Both the birth control shot (otherwise known as Depo-Provera) and birth control pills are highly effective forms of contraception. But they have their differences.
While they both contain hormones that prevent ovulation, birth control pills must be taken daily, while the shot is administered by a healthcare professional once every 3 months.
To decide which one’s right for you, read on to find out more about how each method works, as well as the pros and cons.
Depo-Provera is an injection that prevents pregnancy for 3 months at a time. It contains a synthetic hormone called progestin.
The birth control shot works similarly to the pill by preventing ovulation, thickening cervical mucus, and thinning the lining of the uterus.
According to Planned Parenthood, the shot is 99 percent effective when received every 3 months. If you have your shot on time without being late, there’s less than a 1 in 100 chance you’ll become pregnant during a given year.
For those who don’t take the shot exactly as prescribed — often called typical use — the efficacy rate slips to around 94 percent, which means 6 out of 100 people getting the shot will get pregnant each year.
It can take around 10 months on average for people to become pregnant after stopping the shot, according to the American College of Obstetricians and Gynecologists (ACOG). In some cases, typical fertility levels may take a little longer to return.
The shot doesn’t protect against sexually transmitted infections (STIs). You should still use a barrier method of protection, like condoms, to help prevent contracting an STI and potentially developing a sexually transmitted disease (STD).
How does the birth control shot work?
For a successful pregnancy to occur, an egg must be released into the fallopian tube and then fertilized by sperm.
The sperm must move through the cervix (the opening on the bottom of the uterus). That fertilized egg must then travel down the fallopian tube and attach to the uterine wall.
The birth control shot releases progestin into the bloodstream to stop an egg from being released from the ovary (ovulation) and thicken the mucus around the opening of the cervix.
When there’s no egg present in the fallopian tube, pregnancy is prevented because there’s nothing for sperm to fertilize. And when the opening of the cervix is blocked by thickened mucus, sperm can’t travel through as well.
Progestin also thins the lining of the uterus. In the event that an egg is fertilized, this prevents it from sticking to the uterine wall (implantation).
The hormone released by the shot remains in the body for 3 months. After that, another shot is required to prevent pregnancy.
- You only have to get it every 3 months, making it a lower maintenance and more convenient option for many.
- It’s highly effective when used exactly as directed. With typical use, it’s around 94 percent effective, which is slightly higher than the pill.
- It only contains progestin, so it’s a good choice for people who can’t take estrogen.
- It may come with health benefits, such as reducing symptoms of endometriosis and premenstrual syndrome (PMS), as well as reducing the risk of pelvic inflammatory disease.
- You have to go to a doctor’s office or a health center to get it, which may be difficult to schedule. Sometimes, you may be given a supply to take home with you.
- There may be some unwanted side effects, such as irregular bleeding, changes to your period, headaches, and acne. These may only last a short while. However, 1 in 10 people continue to have irregular bleeding after the first year of use.
- It can take a while to become pregnant after you stop receiving the shot — around 10 months on average. Similarly, your period may not return to the way it was before the shot for several months.
- It can decrease bone mineral density, especially in the first 2 years of use. But, according to ACOG, any loss has been found to fully or substantially recover after stopping the shot.
Birth control pills are a form of hormonal contraception. They can also be used to:
- reduce heavy periods
- treat acne
- ease symptoms of certain reproductive conditions, such as PMS and endometriosis
Birth control pills come as combination pills and progestin-only minipills:
- Combination pills contain two types of hormones: progestin and estrogen. Pill packs with combination pills typically contain 3 weeks of active pills and 1 week of inactive (placebo) pills. During the week of inactive pills, you may have a period.
- Progestin-only pill packs usually contain 28 days of active pills. Even though there aren’t any inactive pills, you may still have a period during the fourth week of your pack.
For the highest efficacy (and to help you get into a routine), try to take birth control pills at the same time every day.
Combination pills offer more flexibility — they’re effective as long as you take one every day. But progestin-only pills must be taken within the same daily 3-hour window.
According to Planned Parenthood, birth control pills are 99 percent effective in preventing pregnancy when taken as directed. However, most practice typical use.
