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

The drugs are marketed by Akrimax Products under the brand Lo/Ovral-28 and generic Norgestrel and Ethinyl Estradiol tablets. Pfizer found that some packets of the drugs had too many active tablets, while others had too few. Oral birth control products use a series of 21 drug tablets and 7 inactive sugar tablets to regulate the menstrual period while providing contraception.  The company says the problem is not related to safety. It just raises the risk of unintended pregnancy.

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