B'Sha'ah tovah!
All prenatal vitamins may be taken on Pesach so long as they are in pill form (i.e not liquid or chewable) and do not have a flavored coating.
A general note on the kashrut of pills: According to many authorities, including our website's rabbinic supervisor Rav Yehuda Henkin, it is permitted to take pills without kosher certification unless they have a flavored coating. Pills that have no flavor, and are swallowed rather than chewed, are not halachically considered edible and there is no concern about kashrut. However, many pills are certified as kosher and you may wish to ask your doctor to prescribe such pills whenever possible. Kosher over-the-counter prenatal vitamins can be found at www.koshervitamins.com. A list of kosher prescription prenatal vitamins is available at http://www.star-k.org/cons-appr-obgyn.htm