Pfizer birth control pills recalled due to pregnancy risk

Roughly one million packets of birth control pills have been recalled in the US, after pharmaceutical company Pfizer said they might not provide the correct dose to prevent pregnancy.

Some of the packs of the pill, Lo/Ovral, have been found to contain too many active ingredients, others too few, the Associated Press reported.

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The voluntary recall affects 14 lots of Lo/Ovral-28 (norgestrel and ethinyl estradiol) tablets and 14 lots of Norgestrel and Ethinyl Estradiol tablets (generic) with expiration dates between July 31, 2013 and March 31, 2014, according to Pfizer's statement. The lot numbers concerned can be found on the company's website.

The pills are labeled under the Akrimax Pharmaceuticals brand.

Women taking them should "immediately" begin using a a non-hormonal form of contraception such as condoms in order to avoid accidental pregnancy, Pfizer said. No other health risks are reported.

The company blamed the problem on a "packaging error" which it said had been corrected. There were "both mechanical and visual inspection failures on the packaging line," a spokeswoman told the AP.

A one-month pack should contain 21 active pills and seven inert ones. The correct dosage and sequence is crucial to prevent pregnancy.

Women are advised to return the packs to a pharmacy and notify their doctor.

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