Would Initiative 26 open the door to prohibiting many common forms of birth control? The simple answer is yes.
Yes On 26′s own website makes it clear that IUDs are incompatible with personhood. Presumably this would also extend to women who already have IUDs in place, since the violation of personhood is caused by the existence of the IUD, not by the insertion process.
Hormonal birth control is a more complicated issue. All forms of hormonal birth control can potentially prevent implantation, which Yes On 26 claims is incompatible with personhood.
It should be noted that prominent members of the Yes On 26 Advisory Board, and Personhood Colorado, have quite explicitly stated that they consider hormonal contraceptives to be “chemical abortifacients” and that “they do in fact cause abortions”.