What are birth control pills

More than 45 years since the U.S. Food and Drug Administration (FDA) approved “the pill” in 1960, it continues to be the most popular and one of the most effective forms of reversible birth control. Today, American women have more than 40 different oral contraceptive products from which to choose.

“The pill” is the common name for oral contraception. There are two basic types of birth control pills: combination pills and progestin-only pills. Both are made of hormones like those made by a woman’s ovaries. Combination pills contain estrogen and progestin. Both types require a medical evaluation and prescription. Both can prevent pregnancy.

Progestin-only pills

The progestin-only pills (also called “mini-pills”) became available in the 1970s. Their use was and has been limited – making up only 1 to 10 % of contraceptive market. This type of pills contains no estrogen and therefore they do not usually prevent ovulation. To work effectively, they must be taken at a certain time every 24 hours. Even missing one pill can greatly reduce effectiveness.

Progestin-only pills have specific advantages over combined oral contraceptives. Because they do not contain estrogen, they are a good contraceptive choice for breastfeeding women, as estrogen reduces milk production, and for women with health conditions that preclude use of combined oral contraceptives pills, such as migraine headaches, thromboembolism, and cardiovascular disease. In addition, progestin-only pills do not have most of the estrogen-related side effects of oral contraception: nausea, headaches and other symptoms associated with starting the combined pill are minimal. However, bleeding and spotting days during the intramenstrual period may be higher than with the combined pills and missed pills may result in a higher chance of pregnancy that with the combined oral contraceptives.

Combination pills

When you hear the term “birth control pill,” it most often refers to oral contraceptives containing estrogen and progestin. Combination pills contain a combination of these two hormones. 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.

Combined birth control pills work by preventing ovulation – the release of a mature egg from a woman’s ovary. The estrogen in the pill causes this.

Monophasic pills

Monophasic pills contain the same amount of estrogen and progestin in all of the active pills in a pack. Examples of monophasic pills include Alesse, Brevicon, Desogen, Levlen, Levlite, Loestrin, Modicon, Nelova, Nordette, Norinyl, Ortho-Cept, Ortho-Cyclen, Ortho-Novum, Ovcon, Yasmin. 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.

The FDA approved a new packaging of a monophasic birth-control pill called Seasonale in 2003. The product is packaged in a 91-day supply and is designed to prevent menstruation for the entire time period. Women taking Seasonale will have only four periods a year. Seasonale contains the same estrogen and progestin in the same amount as many other monophasic birth control pills. Although many other monophasic birth control pills are used in this way, Seasonale is the only product approved for use.

Multiphasic pills

Phasic pills were developed in the 1980s. Multiphasic oral contraceptives contain varied amounts of hormones and are designed to be taken at specific times throughout the entire pill-taking schedule. They were developed to reduce side effects of oral contraceptives, including breakthrough bleeding, spotting and amenorrhea, associated with higher levels of hormones.

Biphasic pills change the level of hormones once during the menstrual cycle. The progesterone dose is increased about halfway through the cycle. Examples of biphasic pills include Jenest, Mircette, Necon 10/11, Nelova 10/11, Ortho-Novum 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 gradually increase the dose of estrogen and some pills also increase the progesterone dose. Triphasic pills include Cyclessa, Ortho-Novum 7/7/7, Ortho Tri-Cyclen, Triphasil, Tri-Levlen, Trivora, Tri-Norinyl.

Emergency contraceptive pills (ECP)

Emergency contraceptive pills are not intended to be used regularly as a contraceptive. They are designed to prevent pregnancy after unprotected sex. The FDA has approved one emergency contraception pill called Plan B, which contains the progestin levonorgestrel.

Advantages of ECP:

• Reduces the chance of unintended pregnancy
• Can be obtained easily – Plan B will soon be available over the counter for women 18 and over can be obtained in advance and kept handy in case of an emergency.

Disadvantages:

• Timing. Because you must take the first dose within 120 hour of having unprotected sex. The sooner you take them after unprotected intercourse, the more effective they are.

Which Pill is better?

Monophasic birth control pills work as well as the more expensive and more complicated biphasic and triphasic products. Monophasic products with low amounts of estrogen may cause less bloating or breast tenderness but more breakthrough bleeding. So for most women, the monophasic birth control pills represent a good first option. All combination products containing both estrogen and progestogen are more effective in preventing pregnancy than are the “mini-pills.” However, progestin-only pills are a good choice for breastfeeding women and for women who can’t use combined oral contraceptives pills.