Progesterone Injection: Uses, Types, Storage, Side Effects and Pain Tips

A progesterone injection gives your body the hormone that keeps the womb lining ready for an embryo and supports a very early pregnancy. It is mostly used after IVF, frozen embryo transfer and sometimes IUI, when the body's own progesterone may not be enough, and in some pregnancies at risk of miscarriage. It is usually continued until the pregnancy test and, if positive, until about 8 to 12 weeks, when the placenta takes over. At Yaal Fertility Centre in Chennai, Dr. Rukkayal Fathima and our team choose the form of progesterone that suits your treatment and show you or your partner how to give it.

What Progesterone Does in Early Pregnancy

Progesterone is the hormone of the second half of the menstrual cycle. After an egg is released, the empty follicle turns into a small gland called the corpus luteum, which makes progesterone. This hormone:

• Turns the womb lining from a growing lining into a soft, receptive one that an embryo can attach to.
• Keeps the womb muscle calm, so it does not contract and disturb an implanting embryo.
• Keeps the lining in place so it does not shed as a period.

If an embryo implants, it makes the hormone hCG, which keeps the corpus luteum making progesterone. Around 8 to 10 weeks of pregnancy, the placenta gradually takes over this job. If there is no pregnancy, progesterone falls and your period starts.

Why Some Women Need Extra Progesterone

In a natural cycle, most women make enough progesterone on their own. Fertility treatment changes that:

• After IVF: the medicines used to stimulate the ovaries and prevent early ovulation, and the egg collection itself, can reduce the body's own progesterone in the weeks that follow.
• In a medicated frozen embryo transfer: ovulation is switched off and the lining is built with estrogen, so there is no corpus luteum at all. All the progesterone has to come from medicine.
• After IUI or ovulation induction: progesterone support is sometimes added, depending on the medicines used and your doctor's plan.

Doctors call this luteal phase support, because it supports the second (luteal) half of the cycle.

Progesterone Injection or Natural Progesterone?

If you are not having fertility treatment and want to understand your own progesterone levels, ovulation and lifestyle, see our separate guide on how to increase progesterone naturally. This post is about prescribed progesterone given as medicine.

Progesterone Injection Uses

After IVF and Embryo Transfer

Progesterone support is a routine part of IVF treatment. It usually starts around the day of egg collection or a few days before the embryo transfer and continues through the wait for the pregnancy test.

In Frozen Embryo Transfer Cycles

In a medicated frozen embryo transfer, the timing of progesterone is carefully matched to the age of the embryo, because the lining has a short "window" when it is ready. That is why your clinic will give you an exact start date and time. Our frozen embryo transfer guide explains natural and medicated cycles in more detail.

After IUI

Some doctors add vaginal or injectable progesterone after IUI, particularly when injections were used to grow the follicles. Others do not, if you ovulated well on your own. Your doctor will explain which applies to you.

In Some Pregnancies

Progesterone may be prescribed in early pregnancy for women who have had previous miscarriages and now have bleeding, and in some other specific situations. The evidence and the preferred form differ by situation, and in many of these cases vaginal progesterone is the usual choice. If you have had two or more losses, see recurrent pregnancy loss: causes and treatment.

Forms of Progesterone Compared

Progesterone support does not always mean injections. Doctors choose between several forms, and many women use vaginal progesterone alone.

Many studies show that vaginal and injectable progesterone work similarly well for most IVF patients, so the choice often comes down to your protocol, your history, cost and what you find easiest. Some clinics combine two forms. Do not switch between forms on your own; ask your doctor first.

Intramuscular and Subcutaneous: The Difference in Plain Words

• Intramuscular (IM) means into a muscle. The medicine is dissolved in oil and given deep into a large muscle, usually the upper outer part of the buttock, with a longer needle. The oil releases the hormone slowly.
• Subcutaneous (SC) means just under the skin, into the fatty layer of the tummy or thigh, with a short, fine needle. It is the same type of injection used for most IVF stimulation medicines.

For how all the other IVF injections work, from stimulation to the trigger shot, see our IVF injections guide.

How Progesterone Injections Are Given

Your nurse or doctor will show you or your partner exactly how to give your injection, and you should follow their instructions and the product leaflet. The outline below is to help you feel prepared, not to replace that teaching.

Getting Ready

• Wash your hands well and work on a clean, dry surface.
• Check the name, strength and expiry date on the pack.
• Look at the liquid. It should be clear and free of particles. If it looks cloudy or has crystals that do not clear when gently warmed in your hands, do not use it and ask your clinic or pharmacy.
• Lay out the vial, syringe, needles, alcohol swabs, cotton and a sharps container.

Giving an Intramuscular Injection

1. Choose the site. The usual site is the upper outer part of the buttock. Your nurse will show you where; staying in this area avoids the large nerve in the middle of the buttock.
2. Clean the skin with an alcohol swab and let it dry completely, which reduces stinging.
3. Relax the muscle. Lying face down or standing with your weight on the opposite leg helps.
4. Insert the needle straight in with a quick, firm movement, as you were taught.
5. Inject slowly and steadily. Thick oil goes in more comfortably when pushed slowly.
6. Withdraw the needle, press gently with cotton and put the needle straight into the sharps container.
7. Alternate sides each day.

Giving a Subcutaneous Injection

1. Choose the site, usually the tummy a few finger-widths away from the belly button, or the front of the thigh.
2. Clean the skin and let it dry.
3. Pinch a fold of skin and insert the short needle as shown.
4. Inject steadily, release the skin, withdraw, and press lightly. Do not rub.
5. Change the spot each time.

