By Jennifer Corbett Dooren WASHINGTON--The U.S. Food and Drug Administration said Wednesday that a Novartis AG (NVS, NOVN.VX) unit is recalling a three-month birth-control regimen sold in the U.S. because of a packing error. The recall involves a birth-control pill called Introvale that is marketed by Sandoz. The product contains 84 active pills that are peach colored and seven inactive pills in week 13 that are white. FDA said the recall, which affects 10 lots distributed between January and May 2012, was prompted by a consumer report of the inactive pills being located in the row labeled week nine. "While the white placebo tablets can be clearly distinguished from the peach-colored active tablets, the risk of an unintended pregnancy for a patient taking the wrong tablet over several days cannot be excluded," FDA said. The agency said Sandoz was not aware of any unintended pregnancies or other problems from the packaging error. The lot numbers involved in the recall are as follows: LF00478C, LF00479C, LF00551C, LF00552C, LF00687C, LF00688C, LF00763C, LF00764C, LF00765C and LF01261C. It is not clear how many packages were impacted by the error. A Sandoz spokesman didn't immediately return a request for comment left late Wednesday. The FDA said if patients finds a white placebo tablet in any position other than the 13th and final row, they should immediately begin using a non-hormonal form of contraception and contact their doctors. Write to Jennifer Corbett Dooren at jennifer.corbett@dowjones.com