Center for Young Women's Health

Estrogen/Progestin Hormonal Injections 


Estrogen-Progestin hormonal injections are very effective in preventing pregnancy. One example is Cyclofem® which contains two hormones: estrogen and a progestin. Cyclofem® is sold in 18 countries worldwide, although it is not available in the US.

Out of 100 women using estrogen/progestin injections
Typical use: 1 or fewer women become pregnant icon representing less than one pregnant woman
Perfect use: 1 or fewer women become pregnant icon representing less than one pregnant woman


What are Cyclofem® injections?

Cyclofem® injections contain synthetic (man-made) forms of the hormones estrogen and progestin (which your body makes). The hormones suppress your pituitary gland which stops your ovaries from releasing eggs. Without these eggs, pregnancy can't happen. The injections also change the lining of your uterus and the mucus in your cervix. By changing your cervical mucus, the hormones make it more difficult for sperm to reach the egg.


How often and when should I get Cyclofem® injections?

The Cyclofem® injection gives one month protection against pregnancy. Therefore, you should get one injection every month to get the best protection against pregnancy. The injection should be given every 28-30 days. There should never be more than 33 days between injections, or you won't be protected against pregnancy. The first injection is given within 5 days of a normal menstrual period, within 7 days of stopping oral contraceptives, or 11-13 weeks after the last dose of Depo-Provera®.


How effective are Cyclofem® injections?

If women get Cyclofem® injections at the right time every month, they are more than 99% effective. This means that if 100 women get Cyclofem® injections at the right time, less than 1 woman will become pregnant in a year.


Cyclofem® injections do not protect against sexually transmitted infections. So you need to use a condom to protect against STDs.


Are there any side effects of Cyclofem® injections?

There are possible side effects from Cyclofem® injections. They can be different for each woman.


They include:

If you get any of these side effects, talk with your health care provider.


Will I get my period while I'm getting Cyclofem® injections?

Some women have regular periods, others have irregular cycles (especially in the beginning), and some stop getting their menstrual periods while getting Cyclofem® injections. It's not a medical problem if you aren't getting your period. It just means that your ovaries are resting and the lining in your uterus does not grow, so there is no menstrual bleeding. You will get your menstrual period back after you stop getting Cyclofem® injections.


Can any woman get Cyclofem® injections?

No. Cyclofem® cannot be used by women who:

If you are interested in Cyclofem®, your health care provider will want to do a physical exam and ask you about your medical history and your family's medical history. This way, he or she can find out if Cyclofem® injections are a good type of contraception for you.


What are the differences between Depo-Provera® and Cyclofem injections?

You have to get a shot once every month with Cyclofem®, whereas only once every three months with Depo-Provera®. However, Cyclofem® causes less menstrual irregularities than Depo-Provera®. There are fewer reports of amenorrhea (not getting your menstrual period), infrequent bleeding, irregular bleeding, and extra-long menstrual bleeding in Cyclofem® users than in Depo-Provera® users. Also, fertility (being able to get pregnant) comes back quicker with Cyclofem® than with Depo-Provera®. Depo-Provera® may possibly cause a decrease in bone density, but it's not a problem with Cyclofem®. Talk with your health care provider about which choice is best for you.


Written and reviewed by the CYWH Staff at Boston Children's Hospital


Updated: 7/1/2011


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