Oligohydramnios; Insomnia; Vaccine exposure during pregnancy; This is an observational study case, initially received from other health professional on 06-Sep-2019, concerning a 33-year-old, pregnant, female subject of body weight 155 lbs, height: 63.5 inches and body mass index (BMI) 27.1, enrolled in a prospective observational safety study during pregnancy.  The subject's obstetrical history noted that the subject had 5 previous pregnancies which included three full term live births, one preterm live birth and one spontaneous abortion. No birth defects were reported. 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 medical history included hypothyroidism. The subject's concomitant medications included Prenatal Vitamins (mineral NOS, vitamin NOS) as a supplement.  The subject's last menstrual period (LMP) date was 30-Nov-2018, estimated delivery date (EDD) and corrected estimated date of delivery (CEDD) were reported as 06-Sep-2019. The type of pregnancy was singleton.   On 24-Jan-2019, the subject underwent ultrasound scan, and no major congenital malformation was noted.  On 31-Jan-2019, at gestation age of 8.9 weeks, the subject received Flu Vaccine Egg Split QIV CSL [influenza vaccine, batch number: YF41608; dose, expiration date, route of administration and anatomical location: not reported] (explicitly coded as 'vaccine exposure during pregnancy') for influenza immunisation.  On 05-Apr-2019, the subject underwent ultrasound scan, and no major congenital malformation was noted.  On 19-Aug-2019, approximately six months after vaccination, the subject developed insomnia. The subject received Ambien (zolpidem tartrate) at a dose of 5 mg, administered via oral route, every day as required, as a corrective treatment.  On 27-Aug-2019, approximately six months after vaccination, the subject developed oligohydramnios.   At gestational age of 39 weeks, the subject vaginally delivered live birth, female neonate. The neonate's birth weight was 3439 g, head circumference 35.5 cm and length 53.3 cm. The appearance, pulse, grimace, activity and respiration (APGAR) scores were 8 (one minute) and 9 (five minutes). No major congenital malformation was identified at birth. Oligohydramnios was noted as pregnancy complication.  On the same day, the subject recovered from the event 'oligohydramnios'.   At the time of initial reporting, the patient had not recovered from the event of 'insomnia'.  Company comment: A pregnant subject was administered Flu Vaccine Egg Split QIV CSL at 8.9 weeks of gestation. The subject developed insomnia and oligohydramnios, approximately six months after vaccination. Considering the implausible temporal relationship between vaccination and reported events, medical history of one preterm live birth and one spontaneous abortion, causality was confounded. However, causal role of the suspect vaccine cannot be totally excluded and it is assessed as related. The event of vaccine exposure during pregnancy is assessed as unrelated per company's conventions.; Reporter's Comments: A pregnant subject was administered Flu Vaccine Egg Split QIV CSL at 8.9 weeks of gestation. The subject developed insomnia and oligohydramnios, approximately six months after vaccination. Considering the implausible temporal relationship between vaccination and reported events, medical history of one preterm live birth and one spontaneous abortion, causality was confounded. However, causal role of the suspect vaccine cannot be totally excluded and it is assessed as related. The event of vaccine exposure during pregnancy is assessed as unrelated per company's conventions.