Typical use accounts for missing a pill or two, being a bit late with a new pack, or some other incident that prevents someone from taking the pill every day at the same time.
With typical use, birth control pills are 91 percent effective, which means around 9 out of 100 people taking the pill will become pregnant in a given year.
Once you stop taking birth control pills, you may return to your typical cycle almost immediately and experience your first regular period in as few as 2 months.
It’s important to realize you can get pregnant immediately after coming off the pill, whether you’re having regular periods or not.
Birth control pills don’t protect against STIs, so it’s advisable to still use a barrier method, such as condoms.
How do birth control pills work?
Birth control pills prevent pregnancy in the same ways as the shot. First, the hormones inside can prevent ovulation. If no eggs are released, there’s nothing for the sperm to fertilize.
(Note that ovulation is more likely to be prevented with a combination pill. A progestin-only pill results in around 4 in 10 users continuing to ovulate, according to the ACOG.)
Second, the hormones increase the buildup of mucus around the opening of the cervix. If this sticky substance thickens, any sperm that enter the body will be stopped before getting near an egg.
Both types of pill can also thin the uterine lining, ensuring any egg that is fertilized is unable to attach.
- They’re highly effective when taken correctly, with about 1 in 100 people becoming pregnant with perfect use.
- The side effects can be positive, like lighter, more regular periods and reduced menstrual cramps. The combination pill can also reduce or help prevent acne, PMS, and endometrial or ovarian cancers.
- You can use birth control pills to skip your period — this is safe to do in the long term if you choose.
- You can become pregnant as soon as you stop taking them, even if it takes a while for your period to become regular again.
- They’re often convenient. You can take them anywhere, rather than having to visit a clinician’s office, and they won’t interrupt any sexual activity.
- With typical use, they’re slightly less effective than the shot. Pills are around 91 percent effective whereas the shot is around 94 percent.
- Side effects may occur. These can include bleeding between periods, nausea, and headaches, and they often only last a few months. More serious side effects are rarer, but can include stroke and blood clots. The risk of these is slightly higher with combination pills.
- You’ll need to remember to take them every day in order to be protected from pregnancy. Progestin-only pills must be taken on an even stricter schedule — within the same 3-hour window each day.
Both birth control pills and the Depo-Provera shot are safe for a lot of people. However, they may not be suitable for all.
For example, the combination pill has been linked to a small increased risk of:
- heart attack
- deep vein thrombosis (DVT)
This risk is higher in some people, such as those with a history of these conditions or those who are at greater risk of cardiovascular disease due to the likes of high cholesterol and high blood pressure.
People who have given birth should avoid the combination pill for at least 3 weeks after delivery — and even longer if they have extra risk factors for DVT.
Additionally, you shouldn’t take either type of birth control pill if you:
- have an inherited blood clotting disorder or a history of blood clots
- experience migraine with aura
- have a history of heart attack or a serious heart condition
- smoke and are over 35 years old
- have been diagnosed with lupus
- have diabetes that isn’t well managed (complications exist) or have had the condition for more than 20 years
You shouldn’t use a birth control shot if you:
- have or have had breast cancer (this also applies to the progestin-only pill)
- take aminoglutethimide, which is a prescription medication used to treat Cushing’s syndrome
- have thinning of the bones or bone fragility
- have diabetes that’s not well managed (complications exist)
- have a history of stroke
- have unexplained vaginal bleeding
Note that people with numerous risk factors for cardiovascular diseases, such as smoking and diabetes mellitus, may have an increased risk of this disease while taking the shot.
As with any medication, both birth control pills and the shot may have effects on your body.
For birth control pills, side effects include:
- breakthrough bleeding, or bleeding during active pill days
- breast tenderness
- breast sensitivity
- breast swelling
Most of these side effects will ease within the first 2 to 3 months after you begin taking the pills.
The side effects of the birth control shot include:
- irregular periods, which are more common in the first 6 to 12 months after your first injection
- increased spotting and breakthrough bleeding
- change in appetite
- weight gain
- change in libido and interest
- tender, sore breasts
- mood changes
As the hormones from the shot remain inside your body for 3 months, the side effects can last for the entirety of this period.
