Life starts with contamination. It starts out dirty. Childbirth is messy. It’s not sinful; it’s just a fact of life.
The general Bible term for infections of skin and surfaces is “leprosy,” but it covers a host of conditions. It’s also a good parable for “rot” in our character — if the lesson isn’t taken too far.
The Torah reading תזריע Tazria (“she will conceive,” Leviticus 12–13) is concerned about what is physically dirty vs. clean, but the LORD’s lesson for us is more than skin-deep.