Sheikh Muhammad Saleh Al-Munajjid, a prominent Saudi Islamic lecturer and author, states: “It is permissible for a man to have intercourse with his pregnant wife whenever he wants, unless that will cause her harm, for doing anything that will cause harm to the pregnant wife is forbidden. The same applies to the case when sexual intercourse in that stage turns to be a difficult task for the wife, because the principle of honorable cohabitation implies that one should not involve one’s wife in a grueling and painful task. Allah Almighty says: ‘…and live with them honorably…’ (An-Nisa’: 19)
But it is haram (prohibited) for a man to have intercourse with his wife when she is menstruating, or to have anal sex with her, or to have intercourse with her when she is experiencing post-child birth bleeding.
However, during menstruation, one can still enjoy one’s wife in other ways, apart from vaginal or anal intercourse, because the Prophet (peace and blessings be upon him) is reported to have said: ‘Do whatever you like apart from intercourse.’ (Reported by Muslim)