WASHINGTON - (AP) - Pfizer Inc. is recalling 28 lots of birthcontrol pills after uncovering a packaging error that could leavewomen with an inadequate dose of the hormone-based drugs and raisethe risk that they will get pregnant accidentally.

The drugs are marketed by Akrimax Products under the brandLo/Ovral-28 and generic Norgestrel and Ethinyl Estradiol tablets.

Pfizer found that some packets of the drugs had too many activetablets, while others had too few. Oral birth control products usea series of 21 drug tablets and 7 inactive sugar tablets toregulate the menstrual period while providing contraception.

The company says the problem is not related to safety. It justraises the risk of unintended pregnancy.

Pfizer recall