Low lying placenta; Vaccine exposure during pregnancy; This is an observational study case, received from other health professional on 07-Dec-2020 and concerned a 33-year-old, pregnant female subject of body weight: 149 lbs, height: 66 inches and body mass index (BMI): 24, enrolled, a prospective observational safety study on pregnancy outcomes in women immunized with Afluria QIV, a seasonal quadrivalent vaccine, during pregnancy.   The subject's medical history was not reported. The subject's concomitant medication included prenatal vitamin (unspecified vitamins and minerals) used for pregnancy.  The subject had one previous pregnancy with one full time live birth. The subject had no history of offspring with major congenital malformation (MCM). The subject had no maternal or paternal history with MCM. The subject did not use tobacco, alcohol or illicit drugs during pregnancy.   The subject's last menstrual period (LMP) date was 08-Jun-2020, estimated delivery date (EDD) was reported as 14-Mar-2021 and corrected estimated date of delivery (CEDD) was reported as 22-Mar-2021. The type of pregnancy was singleton.   On 06-Aug-2020, ultrasound revealed no MCMs.  On 04-Sep-2020, at gestational age of 12 weeks (calculated per LMP), the subject was vaccinated with Afluria QIV (Flu Vaccine Egg Split QIV CSL) (influenza vaccine; dose, route of administration and  anatomical location: not reported) (explicitly coded as 'Vaccine exposure during pregnancy') for influenza immunisation. The batch number reported was P100230203.   On 05-Nov-2020, ultrasound revealed low-lying placenta. There was no MCM noted.   The outcome from the event of low-lying placenta was not reported.  The reporter did not provide a causality assessment to Afluria QIV.  The event of low-lying placenta was considered to be medically significant by a Physician within Seqirus's Pharmacovigilance and Risk Management Department.  Company comment:The subject experienced placenta praevia two months after vaccination with the suspect product Afluria QIV. Reportedly, vaccination occurred during pregnancy at gestational age of approximately 12 weeks of gestation. Temporal relationship is implausible because location of the placenta is determined at implantation (first 3 weeks of gestation). The subject's medical history was not reported. Causal relationship between the suspect product and the event placenta praevia is assessed as not related due to biological implausibility and implausible chronology. Causal relationship between the suspect product and exposure during pregnancy is assessed as not related per company conventions.; Sender's Comments: The subject experienced placenta praevia two months after vaccination with the suspect product Afluria QIV. Reportedly, vaccination occurred during pregnancy at gestational age of approximately 12 weeks of gestation. Temporal relationship is implausible because location of the placenta is determined at implantation (first 3 weeks of gestation). The subject's medical history was not reported. Causal relationship between the suspect product and the event placenta praevia is assessed as not related due to biological implausibility and implausible chronology. Causal relationship between the suspect product and exposure during pregnancy is assessed as not related per company conventions.