Delivery at 36.7 weeks of gestation; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 14-May-2020, concerning a 30-year-old, pregnant female subject of body weight: 173.5 lbs, height: 67 inches and body mass index (BMI): 27.2 enrolled in a prospective observational safety study on pregnancy outcomes in woman immunized with Afluria QIV, a seasonal quadrivalent vaccine, during pregnancy.  The subject's medical history included BMI high and uterine leiomyoma.  The subject's concomitant medications included Vitamin C (ascorbic acid) as supplement and prenatal gummy (unspecified vitamins and minerals) for pregnancy.  The subject's obstetrical history noted that subject had no previous pregnancies. The subject had no history of offspring with major congenital malformation (MCM). The subject had no relevant maternal and paternal medical history. The subject did not use tobacco, illicit drug or alcohol during pregnancy.  The subject's last menstrual period (LMP) date was reported as 16-Jun-2019. The subject's estimated delivery date (EDD) was reported as 23-Mar-2020 and corrected estimated date of delivery (CEDD) was reported as 22-Mar-2020-2020. The type of pregnancy was singleton.  On 12-Sep-2019, the subject underwent ultrasound and no MCM was noted.  On 26-Sep-2019, at approximately 14 weeks of gestation (calculated per LMP), the subject was administered Afluria QIV (Flu Vaccine Egg Split QIV CSL) [influenza vaccine; batch number: P100118566, dose, anatomical location, route of administration and expiration date: not reported] (explicitly coded as Vaccine exposure during pregnancy') for influenza immunisation.  On 01-Nov-2019, the subject underwent ultrasound and no MCM was noted.  At gestational age of 36.7 weeks (as reported), the subject vaginally delivered live birth, male neonate. The neonate's birth weight was 3118 g, his length was 45.7 cm and head circumference were not provided. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were for one, five and ten minutes were not provided. No MCM was noted on delivery.   At the time of this report, the outcome of the event premature delivery' was not reported.  The event of premature delivery' was assessed as serious, due to criterion of medical significance, per company.   The reporter did not provide causality assessment.  The case is linked to 202003408, the corresponding child case.  Company Comment: A 30-year-old pregnant subject has experienced premature delivery five months after receiving Afluria QIV. The vaccine was administered at gestational age of 14 weeks. The subject's medical history included BMI high and uterine leiomyoma which may provide alterative aetiology for the event. Causal relationship is assessed as not related because of biological implausibility and unsuggestive chronology. Vaccine exposure during pregnancy assessed as unrelated per company's conventions.; Sender's Comments: A 30-year-old pregnant subject has experienced premature delivery five months after receiving Afluria QIV. The vaccine was administered at gestational age of 14 weeks. The subject's medical history included BMI high and uterine leiomyoma which may provide alterative aetiology for the event. Causal relationship is assessed as not related because of biological implausibility and unsuggestive chronology. Vaccine exposure during pregnancy assessed as unrelated per company's conventions.