Trigger Shots For Fertility – What They Are and How They Help

9 min read

Written by Editorial Team

Editorial Team

Trigger Shot fertility

Infertility is one of the most pressing issues for today’s couples. And assisted reproductive technologies are evolving every day to provide a solution to this mounting problem. Trigger shots for fertility as a part of the solution for couples struggling to conceive. A trigger shot, also known as an ovulation induction injection, is a hormone injection used in a variety of fertility treatments.

Tigger shots are essential for ART, the one term given to describe several different treatments that can help a couple to achieve pregnancy. The use of trigger shots and fertility treatments should be done under the guidance and supervision of a fertility specialist or reproductive endocrinologist. They will assess your specific fertility situation and determine the appropriate treatment protocol for you.

In This Article

What is a Trigger Shot?

A trigger shot, also known as an ovulation trigger or ovulation induction injection, is a medication used in fertility treatments to induce ovulation. It is given to women who are undergoing assisted reproductive technologies (ART) such as in vitro fertilization (IVF) or intrauterine insemination (IUI).

The most common medication for a trigger shot is human chorionic gonadotropin (hCG). hCG mimics luteinizing hormone (LH), a hormone your body naturally produces. LH surge indicates the release of an egg from the ovary, and hCG injection tries to do the same.

How Does Trigger Shot For Fertility Help?

How Trigger Shot Helps

The purpose of a trigger shot is to stimulate the release of mature eggs from the ovaries. It is usually given when the eggs have reached an appropriate size and maturity. The timing of the trigger shot is crucial, as it aims to replicate the natural hormonal surge that triggers ovulation.

With a trigger shot, healthcare professionals will ensure that ovulation occurs at the right time to ensure the best chance of successful fertilization and conception. Monitoring the woman’s ovarian response through ultrasounds and hormone tests helps determine the appropriate timing for the trigger shot.

It’s important to consult with a fertility specialist or reproductive endocrinologist who can guide you through the process and determine if a trigger shot is necessary or suitable for your specific fertility situation. They will monitor your progress and decide on the right time to give this injection.

[Read : Best Ovulation Period For Pregnancy]

Importance of Trigger Shots For Fertility

Trigger shots play an important role in fertility treatments for several reasons:

1. Ovulation Induction

Trigger shots help stimulate the release of mature eggs from the ovaries. In fertility treatments such as IVF or IUI, timing is crucial for successful fertilization. The trigger shot ensures that ovulation occurs at the optimal time. This increases the chances of the sperm and egg meeting for fertilization.

2. Timed Ovulation

The precise timing of ovulation is essential for various fertility procedures. By administering a trigger shot, healthcare professionals can accurately control the timing of ovulation, allowing for proper scheduling of procedures like egg retrieval or intrauterine insemination.

3. Increased Chances of Successful Conception

In assisted reproductive technologies, such as IVF, triggering ovulation with a shot increases the likelihood of retrieving mature eggs for fertilization. This improves the chances of successful fertilization and subsequent embryo development.

4. Facilitating Fertility Treatment Protocols

Fertility treatment protocols involve controlled ovarian stimulation, where medications are administered to stimulate the ovaries to produce multiple mature eggs. The trigger shot is the final step in this process, ensuring the mature eggs release for fertilization at the right time.

5. Monitoring and Optimization

The fertility specialist will determine the timing of the trigger shot through close monitoring of follicle development using ultrasounds and hormone tests. This monitoring allows them to assess the growth and maturity of the eggs and make decisions regarding the timing of the trigger shot.

Overall, trigger shots are a crucial component of fertility treatments, assisting in the precise timing of ovulation and optimizing the chances of successful conception. They are used in conjunction with other fertility medications and under the guidance of a fertility specialist or reproductive endocrinologist to achieve the best possible outcomes.

[Read : Normal Follicle Stimulating Hormone (FSH) Level to Get Pregnant]

When to Take Trigger Shots For Fertility?

When to Take Trigger Shot

The timing of a trigger shot is crucial for successful ovulation induction in fertility treatments. The specific timing will depend on various factors, including the individual’s fertility treatment protocol, the response to ovarian stimulation medications, and the recommendation of the fertility specialist. Here are some general guidelines for when to take a trigger shot.

1. Follicle Development

Throughout the fertility treatment cycle, your fertility specialist will monitor the growth and development of follicles using ultrasounds and hormone tests. These follicles are fluid-filled sacs containing the eggs. The size and maturity of the follicles become the basis to determine the optimal time for the trigger shot.

2. Timing Relative to Ovulation

The trigger shot is administered when the leading follicles have reached an appropriate size, usually around 18-20 millimeters in diameter. This indicates that the eggs within the follicles are mature and ready for release.

3. Individual Treatment Protocols

The specific protocol for trigger shot timing may vary depending on the fertility treatment. For example, in IVF, the trigger shot will be given about 36 hours before the egg retrieval procedure. In IUI, the shot may be given when the follicles are close to ovulation, to time the insemination accurately.

4. Fertility Specialist’s Guidance

It’s important to follow the guidance of your fertility specialist or reproductive endocrinologist regarding the timing of the trigger shot. They will closely monitor your progress, assess your response to medications, and determine the most appropriate time for the trigger shot based on your individual circumstances.

Remember that the timing of the trigger shot is critical, and administering it too early or too late can affect the success of the fertility treatment. Close communication with your healthcare provider and adherence to their instructions are essential to ensure the optimal timing of the trigger shot for your specific fertility treatment.

How to Take the Trigger Shots For Fertility?

