"The use of contraceptives can be morally acceptable in other contexts as well, again, because such uses do not constitute acts of contraception. For example, when a woman has severe menstrual bleeding, or pain from ovarian cysts, the hormonal regimen contained in the Pill may sometimes provide a directly therapeutic medical treatment for the bleeding or the pain. This use of contraceptives is an act of medical therapy to address a pathological situation, not an act of contraception. The secondary effect from the treatment, namely, marital infertility, is only tolerated, and should not be willed, desired, or in-tended in any way by the couple. It is worth noting that it would not be acceptable to make use of contraceptives like the Pill for these medical cases if other pharmacological agents or treatments were available which would offer the same therapeutic benefits and effects without impeding fertility."
January 1, 1970
https://en.wikiquote.org/wiki/Principle_of_double_effect