This is a serious observational study case, initially received on 13-May-2019, concerning a 38-year-old adult female, pregnant subject, of body weight 141 lbs, height 60 inches and body mass index (BMI) 27.5, enrolled in a prospective observational safety study. The subject's obstetrical history noted that the subject had 3 previous pregnancies with 1 full term live births, one molar pregnancy and one pregnancy with spontaneous abortion. No birth defects were reported. The subject had no history of offspring with major congenital malformation. 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 last menstrual period (LMP) date was 27-Aug-2018. The type of pregnancy was singleton. The subject's pregnancy status was collected, and no pregnancy complications were noted. The subject's current conditions included genital herpes simplex, migraine and asthma since an unspecified date. The subject's concomitant medication included Valacyclovir for genital herpes simplex. On 25-Oct-2018, at approximately 08 weeks gestation, the subject was administered Flu Vaccine Egg Split QIV CSL (dose, route of administration, anatomical location, batch number and expiry date: not reported) for an unknown indication. On 26-Nov-2018, the subject underwent prenatal screening test (nuchal translucency) and no major congenital malformations were noted. On 24-Dec-2018, the subject underwent maternal serum alpha-fetoprotein (MSAFP)/serum markers and no major congenital malformations were noted. On 25-Dec-2018, the subject underwent ultrasound scan and no major congenital malformations were noted. On 12-Mar-2019, 4 months and 15 days after vaccination, the subject developed gestational diabetes. On 01-Apr-2019, 5 months and 7 days after vaccination, the subject developed anaemia. On the same day, the subject was treated with ferrous sulfate [dose: 325 mg, route of administration: oral, frequency: daily (qd) and stop date: reported as ongoing] for anaemia. On 16-Apr-2019, the subject started to take Preplus iron (as reported) [dose: 27 mg, route of administration: oral, frequency: daily (qd) and stop date: reported as ongoing] as a supplement for anaemia. The outcome of the events gestational diabetes and anaemia was not recovered (reported as ongoing). The subject's estimated date of delivery (EDD) was reported as 03-Jun-2019. Reporter's Comments: A 38-year-old pregnant subject with obstetrical history (3 previous pregnancies with 1 full term live birth, one molar pregnancy and one pregnancy with spontaneous abortion) experienced gestational diabetes, 4 months 15 days after administration of study vaccine and anaemia 5 months and 7 days post vaccination, administered at 8 weeks of gestation. Considering the implausible temporal relationship between vaccination and reported events, advanced maternal age, significant obstetrical history and no evidence suggesting a biological mechanism that could cause the events, the events were assessed as not related to the study vaccine. The reported events appear to be pregnancy related complications confounded by underlying conditions (genital herpes simplex, migraine and asthma) rather than caused by study vaccine. The decision to administer a vaccine during pregnancy is related to medical decision making by the mother and her physician and is not related to any property of the medication. The event of exposure during pregnancy was assessed as not related considering the intended use of the vaccine. The company assessed the event 'gestational diabetes' as serious (medically significant).