Safety and Effectiveness of the KOKO Device to Treat Primary Abnormal Postpartum Uterine Bleeding or Hemorrhage

Inclusion Criteria: * Adult Female, 18 years of age or older at time of consent. * Subject is able to understand and provide informed consent to participate in the study. * Diagnosis of abnormal postpartum uterine bleeding (500 - 999 ml for vaginal birth) or postpartum hemorrhage (1000 - 1500 ml for vaginal or Cesarean birth) with suspected atony within 24 hours after vaginal or cesarean birth. * EBL, to be determined when investigator is ready to have the KOKO packaging opened: Vaginal birth: 500 - 1500 ml EBL or Cesarean birth: 1000 - 1500 ml EBL. * Failed first - line intervention of uterotonics and uterine massage/bimanual uterine massage to stop bleeding. Note: Uterotonic administration may continue concomitant with and post KOKO use. Exclusion Criteria: * EBL \>1500ml, to be determined when investigator is ready to have the KOKO packaging opened. * Delivery at a gestational age \< 34 weeks or, if multiples, uterus is judged \<34 weeks size. * For cesarean births: Cervix \< 2.5 cm dilated before use of KOKO. * Abnormal postpartum uterine bleeding or hemorrhage that the investigator determines to require more aggressive treatment, including any of the following: 1. hysterectomy; 2. B-lynch suture; 3. uterine artery embolization or ligation; 4. hypogastric ligation. * Known uterine anomaly. * Ongoing intrauterine pregnancy. * Placental abnormality including any of the following: 1. known placenta accreta; 2. retained placenta with known risk factors for placenta accreta (e.g., history of prior uterine surgery, including prior cesarean and placenta previa); 3. retained placenta without easy manual removal. * Known uterine rupture. * Unresolved uterine inversion. * Subject has undergone intrauterine balloon therapy, uterine packing or use of other negative pressure system(s) for tamponade treatment of this episode of abnormal postpartum uterine bleeding or hemorrhage prior to use of the KOKO™ device. * Current cervical cancer. * Current purulent infection of vagina, cervix, uterus. * Diagnosis of coagulopathy.