We have explained in the previous Halachot that our Sages prohibited one who is not truly ill to take medicine on Shabbat. Only if one feels ill throughout his body or must lie down in bed may one take medication to heal one’s self. We have discussed several details regarding this law.
Let us now discuss the law regarding a woman who is taking pills for several days in order to conceive. It seems that there is room for leniency since we have already written that our Sages never enacted their edict in the place of great illness and the inability to become pregnant is certainly worse than an illness which causes one to lie in bed. Hagaon Harav Shlomo Zalman Auerbach zt”l therefore rules that there is room for leniency regarding taking such pills on Shabbat for medical purposes.
Some question this lenient ruling, for we find that our Sages permitted taking medicine on Shabbat when there is a situation of illness before us, such as when an individual is lying in bed as a result of an illness; however, in our situation where the woman is not actually ill, there is no room for leniency. Nevertheless, this is incorrect, for regarding any major illness, we are lenient and allow taking medicine even if the individual is not so ill yet and will merely become that ill by abstaining from taking the medication. The same therefore applies to a woman who is having trouble conceiving, for this situation is certainly worse than a great illness.
Hagaon Harav Moshe Stern zt”l (the late Debreciner Rav) writes another reason for leniency which is that our Sages prohibited only an ill individual to take medication; however, we have not heard that our Sages prohibited a healthy individual to take medication. On the contrary, we have already explained that the reason behind this edict was the concern that one will transgress Torah prohibitions while trying to heal an ill family member, however, when the individual is not ill, there is no such concern. Thus, in our situation where the woman is not ill at all, our Sages never established their edict in this case and the woman may take pills in order to help her become pregnant (see Chazon Ovadia-Shabbat, Part 3, page 366).
Based on the above, it would seem that the same would apply regarding contraception pills (in a situation where a woman has permission from a competent halachic authority to take them); since the woman taking these pills is not ill in addition to the fact that these pills are not meant to heal, there is no prohibition to take these pills on Shabbat. This is especially true since these pills are usually taken for several days (or weeks) consecutively, in which case there is even more room for leniency as we have already established.
Regarding taking vitamins on Shabbat, since vitamins are not a medication and are meant even for healthy individuals who wish to better improve their health, there is room to permit taking them on Shabbat. Nevertheless, since taking them is not so imperative, one who acts stringently and abstains from doing so shall be blessed. However, as we have said above, according to the letter of the law, there is room for leniency, especially for pregnant and nursing women for whom this is quite necessary. The great Rishon Le’Zion, Hagaon Harav Yitzchak Yosef Shlit”a, ruled likewise many years ago in his Sefer Yalkut Yosef, Volume 4. When the Chazon Ovadia on the laws of Shabbat (Part 3, pages 363-365) was later published, Maran zt”l deals with this matter extensively and rules leniently, as we have written.
Summary: A woman may take conception or contraception pills on Shabbat. Similarly, it is likewise permissible to take vitamins on Shabbat according to the letter of the law. However, one who acts stringently and abstains from taking vitamins on Shabbat shall be blessed.