019.; Reporter's Comments: A 23-year-old pregnant subject was diagnosed with anaemia, 4 months 11 days after receipt of Flu Vaccine Egg Split QIV at 8 weeks 1 day of gestation (considered as vaccine exposure during pregnancy) and gestational diabetes, 5 months 11 days post vaccination. The subject was also diagnosed with Group B Streptococcus positive, 6 months 6 days post vaccination. Considering the infectious (bacterial) aetiology of the event Group B Streptococcus infection, the causal role of study vaccine assessed as not related. Despite plausible temporal relationship, the events (anaemia and gestational diabetes) lack investigational evidence in association with study vaccine and the pregnant state of the subject provide more plausible explanation rather than study vaccine. Hence, the events anaemia and gestational diabetes assessed as not related to study vaccine. 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).