Spontaneous rupture of membranes; Preterm delivery at 25 weeks; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 25-Feb-2020, concerning a 23-year-old, pregnant, female subject of height 66 inches, weight 129 lbs and body mass index (BMI): 20.8, enrolled in, a prospective observational safety study on pregnancy outcome in women immunized with immunized with seasonal cell culture influenza trivalent (TIVc) or quadrivalent (QIVc) vaccine during pregnancy.  The subject's relevant medical history was not reported.  The subject's concomitant medications included Prenatal (unspecified vitamins and minerals) for neonatal care.  The subject's obstetrical history noted that the subject had one previous full term live birth with no birth defects. The subject had no maternal or paternal history with major congenital malformations (MCMs). The subject had no history of offspring with MCMs. The subject did not use tobacco, alcohol or illicit drugs during pregnancy.  The subject's last menstrual period (LMP) date was 04-Aug-2019. Estimated delivery date (EDD) was reported as 10-May-2020, while corrected delivery date (CEDD) was reported as 09-May-2020. The type of pregnancy was singleton.  On 09-Oct-2019, at approximately 9 weeks of gestation, the subject was administered Flucelvax QIV (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine; batch number: 261207, dose: 0,5 mL, anatomical location, route of administration and expiration date: not reported] (explicitly coded as Vaccine exposure during pregnancy') for an influenza immunisation.   On the same day, the subject underwent ultrasound and no MCMs were noted.  At 25 weeks of gestation, the subject gave premature live birth to a female neonate via Caesarean method. Pregnancy complications were noted and included spontaneous rupture of membranes. The characteristics of the neonate included birth weight: 750 grams, length: 12,5 and head circumference was not reported. Appearance, pulse, grimace, activity, and respiration (APGAR) scores were 1 (one minute), 1 (five minutes) and 2 (ten minutes). No MCMs were identified at the time of birth.   At the time of this report, the outcome of the events premature delivery' and premature rupture of membranes' was not reported.  The events of premature delivery' and premature rupture of membranes' were considered serious due to criterion of medical significance, per company.   The reporter did not provide causality assessment to Flucelvax QIV.  This case is linked to 202001906, the corresponding child case.  Company comment: The pregnant patient was administered Flucelvax QIV at approximately 9 weeks of gestation and experienced premature delivery 3 months 17 days later. Pregnancy complications included premature rupture of membranes. Chronology is unsuggestive. No alternative aetiology was provided. With information available, causal role of the suspect vaccine cannot be excluded and is assessed as unlikely related (defaults to "related" in the safety database for reporting purposes) to the events of premature delivery and premature rupture of membranes. Vaccine exposure during pregnancy are assessed as unrelated per company's conventions.; Sender's Comments: The pregnant patient was administered Flucelvax QIV at approximately 9 weeks of gestation and experienced premature delivery 3 months 17 days later. Pregnancy complications included premature rupture of membranes. Chronology is unsuggestive. No alternative aetiology was provided. With information available, causal role of the suspect vaccine cannot be excluded and is assessed as unlikely related (defaults to "related" in the safety database for reporting purposes) to the events of premature delivery and premature rupture of membranes. Vaccine exposure during pregnancy are assessed as unrelated per company's conventions.