UNDERSTANDING HORMONAL BIRTH CONTROL

Many commonly used birth control products are “hormonal”—meaning they use hormones to prevent pregnancy. These products contain either a combination of two hormones (progestin and estrogen) or only one hormone (progestin). Your body produces progestin and estrogen naturally. Birth control products provide additional progestin and estrogen to prevent pregnancy.

The products that contain a combination of progestin and estrogen include certain types of birth control pills, the patch, and the ring
The products that contain only progestin include the "mini pill,” injection, implant, and the hormonal intrauterine device (IUD)

As you think about which type of birth control might be right for you, you may find it helpful to review the role of hormones in your menstrual cycle and in pregnancy prevention. The figure below illustrates what happens during a typical (28-day) cycle. Keep in mind that many women's menstrual cycles may be shorter or longer than 28 days.

Hormones and Your Menstrual Cycle

Days 1 to 7:
For women who are not pregnant, menstruation begins on the first day of the menstrual cycle when the old lining of the uterus sheds off. This is due to low levels of estrogen and progesterone.

At about day 7, egg-containing follicles are recruited by follicle-stimulating hormones (FSH), and secrete estrogen. This causes the inner lining of the uterus to grow and thicken. Luteinizing hormone and FSH support follicular growth until a single follicle matures – known as the dominant follicle. FSH declines with dominant follicle selection.
Days 8 to 14:
The dominant follicle begins to produce estrogen, which breaks down the other non-dominant follicles. Increasing estrogen levels stimulate a surge in luteinizing hormone which results in the release of the dominant follicle from the ovary. Ovulation occurs when the egg separates from its follicle.
Pregnancy occurs
Continued secretion of estrogen and progesterone sustain the pregnancy.
No Pregnancy occurs
Estrogen and progesterone levels will eventually decrease.
Hormonal birth control products vary in terms of how they are used and whether anyone can tell if you are using them. Use this website to educate yourself about your options.