An exceptional archaeological discovery from the Muslim Baza necropolis is reported. An unusual double inhumation presents a complete skeleton of a pregnant woman close to childbirth time, and the skeletal remains of a fetus located between her femora (i.e., outside the abdominal or pelvic area). A first osteological review showed a complete fetus skeleton apparently disconnected. However, a deeper evaluation of the material revealed a more articulated state without signs of any taphonomic alterations or scavenger marks. On the one hand, ancient Muslim traditions suggest that if a baby dies during pregnancy or in premature childbirth, but the mother survives, the baby must be extracted and entombed individually. On the other hand, both skeletons do not present evidences of obstetric problems that could explain unexpected labour complications. Therefore, in the case reported in the present work, it is clear that the mother died before or at the same time as the baby, and she was entombed with the baby inside. A multidisciplinary revision of anthropological, archaeological, taphonomic and cultural data obtained through literature, has been combined with recent data extracted from decomposition experiments (i.e., actuo-taphonomy). This heuristic scenario has allowed us to build a parsimonious hypothesis in which such an unusual location of the fetus remains could be explained by analyzing the known steps in taphonomic-forensic dynamics. It is argued that before both corpses were finally skeletonized and covered with sediment, the mother corpse accumulated gas due to organic tissue degradation, and ejected the fetus remains out of the abdominal cavity.