When should a man avoid having intercourse with his pregnant wife?
Does intercourse during the first three months of pregnancy have an adverse affect on the fetus?
There is nothing wrong with having sexual intercourse with one's pregnant wife as long as it is not medically proven that it may cause harm to the fetus. What is forbidden is to have sexual intercourse with one's wife during her period, for Allah (Exalted be He) says,
...therefore keep away from women during menses and go not unto them till they are purified (from menses and have taken a bath). And when they have purified themselves, then go in unto them as Allâh has ordained for you (go in unto them in any manner as long as it is in their vagina).
The same applies to a woman in childbirth until she becomes pure of postpartum bleeding, and the woman who is Muhrim (pilgrim in the ritual state for Hajj and `Umrah). May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.