The two largest pharmacy chains in the United States will start dispensing the abortion pill mifepristone this month, a step that could make access easier for some patients.

Officials at CVS and Walgreens said in interviews on Friday that they had received certification to dispense mifepristone under guidelines that the Food and Drug Administration issued last year. The chains plan to make the medication available in stores in a handful of states at first. They will not be providing the medication by mail.

Both chains said they would gradually expand to all other states where abortion was legal and where pharmacies were legally able to dispense abortion pills — about half of the states.

Walgreens will start providing the pill within the next week in a small number of its pharmacies in New York, Pennsylvania, Massachusetts, California and Illinois, said Fraser Engerman, a spokesman for the chain. “We are beginning a phased rollout in select locations to allow us to ensure quality, safety and privacy for our patients, providers and team members,” he said.

CVS will begin dispensing in all of its pharmacies in Massachusetts and Rhode Island “in the weeks ahead,” Amy Thibault, a spokeswoman for the company, said.

The chains will be monitoring the prospects in a few states, including Kansas, Montana and Wyoming, where abortion bans or strict limitations have been enacted but are enjoined because of legal challenges.