Many popular methods of birth control contain synthetic female hormones to prevent pregnancy. This page answers your questions about the most common hormonal contraceptives.
Contain Estrogen & Progestin
Contain Progestin Only
Methods containing higher levels of hormones are more effective but have more side-effects.
Methods that contain estrogen have more serious side-effects and health hazards (such as heart attacks and strokes) than methods with only progestin. Estrogen-free contraceptives are less effective than combined hormonal contraceptives. Visit our hormonal contraceptive page for the chemical names of the different types of artificial hormones.
Birth control chemicals containing estrogen and/or progestin have several major mechanisms of action.
Contraceptive mechanisms prevent fertilization; when these fail, additional mechanisms prevent implantation.
More about post-conception mechanisms...
If you start the Pill, Implanon, or Depo-Provera on the first day of your period, it is considered effective right away. It takes up to seven days for the hormones to become fully effective. However, the first seven days of a woman's cycle are already infertile, so no additional protection is required. If you start the method on any other day than the first day of your period, you need to use a backup plan for up to seven days. For the minipill, you may need a backup method for 28 days. Ask your doctor to be sure. For the Pill, some doctors recommend using a backup method for the first 30 days. This is mainly to be sure that a pregnancy does not occur while you are still getting in the habit of taking a pill every day.
It is recommended that you wait until you have had 2-3 normal menstrual cycles before trying to get pregnant. This is because it may take several months before your cycles return to normal after discontinuing a hormonal method. Doctors use the first day of your last menstrual period to determine your due date; if your periods are irregular this may result in an inaccurate date. Also, there is some evidence that birth control drugs may exert a prolonged effect on the endometrium, making it more difficult to become pregnant.
Because of the prolonged effect of the birth control drugs on your body, you may be infertile for some time. For combined oral contraceptives, the average length of infertility is 2-3 months, but some women will remain infertile for 6 months or more. For Depo-Provera users, infertility typically lasts from 6 to 12 months. You may not have any periods during this time.
For users of combined oral-contraceptives, missing a period is not uncommon. If you have not missed a pill you are probably not pregnant, but a pregnancy test may not be a bad idea. If you miss two periods in a row OR if you miss your period and you did miss one of your pills, you could be pregnant. Contact your local pregnancy center immediately for a pregnancy test.
For users of progestin-only methods, like the min-pill, lack of periods is common. It probably means that you are not ovulating. However, if you are experiencing pregnancy symptoms (nausea, fatigue, sore breasts, frequent urination, etc.) contact your local pregnancy center for a pregnancy test right away.
Half of all Depo-Provera users have no periods at all during the first year of use. And pregnancy symptoms such as weight gain, mild headaches, and breast tenderness are also common side effects of the drug. This can be alarming for Depo-Provera users, but usually the pregnancy-like symptoms disappear. Even after using Depo-Provera, it takes on average 10 months from the time of the last injection for normal periods and fertility to return.
Other reasons why your period may be late.
If you have stopped using your method, it may take time for your periods to return to normal. See above.
If your period does not start during the last few days on the "reminder" pills or during the first 3 days of the pill-free interval, take your temperature with a Basal Body Temperature (BBT) thermometer in the morning before you get out of bed. (You can get a BBT thermometer from most drug stores.) If your temperature is 98 degrees F for 3 days in a row during the pill-free week, you are probably not pregnant. You can also take a home pregnancy test, which are usually accurate by the time you miss your period, or visit a local pregnancy resource center for a free, accurate test.
Combined OCs It is recommended that you take that pill as soon as you remember, and take your next pill at the regular time, even if it means you take two pills in one day. You will probably not get pregnant, but just to be sure, you might use a back-up method for 7 days. If you have missed any of pills 15-21, ask your doctor or pharmacist for special instructions. S/he may ask you to continue taking your pills, but to start a new pack instead of taking the reminder pills.
Progestin-Only OCs It is recommended that you take that pill as soon as you remember, and take your next pill at the regular time, even if it means you take two pills in one day. You will need to use a back-up method for the next 2 days.
Contact your doctor or pharmacist for instructions. You may need to start a new pack or double up on pills for a while depending on what type of pill you were taking.
If you took a combined oral contraceptive pill two hours or more before you vomited, then you do not need to take it again. If the vomiting ocurred within two hours, you will need a replacement pill.
Yes, but you will need to talk to your doctor or pharmacist for details. This practice can compromise the effectiveness of the pill. You might also ask your doctor about a type of combined OC pill, extended cycle pills, where women get their periods only four times a year. It works by reducing the number of pill-free intervals which trigger menstruation.
Mid-cycle spotting is not uncommon for users of the pill, especially during the first few months of use. When this happens, typically doctors prescribe a stronger formulation of the pill. Spotting is an indication of decreased pill effectiveness, so some doctors recommend using a back-up method should spotting occur. However, spotting could also be a symptom of the STD chlamydia, so you should be tested if you are at risk.
Users of Implanon and Depo-Provera can expect irregular menstrual patterns. No periods, light periods, and even prolonged or heavy bleeding are all potential side-effects. If you have prolonged or heavy bleeding, you should contact your doctor.
Yes. All methods of birth control can fail, even if you use them perfectly. If you miss a pill, take a mini-pill only a few hours late, or take antibiotics that will increase the likelihood of contraceptive failure. One in ten pill users get pregnant every year.
There is no conclusive evidence that a brief exposure to birth control chemicals will cause any sort of birth defect in the unborn child. However, you should avoid taking if these drugs if you think you might be pregnant.
Combined OCs
Progestin-Only Methods
One of the most common complains we hear from women is that after starting hormonal contraceptives they just don't feel like having sex any more. Doctors frequently dismiss women's concerns about sex drive while partners are left sulking. Until recently, few studies have examined this issue, other than those conducted by pharmaceutical companies (which tend to be invested in not finding problems). Earlier studies found conflicting results. The most recent research has found that loss of libido is a common problem and may not be reversible.
There is no one answer to this question. Weight gain is a very common side effect in response to hormonal birth control and varies on an individual basis. For most women, extra female hormones make fat deposition easier and increase the appetite. Conversely, weight loss usually becomes easier when hormonal birth control is discontinued.
For Depo-Provera the average weight gain is 5.4 lbs the first year, 8.1 lbs after two years, and 13.8 lbs after four years. But this is an average, and for many women weight gain can be extreme as this drug can increase the appetite. The average weight gain while on Implanon is 2.8 lbs after the first year.
No. In fact, women who use Depo-Provera may double their risk of acquiring STDs, such as chlamydia, gonorrhea, and HIV.
Other hormonal contraceptives seem to also increase the risk of getting an STD.
This is because these drugs cause dryness in the genital tract, which facilitates small tears and abrasions, making it easier for infections to enter the body.
Also hormonal contraceptives may supresses the immune system, which makes it easier for infections to proliferate.
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