What is the ruling regarding a woman who deliberately leaves her waiting period (iddah) after her husband's death?

If a woman whose husband has died leaves off the iddah due to ignorance, the iddah is a right of Allah that concludes with the passage of the period prescribed by shareeah, and it is not to be recommenced. If the woman observing iddah goes out without necessity or adorns herself, she must repent and seek forgiveness. The iddah for a pregnant woman is upon delivery, and for a non-pregnant woman it is four months and ten days.