Amazon is limiting customers to three units of emergency contraceptive pills a week in response to a spike in demand after the Supreme Court ended federal abortion rights, the company told CNBC.

Other retailers are also limiting purchases of drugs like Plan B and Aftera — CVS and Rite Aid are likewise limiting customers to three pills per customer. The companies say there is enough supply of the drugs but that they’re trying to keep them on the shelves consistently. The drugs, often called the morning-after pill, can prevent pregnancy if taken after unprotected sex.

On the Amazon website, users can only select up to a quantity of three for Plan B. But as of publication, the website shows an option to select up to 30 units of My Choice, another brand of emergency contraceptive.

In the aftermath of the Supreme Court ruling last week overturning Roe v. Wade, people told The New York Times that they were stocking up on the morning after pill. “I’m doing this because now abortion won’t be available and I’m worried that this sort of contraception soon won’t be either,” Chrissy Bowen, who lives in Texas, told The New York Times.

These pills have a long shelf-life — Plan B, for example, is good for four years if it’s stored correctly in a cool and dry environment.