Is it incumbent upon a woman in her waiting period (iddah) due to the death of her husband to do anything specific regarding her seeing a strange, flesh-like object during her menstruation, even though the doctor denied the existence of a pregnancy? And is it sufficient for her to observe the prescribed waiting period of four months and ten days?

This matter is mere whispering (waswasah). As long as the woman saw her menstruation after her husband's death, and the doctor informed her that she is not pregnant, then what she suspects about a miscarriage is pure doubt and whispering. Therefore, she should cast aside these doubts and observe the 'iddah (waiting period) of four months and ten days, like a woman observing 'iddah after the death of her husband.