The U.S. Supreme Court heard oral arguments Wednesday over a Mississippi law that bans abortions after 15 weeks of pregnancy. If the law is allowed to stand, it would be the most significant roll back of abortion rights since the Roe v. Wade ruling in 1973.

“We are gravely concerned that the court may further erode or even overturn the protections offered by Roe v. Wade and put the lives and welfare of millions of women at risk,” said California Medical Association (CMA) President Robert E. Wailes, M.D. “California must do all it can to protect reproductive freedom for all women and depoliticize individual health care decisions that should be made between a woman and her health care provider.”

The Mississippi law is a direct challenge to Roe, the 1973 decision that established a constitutional right to abortion and prohibited states from banning the procedure before fetal viability, currently around 23 weeks. If the court allows the Mississippi law to stand, it could pave the way for states around the country to further restrict or ban abortion rights.

That has serious consequences for states like California, which may find themselves as medical refuge sites for women seeking access to reproductive health care.

“California policymakers must begin preparing the state to serve potentially millions of more people seeking abortion care as other states prepare extreme bans to an essential health service,” said Planned Parenthood Affiliates of California President and CEO Jodi Hicks. “It is imperative California builds upon its status as a reproductive freedom state.”