The action for disavowal of paternity is subject to a liberative prescription of one year. This prescription commences to run from the day of the birth of the child, or the day the husband knew or should have known that he may not be the biological father of the child, whichever occurs later.
Nevertheless, if the husband lived separate and apart from the mother continuously during the three hundred days immediately preceding the birth of the child, this prescription does not commence to run until the husband is notified in writing that a party in interest has asserted that the husband is the father of the child.
La. C.C. § 189