(NEXSTAR) — Several major pharmacies are imposing purchase limits on emergency contraception — also known as “morning-after pills” — after a surge in demand following last week’s overturning of Roe v. Wade by the U.S. Supreme Court.

Both CVS and Rite Aid confirmed three-per-customer purchase limits to NBC News on Tuesday morning. Limits include Plan B One-Step and Aftera, which are brand-name products for the drug Levonorgestrel. CVS told NBC it has “ample supply” of the medications but that the company wants to ensure “equitable access” and a consistent supply.

Meanwhile, Walmart is limiting emergency contraception medication purchases to 4-6 per-customer, Wall Street Journal explains. Walmart is, however, offering some unlimited purchases, but only on pills that don’t ship until next month.

Walgreens isn’t currently limiting purchases, though the company says home delivery isn’t available at this time due to demand.

Doctors and pharmacies urge that emergency contraception is not intended for regular use. Plan B and similar brands are not abortion-inducing drugs and are intended to prevent ovulation if taken with 72 hours of unprotected sex.