Spotting during one pregnancy but not others?

Millie

I’m around six weeks along and for the past 3-4 days, I have had very light spotting that ranges from pale pink to pale brown. It hasn’t progressed at all—in fact, yesterday there was none at all. Today there was the same small amount.

I know this can be normal, but I never had a drop with my other two pregnancies that I carried to term. Even with my miscarriage at 8 weeks, I never spotted (it was a missed miscarriage). Has anyone else had spotting in one/some of your pregnancies but not others?