What happens if menstruation ceases and later returns after only one or two periods?

Primary text

If a woman's menstruation ceases after only one or two periods, and the cause is unknown, she must observe a full year's waiting period due to uncertainty. This is consistent with the position of those who agree on the primary ruling concerning unknown cessation, as uncertainty mandates a transition to the one-year standard. A full year must be observed because the waiting period cannot be built upon a preceding, incomplete period. Similarly, if she despairs after one or two periods, she transitions to a full three months, and if a minor woman menstruates after observing one or two months of waiting, she transitions to the measure of three complete Quru'.