Roe wasn’t 12 weeks. There was a companion bill, Doe vs Bolton, which allowed abortion on demand “if the health of the mother was at stake.” That term included physical, mental, emotional and socio-economic health. As long as a “healthcare professional” signed off on it, you got your abortion up until the delivery date. The only problem was finding someone to perform a third-trimester abortion, which was a very expensive procedure. Even so, 10% of abortions (approximately 100,000) were late term.
Roe was first trimester. That’s 3 months, this 12 weeks.