Preterm delivery at 32.7 weeks of gestational age; Vaccine exposure during pregnancy; This observational study case was received on 14-Dec-2020 from other health professional and concerned a 32-year-old pregnant, female subject of body weight 272.5 lbs, height 67 inches and body mass index (BMI) 42.7, enrolled in a prospective observational safety study on pregnancy outcomes in women immunized with Afluria QIV, a seasonal quadrivalent vaccine, during pregnancy.   The subject's concurrent conditions included obesity, uterine fibroids and asthma. The subject's concomitant medication included Prenatal plus DHA (unspecified vitamins, minerals and docosahexaenoic acid) used for pregnancy.  The subject's obstetrical history included one previous pregnancy with one full-term live birth. The subject had no history of offspring with major congenital malformation (MCM). Also, 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 reported as 20-Jun-2020. The subject's estimated delivery date (EDD) was reported as 27-Mar-2021 and corrected estimated date of delivery (CEDD) was reported as 07-Apr-2021. The type of pregnancy was singleton.   On 18-Aug-2020, the ultrasound revealed no MCM.  On 11-Sep-2020, at approximately 11 weeks of gestation (calculated per LMP), the subject was vaccinated with Afluria QIV (Flu Vaccine Egg Split QIV CSL) (influenza vaccine, route of administration, anatomical location: not reported) (explicitly coded as 'vaccine exposure during pregnancy') for an influenza immunisation. The batch number reported was P100230203.  On the same day, the ultrasound revealed no MCM.  On 25-Nov-2020, the ultrasound revealed no MCM.  At gestational age of 32.7 weeks (as reported), the subject delivered a premature live, male neonate via caesarean method. The neonate's birth weight was 2231 grams, head circumference was 30.5 cm, and body length was 47 cm. Appearance, pulse, grimace, activity, and respiration (APGAR) scores were 5 (one minute), 6 (five minutes) and 8 (ten minutes). No MCM was identified at birth. The obesity complicating childbirth was marked as pregnancy complication.   The outcome of the event 'premature delivery' was not reported.   The reporter did not provide a causality assessment.  The event of 'premature delivery' was considered to be medically significant by a Physician within Seqirus's Pharmacovigilance and Risk Management Department.  This case is linked to case 202102139 (the corresponding neonate's case).  Additional information received on 26-Mar-2021 from other health professional: Pregnancy outcome received. The event 'premature delivery' added and case upgraded to serious. Stop date for the event 'vaccine exposure during pregnancy' added and outcome for this event changed from 'not reported' to 'resolved'. Narrative amended accordingly.  Company comment: The event of 'vaccine exposure during pregnancy' is considered as not related to Afluria QIV.  Company comment: A 32-year-old subject was administered with Afluria QIV, at gestational age of 11 weeks. On 15-Feb-2021, at gestational age of 32.7 weeks, the subject delivered a premature live, male neonate via caesarean method. The subject's concurrent conditions included obesity, uterine fibroids and asthma. Causal role of the suspect vaccine is assessed as not related, due to biological implausibility and strong confounder from medical history (uterine fibroids). Vaccine exposure during pregnancy is assessed as not related.; Sender's Comments: A 32-year-old subject was administered with Afluria QIV, at gestational age of 11 weeks. On 15-Feb-2021, at gestational age of 32.7 weeks, the subject delivered a premature live, male neonate via caesarean method. The subject's concurrent conditions included obesity, uterine fibroids and asthma. Causal role of the suspect vaccine is assessed as not related, due to biological implausibility and strong confounder from medical history (uterine fibroids). Vaccine exposure during pregnancy is assessed as not related.