http://revach.net/article.php?id=4318

Section: Halacha   Category: Shabbos
Shearim Mitzuyanim BaHalacha: Birth Control Pills On Shabbos
It is assur to take any sort of medication on Shabbos.  Vitamins according to poskim are also assur to take on Shabbos since it is for Refuah.  The Mogen Avrohom (328:43) says that anything that is for Refuah is assur even if the person is healthy.  What about birth control pills in a case where a woman has a heter to use them because it is dangerous for her to become pregnant?  Is this considered refuah and therefore assur, or not?

Rav Shloime Braun in Shearim Mitzuyanim BaHalacha (91:2), although he does not pasken definitively, says that this may not be considered a pill for Refuah.  It merely is a mechanism to prevent pregnancy.  He compares this to the Din of the Taz (328:27) who says that it is permitted to treat a drunken hangover since intoxication is not a medical condition.  It is also like a Chazzan swallowing a raw egg which the Shulchan Aruch permits (328:38). 

Based on this he says in a case of Mitzvas Onah, "Efshar... D'Mutar"

Important Note: We bring this tshuvah as a starting point for discussion and not to convey any halacha.  We try to convey the Tshuva to the best of our ability. We admit that our understanding may not be accurate. One should learn the tshuva to verify the accuracy of our interpretation.  Please understand that this Tshuva may not be the final word on this topic. One should consult a Rav before drawing any conclusions.