Size less than dates; Foetal exposure during pregnancy; This is an observational study case, initially received from other health professional on 16-Dec-2019, concerning a foetal subject of an unspecified gender. The subject's mother was 25-year-old, female pregnant subject of body weight 110 lbs, height 61 inches and body mass index (BMI) 20.8 enrolled in a prospective observational safety study.  The mother's relevant medical history was not reported. The mother's concomitant medication included prenatal vitamins (unspecified vitamins and minerals) for pregnancy.  The subject's mother had no previous pregnancies. The subject's mother had no maternal or paternal history with major congenital malformations (MCMs). Also, the subject had no maternal or paternal history with MCM. The subject's mother did not use tobacco, alcohol or illicit drugs during pregnancy.   The mother's last menstrual period (LMP) date was 03-Apr-2019. The subject's mother estimated date of delivery (EDD) was reported as 08-Jan-2020 and corrected estimated date of delivery (CEDD) was not reported. The type of pregnancy was singleton.   On 22-Aug-2019, the subject's mother underwent targeted ultrasound and no MCM was noted.  On 18-Oct-2019, at approximately 28 weeks of gestation, the subject's mother was administered Afluria QIV [influenza vaccine, subunit influenza virus vaccine polyvalent, cell cultured derived, batch number: P100112488, dose, route of administration, anatomical location and expiration date: not reported] (explicitly coded as Foetal exposure during pregnancy') for an influenza immunisation.  On 31-Oct-2019, 13 days after vaccination, the subject's size was less than dates, as reported. On the same day, the subject's mother underwent growth ultrasound and no MCM was noted.  On 25-Nov-2019, the subject's mother underwent growth ultrasound and no MCM was noted.  At the time of initial reporting, the subject did not recover from the event of small for dates baby.  The event of small for dates baby was considered as serious due to criterion of medical significance.  The reporter did not provide causality assessment to Afluria QIV.  This case is linked to case 201907409 (corresponding mother case).  Company comment: The subject's mother underwent growth ultrasound and no MCM was noted, however small for dates baby (reported as "size small for dates") was reported. The subject's mother was administered Afluria QIV at approximately 28 weeks of gestation. The mentioned events were noted 13 days after vaccination. Chronology is plausible. Causal role of the suspect product cannot be totally excluded and is assessed as unlikely related. Foetal exposure during pregnancy is assessed as unrelated per company's conventions.; Sender's Comments: The subject's mother underwent growth ultrasound and no MCM was noted, however small for dates baby (reported as "size small for dates") was reported. The subject's mother was administered Afluria QIV at approximately 28 weeks of gestation. The mentioned events were noted 13 days after vaccination. Chronology is plausible. Causal role of the suspect product cannot be totally excluded and is assessed as unlikely related. Foetal exposure during pregnancy is assessed as unrelated per company's conventions.