Arrest of dilation; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 16-Jan-2020, concerning a 20-year-old, pregnant female subject of body weight: 150 lbs, height: 69 inches and body mass index (BMI): 22.1, enrolled in, a prospective observational safety study.    The subject's current condition included herpes simplex virus 1, anxiety and the subject was group B Streptococcus positive. The subject's past medical history included urinary tract infection.   The subject's concomitant medications included prenatal vitamins (minerals nos; vitamins nos) for vitamin supplementation and Tdap (diphtheria vaccine toxoid, pertussis vaccine acellular, tetanus vaccine toxoid) indication reported as vaccine. The subject's past medication included Monurol (fosfomycin) used for urinary tract infection.   The subject had no previous pregnancies. The subject had no history of offspring with major congenital malformation (MCM) and no relevant maternal and paternal medical history. The subject did not use tobacco, alcohol or illicit drugs during pregnancy.  The subject's last menstrual period (LMP) was on 14-Mar-2019, the estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were reported as 19-Dec-2019. The type of pregnancy was singleton.  On 11-Jun-2019, the subject underwent first trimester screen and nuchal translucency screen and no MCM was noted.   On 08-Jul-2019, the subject underwent MSAFP/serum markers analysis and second trimester screen and no MCM was noted.   On 25-Jul-2019, the subject underwent anatomy ultrasound scan and no MCM was noted.   On 18-Oct-2019, at approximately 31 weeks of gestation, the subject was administered Flucelvax TIV (Flu Vaccine Cell Subunit TIV NVD) [influenza vaccine, subunit influenza virus vaccine polyvalent; batch number: 261727; dose: 0.5 ml; route of administration, anatomical location and expiry date: not reported] (explicitly coded as 'Vaccine exposure during pregnancy') for influenza immunisation.   At approximately 40.9 weeks of gestation, the subject delivered live birth, male neonate via caesarean section method. The neonate's birth weight was 4196 g, head circumference and length were not reported. The appearance, pulse, grimace, activity and respiration (APGAR) scores were 1 (one minute), 6 (five minutes) and 8 (ten minutes). No major congenital malformations (MCMs) were identified at birth. Delivery complications included arrest of dilatation, macrosomia and foetal intolerance.  On the same day, the subject recovered from the event of arrested labour.   The event of arrested labour was considered serious due to the criterion of medical significance, per company.   The reporter did not provide causality assessment.   This case is linked to the case 202000271 (the corresponding baby case).  Company comment: Reportedly, arrested labour was associated with Flucelvax TIV. Vaccine was administered at 31 weeks of gestation. Chronology is plausible. Causal role of the suspect vaccine cannot be totally excluded and is assessed as unlikely related. Vaccine exposure during pregnancy is assessed as unrelated per company's conventions.; Sender's Comments: Reportedly, arrested labour was associated with Flucelvax TIV. Vaccine was administered at 31 weeks of gestation. Chronology is plausible. Causal role of the suspect vaccine cannot be totally excluded and is assessed as unlikely related. Vaccine exposure during pregnancy is assessed as unrelated per company's conventions.