There are three main types of pill packs and hormone combinations – monophasic, biphasic, and triphasic.
Monophasic has a 28-day pill pack with seven placebo pill and 21 pills with the same amount of hormones.
Combination pills are available in monophasic, biphasic, and triphasic.
Monophasic pills contain the same level of hormones.
Many women and many physicians prefer monophasic pills because hormone levels remain consistent, but biphasic and triphasic oral contraceptives are equally effective.