More than a million packages of birth control pills have been recalled as of Saturday. What does that mean?

Women taking them could potentially become pregnant.

Qualitest Pharmaceuticals, a unit of Endo Pharmaceuticals Holdings Inc., issued a nationwide voluntary recall of 1.4 million lots of its oral contraceptives because of a packaging error that could leave women at risk for unplanned pregnancy, the U.S. Food and Drug Administration (FDA) said on Thursday.

Select blister packs were rotated 180 degrees, and the defective packaging may inadvertently cause women to take the incorrect birth control dose.

The rotation also revealed that the weekly tablet orientation, lot number and expiration date were no longer visible, the FDA said in a statement.

The error means the daily regimen for the oral contraceptives may be incorrect and could leave women at risk of an unplanned pregnancy, it said.

The recall takes effect immediately.

However, there aren't any immediate health risks from the error, according an FDA written statement.

This packaging error and the potential for this error to have affected other oral contraceptive products resulted in the company issuing the recall of multiple lots, the agency said.

The recalled pill products include:

Cyclafem 7/7/7
Cyclafem 1/35
Gildess FE 1.5/30
Gildess FE 1/20

Lot numbers and expiration dates of the pills in question can be found here.

Qualitest Pharmaceuticals spokesperson Kevin Wiggins reiterated that absence of health risk to women taking the pills. The unintended consequence of pregnancy is really the issue, Wiggins said in a statement to CNN.

Wiggins told CNN the recall affects 1.4 million packages of birth control that have been distributed since last year.

Oral contraceptives are the most popular form of birth control in the U.S., with a usage estimate upwards of 12 million women.

Health regulators are urging women to check these numbers against the lot numbers on bottom of the box or the individual blister card.

Pharmacies have also been instructed to contact people who have received these pills, according to Consumer Reports.

Women affected by the recall should use a non-hormonal form of birth control immediately and consult a health-care provider or pharmacist, they said.