You could describe a mother's love for her child as transcultural, since it exists in all human cultures.
Something that's true across all cultures of people, no matter how different, can be described with the adjective transcultural. The key to the word's meaning is found in the prefix trans, or "across" in Latin. Sociologists, anthropologists, and historians are particularly interested in things that are transcultural, as they study the way humans interact in various societies, cultures, and time periods.