Women's Health Services

History shows that women used to resort to all kinds of unusual methods to avoid getting pregnant, from drinking a brew of beaver’s testicles soaked in alcohol to ingesting mercury. Today, women who want to avoid pregnancy may choose from a variety of safe contraception options. But some are more reliable than others, and it benefits you to understand how they work and how they might fail.

Some birth control methods can change a women’s menstrual cycle; and the most important point to understand about most menstrual changes with contraception is that they are to be expected and are not harmful to the body.

Your physician can help you in selecting the most suitable contraceptive method from among the following:

Oral contraceptives, or "the pill"

In use since 1960, the pill has grown in popularity from 1.2 million users to more than 16 million today. Oral contraceptives regulate menstrual cycles to predictable lengths. Active hormones are taken every day for 3 weeks and then inactive pills are taken during the fourth week. During the fourth week the woman will bleed. When taking the pill, a woman can anticipate when she should get her period. The pill has been the most popular form of birth control for four decades – a testament to its safety and efficacy. The hormones in the pill, a combination of estrogen and progestin or progestin alone, prevent pregnancy by stopping the ovaries from releasing eggs and by keeping the cervical mucus thick so that sperm can’t easily pass through it.

The various types of oral contraceptives are equally effective. Low-dose pills pose very few health risks and may offer health benefits unrelated to contraception. For example, low-dose pills appear to reduce the risk of uterine and ovarian cancer and regulate menstrual cycles and bleeding. There are certain subsets of women, however, for whom risks and side effects outnumber benefits. The percentage of women who become pregnant on the pill during the first year of use is only 0.1 to 3%.

Barrier contraceptives

These include condoms, the diaphragm, the cervical sponge, and the cervical cap. These block the sperm’s access to a woman’s uterus. Spermicides (substances that kill sperm) should be used with condoms and other barrier products that don’t contain them already. Not all barrier contraceptives are equally effective. The percentage of pregnancies the first year of use is 3 to12% with the male condom, 5 to 21% with the female condom, 6 to 18% with the diaphragm, and 11 to 18% with the cervical cap. Vaginal foams, gels, creams, and suppositories used without physical barriers may be even less effective.

Contraceptive Implants

Implants (such as Norplant) are plastic capsules that are inserted via a needle under the skin of the inside inner arm (no stitches are needed). The contraceptive implants consist of 6 small rods (each about the size of a matchstick) made of soft, flexible plastic. The small rods release the hormone progestin into the bloodstream slowly and can remain in place for several years. The hormone works to prevent pregnancy in several ways. First, the progestin prevents an egg from being released from the ovary in some women. Second, the hormone thickens the cervical mucus in all women, making it difficult for sperm to enter the uterus. Implants can cause irregular menstrual bleeding and are often removed for this reason. Many women experience regular cycles again within a year of starting use. They are as effective as the pill – the pregnancy rate is less than 0.1% for the first year of use.

Intrauterine devices (IUDs)

Two types of IUDs are available in the United States – one containing copper and one containing progesterone. IUDs are made of molded plastic, are inserted through the vagina into the uterus. They prevent contraception by causing an inflammatory reaction inside the uterus, attracting white blood cells and thereby preventing fertilization. Depending on the type, IUDs can remain in place for up to10 years or must be changed annually. IUDs are very effective, with only 0.6 to 2% of women becoming pregnant the first year of use, and they cause few side effects.

The copper-containing IUD tends to cause increased cramping and heavier bleeding during periods. The progesterone IUD, on the other hand, reduces cramping and bleeding. IUDs should not cause bleeding between periods. As the uterus develops a tolerance for the copper IUD, the cramping and bleeding may lessen.

Injectable Contraception or "The Shot" (such as Depo-Provera)

Injectable contraception’s main side effect is menstrual change. These changes include irregular cycles, bleeding between periods, and occasionally heavier bleeding. Another change may be no bleeding at all. Especially with longer duration of use, women are more likely not to bleed. By the end of one year, about half of women using injectable contraception will stop having their periods. Not getting your period is fairly common and does not mean you’re pregnant. As long as you are not pregnant before getting your first injection and have returned on time for your next injection, it is unlikely you are pregnant. Injectable contraception is 99% effective when used as directed. After discontinuing this method of contraception, it may take several months for your menstrual periods to return.