Is irregular bleeding (Istihadah) considered like Hayd?

No. Abnormal vaginal bleeding outside the usual menstrual period is Istihadah, not Hayd. Since it doesn’t match the characteristics of menstrual blood and does not occur at the usual time, it does not prevent fasting or praying. She continues worship normally while taking steps to avoid soiling her clothes (e.g., using pads) and performing Wudu before each prayer.

There are three cases of Istihadah:

1. A woman with no regular cycle but can distinguish menstrual blood:

• She differentiates by characteristics: menstrual blood is dark, thick, and has a distinct odor.
• Anything else is Istihadah.

1. A woman with a known regular menstrual cycle but cannot distinguish the blood:

• She follows her usual known period length.
• Bleeding outside that time is Istihadah.
• Example: If her usual period was 6 days and she begins continuous bleeding, she considers the first 6 days her menses and the rest Istihadah.

1. A woman with no regular cycle and cannot distinguish menstrual blood:

• She follows the general pattern of women (typically 6 to 7 days per month).
• Any bleeding beyond that is Istihadah.

This is supported by the hadith of Hamnah bint Jahsh, where the Prophet (ﷺ) told her to count her menses as 6 or 7 days, then purify herself and pray for the remaining 24 or 23 days.

Most scholars agree that any bleeding beyond 15 days of Hayd is considered Istihadah.