Can a silicone menstrual cup be used while fasting and praying, knowing that I suffer from metrorrhagia and that pads and tampons cause me dryness and itching?

Using a menstrual cup does not invalidate the fast. This is the view of some scholars, who argue that what enters the body cavity is not considered a fast-breaker if it is not food, drink, or something that takes their place, such as an enema or vaginal suppositories. The Islamic Fiqh Academy has affirmed this, indicating that what enters the vagina or uterus is not considered among the things that break the fast. However, during menstruation, it is forbidden for a woman to fast, even if she uses the cup to prevent the flow of blood.