The baby, Isabel, in the movie The Other Woman, died of Sudden Infant Death Syndrome (SIDS).
During the film, flashbacks reveal the tragic circumstances surrounding Isabel's death. Emilia, the baby's mother, appears to believe that Isabel died in her arms when she fell asleep while feeding her. This devastating event heavily impacted Emilia and significantly contributed to her struggles and subsequent actions in the movie. The quick divorce and remarriage are implied to be, at least in part, a consequence of this trauma.
