Premature delivery; Vaccine exposure during pregnancy; Preterm premature rupture of membrane; This is an observational study case, initially received on 21-Nov-2019, concerning a 29-year-old, pregnant, female subject of body weight: 166 lbs, height: 69 inches and body mass index (BMI): 24.5, who was enrolled, a prospective observational safety study.  The subject's medical history was not reported. The subject's current conditions include anxiety, history of hypertension and Crohn's. The subject's past medication includes T Dap vaccine for vaccination, while the concomitant medications included Prenatal vitamins (unspecified minerals and vitamins) for pregnancy and sertraline for anxiety.    The subject had no previous pregnancies. The subject had no history of offspring with major congenital malformation (MCM). The subject had no maternal or paternal history with MCMs. 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) was on 02-Feb-2019. The type of pregnancy was singleton. The subject's estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were 09-Nov-2019.   On 03-May-2019, initial ultrasound was performed, and no MCM was noted.   On 10-May-2019, nuchal translucency and first trimester screen tests were performed, and no MCMs were noted.   On 28-May-2019, second trimester screen alpha-fetoprotein (AFP) was performed, and no MCM was noted.  On 18-Jun-2019, anatomy ultrasound was performed, and no MCM was noted.  On 25-Sep-2019, at approximately 33 weeks of gestation, the subject received Flu Vaccine Cell Subunit QIV Flucelvax QIVc [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 261200, dose: 0.5 ml, route of administration, expiry date and anatomical location: not reported] (explicitly coded as 'Vaccine exposure during pregnancy') for an influenza immunisation.  On an unspecified date in 2019, an unknown amount of time after vaccination, the pregnancy status of the subject was collected, and it was noted that the pregnancy was complicated with preterm premature rupture of the membranes (PPROM).  On 12-Oct-2019, at 36 weeks of gestational age, the subject delivered live male neonate via caesarean method. The neonate's birth weight was 2495 grams, body length and head circumference were not reported and the appearance, pulse, grimace, activity and respiration (APGAR) scores were 8 (one minute), 9 (five minutes) and for ten minutes was not reported. There was no MCM identified at birth.   The events of 'preterm premature rupture of membrane' and 'premature delivery' were assessed as serious (medically significant).  The reporter did not provide causality assessment.   This case is linked with case ID 201906256 corresponding baby case.  Company Comment: The subject experienced preterm premature rupture of membranes and premature delivery an unknown amount of time after vaccination with the suspect product, Flucelvax QIV. Reportedly, vaccination occurred during pregnancy at 33 weeks of gestation. Chronology is unclear. Medical history of Crohn's disease may have contributed to development of the events. Causality was also confounded with concomitant medication, sertraline. Pregnant state may provide more plausible alternative aetiology for the events. Vaccine exposure during pregnancy is assessed as not related per company's conventions. Considering all the above mentioned, causality between suspect product and the events preterm premature rupture of membranes and premature delivery is assessed as unlikely related.; Sender's Comments: The subject experienced preterm premature rupture of membranes and premature delivery an unknown amount of time after vaccination with the suspect product, Flucelvax QIV. Reportedly, vaccination occurred during pregnancy at 33 weeks of gestation. Chronology is unclear. Medical history of Crohn's disease may have contributed to development of the events. Causality was also confounded with concomitant medication, sertraline. Pregnant state may provide more plausible alternative aetiology for the events. Vaccine exposure during pregnancy is assessed as not related per company's conventions. Considering all the above mentioned, causality between suspect product and the events preterm premature rupture of membranes and premature delivery is assessed as unlikely related.