Getting Pregnant

Trigger Shots for Fertility – Importance and Procedure

Many couples who are trying to get pregnant but in vain often don’t consider that they might not be getting the desired result because of a fertility issue. There are several reasons why a couple may not be able to have a child, but infertility is the major cause. Fertility issues can make it very difficult to conceive, but there’s no need to lose hope if you have faith in medical science. The advancements in the medical field have made it possible to improve fertility. Trigger shots, a part of the fertility-enhancing techniques and drugs, are commonly used by doctors to increase one’s chances of getting pregnant. If you’ve been trying to conceive for over a year now, you can consider this option, but before that, you must learn everything there is to know about trigger shots.


What Is a Trigger Shot?

A trigger shot is an injection of hormones that signals the ovaries to mature and release eggs. The shot contains human chorionic gonadotropin (hCG) that sends trigger to the ovary to mature and release an egg. The shot kickstarts the process of an egg maturing to help it become capable of fertilization. Maturation of an egg is called meiosis. During this process, an egg sheds about 23 or half of the 46 chromosomes. A trigger shot is used in two instances – the first one is used to time intrauterine insemination (IUI) and the second as a part of an in vitro fertilization (IVF) process to prepare for the egg retrieval procedure. The trigger shot is also called an hCG trigger shot.

The Need for Trigger Shot for Fertility

A trigger shot is needed to get the eggs ready to mature for collection. During IVF, trigger shots trigger the ovaries into a cycle of development. This allows the fertility team that is monitoring your treatment to collect the eggs at a specific time.


When to Take a Trigger Shot

Your doctor will be able to guide you better on when to administer trigger shots. It will all be tracked with the development of the ovarian follicles (which need to grow to an optimal size) and it is important to follow the routine as any change could cause a delay in your treatment.

Trigger shots are recommended in the following instances:

  • If you suffer from ovulatory infertility
  • In case you have been diagnosed with inexplicable infertility
  • As part of the IVF treatment procedure, irrespective of the reason for infertility

Ovidrel is a common fertility drug that triggers and enhances the chances of ovulation. Ovidrel shots are an injectable medication that may be used as a trigger shot during IUI, timed sexual intercourse of in vitro fertilization. Ovidrel is used by itself but also with other fertility drugs as below:


  • It is often used with Clomid, which is another fertility drug
  • It is often used with gonadotropins

How to Take a Trigger Shot

Trigger shots are made of recombinant human chorionic gonadotropin( r-HCG). This is made in the lab using DNA technology. The hormone is similar to the natural luteinizing hormone (LH) of the body that triggers ovulation during the menstrual cycle. Mostly, the trigger shots are administered by doctors. But one can administer a shot on their own. In case you have to do it yourself, you can follow the guide below on how to administer the hCG trigger shot:


Things You Will Need:

  • Ovidrel prefilled syringe
  • Alcohol swabs and gauze for medical use
  • A safe container to dispose of used needles

How to Administer the Shot:


  • Start with placing the supplies on a flat, clean and dry surface.
  • Wash your hands in warm water with soap for at least 45 seconds. Dry using a clean towel.
  • Remove the Ovidrel pre-filled syringe from the box.
  • Point the needle upwards and remove the safety cap.
  • Tap the syringe lightly to remove any trapped air bubbles while still pointing the needle upwards.
  • Push the plunger to remove excess air until you can see tiny droplets of medication at the tip of the needle.
  • Choose a spot on the abdomen a couple of inches away from the belly button to inject the medication.
  • Disinfect the area where the injection needs to be administered using an alcohol swab. Let it dry.
  • Now carefully hold the Ovidrel needle with one hand and a finger on the plunger. The remaining three fingers must hold the canister. Use your other hand to pinch a generous amount of fatty tissue in a fold around your abdomen to insert the needle.
  • Slowly insert the full needle into the area at a 45-degree or 90-degree angle.
  • Once the needle is in, leave the skin and insert the Ovidrel syringe by carefully pushing the plunger until all the medication is injected.
  • Once the medication is inserted, gradually release the needle from your belly. Apply a gauze pad on the area to prevent it from bleeding.
  • Now place the needle in a container and dispose of.

How Does a Trigger Shot Work?

