Can You Get Pregnant On Depo Shot And How Does It Work?

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Depo-Provera is one of the most effective contraceptives that prevent undesired pregnancies. But can you get pregnant on Depo shot? Getting pregnant on Depo shot (DMPA) is a rare incidence. This hormonal shot releases progestin hormone that prevents ovulation and alters the cervical mucus to prevent unwanted pregnancies.

Inaccurate use, such as not using additional barrier protection if the shot is taken after the first five days of menstruation for a few days or delay in taking a shot, can be a reason for most pregnancies on Depo shot.

Read on to learn more about reasons for getting pregnant on Depo-Provera shot, how to avoid such incidents, and ways to prevent pregnancy.

What Is Depo-Provera/ Depo Shot?

Depo-Provera is a female contraceptive injection containing a synthetic progesterone hormone called depo-medroxyprogesterone (DMPA).

Usually, 150mg of the drug is administered through a deep intramuscular injection (1). The injection is given by a doctor or a nurse in the upper arms or buttocks. One depo shot is given within five days of menstruation and it remains effective for about 12 weeks.

But a depo shot cannot be taken if you have any of these health issues (2):

  • Breast cancer
  • Blood clots
  • Liver disease
  • Osteoporosis
  • Diabetes
  • High risk for heart disease
  • High blood pressure
  • Migraine headaches
  • Epilepsy

You should inform your doctor if you have any of the above health issues or if you are taking other medications because Depo-Provera goes into your body and changes the way your menstrual system works.

How Does A Depo Shot Work?

As mentioned earlier, Depo-Provera is a synthesized form of progesterone. When the body senses the presence of progesterone, it will stop producing the hormone naturally, thereby inhibiting the release of the egg.

The contraceptive injection works in more than one way:

  • Prevents the release of eggs from ovaries.
  • Thickens the cervical mucus, which prevents the sperm from reaching the egg.
  • Restricts implantation by bringing a change in the uterine lining.

The shot, once taken, is effective for 12 weeks or three months.

How Effective Is A Depo Shot?

The depo shot is the most effective contraceptive with an accuracy of 97% (3). If you take it every 12 weeks, it can be 99.7% effective. However, no birth control method is 100% effective.

What if you miss a shot?

If you haven’t taken a shot after 12 to 13 weeks, you may have to use alternative contraceptive methods to avoid pregnancy. Also, go for a pregnancy test before taking the shot after a gap.

Though the shot is very effective, the US Food and Drug Administration (FDA) advises the users to take it for not more than two years as it weakens the bone mass density, so supplementary calcium may be taken. However, the World Health Organization does not put any such restrictions (4).

But the drug is not free of side effects.

What Are The Side Effects Of A Depo Shot?

Depo-Provera’s side effects include (5):

  • Headaches
  • Abdominal discomfort
  • Mood changes
  • Reduced interest in sex
  • Depression
  • Allergic reactions
  • Fluid retention
  • Breast soreness
  • Nervousness
  • Dizziness
  • Nausea
  • Fatigue
  • Irregular or no periods
  • Spotting or heavy bleeding
  • Loss of bone density. This risk increases if you have a family history of osteoporosis
  • There is a risk of blood clot in the head, heart, legs or lungs due to the high levels of progesterone
  • According to research, women on depo shots have a higher risk of contracting HIV possibly because the DMPA weakens the immunity system (6)

Other mild side effects are:

  • Acne
  • Bloating
  • Backaches
  • Leg cramps
  • Pain at injection site
  • Hair loss on the head or unwanted hair growth on the body
  • Slight bruising where the shot has been given
  • A small, permanent dent in the skin where the shot has been given

The side effects of the depo shot are significant, and there is a reason why you might have these issues if you take the injection.

Why Does A Depo Shot Have Side Effects?

When a high dose of progestin is injected, it takes some time for the body to cope with this synthetic hormone. Since this contraceptive medication has a long-lasting effect, you may experience certain side-effects.

However, as the shots become regular, you might notice a reduction in the level of discomfort as the body gets used to the presence of progestin. The side effects also subside if you stop taking the shots.

One thing to note about the side effects is that they are similar to the symptoms of pregnancy.

Depo shot side effects that are similar to pregnancy symptoms:

Do not panic if you have the below effects after having the injection:

  1. Depo shots alter the menstrual cycle and lead to a missed period or amenorrhea for a longer period.
  1. Fatigue is one of the side effects of depo shot and also an early sign of pregnancy.
  1. If you are taking the depo shot for the first time, you may feel nauseous.
  1. Due to the hormonal changes, your breasts might become tender similar to what happens during pregnancy.
  1. Headaches are another discomfort common in both the cases.
  1. Frequent urination might confuse you if it is an early sign of pregnancy.
  1. Cravings for certain foods due to the depo shot-induced hormonal changes.

As long as the side effects are just minor irritants, it is alright. However, if they become severe, talk to your doctor.

When To Call The Doctor?

