I wonder how the various forms of BC work with this...like, the Depo shot ONLY gives progesterone , no estrogen, so the body releasing estrogen makes it more like the pill, which releases both progesterone and estrogen, just in smaller amounts...the two forms mentioned in this on BC also thicken the cervical mucus (eew) and make the uterine walls less likely to let an egg "stick" to them. I wonder if all three things are negated (no egg, mucus, and wall) or just the no egg...be interesting to find out.