Islamic law imposes certain duties and responsibilities on the parties during the dissolution of the family union. One of these duties is iddah, which is an important issue for the woman in the event of the termination of the marriage or the emergence of a suspicion of marriage. While iddat refers to the period of time that must be waited in line with the transactions that cause the marriage to end and the physiological condition of the woman, the causes of iddah include death, talaq, annulment and similar transactions. This article examines the iddah of women who have problems during menstruation. This refers to women who do not menstruate for known or unknown reasons after the onset of menstruation, and women who constantly see istiḥāḍa blood and cannot distinguish it from menstrual blood. Although there is no Qur'ān or Sunnah that directly explains this situation, there are different approaches to the subject in the literature. In particular, some interpretations around the phrase “irtebtum/if you doubt” in verse 4 of al-Ṭalāḳ have been linked to this issue. In addition, the iddah of a woman who does not menstruate again after she starts menstruating has been the subject of disputes due to the events that took place during the time of the Companions, and these disputes formed the basis of the differences of opinion among the sects. The article is based on the inductive method and analyzes the verse, the practice of the Companions and the views of the sects by utilizing the elements of categorical elaboration and interpretation. In order to draw attention to the actual aspect of the issue, reference is also made to the family law laws established within the framework of Islamic law today. According to the findings, it was found more accurate in terms of both the achievement of benefit and the elimination of harm that the menstrual period of the menstruating woman and the musteḥāḍa should be three months, provided that it is medically proven that the menstruation is continuous.