This is a serious observational study case initially received on 26-Nov-2018, concerning a 39-year-old adult, female, pregnant subject of body weight 124 lbs, height 60 inches and body mass index (BMI) 24.2, enrolled in a prospective observational safety study on pregnancy outcomes in women immunized with seasonal cell culture influenza trivalent (TIVc) or quadrivalent (QIVc) vaccine during pregnancy. The subject's obstetrical history noted that the subject had 2 previous pregnancies with live births and one pregnancy with spontaneous abortion. The subject had no history of offspring with major congenital malformation. Also, the subject had no maternal or paternal history with major congenital malformations. The subject did not have a prior history of use of tobacco, alcohol or illicit drugs during pregnancy. The subject's current condition included vaginitis (since an unspecified date). The subject's concomitant medications included Metrogel-vaginal (metronidazole) and terconazole for vaginitis, Vitafol one (ascorbic acid, betacarotene, colecalciferol, cupric oxide, cyanocobalamin, folic acid, magnesium oxide, nicotinamide, omega-3 fatty acids, polysaccharide-iron complex, potassium iodide, pyridoxine hydrochloride, riboflavin, thiamine mononitrate, tocopheryl acetate, zinc oxide) for healthy pregnancy. The subject's last menstrual period (LMP) date was 12-Jul-2018. The gestational age of the subject was 10 weeks. The pregnancy status of the subject was collected, and no pregnancy complications with singleton pregnancy was noted. On 22-Sep-2018, the subject was administered Flu Vaccine Cell Subunit QIV NVD (batch number: 252232, dose, route of administration, expiry date and anatomical location: not reported) for an unknown indication (explicitly considered as vaccine exposure during pregnancy). On 05-Oct-2018, the subject had undergone non-invasive prenatal test and no major congenital malformations were noted. On 15-Oct-2018, the subject had undergone amniocentesis and no major congenital malformations were noted. On 29-Dec-2018, 3 months and 7 days after vaccination, the subject developed gestational diabetes mellitus. On 29-Dec-2018, the subject had undergone 1-hour glucose challenge test (GCT) and no major congenital malformations were noted. On 05-Jan-2019, the subject had undergone 3 hours glucose challenge test (GCT) and no major congenital malformations were noted. The subject gave a live birth to a female neonate at the gestational age of 34 weeks via caesarean method of delivery. The subject's pregnancy complication at the time of delivery included placenta previa. The characteristics of the neonate included birth weight: 2085 grams, head circumference: 34.5 cm, length: 41.9 cm and APGAR (appearance, pulse, grimace, activity, and respiration) scores were 9 (at one minute, five minutes and ten minutes). No major congenital malformations (MCMs) were identified at birth. The subject's estimated date of delivery (EDD) was reported as 28-Feb-2019. The outcome of the event gestational diabetes mellitus was not recovered (reported as ongoing). The outcome of the event placenta previa was not reported. This case is linked to 201902748 (mother-baby case). Follow up received from the investigator on 20-Mar-2019: The subject's EDD was changed from 18-Apr-2019 to 28-Feb-2019 in the patient tab. The reported pregnancy outcome details (pregnancy outcome: live birth, gestational age at outcome: 34 weeks, delivery method: caesarean) with the infant characteristics (gender: female, birth weight: 2085 grams, head circumference: 34.5 cm, length: 41.9 cm and APGAR scores: 9 (at one minute, five minutes and 10 minutes) were added in the patient tab. Added the prenatal tests 1-hour glucose challenge test (GCT) and 3 hours glucose challenge test (GCT) in the patient tab. The dose of the subject's concomitant medication Metrogel-vaginal (metronidazole) was changed from 5000 mg to 0.75 percent in the product tab. Added two events gestational diabetes mellitus and placenta previa in the event tab. Hence, changed the case seriousness from non-serious to serious. No major congenital malformations were identified at birth. The linking sentence was added in the narrative. The narrative and case comment were amended accordingly.; Reporter's Comments: A 39-year-old pregnant subject with obstetrical history (2 previous pregnancies with live births and one pregnancy with spontaneous abortion) experienced gestational diabetes, 3 months 7 days after administration of study vaccine, administered at 10 weeks of gestation (coded to Exposure during pregnancy). The subject gave a live birth to a female neonate at the gestational age of 34 weeks via caesarean method of delivery and noted to have placenta previa. Considering the clinical course of events (gestational diabetes and placenta previa) and lack of evidence suggesting any causal role, the underlying pregnancy associated with risk factors (maternal age, vaginitis and treatment drugs metrogel-vaginal and terconazole) appears as a more possible explanation rather than study vaccine and were assessed as not related to study vaccine.The decision to administer a vaccine during pregnancy is related to medical decision making by the mother and her physician and is not related to any property of the medication. The event of exposure during pregnancy was assessed as not related considering the intended use of the vaccine.