For 50 years there was a court created US Constitutional Right. (Some say the Roe court simply recognized this fundamental liberty/privacy right.)
Substantive Due Process is a somewhat controversial principle because it goes beyond the enumerated rights explicitly written into the constitution. See attached link if you want the details.
Dobbs essentially says the courts can’t just make these new rights up. Go create laws or amend the constitution.
Link: https://www.law.cornell.edu/wex/substantive_due_process