Wal-Mart is being sued by three women who claim the retailer violated a Massachusetts regulation by failing to make emergency contraception pills available in its pharmacies.

The lawsuit, backed by three abortion rights groups, seeks to force the retail giant to stock the morning-after-pill in 44 Wal-Marts and four Sam Club stores in the state.

Spokesman for Wal-Mart Dan Fogleman says the company only carries the pill in Illinois, where it is required under state law.

However, the plaintiffs argue that because Massachusetts policy requires pharmacies to provide all "commonly prescribed medicines," Wal-Mart is mandated to carry the morning-after-pill.

Fogleman says the company "chooses not to carry many products for business reasons." However, he declined to elaborate.

In a letter to the plaintiffs' lawyer, Wal-Mart said the company does not regard the drug as "commonly prescribed."