What You Should Know About the Birth Control Shot

A birth control shot is a very effective method for preventing pregnancy. Its effectiveness rate is 99% -- but only when applied in a timely manner. Today, we'd like to tell you more about it.
What You Should Know About the Birth Control Shot

Last update: 15 November, 2019

A birth control shot is a substance that’s usually applied to an arm or a buttock through a syringe to temporarily prevent pregnancy. It’s a highly effective method of contraception for women. Estimates indicate that only one of every 100 women who use it correctly becomes pregnant.

Depending on its components, the effects of a birth control shot might last from one to three months. Also, the monthly supply is widely recommended for teenage women. The reason for it is these contain a lower dose of hormones.

Birth control shots protect a woman for about 33 days from the date of application. Once this time elapses, all protection against pregnancy is gone, even if they miss it by one day only. So, a woman should schedule and get a shot on the same day of every month.

Other types of birth control shots have a longer-lasting effect, as we’ll show you below. Continue reading to learn more about it.

How does the birth control shot work?

These contraceptive injections contain hormones similar to those synthesized in the female body – the same that inhibit ovulation. The shots have various names such as “Depo Provera,” “Depo injection,” “contraceptive injection,” “DMPA or medroxyprogesterone acetate.”

As we said above, they’re made of hormones that inhibit ovulation: Progestin, to be precise. However, there are also some combinations of progestin and estrogen. As for the former, they have an effective life of 2 to 3 months. The duration of the combined ones is one month.

Progestin prevents pregnancy by preventing ovulation. A pregnancy cannot happen if there isn’t an ovule in the fallopian tubes. In addition, this hormone causes cervical mucus thickness, which makes the passage of sperm difficult.

Advantages and disadvantages of the birth control shot

Various contraceptive methods.
Before opting for a birth control shot, it’s important to evaluate the advantages and disadvantages.

Like almost all products, contraceptive injections have both advantages and disadvantages. So, it’s up to each person to decide whether they should use this method of pregnancy prevention or not.

Let’s start with the advantages. This kind of contraceptive method stands out for its effectiveness. As we mentioned before, it has a less than 1% probability of failure. Also, they don’t interfere with sexual intercourse. Similarly, we must mention that this shot may improve acne and premenstrual symptoms.

A woman can get a shot once a month, so its use is discreet and reliable. However, this method doesn’t protect against HIV or other sexually transmitted infections and they should keep this in mind. Doctors don’t recommend its use during the breastfeeding stage. Also, it could be a bit much for those who don’t like injections.

Many people think that it can lead to infertility and that teenagers shouldn’t use it. However, this myth is false. In reality, a woman recovers her ability to reproduce as soon as she stops using it. 

Birth control shot side effects

A nauseated woman.
Nausea is one of the side effects of using a birth control shot. However, these are not the rule.

As with everything, there are certain risks to using these injections, so you must assess them before their application.

Some women describe episodes of nausea and irregular periods. This is mainly due to the effect of the hormones contained by the injections. They can alter the normal course of the functions of the body. Also, it’s possible that contraceptive injections could lead to slight weight gain in women who use them regularly for the same reason.

So, to be safe, consult a doctor before using this method so they can advise you on the method that’s most suitable for you.


Birth control shots are effective in the prevention of pregnancy if a woman follows a proper schedule. As we said above, the success rate is 99%. This is a method that’s as effective as tubal ligation.

However, you must keep in mind that this type of contraceptive method doesn’t protect against sexually transmitted diseases, so use condoms with any new sexual partners.

Consult your doctor about the most convenient contraceptive method for you and follow their instructions.

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