This is another article in the chapter Probable Enormities from the classical manual on Sharia called Reliance of the Traveller. The articles are posted one by one in the order they are given in the book.
INTERCOURSE WITH ONE’S WIFE DURING MENSTRUATION
p75.21 The Prophet (Allah bless him and give him peace) said,
“Whoever has intercourse with a woman during her period, or sodomizes a woman, or who goes to a fortune-teller and believes him, has committed unbelief [A: if he considers any of these permissible].”