- May a married couple engage in natural intercourse during the wife’s pregnancy, or during her period?
Yes, natural intercourse is permitted between a husband and wife during those times.
Although the natural marital act does not result in a new conception during pregnancy, the act itself is still inherently directed toward procreation. Natural intercourse is the type of sexual act that is inherently ordered toward the procreative meaning, as well as toward the marital and unitive meanings. And so the marital act remains moral even when conception cannot occur due to pregnancy.
There are two common reasons that Catholics ask if marital relations is moral during the wife’s period. First, some ask because St. Thomas Aquinas wrote that marital relations is not moral during menstruation. However, his opinion was based on a misunderstanding about reproductive biology, in that he thought harm would result to the offspring. Given the medical knowledge that no such harm results to the offspring from marital relations during menstruation, his opinion on this point is in error.
Second, some ask because they mistakenly think that conception cannot occur as a result of sexual relations during menstruation, and they mistakenly think that marital relations is not moral if procreation cannot possibly result. But as long as the sexual act is the type of act inherently directed at procreation, i.e. natural genital-to-genital intercourse, the act retains the procreative meaning intended by God for marital relations. For it is the inherent ordering of an act toward its moral object, not the attainment of the moral object, that causes an act to be either good, or intrinsically evil.
Even when natural intercourse is unable to attain procreation, it remains ordered toward procreation, and so it retains its proper procreative meaning. Natural marital relations is moral, even when the husband and wife are unable to conceive, because the essential moral nature of the act remains inherently ordered toward the threefold good intended by God for sexual relations: the marital, unitive, and procreative meanings.
Here is the whole article on what can be done according to the catechism. As long as it ends inside of her anything foreplay wise is fine.