Delivery at 36.1 weeks of gestation; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 06-Apr-2020, concerning a 24-year-old, pregnant female subject of body weight 169 lbs, height 64 inches and body mass index (BMI) 29, enrolled in a prospective observational safety study.  The subject's current conditions included increased BMI, and nausea.  The subject's concomitant medications included Prenatal Vitamins (unspecified vitamins and minerals) for pregnancy, and ondansetron for nausea.   The subject's obstetrical history noted that the subject had no previous pregnancies. 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 15-May-2019. The subject's estimated delivery date (EDD) was reported as 12-Mar-2020, while the corrected estimated date of delivery (CEDD) was reported as 13-Mar-2020. The type of pregnancy was singleton.  On 08-Aug-2019, the subject underwent first trimester screening and no MCMs was noted.   On 30-Aug-2019, the subject underwent an ultrasound scan and no MCMs were noted.   On 17-Oct-2019, at gestational age of approximately 22 weeks (calculated per LMP), the subject was administered Flucelvax (Flu Vaccine Cell Subunit QIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent, batch number: 261226, dose: 0.5 ml, route of administration, anatomical location and expiration date: not reported] (explicitly coded as Vaccine exposure during pregnancy') for an influenza immunization.  At gestational age of 36.1 weeks (as reported), the subject delivered a live male neonate by caesarean method. The neonate's birth weight was 2523 grams, head circumference 31 cm and body length 42 cm. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 3 at one minute and 7 at five minutes. APGAR score was not reported for 10 minutes. There was no MCM identified at birth.  At the time of initial reporting, the outcome of event premature delivery' was not reported.  The event of premature delivery' was considered serious due to the criterion of medical significance.  The reporter did not provide the causality assessment.  This case is linked to case 202002764, the corresponding child case.  Company comment: A pregnant subject experienced premature delivery, 3 months and 28 days after receiving Flucelvax QIV. Chronology is unsuggestive. The subject's medical history included increased BMI and nausea. 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). Vaccine exposure during pregnancy assessed as not related per company's conventions.; Sender's Comments: A pregnant subject experienced premature delivery, 3 months and 28 days after receiving Flucelvax QIV. Chronology is unsuggestive. The subject's medical history included increased BMI and nausea. 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). Vaccine exposure during pregnancy assessed as not related per company's conventions.