Causes of side effects
Both birth control pills and the birth control shot deliver increased doses of hormones to your body. So anytime your hormones are purposefully altered, you can expect to experience some side effects or symptoms.
The hormones in birth control pills are delivered gradually on a daily basis. The level of hormones in the pills isn’t very high.
The Depo-Provera shot, however, delivers a high dose of hormones all at once. For that reason, you may experience greater side effects immediately following the shot.
How effective is the birth control shot and pill?
When used correctly, according to Planned Parenthood, the birth control shot is 99 percent effective, meaning 1 out of 100 people will become pregnant while taking it. If you don’t get your shot on time, the effectiveness drops to 94 percent, meaning 6 out of 100 people will become pregnant.
Similarly, birth control pills are 99 percent effective when used as directed. But this drops to 91 percent with typical use.
Is the birth control shot better than the pill?
Just like the birth control pill, there are pros and cons to the birth control shot.
One form isn’t necessarily better than the other. It comes down to your personal preferences and what’s right for you and your lifestyle.
If you’re not sure which form of birth control is better for you, talk with a healthcare professional and weigh your options before making your decision.
Do you get a period on the birth control shot or pill?
For the first 1 to 6 months of taking the birth control shot, you’ll likely experience irregular periods. As your body adjusts, it’s possible your periods will get lighter and shorter, and then stop altogether after 1 year. (This happens to about half of people taking the birth control shot, according to Planned Parenthood.)
The pill, on the other hand, can result in no periods if you’re on a continuous regimen where you take an active pill every day. But even if you’re prescribed a pill with 3 active weeks and 1 inactive week, you can continue taking the active pill to delay or skip your period.
Do you need a prescription for the birth control shot and pill?
Yes, you need a prescription for any form of hormonal birth control. The only exception is emergency contraception, often called “the morning-after pill,” which is available without a prescription at most pharmacies.
Besides visiting a clinician in person, you can use online birth control services to receive a birth control pill prescription and regular deliveries.
Healthline’s picks for the best online birth control services
How can you prepare for getting the birth control shot?
There’s nothing special you have to do to prepare for getting the birth control shot. However, eating a nutrient-rich meal and making sure you’re hydrated is always a good idea.
If needles make you uneasy, let your healthcare professional know before they administer the shot. They may ask you to sit or lie down to help ease your nerves and reduce your risk of fainting.
How quickly can you become pregnant after stopping the birth control shot or pills?
As the pill is required to be taken on a daily basis, it’s possible to become pregnant immediately after stopping it. This is still the case if your period’s irregular.
Due to the higher level of hormones administered, it can take an average of 10 months for people to become pregnant after stopping the shot. This may be longer for some.
Can you switch from the pill to the shot or vice versa?
Yes, you can switch. If you want to stop taking the pill and change to the shot, you’ll need to get your first shot 7 days before stopping the pill. Plus, you’ll need to make sure you finish your current pill back before making the change.
Going from the shot to the pill is a little simpler. You’ll just need to ensure the first pill is taken at least 15 weeks after your last shot was administered.
Alternatively, you can use a backup method, like condoms, instead of overlapping the two.
Deciding between the birth control pill and the shot comes down to a few things.
If effectiveness is your main concern, note that both forms of birth control are 99 percent effective when used perfectly. However, with typical use, the shot is slightly more effective at 94 percent compared with the pill’s 91 percent.
If you want to prioritize convenience, the shot may be the better option. It only has to be administered once every 3 months, whereas the pill needs to be taken daily.
Each type of birth control also has a number of possible side effects and safety considerations, which may affect your choice.
Discussing your options with a healthcare professional can help you weigh the pros and cons. It all comes down to what’s right for you and your lifestyle.
Lauren Sharkey is a U.K.-based journalist and author specializing in women’s issues. When she isn’t trying to discover a way to banish migraines, she can be found uncovering the answers to your lurking health questions. She has also written a book profiling young female activists across the globe and is currently building a community of such resisters. Catch her on Twitter.