An unwanted pregnancy was the key risk faced by some U.S. women when they were given a sample package of an Allergan birth control drug.

A voluntary nationwide recall of 168,768 physician sample packs of Taytulla capsules was issued by the Dublin-based drug maker. The action came in the wake of a discovery by a physician of a package in which four non-hormonal placebo capsules replaced active capsules in the first four days of therapy.

According to the recall notice, a Taytulla pill pack is a 28-count blister card having 24 “active” oink softgel capsules, ones with hormones, followed by 4 maroon softgel capsules not having hormones. With an expiry date of May 2019, the packages are from lot #5620706. The packaging error may lead to taking the capsules out of sequence and placing the user at risk of unintended pregnancy and contraceptive failure. A statement by Allergan said that the reversal of the order may not be apparent to new users or even previous users of the product.

The packaging error is not a new incident. In 2015, shortly after the merger of Allergan and Actavis, 26 lots were recalled by Actavis, amounting to 511,283 boxes of Lutera birth control pill, following the discovery of the missing package inserts.