1m birth control pills withdrawn because they don't contain enough contraceptive

One million packets of birth control pills in the U.S. have been recalled because they may not contain enough contraceptive to prevent pregnancy.

Pfizer Inc said the pills posed no threat to the health of women, but it urged consumers to 'begin using a non-hormonal form of contraception immediately'.

The drugmaker said the issue involved 14 batches of Lo/Ovral-28 tablets and 14 batches of Norgestrel and Ethinyl Estradiol tablets.

Recall: Pfizer has said one million packets of birth control pills it produces, including Norgestrel, may not contain the correct amount of contraceptive

It said an investigation had found that some blister packs of the oral contraceptive might contain an inexact count of inert or active ingredients in the tablets.

The pills were manufactured by Pfizer and marketed by Akrimax Pharmaceuticals and shipped to warehouses, clinics and retail pharmacies nationwide.

A statement on its website said: 'As a result of this packaging error, the daily regimen for these oral contraceptives may be incorrect and could leave women without adequate contraception, and at risk for unintended pregnancy.'

Some packets of the drugs were found to have too many active tablets, while others had too few.

Oral birth control products use a series of 21 drug tablets and seven inactive sugar tablets to regulate the menstrual period while providing contraception.

A company spokesman said the problem was caused by both mechanical and visual inspection failures on the packaging line.