GERD; Delivery at 36.7 weeks of gestation; Vaccine exposure during pregnancy; This observational study case was received on 25-Feb-2021 from other health professional and concerned a 30-year-old, pregnant female subject of body weight: 147 lbs, height: 64 inches and body mass index (BMI): 25.2, enrolled, a prospective observational safety study.   The subject's concurrent conditions included body mass index high and nausea. The subject's concomitant medications included prenatal vitamins (unspecified minerals and vitamins) for healthy pregnancy and Zofran (ondansetron) for nausea.  The subject's obstetrical history included three previous pregnancies with one full term live birth and two elective abortions. The subject had no history offspring with major congenital malformations MCMs) and 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) date was 08-May-2020, the estimated delivery date (EDD) was reported as 21-Feb-2021, while corrected estimated date of delivery (CEDD) was not reported. The type of pregnancy was singleton.   On 28-Aug-2020, maternal serum alpha 1 fetoprotein (MSAFT) revealed no MCM.  On 25-Sep-2020, at gestation age of 20 weeks (calculated per LMP), the subject was administered with Alfuria QIV (Flu Vaccine Egg Split QIV CSL) (influenza vaccine; dose, route of administration and anatomical location: not reported) (explicitly considered as 'Vaccine exposure during pregnancy') for influenza immunisation. The batch number reported was P100239705.  On an unspecified date, unknown amount of time after receiving Afluria QIV, the subject developed gastroesophageal reflux disease (GERD).   On 08-Jan-2021, the subject commenced treatment with Pepcid Ac (famotidine), 20 mg three times a day, via oral route of administration for GERD.  At gestational age of 36.7 weeks (as reported), the subject vaginally delivered premature, live male neonate. The birth weight of the neonate was 2727 g, head circumference 33.5 cm and length 50.2 cm. Appearance, pulse, grimace, activity and respiration (APGAR) score at one minute was 9, at five minutes was 9 and at ten minutes was not reported. No pregnancy complications noted. No MCM was identified at birth.   On the same day, treatment with Pepcid Ac (famotidine) was stopped.  The outcome of 'premature delivery' and GERD was not reported.   The reporter did not provide causality assessment.  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 202101523 (baby case).  Company comment: A 30-year-old subject was administered Afluria QIV at gestational age of 20 weeks. On an unspecified date, unknown amount of time after receiving Afluria QIV, the subject developed gastroesophageal reflux disease (GERD). At gestational age of 36.7 weeks, the subject vaginally delivered premature, live male neonate. Causal role of the suspect vaccine is assessed as not related, due to unsuggestive temporal relationship with premature delivery, biological implausibility and pregnancy as a strong confounder for GERD (reported in up to 80% of pregnancies). Vaccine exposure during pregnancy is assessed as unrelated per company's conventions.; Sender's Comments: A 30-year-old subject was administered Afluria QIV at gestational age of 20 weeks. On an unspecified date, unknown amount of time after receiving Afluria QIV, the subject developed gastroesophageal reflux disease (GERD). At gestational age of 36.7 weeks, the subject vaginally delivered premature, live male neonate. Causal role of the suspect vaccine is assessed as not related, due to unsuggestive temporal relationship with premature delivery, biological implausibility and pregnancy as a strong confounder for GERD (reported in up to 80% of pregnancies). Vaccine exposure during pregnancy is assessed as unrelated per company's conventions.