Bilateral choroid plexus cysts; Vaccine fetal exposure during pregnancy; This is an observational study case, initially received from other health professional on 04-Nov-2019, concerning a foetal subject, whose mother was 31-year-old, pregnant, female subject of body weight: 136 lbs, height: 63 inches and body mass index (BMI): 24.1 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 mother obstetrical history was collected, and it was noted that the mother did not have any previous pregnancies, nor maternal and paternal history with major congenital malformation (MCM). The mother did not consume tobacco, alcohol and illicit-drugs during pregnancy.  The subject's mother current condition included chlamydia. Concomitant medications included Prenatal vitamin (unspecified vitamins) for an unknown indication.   The mother's last menstrual period (LMP) date was 23-May-2019, and estimated delivery date (EDD) was reported as 27-Feb-2020. The corrected estimated date of delivery was not reported. The type of pregnancy was singleton.  On 15-Aug-2019, the subject's mother underwent Sequential 1 and Nuchal translucency prenatal tests and no MCM was noted.  On 12-Sep-2019, the subject's mother underwent Sequential 2 test and no MCM was noted.  On 10-Oct-2019, at gestational age of 20 weeks, the subject's mother was administered Flu Vaccine Egg Split QIV CSL (Afluria QIV) [Influenza Vaccine, batch number: P100112488, dose, route of administration, anatomical location and expiry date: not reported) (explicitly coded as 'Foetal exposure during pregnancy, second trimester') for influenza immunisation.  On the same day, the subject's mother underwent targeted ultrasound scan and bilateral choroid plexus cysts were noted.  At the time of initial reporting, the outcome of the event was not reported.   This case was assessed as serious.  The reporter did not provide causality assessment.  This case is linked to 201905903, the corresponding mother case.  Company comment: In foetal subject of an unspecified gender, congenital choroid plexus cyst was noted after foetal exposure during pregnancy, at gestation age of 20 weeks with the suspect product Afluria QIV. Temporal relationship is implausible because congenital choroid plexus cyst was found on the day of vaccination and cyst need more time to form. Mother's current condition of chlamydia infection may provide alternative aetiology for the event. Foetal exposure during pregnancy is assessed as not related per company's conventions. For the event congenital choroid plexus cyst, causality between suspect product and the events is assessed as not related.; Sender's Comments: In foetal subject of an unspecified gender, congenital choroid plexus cyst was noted after foetal exposure during pregnancy, at gestation age of 20 weeks with the suspect product Afluria QIV. Temporal relationship is implausible because congenital choroid plexus cyst was found on the day of vaccination and cyst need more time to form. Mother's current condition of chlamydia infection may provide alternative aetiology for the event. Foetal exposure during pregnancy is assessed as not related per company's conventions. For the event congenital choroid plexus cyst, causality between suspect product and the events is assessed as not related.