Preterm delivery at 36.4 weeks of gestation; Vaccine exposure during pregnancy; This is an observational study case from the United States, received on 23-Apr-2021 from other health professional and concerned a 29-year-old, pregnant female subject of body weight: 181.5 lbs, height: 68.3 inches and body mass index (BMI): 27.4, enrolled in a prospective observational safety study.  The subject's concurrent condition included BMI increased, mushroom allergy, anxiety and discoid lupus erythematosus. The subject's concomitant medication included Prenatal DHA vitamin (unspecified vitamins and docosahexaenoic acid) for pregnancy, escitalopram for anxiety and hydroxychloroquine for discoid lupus erythematous.   The subject's obstetrical history noted that subject did not have previous pregnancies. 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 17-Jul-2020, estimated delivery date (EDD) was reported as 23-Apr-2021 and corrected estimated date of delivery (CEDD) was reported as 14-Apr-2021. The type of pregnancy was singleton.   On 10-Sep-2020, at gestational age of seven 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 the same day, ultrasound scan revealed no MCM.   On 01-Oct-2020, counsyl Ashkenazi Jewish panel with fragile X (20 conditions) and counsyl chromosomes 13, 18, 21 plus sex chromosome analysis revealed no MCM.   On 05-Nov-2020, maternal serum alpha-fetoprotein (MSFP)/ serum markers revealed   On 03-Dec-2020, ultrasound scan revealed no MCM.   At gestational age of 36.4 weeks (as reported), the subject delivered live preterm female neonate via caesarean method of delivery. The neonate's birth weight was 2863 grams, head circumference: 25 cm and body length: 48 cm. The appearance, pulse, grimace, activity, and respiration (APGAR) scores were 7 (one minute) and 9 (five minutes).  The APGAR score at ten minutes was not provided. No MCM and no pregnancy complications were identified at delivery.   The outcome of 'premature delivery' was not reported.   The reporter did not provide a causality assessment to Afluria QIV.  The event of 'premature delivery' was considered to be medically significant by a Physician within Seqirus' Pharmacovigilance and Risk Management Department.  This case is linked to a case 202102296 (the corresponding baby case).  Company comment: A 29-year-old subject was vaccinated with Afluria QIV at gestational age of seven weeks. At gestational age of 36.4 weeks (as reported), the subject delivered live preterm female neonate via caesarean method of delivery. Chronology is unsuggestive. The subject's concurrent condition included BMI increased which may have contributed to development of premature delivery. Causality is assessed as not related. Vaccine exposure during pregnancy is assessed as unrelated per company conventions.; Sender's Comments: A 29-year-old subject was vaccinated with Afluria QIV at gestational age of seven weeks. At gestational age of 36.4 weeks (as reported), the subject delivered live preterm female neonate via caesarean method of delivery. Chronology is unsuggestive. The subject's concurrent condition included BMI increased which may have contributed to development of premature delivery. Causality is assessed as not related. Vaccine exposure during pregnancy is assessed as unrelated per company conventions.