This is a serious observational study case initially received on 13-May-2019, concerning a 31-year-old adult, female, pregnant subject of body weight 122 lbs, height 64.8 inches and body mass index (BMI) 20.4, enrolled in a prospective observational safety study on pregnancy outcomes in women immunized with seasonal cell culture influenza trivalent (TIVc) or quadrivalent (QIVc) vaccine during pregnancy. The subject had no previous pregnancies and had no history of offspring with major congenital malformation. Also, the subject had no maternal/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 22-Sep-2018 and the type of pregnancy was singleton. On an unspecified date, prior to vaccination, the pregnancy status of the subject was collected, and no pregnancy complications were noted. On 01-Nov-2018, the pregnant subject at the gestational age of 5 weeks was administered Flu Vaccine Cell Subunit QIV NVD (influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 252232, dose, route of administration, expiry date and anatomical location: not reported) for an unknown indication (explicitly considered as vaccine exposure during pregnancy). On the same day, the subject started Vitafol One (ascorbic acid, betacarotene, colecalciferol, cupric oxide, cyanocobalamin, folic acid, magnesium oxide, nicotinamide, omega-3 fatty acids, polysaccharide-iron complex, potassium iodide, pyridoxine hydrochloride, riboflavin, thiamine mononitrate, tocopheryl acetate, zinc oxide, dose: 200 mg, once a day [qd] via oral route, ongoing) for healthy pregnancy. On an unspecified date post vaccination, the subject experienced preterm labour which did not result in birth. On an unspecified date, the subject developed streptococcus agalactiae infection and anemia. On 30-Nov-2018, the subject underwent cystic fibrosis mutation analysis and no major congenital malformation was noted. On 14-Dec-2018, the subject started taking amoxicillin (dose: 500 mg, as needed [prn], orally, till 21-Dec-2018) for streptococcus agalactiae infection. On 17-Dec-2018, the subject underwent first trimester screening and no major congenital malformation was noted. On 10-Jan-2019, the subject underwent second trimester screening and no major congenital malformation was noted. On 01-Apr-2019, the subject started taking Ferrousul [ferrous sulfate, dose: 325 mg, once a day (qd), orally] for anemia. At the time of this report, the outcome of the events anemia and streptococcuus agalactiae were not reported. The subject's estimated date of delivery was reported as 29-Jun-2019.; Reporter's Comments: A 31-year-old female pregnant subject experienced preterm labour which did not result in birth, streptococcus agalactiae infection and anaemia, unspecified period of time after receipt of Flu Vaccine Cell Subunit QIV at 5 weeks of gestation (considered as vaccine exposure during pregnancy). The reported events lack of onset latency. The event streptococcus agalactiae infection, is due to infective aetiology (bacterial) and the event anaemia can be alternately explained by pregnancy state of the subject rather than study vaccine, hence causality assessed as not related. The event preterm labour assessed as not related, is no evidence for a biological mechanism that could cause the event. Also, events streptococcus agalactiae infection and anaemia are known risk factors. Concomitant medications (amoxicillin, Vitafol one and Ferrousul) represent a confounding factor. 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).