Is it permissible to have sexual intercourse through the vagina during pregnancy? Medically it is said that it is not harmful if the woman does not experience any pain during intercourse.

Praise be to Allah, the Lord of the Worlds; and blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

There is no harm to have sexual intercourse with the pregnant woman if it does not cause any physical harm to her. Muslim scholars have agreed on this rule.
Allah knows best.