Endometriosis can be associated with adverse pregnancy outcomes. We report six cases of endometriosis-related spontaneous hemoperitoneum diagnosed in pregnant and postpartum women over 13 years. Spontaneous hemoperitoneum in pregnancy mainly occurred in the second half of gestation. All women presented with acute abdominal pain; four of them needed an emergent surgery, two were managed expectantly. The median estimated blood loss was 4250 ml, four women required massive transfusion. Three out of six women had a known history of endometriosis, all of them had histologically confirmed endometriosis after surgery. No maternal or perinatal deaths occurred. In one case, reticence to perform a computed tomography scan led to delayed diagnosis. Since delay can lead to lethal consequences, high levels of suspicion for spontaneous hemoperitoneum should be maintained in cases of severe abdominal pain, even with a woman's negative history of endometriosis. Improved knowledge and regular interdisciplinary meetings are pivotal to ameliorate outcomes.