How long does it take for birth control to leave your system depo

Depo-Provera, also known as the birth control shot, can completely stop your menstrual cycles, especially with repeated use. This can be worrisome if you’re not expecting it, and you may worry about whether and when your cycles will come back. Depo-Provera has a poor reputation online and in fertility forums. Previous users are often surprised by how long it takes for their fertility to return after discontinuing the injections.

If you have stopped using Depo-Provera and want to get pregnant, you may have concerns and questions. For example, when will you be able to get pregnant again? Is it normal to take so long for your fertility to return? Can Depo-Provera cause long-term infertility? Learn more about getting pregnant after Depo-Provera.

What Is Depo-Provera and How Does It Work?

Depo-Provera is the brand name for depot medroxyprogesterone acetate (DMPA), progestin-based contraceptive injection. It works by suppressing ovulation and thickening cervical mucus and provides three months of reliable birth control. Injections are repeated every three months for as long as birth control is desired.

Unlike birth control pills, which need to be taken daily, Depo-Provera only needs to be taken once every 90 days. This is because the injection creates a depot (or storage) of medroxyprogesterone acetate in the body at the site of the injection.

After the injection, progesterone levels in the body gradually rise for about three weeks. After three weeks, it reaches its peak. Then, the levels of progesterone slowly decline. When progesterone levels are below a certain level (less than 0.1 nanograms per milliliter), ovulation and regular menstruation begin again.

Amenorrhea (lack of menstrual periods) is a common side effect of Depo-Provera. After about one year (or four injections) of taking Depo-Provera, 50% of women stop having their menstrual periods. This is not a sign of infertility. Usually, your period will return within 6 months of the last injection, but it may take longer.

Getting Pregnant on Depo-Provera

There is always a very small chance of getting pregnant on Depo-Provera. This possibility is lowest if you get the shot on time.. When used perfectly, Depo-Provera is about 99% effective. Statistically, there are times when people don't get their shots on time, so the overall effectiveness of Depo-Provera is 96%.

Pregnancy Symptoms While on Depo-Provera

Whether you are on Depo-Provera or using another form of birth control, the following symptoms could indicate that you are pregnant:

• A heightened sense of smell
• Bloating
• Nausea or vomiting
• Fatigue
• Food aversions
• Sore or enlarged breasts

Getting Pregnant After Depo

As long as you want to prevent pregnancy, you need to receive an injection every 90 days. This is because, after 90 days, the levels of Depo-Provera are not high enough for most women to reliably prevent pregnancy.

Let’s say you want to get pregnant and you discontinue injections. You might assume your fertility will return on day 91, but this isn’t how the medication works. While the levels of Depo-Provera after 90 days may not be high enough to be considered effective for pregnancy prevention, they may still be too high to get pregnant.

Some women will get pregnant the very first month after the 90 days, but this isn’t common. Most women will see their fertility return within 5 to 7 months of their last injection. In other words, about two months after that 90-day period ends.

Within 10 months of the last injection, 50% of women who discontinue Depo-Provera will get pregnant.

Ovulation After Depo

There are three ways to know if your fertility has finally returned after stopping Depo-Provera: having a regular menstrual cycle again, getting positive results on an ovulation predictor test, and having ovulation detected on a basal body temperature chart. Of course, this assumes there are no additional fertility problems.

Regular Menstrual Cycle Returns

Having a regular menstrual cycle is the most obvious sign that ovulation has started. Your menstrual cycle lasts from the first day of your period to the first day of your next period. Your cycles are considered regular or normal when they meet the following conditions:

• Duration: Your periods last 8 days or fewer
• Flow volume: You lose between 2 to 3 tablespoons of menstrual fluid during each period. Just spotting could be a sign that you're not ovulating. 
• Frequency: Your periods typically come every 24 to 38 days (the average is 28 days). This means that from the first day of your last period up to the start of your next period is at least 24 days but no more than 38 days.
• Regularity: Your cycles are consistent from month to month. For example, your cycle is 27 days long one month, and 29 the next. Cycles that vary in length by more than 7 to 9 days (for example, a cycle that is 26 days long one month and 45 the next) are considered irregular.

Test Positive on an Ovulation Predictor Test

These are ovulation test kits you can buy in any pharmacy or online. They work a lot like a pregnancy test, in that you use your urine to test your hormones. While pregnancy tests look for hCG, an ovulation predictor test looks for the hormone luteinizing hormone (LH). LH spikes just before you ovulate.

Ovulation Detected Using a BBT Chart

Your basal body temperature (BBT) is your body's temperature at complete rest. This temperature changes depending on where you are in your cycle. If you're ovulating, your BBT will jump up and remain higher until you get your period. Then, it will drop back down and stay there until ovulation occurs again.

You can track your BBT at home. This is a way to know if ovulation has returned after Depo-Provera, and it can help your doctor help you if you find that ovulation has not returned as expected.

Temporary Infertility After Depo

But not every woman will get their cycle back 5 months after the last injection. In some cases, it may take up to 22 months—or almost two years—for fertility to return after the last injection. Why does this happen?

According to the research, the delay seems to be related to a woman’s weight. Women who weigh less will have their fertility return faster than women who tend to weigh more. This has to do with how long it takes your body to completely metabolize the progestin.

How long you’ve used Depo-Provera is not associated with a longer period of lack of ovulation. In other words, whether you used Depo-Provera injections for 6 months or two years doesn’t matter. Your fertility will likely take the same amount of time to return in either case.

If you received the subcutaneous version of Depo-Provera (as opposed to the older more commonly used intramuscular injection), your risk for experiencing a lack of ovulation for up to two years is significantly less. According to at least one study, 97% of women who received the subcutaneous version of Depo-Provera had ovulation return after 12 months.

Interpreting Forum Posts About Depo

The most important thing to know is that Depo-Provera is not known to increase your risk of infertility after that those 12 to 22 months. In other words, Depo-Provera use is not associated with an increased risk of infertility in general.

Ovulation (and possibly your menstrual cycles) take a while to return due to your body not yet metabolizing the medication completely. Not because Depo-Provera has somehow caused a long-term infertility problem.

With that said, in just about every thread about Depo-Provera on infertility forums, you’ll find women saying their fertility never returned, even after 2 years. Sometimes, they will assume that this was caused by the shot. This isn’t backed up by the research.

Remember that infertility occurs in 1 in 8 couples. This includes couples who choose to use Depo-Provera. There will be women who can’t conceive after Depo, even two years after Depo, but this isn’t due to the birth control shot. They would have struggled to conceive without Depo-Provera as well.

When to See Your Doctor

If your cycles are not coming back or you’re not ovulating, and it’s within two years of your last shot, there is unfortunately very little your doctor can do to help. You just need to wait. Which can be extremely frustrating.

You should see your doctor if:

• It has been 24 months since your last injection and you are still not ovulating
• Your cycles are irregular two years after your last injection
• You don’t conceive within 12 months of ovulation returning (or 6 months if you're age 35 or older)
• You have other risk factors or signs of a possible fertility problem

A Word From Verywell

Hopefully, your fertility will come back within three or six months after your last shot. This is how it should work, and many women do get pregnant within 8 to 10 months of their last Depo-Provera shot. However, in some cases, it can take longer. If you struggle to conceive after stopping Depo-Provera, talk to your doctor.