Nine senators, led by Richard Blumenthal of Connecticut and Elizabeth Warren of Massachusetts, wrote letters to the chief executives of Verizon and XPO Logistics demanding that the companies account for the conditions in a Memphis warehouse where several women suffered miscarriages.

The senators’ inquiry was spurred by a New York Times investigation last month that revealed that six women had lost their pregnancies after being denied breaks from heavy lifting at the warehouse. The facility is operated by XPO Logistics and handles cellphones, tablets and other gadgets that Verizon ships to customers on the East Coast.

“In light of this latest disturbing report that chronicles XPO turning a blind eye to pregnant workers, we urge XPO to re-evaluate its priorities with its work force and make immediate changes to its current, allegedly deleterious workplace practices,” the senators wrote to XPO’s chief executive, Bradley Jacobs.

In a letter to Verizon’s chief executive, Hans Vestberg, the senators urged the telecommunications giant to push XPO to change its practices.