By Denise DeWitt
If you are a woman in your childbearing years, you probably use some form of birth control to prevent an unwanted pregnancy. But do you know why your birth control works? If you take birth control pills or have certain kinds of intrauterine implants, the answer is hormones.
Hormones are your body’s chemical messengers that help carry instructions from the brain to different parts of the body. In women, the primary reproductive hormone is estrogen, which is produced in the ovaries. Estrogen regulates a woman’s monthly cycle by helping control the functions of the uterus and ovaries.
Most common oral contraceptives or birth control pills contain a combination of the hormones estrogen and progestin. Taken together every day, these hormones prevent pregnancy by keeping the ovaries from releasing eggs. These hormones also cause changes in the lining of the uterus that help prevent sperm from reaching or fertilizing eggs.
Hormones are also available as birth control in other forms including a patch, injections, and a flexible ring that is inserted into the vagina. Like birth control pills, these methods provide a combination of estrogen and progestin to prevent pregnancy.
These hormonal birth control methods need to be repeated on a regular schedule, whether daily, weekly or monthly. Another type of birth control that can last several years which may also contain hormones is the intrauterine device or IUD. IUDs are plastic pieces shaped like the letter “T” which are inserted by your doctor into your uterus.
There are two basic types of IUD: copper and hormonal. Copper IUDs release small amounts of copper into the uterus and can be effective for up to 10 years. Hormonal IUDs release the hormone progestin and can be effective for up to five years. Both types of IUD are believed to prevent pregnancy by stopping eggs from being fertilized by sperm.
IUDs do not interfere with sexual activity or tampon use, and may help decrease pain and heavy bleeding during menstruation. IUDs can be removed at any time if problems occur or a decision is made to become pregnant.