Contraceptive injection: understand how the method works and get your doubts cleared

The contraceptive injection is made up of injectable hormones, which are applied monthly or every three months in the gluteal region, for those who want to avoid pregnancy.

This method is ideal for those who forget to take the pill daily or cannot use oral contraceptives on medical advice. Also, it has a lower cost.

But it’s not all advantages. The contraceptive injection can cause some adverse reactions, in addition to making pregnancy more difficult even after stopping use.

The gynecologist and obstetrician Rodrigo da Rosa Filho, a specialist in human reproduction, explains better the positive and negative points, the right way to use the injectable contraceptive and clarifies other doubts about this method.

How does it work and who is it for?

The contraceptive injection should only be taken if there is professional guidance. This indication takes into account several factors, such as health issues, intolerance to certain types of hormones, habits and even lifestyle. “Between the monthly injection, the oral pill or contraceptive patch, the basic difference is more in the form of application. And it changes the practicality, since forgetfulness is a very common problem. But the effectiveness is the same”, says the doctor.

The application should always be done at the pharmacy, as it is an intramuscular application. According to the doctor, it is not painful. “It only hurts if it’s poorly applied”, he says.

Monthly x quarterly injectable contraceptive

The gynecologist also clarifies that there are two types of injectable methods. One is applied monthly, with combined hormones (derived from estradiol and progesterone), synthetic, which have the same characteristics as the pill and the contraceptive patch.

It is widely used by teenagers who often forget the pill, it also has fewer side effects, especially gastrointestinal, such as nausea. “This injection is applied every 30 days, always on the same day of the month. The first should be applied on the first day of menstruation. And the cycle is normal, without any change,” he says.

The other has quarterly application. Its composition is based only on progestin (similar to natural progesterone), without estrogen. “She has the advantage of not having contraindications. It is even widely used in the postpartum period, because it does not interfere with breastfeeding. But it has the disadvantage of increasing fluid retention over time”, explains Rodrigo.

Another different feature of the quarterly injection is that women do not menstruate. “It is very indicated in cases where we do not want the patient to menstruate, as in endometriosis.”, she says.

Possible side effects

The monthly injection, because of the combined hormones, has the same risks as the contraceptive pill or patch, such as thrombosis, heart attack, stroke, liver problems. This does not change regardless of the route of administration, that is, whether it is oral or injectable.

Therefore, it is a contraindicated method for those who are predisposed to any of these problems and also for smokers. Women who are breastfeeding cannot use the method either, as there is interference.

The quarterly injection does not have any of these contraindications, as it has no estrogen in its composition.

More questions answered

Before opting for an injectable contraceptive method, it is important to know more details about it, its advantages, disadvantages and risks. The gynecologist and obstetrician Rodrigo da Rosa Filho answers some common questions.

Injectable contraceptive fattening?

Yup. Injectables have a higher amount of hormone, which increases fluid retention. That’s why any woman who starts using the injections is likely to gain more weight, but this also varies a lot from body to body.

Will my menstrual cycle change with the injection?

It depends. In the monthly injection the person continues menstruating monthly. In the quarter there is no menstruation.

Does the injection dispense with the use of condoms?

To avoid sexually transmitted diseases, no. Condoms are still needed. But for contraception the injection is very effective.

I started taking the injection this month, am I already protected?

Yup. Efficacy is from the first time you take the injection.

When will I be able to get pregnant after stopping the injections?

The monthly does not interfere with fertility. If you stopped taking it, the following month you will be back to your normal cycle and there is already a chance of pregnancy in the next cycle. In the quarterly period, after stopping use, it can take from six months to a year for the woman to ovulate and menstruate again. Therefore, it is only indicated in very specific cases.

I forgot to take it on the right day, is it okay to take it late?

If you forget, you have up to three days to take it again without risk. In the quarterly it is even more relaxed, with a more flexible deadline.

If I want to stop my period, is there a way?

In the case of injection, there is no way to interrupt menstruation, because it is not recommended to apply more than one per month. If you don’t want to menstruate, this is not a good method.

How long can I use the injectable contraceptive?

There is no deadline for using the monthly injection. If you are feeling well, without contraindications, you can always use it. It can start in adolescence and go up to the pre-menopause stage. But the quarterly can be applied for a maximum of three years, because it can induce osteoporosis.

How much does each injection cost?

The monthly cost around 30 reais, a much lower value compared to other methods. According to the doctor, many women opt for the injection because of the cost. The quarterly one goes for about 40 reais, it’s even cheaper.

It is important to emphasize that only a doctor can evaluate each case and prescribe the best contraceptive method, in order to avoid damage to health.

The information contained on this page is for informational purposes only. They do not replace the advice and follow-up of doctors, nutritionists, psychologists, physical education professionals and other specialists.