The timing and administration of a trigger shot entirely depend on how it is being used. Ovidrel is usually timed and administered according to the fertility treatment protocol. Ovidrel is a subcutaneous injection that comes in a pre-filled device which is ready to inject. It is a liquid injected into the fatty tissue just below the skin. On being administered, the hCG triggers the eggs to go through a final growth spurt and ovulate. One must take care and precaution to follow the doctor’s instructions to administer the trigger shot. Even a few hours of delay could cause problems or issues in the treatment.


Side Effects of Trigger Shot

Apart from experiencing some discomfort at the injection spot, trigger shots can lead to following side effects.


  • Upset stomach
  • Pain in the abdomen
  • Vomiting or nausea
  • Bruising or pain at the injection site

The use of fertility drugs may also increase the chances of developing ovarian hyperstimulation syndrome (OHSS).  When Ovidrel is used as part of IVF, chances are that one in three women can experience adverse effects. OHSS is more common when Ovidrel is used with gonadotropins.


What If You Miss Your Trigger Shot?

If you happen to miss a trigger shot, it is important to inform your doctor about the same. Your doctor will be able to guide you the best if such a situation arises. An egg cannot be retrieved once the ovary has released it so the medical team is aware of the situation to put the necessary things in place to correct the situation. In some instances, it is possible to adjust the collection time of eggs.


When to Avoid Using a Trigger Shot

Doctors usually inform the expecting couples about the possible side effects of trigger shots beforehand. Trigger shots are not recommended to women with primary ovarian insufficiency or with poor ovarian reserves. If your doctor believes that you are at the risk of developing OHSS, then he/she may not suggest trigger shot. The chances of developing OHSS are more in the following circumstances:

  • Symptoms of moderate to severe OHSS experienced during any of infertility treatment cycles.
  • High estrogen levels before the scheduled time for shots.
  • Overreaction of ovaries to the fertility drugs and the ovaries have produced too many follicles.
  • Any previous allergies to Ovidrel or injectable hCG’s.

Doctors also cancel the fertility treatment cycle if the hormonal blood reports and ultrasounds of the ovaries do not look encouraging or promising.


Should You Use Trigger Shot If You Have PCOS?

Polycystic Ovarian Syndrome is a common hormonal issue in many women today. Women who suffer from PCOS run a high risk of developing Ovarian Hyperstimulation Syndrome (OHSS). This does not mean that women with PCOS cannot be administered trigger shots or Ovidrel. Ovidrel is a commonly used drug for fertility treatments in women with PCOS. But it should be administered after consulting with a doctor.

Trigger Shot and Odds of Pregnancy

The trigger shot injection generally stimulates ovulation within 24 to 36 hours after it is administered. If you are taking a trigger shot as a part of timed sexual intercourse, doctors highly recommend having sexual intercourse on the same night when you have taken the injection. Doctors also suggest couples to have sexual intercourse every night for the next two or three days. But if trigger shots are a part of a structured IUI or IVF cycle, then your doctor will give you the specific time to come to the clinic. The timing of the trigger shot will decide the optimal time for your visit.


Success and odds of pregnancy when being administered a trigger shot depends on several factors. Success rates will differ according to prognosis to the medical issue, medical history, age, and kind of fertility treatment chosen. Studies and data have compared if a trigger shot during an IUI cycle is higher when compared to cycles where the shot was administered based on the body’s natural LH surge. Studies proved that using trigger shots increased the chances of pregnancy, especially when it was timed to map the natural LH surge in the body. As per data, the chances of pregnancy are as below:

  • 18% positive overall
  • 18% positive for those who took an r-hCG shot
  • 6% positive for those who did not take an r-hCG shot
  • 31% for those who took the r-hCG shot timed with their body’s natural LH surge level.

A trigger shot can increase the odds of pregnancy but the timing of its administration matters the most. If you’re considering this as one of the options to improve your fertility, you must discuss the same with your doctor. Your doctor will be able to guide you the best on fertility treatments and offer you clear advice on what you can do to improve your chances of getting pregnant.

Also Read:

Infertility in Women
Fertility Treatments Options for Men and Women
When Should You Consult Fertility Doctor


This post was last modified on February 1, 2021 6:05 pm

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