Rupture of a pregnant uterus in early pregnancy and an unscarred uterus are extremely rare, and some non-specific symptoms might appear before this occurrence. We report the case of a multiparous woman (gravida 3, para 2) with uterine fundal rupture in her early second trimester (17+ weeks of gestational age), who presented upper abdominal discomfort and vomiting for 3 days, and progressed into sudden acute abdomen and shock. During emergent laparotomy, the entire amniotic sac was found in the peritoneal cavity with a rupture of the uterine fundus. Although we could not confirm that the appearance of upper gastrointestinal symptoms and severe vomiting was associated with uterine rupture in this pregnant woman, abdominal symptoms or signs might be a hint or cause of severe catastrophic pregnancy-related complications.