Why Quran forbids sexual intercourse during menstruation

According to medical science, intercourse during menstruation is unhealthy and causes various diseases. The vaginal canal is a habitat of many types of bacteria.

The three layers of darkness in the womb-Quranic Science

He has created you in your mother’s womb successively in three layers of darkness. He is Allah your Lord, His is the Kingdom. There is no god but Him. So, where are you getting confused? [ Surah Jumar 39:6 ]