CVS, Rite Aid limiting purchases of emergency contraception

Some large drug store chains are limiting purchases of emergency contraception to three pills per customer, company representatives confirmed to CNN.

"Due to increased demand, at this time we are limiting purchases of Plan B contraceptive pills to three per customer," Alicja Wojczyk, senior manager of external communications for Rite Aid told CNN in an email.

Though CVS has "ample supply" of Plan B and Aftera -- two types of emergency contraception -- the company is limiting purchases to three per customer "to ensure equitable access and consistent supply on store shelves," Matt Blanchette, senior manager of retail communications at CVS Pharmacy told CNN in an email.

Emergency contraception reduces the chance of pregnancy after unprotected sex, according to the American College of Obstetricians and Gynecologists. Common situations when it is used include after forgetting to take several birth control pills or when a condom breaks or falls off.

The purchasing limits for emergency contraception come after the Supreme Court overturned Roe v. Wade on Friday. Several states immediately moved to effectively prohibit abortions.

"Using (emergency contraception) does not cause an abortion. An abortion ends an existing pregnancy. EC prevents pregnancy from occurring. EC must be used soon after unprotected sexual intercourse to be effective. It does not work if pregnancy has already occurred," ACOG said.

Pills, such as Plan B and Aftera, are one type of emergency contraception. Some can be bought over the counter and others require a prescription.

Copper intrauterine devices, or IUDs, can also be used as emergency contraception if inserted within about five days of intercourse.