VANCOUVER -- Health Canada has issued a recall for a single lot of birth control packages that may have "missing and mispackaged" pills, which could put users at higher risk of unwanted pregnancy.

Blister packs in the affected boxes of Linessa 21 may contain pills that are in the wrong order, or have multiple pills packed into one pocket, according to a recall notice issued Saturday. In some cases, pills may be missing.

The packages are labelled DIN 02272903, lot 20049 and have an expiry date of March 2023.

Health Canada said anyone with a box of Linessa 21 that has missing or mispackaged pills should return it to their pharmacy for a replacement.

"Do not miss a pill, take a pill out of order, or take two pills at the same time, as this could lead to undesired pregnancy and other side effects," the recall notice reads. "If you have questions or concerns about your product or about alternatives, talk to a health care professional and use an effective back-up method of contraception."

Those side effects can include spotting and irregular bleeding.

Boxes of Linessa 21 contain three weeks worth of pills in three colours – light yellow, orange and red – and each colour has a different amount of hormone, Health Canada said.

Anyone who can't get to a pharmacy for a replacement box quickly is advised to "take the next light yellow, orange or red pill in the order that you are to take, following the proper order," according to the recall.

"If you have already missed a pill, have no more pills of the proper colour, or if you are unsure which one to take, use a non-hormonal method of birth control (such as condoms) and contact your pharmacist as soon as possible," it reads.

Customers can also contact the manufacturer, Aspen Pharmacare Canada Inc., for more information by emailing can.quality@aspenpharma.com or calling 1-844-330-1213.