If Your Partner or a Relative Is Giving It

Many couples in Chennai find that the husband, mother or a neighbour who is a nurse gives the intramuscular injection. Ask your clinic to teach the person who will actually give it, and do the first one together under supervision. Keep the same time each day; a phone reminder helps.

Storage: Does Progesterone in Oil Need to Be Refrigerated?

Check your pack and the leaflet first, because storage depends on the product. As general guidance:

• Most oil-based progesterone injections are stored at room temperature, away from direct sunlight and heat, and are not kept in the fridge. Cold can make the oil thick and cause crystals to form.
• Water-based and other products may have different instructions. Some need refrigeration, some do not.
• Keep medicines in their original box, out of reach of children.
• In Chennai's heat, do not leave medicine in a parked car, on a sunny windowsill or near the stove. Store it in a cool, shaded cupboard. If your leaflet gives a maximum temperature and your home gets hotter than that, ask your clinic or pharmacist what to do.
• If crystals appear after the vial got cold, gently warming it in your hands usually dissolves them. If they do not clear, do not use it.
• Do not freeze any progesterone product.

If you are travelling during treatment, carry the medicine in your hand luggage with your prescription, and keep it away from hot car boots.

Side Effects of Progesterone Injections

Most side effects are mild and settle once treatment stops.

At the Injection Site

• Pain or soreness that can last a day or two.
• Firm lumps under the skin from the oil, especially after many days of intramuscular injections.
• Bruising, redness or itching.

In the Body

• Breast tenderness or fullness.
• Bloating, mild cramps and constipation.
• Tiredness or sleepiness.
• Mood changes and headaches.
• Light spotting.

Many of these feel exactly like early pregnancy symptoms, which can be confusing during the two-week wait. They come from the medicine, so they do not tell you whether the cycle has worked, and not having them is not a bad sign. Our guide to implantation symptoms explains why.

Allergy to the Oil

Oil-based injections are made with plant oils such as sesame or groundnut (peanut) oil, depending on the brand. Tell your doctor if you have a sesame, peanut or nut allergy, so they can choose a suitable product. Spreading redness, an itchy rash or hives away from the site need a call to your clinic.

How to Reduce Progesterone Injection Pain

• Warm the vial in your hands for a minute or two before drawing it up. Warm oil flows more easily. Do not heat it in a microwave or on the stove.
• Apply a warm compress to the area for a few minutes before and after the injection.
• Let the alcohol dry before injecting, to avoid stinging.
• Relax the muscle. A tense muscle hurts more.
• Inject slowly.
• Massage the area gently after an intramuscular injection, unless your nurse has told you not to, and walk around for a few minutes to help the oil spread.
• Rotate sites every day so the same spot can recover.
• Use ice briefly before an injection if you find it numbs the skin, but warmth is usually more helpful for oil.

If the pain is severe, the lumps are getting larger, or you dread every injection, tell your doctor. Switching to vaginal or subcutaneous progesterone is often possible.

How Long Are Progesterone Injections Continued?

The length of treatment depends on your treatment, your history and your doctor's plan, so always follow your own clinic's instructions.

Before the Pregnancy Test

Progesterone usually continues every day until your blood pregnancy test, about 9 to 14 days after the embryo transfer depending on the embryo's age. Do not stop it early, even if you have spotting or a home test looks negative. See our guide to the pregnancy test after IVF for timing and what beta-hCG results mean.

If the Test Is Positive

Progesterone is typically continued until about 8 to 12 weeks of pregnancy, as your doctor advises, by which time the placenta is making enough on its own. Your doctor will tell you whether to stop at once or reduce gradually, and may switch you from injections to vaginal progesterone partway through.

If the Test Is Negative

Your clinic will usually tell you to stop progesterone. A period normally follows within a few days. Wait for your doctor's instruction before stopping.

Progesterone Blood Tests During Treatment

Some clinics check a progesterone blood level around the time of transfer, especially in medicated frozen cycles, and may add a second form of progesterone if the level is low. Others rely on the standard plan without testing. Both approaches are used, and your doctor will explain which one your clinic follows. A single number on its own rarely changes much, so try not to worry about comparing your result with others online.

Spotting While on Progesterone

Light spotting is common during progesterone support. It can come from the cervix, from vaginal pessaries, from implantation or from an early pregnancy settling in. Keep taking your progesterone and tell your clinic. Heavy bleeding like a period, or bleeding with severe pain, needs a call the same day.

Why You Should Not Stop on Your Own

Stopping suddenly can bring on bleeding or affect a very early pregnancy. If you miss a dose or are late, call your clinic for advice rather than doubling the next dose.

When to Call Your Doctor

Contact your clinic promptly if you have:

• Heat, increasing pain, swelling, red streaks or pus at the injection site, or fever.
• Numbness, tingling or shooting pain down the leg after an intramuscular injection.
• Heavy bleeding, or bleeding with severe tummy pain.
• A rash, hives or itching away from the injection site.
• Pain or swelling in one calf, chest pain or sudden breathlessness (seek emergency help).
• Severe headache, or vision changes.

Questions to Ask Your Clinic

• Which form of progesterone am I using, and why?
• What time of day should I take it, and how strict is the timing?
• Who will teach us to give the injection?
• How should I store this particular product?
• What should I do if I miss a dose?
• When will I stop, and will I stop at once or gradually?