Contact your doctor immediately if you experience:

  • Intense abdominal pain
  • Yellowing of eyes or skin
  • Heavy or prolonged vaginal bleeding
  • Lumps in the breast
  • Severe depression
  • Weakness or numbness in an arm or leg
  • Shortness of breath
  • Problem with eyesight or speech
  • Severe pain in the chest, back or jaw

The doctor might recommend an alternative to depo shot if she thinks that the injection isn’t suiting you. You may discuss the matter in detail with the doctor.

What to ask your doctor?

  • Ask them about how soon you can get pregnant after you stop the shots.
  • This contraceptive method alters the menstrual cycle. Find out as to what is normal and what is not.
  • Weight gain is one of the prominent side effects of Depo. Therefore, ask your doctor what you can do to avoid this problem.

Make sure to discuss the pros and cons of depo shots before moving on or away from it.

Advantages And Disadvantages Of A Depo Shot

Here are some advantages of a depo shot:

  • Highly effective and offers longer protection against pregnancy with a single shot taken every three months
  • No interference with sex
  • Decreases cramping and bleeding during periods
  • Prevents uterine fibroids and may offer protection against ovarian and endometrial cancers
  • No need to remember to take a pill every day
  • More affordable than birth control pills

The disadvantages include:

  • The shots must be received every 12 to 13 weeks
  • The shots need to be stopped several months before you plan your pregnancy
  • Causes irregular bleeding
  • Can result in weight changes and depression
  • The injection is painful
  • Requires frequent visits to the doctor and a prescription
  • Can cause ectopic pregnancy
  • It does not protect you against sexually transmitted diseases, and you may still have to use condoms for this

One of the biggest disadvantages of depo shots is that you have to wait for months to restore your fertility in case you are planning a pregnancy.

How To Get Pregnant On Depo Shot?

If you plan for pregnancy while on depo shots, you need to stop it months before you get pregnant. According to the FDA, the median time to conceive after discontinuing the shots is ten months. However, you may conceive as early as four months or as late as 31 months (2).

The synthetic hormone needs to leave your body so that fertility can be restored. However, the length of the drug’s usage does not influence your chances of getting pregnant. If you have decided to conceive, then you must skip the next shot.

But what happens if you have unknowingly taken the shot when you are pregnant? And can you opt for a shot while breastfeeding your baby? Answers follow.

Is Depo Shot Safe During Pregnancy And Breastfeeding?

In addition to being a contraceptive, a depo shot is also an abortifacient, which means it can abort your pregnancy. The man-made hormone inhibits hCG secretions, thus restricting follicular maturation. It also thins down the endometrial lining.

Therefore, the FDA stipulates that the injection be given only after the doctor confirms that you are not pregnant. Also, it may be given within the first five days of your menstrual cycle.

Depo while breastfeeding

Depo-Provera does pass into the breast milk in small amounts but has no impact on the nursing babies (7).There have been no reports of any long-term effects on the behavior or development of the baby.

However, if you are breastfeeding, you should not take the first shot until at least six weeks after delivery.

Frequently Asked Questions

1. Do any medicines reduce the effect of the depo shot?

Aminoglutethimide (Cytadren), a drug used to suppress adrenal function in women suffering from Cushing’s syndrome, may reduce the effectiveness of the depo shot (8).

2. How can I know if my ovulation has restarted after stopping depo injections?

Getting positive results on an ovulation predictor test, tracking the basal body temperature, and having a regular menstrual cycle may indicate the resumption of ovulation after stopping Depo-Provera injections (9).

Depo shots are hormonal contraceptives that can effectively prevent pregnancy. However, they aren’t the safest choice as they can cause side effects such as headaches, fluid retention, mood changes, and irregular or no periods. Though as you take the shots regularly, the symptoms might reduce. Nonetheless, depo shots are similar to other hormonal contraceptives. So weigh your options carefully before making a decision. Getting pregnant on depo shots is possible but rare. You need to stop taking depo shots months before you get pregnant. Speak to your doctor to understand your options better.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
  1. Depo-Provera: Injectable Abortion.
  3. Depo-Provera (Shot/Injectable).
  4. Injectable Contraception – Depo-Provera.
  5. 3-month contraceptive injection approved.
  6. New PRI Study Shows Depo-Provera Increases Risk of HIV Infection.
  7. T Pardthaisong et al.; (1992); The long-term growth and development of children exposed to Depo-Provera during pregnancy or lactation.
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Dr. Shashwat Jani

Dr. Shashwat Jani is a consultant obstetrician & gynecologist in Smt. N.H.L. Municipal Medical College, Ahmedabad. His field of interests are High Risk Pregnancy, Infertility and Endoscopy. He has written 12 chapters in reference books of Ob/Gyn and published 18 articles in Index journals. Dr. Jani has been invited as faculty in more than 200 national and international conferences. He... more

shreeja pillai

Shreeja holds a postgraduate degree in Chemistry and diploma in Drug Regulatory Affairs. Before joining MomJunction, she worked as a research analyst with a leading multinational pharmaceutical company. Her interest in the field of medical research has developed her passion for writing research-based articles. As a writer, she aims at providing informative articles on health and pharma, especially related to... more