The main difference between monophasic and triphasic birth control is monophasic has the same level of hormones in all of the active pills, while triphasic has three different doses of hormones, according to WebMD. Some examples of monophasic, or one-phase pills include Yaz, Alesse and Ortho-cyclen. Examples of triphasic birth control include Ortho Tri-cyclen and Enpresse.
With triphasic pills, the dosage of hormones in the medication changes every 7 days over a 3-week period. Triphasic birth control is often more difficult to take because the instructions for taking this medication are very different than for monophasic birth control. When taking triphasic birth control, it is important not to begin taking a pack too late because it can increase the chances of pregnancy .