LOS ANGELES (AP) — The Los Angeles branch of Planned Parenthood was hit by a data breach involving about 400,000 patients, but there is no indication that the information was used “for fraudulent purposes," the group said.

A hacker installed computer malware between Oct. 9 and Oct. 17 and “exfiltrated" files containing patient names and possibly addresses, insurance and medical information, including procedures they may have undergone, Planned Parenthood Los Angeles warned Tuesday.

“Patients are encouraged to review statements from their healthcare providers or health insurers and contact them immediately if they see charges for services they did not receive," the branch said in a statement. 

The attack involved ransomware, software that hackers can use to lock an organization out of its own computer network until a ransom is paid, but the group didn't immediately say whether any ransom was paid.

The breach is under investigation, the organization said.

The announcement came a day before the U.S. Supreme Court heard arguments that could affect whether the nationwide right to abortion is overturned. The court’s historic 1973 Roe v. Wade decision legalized abortion throughout the United States, and its 1992 ruling in Planned Parenthood v. Casey reaffirmed Roe.

Planned Parenthood has been hacked before. The Metropolitan Washington branch this year revealed that patient and donor information was breached in 2020, and in 2015, hackers posted online the names and other information on hundreds of Planned Parenthood employees.