Tampon manufacturers say they’re working to replenish the supply of their products after shortages were reported on shelves across the United States.

On Monday, U.S. Sen. Maggie Hassan sent a letter to Procter & Gamble, Edgewell Personal Care, Johnson & Johnson and Kimberly-Clark asking what they plan to do to address reports of diminished supply and price gouging by third-party sellers. The Democrat from New Hampshire cited several news reports chronicling a shortage. It comes on the heels of a baby-formula shortage and rising prices on everything from food to clothes to gas — and menstrual products.

The companies should "take immediate action to increase the tampon supply and end unnecessary price increases,” Hassan said in the letter. "Access to menstrual products should be treated like every other essential good.”