The phrase "undue burden" is relative and has allowed states to make ridiculous regulations upon abortion clinics so that getting a safe abortion becomes nearly impossible. Statistics have only shown that women are now researching how to abort these pregnancies with whatever products they might have at home. If a federal law is not put in place to legalize abortion then there need to be laws in place on the side of the clinics so that they can function safely in each state.
View this article on statistics for increase Google searches for states with extreme restrictions. http://www.nytimes.com/2016/03/06/opinion/sunday/the-return-of-the-diy-a...
Laws are not stopping abortions, they are only increasing risk of death for women.