Each party will have two hours to make its case before the judge. Kacsmaryk laid out several issues for them to discuss, including whether the plaintiffs have the legal standing to sue, whether an injunction would serve the public interest and the regulation under which mifepristone was approved. The judge could issue his decision on the request for a preliminary injunction any time after the hearing, although a quick appeal to the U.S. Circuit Court of Appeals for the 5th Circuit is expected.

Meanwhile, 18 Democratic senators are calling on Walgreens to provide more details about its recently announced plans to restrict access to abortion pills in certain states and pressing other major chains to make it clear where they stand on the issue.

Related: Democratic state Attorneys General send letter to CVS, Walgreens opposing Republicans

"At a time of great confusion about abortion access, your company has done the disservice of adding to it," the senators wrote in a letter led by Patty Murray of Washington and Debbie Stabenow of Michigan. "While we are well aware of threatening letters you received with regard to the distribution of mifepristone in certain states, the response to those pressures was unacceptable and appeared to yield to these threats — ignoring the critical need to ensure patients can get this essential healthcare wherever possible." The Senators also sent letters to Albertsons, Costco, Kroger, Walmart, CVS Health and Rite Aid.

Walgreens announced its decision this month after it came under pressure from a group of Republican attorneys general who said in a letter that it could face legal consequences if it sold abortion medication in their states. The attorneys general sent similar letters to CVS, Rite Aid, Albertsons, Costco, Kroger and Walmart.