In response to heightened demand for emergency contraceptives in the wake of the Supreme Court’s decision to overturn Roe v. Wade, the landmark case that legalized abortion in the U.S., several chain drugstores are reportedly rationing sales of the over-the-counter pills. 

CVS Health, Walmart and Rite Aid are curtailing the number of pills customers can buy, The Wall Street Journal reported on Monday. CVS and Rite Aid were limiting purchases to three, whereas Walmart was allowing as many as four or six. 

CVS told The Journal that the limits were temporary in order to “ensure equitable access” and not due to supply shortages at its stores. 

Indeed, CVS had “ample supply” of two products, the best-selling Plan B, as well as Aftera, according to CBS News.

Rite Aid was also limiting purchases of pills sold under the brand names Plan B and Option 2, per CBS News.

All of the products cited, including those sold under the Plan B name and others, contain levonorgestrel. Made by multiple manufacturers, they run in price from $10 to more than $50 and work by delaying or blocking ovulation. 

These pills are meant as a backup method of birth control, hence the common name “morning-after pills.” They are designed to be taken up to three days after unprotected sex or if a primary birth control method fails.

As such, they’re distinct from medication abortion, sometimes referred to as plan C, which requires a prescription and involves the administration of different pills to end a pregnancy. Mifepristone and misoprostol are approved by the Food and Drug Administration for use in up to 10 weeks of pregnancy. 

Another pharmacy chain, Walgreens Boots Alliance, also had a purchase limit on its website, but a spokesperson told The Journal it was an error and would soon be taken down.

The rationing came as another sign of fallout from last Friday’s ruling by the Supreme Court that overturned the constitutional right to an abortion.