ask your pharmacist

What are the differences among monophasic, biphasic, and triphasic birth control pills?

Most birth control pills contain the hormones estrogen and progestin. They are categorized as monophasic, biphasic, or triphasic pills depending on whether the level of hormones stays the same during the first three weeks of the menstrual cycle or changes. (Pills for the fourth week, if they are included, are usually sugar pills that contain no medicine.)

Monophasic pills contain the same amount of estrogen and progestin in all of the active pills in a pack. Examples of monophasic pills include Ortho-Novum 1/35, >Demulen 1/35, >Lo-Ovral, >Ortho-Cyclen, >Loestrin, >Alesse, Apri and >Ortho-Cept. Because of the uniform hormone level in all the pills, monophasics are least likely to cause side effects, such as mood changes, that can result from fluctuating hormone levels in the body.

Biphasic and triphasic pills contain different dosages of progestin or estrogen throughout the pill pack. Compared with monophasics, these pills reduce the total hormone dosage a woman receives and are thought to better match the body’s natural menstrual cycle. Biphasic pills change the level of hormones once during the menstrual cycle. Examples of biphasic pills include >Ortho-Novum 10/11, Mircette and Necon 10/11.

Triphasic pills contain three different doses of hormones in the active pills (changing every seven days during the first three weeks of pills). Triphasic pills include >Ortho-Novum 7/7/7, >Ortho Tri-Cyclen, Triphasil, >Tri-Levlen, and >Tri-Norinyl.

Despite the differences, no single pill or pill type rates as the "best" one. Experts consider all combination pills equally effective in preventing pregnancy, provided the pills are used appropriately. Your doctor can help you choose a pill based on your age, medical history, and lifestyle, and cost.

Sources:
Dickey, Richard P. Managing Contraceptive Pill Patients. EMIS, Inc., 1998.
Drug Facts and Comparisons. Facts & Comparisons, 2006.
Hatcher, Robert A. Contraceptive Technology. Ardent Media, Inc., 1998.
Micromedex® Healthcare Series. Thomson Micromedex, 2006.

This answer prepared 7/16/2001.
This information updated 1/25/2007.

• >Mircette
• >Necon 10/11