Taking Trigger Shots

Taking a trigger shot typically involves the following steps.

  1. Prescription and medication preparation
  2. Timing instructions
  3. Preparation and hygiene
  4. Mixing the medication
  5. Injection administration
  6. Disposal and follow-up

The exact instructions will differ according to your specific fertility treatment protocol. You must consult with your fertility specialist or reproductive endocrinologist for precise guidance. They will provide you with personalized guidance and support throughout the process of administering the trigger shot in case you are doing it yourself.

How Does a Trigger Shot Work?

A trigger shot works by mimicking the natural hormone surge that triggers ovulation in the female body.

Here’s how it works.

1. Egg Maturation

During a fertility treatment cycle, medications help stimulate the ovaries to produce multiple follicles. These follicles grow and develop under the influence of follicle-stimulating hormone (FSH).

2. Follicle Development

The fertility specialist will closely monitor the growth of follicles through ultrasound scans and hormone level measurements. They will assess the size and maturity of the follicles to determine the optimal time for triggering ovulation.

3. Trigger Shot Timing

Once the follicles reach an appropriate size and maturity, typically around 18-20 millimeters, a trigger shot is administered. This is usually done about 36 hours before a scheduled procedure, such as egg retrieval in IVF or timed insemination in IUI.

4. Mimicking the LH Surge

The trigger shot contains hCG, which is a hormone that acts similarly to luteinizing hormone (LH). LH surge is a natural hormonal event that occurs in the middle of the menstrual cycle, triggering the release of a mature egg from the ovary.

5. Final Maturation and Egg Release

The hCG in the trigger shot mimics the LH surge, causing the final maturation of the eggs within the follicles. It stimulates the release of mature eggs from the follicles, a process known as ovulation.

6. Timing For Fertilization

The goal of the trigger shot is to ensure that ovulation occurs at a specific time, allowing for the best timing for procedures like insemination or egg retrieval. This synchronization increases the chances of successful fertilization and subsequent pregnancy.

It’s important to note that the timing of the trigger shot is critical for its effectiveness. It should be administered as per the guidance of your fertility specialist, who will monitor your follicle development and determine the optimal time for triggering ovulation. By mimicking the natural hormonal process, the trigger shot helps facilitate the final stages of egg maturation and release, improving the chances of successful conception in fertility treatments.

Side Effects of Trigger Shot

Trigger Shot Side Effects

The side effects of a trigger shot can vary from one woman to another. While some may tolerate the medication well, others may experience certain side effects. Side effects can include

It’s important to discuss potential side effects with your healthcare provider before taking the shot. They can provide more specific information based on your individual medical history and treatment protocol. Consult your physician if you experience severe or lingering side effects or if you have any other concerns.

What If You Miss Your Trigger Shot?

Missed Trigger Shot

If you miss your scheduled trigger shot, it is important to contact your healthcare provider as soon as possible. They will provide guidance on how to proceed based on your specific fertility treatment protocol and individual circumstances.

Here are a few general considerations:

1. Timing

The timing of the trigger shot is crucial for successful ovulation induction. Missing the shot may disrupt the treatment cycle. Your healthcare provider will assess the impact of missing the shot and determine the next steps.

2. Rescheduling

Depending on the stage of your treatment cycle and the reason for missing the shot, your healthcare provider may recommend rescheduling the trigger shot. They will consider factors such as follicle development and hormone levels to determine the most appropriate timing for the rescheduled shot.

3. Adjusting the Treatment Protocol

In some cases, missing a trigger shot may require adjustments to your treatment protocol. Your healthcare provider may modify the medication dosage or timing to accommodate the missed shot and optimize your chances of successful ovulation.

4. Assessing Alternatives

If the timing does not allow for rescheduling the trigger shot within the current cycle, your healthcare provider may discuss alternative options. They may recommend canceling the cycle and starting a new one, or they may propose alternative treatments based on your individual situation.

It is crucial to communicate openly and promptly with your healthcare provider in case you miss your trigger shot. They will provide the most appropriate guidance and help you navigate the situation effectively. Each situation is unique, and your healthcare provider will tailor their recommendations to your specific needs and treatment plan.

When to Avoid Using a Trigger Shot For Fertility?

While trigger shots are commonly used in fertility treatments, there are certain situations where they may be avoided or used with caution. It is important to consult with your healthcare provider to assess your individual circumstances and determine the most suitable approach for your fertility treatment. 

Here are some situations that warrant avoiding trigger shots.

  • Ovarian hyperstimulation syndrome (OHSS) risk
  • Premature ovulation
  • Poor ovarian response
  • Hormonal imbalances
  • Allergic reactions or contraindications

Trigger shots for fertility are an essential component of fertility treatment. The main function of a trigger shot is to enhance the egg and develop the quality of the egg for the best chance of fertility. Each individual’s fertility journey is unique and a fertility specialist or reproductive endocrinologist must make the decisions regarding the use of a trigger shot. They will assess your specific situation, consider any risk factors or contraindications, and develop a tailored treatment plan to optimize your chances of successful conception while prioritizing your health and well-being.


1. How Many Days After Trigger Shot Are You Fertile?

The main intention of a trigger shot is to induct ovulation or to prepare the body to ovulate. Ovulation usually happens around 36 hours after the trigger shot. Starting from the trigger shot, you will be fertile for about 48 to 72 hours.

2. Does Trigger Shots Improve Egg Quality?

Administering a trigger shot will help the eggs mature and release for the process of fertilization. Egg quality will depend on the woman’s general health and age and certain other medications that are used as a part of the fertility treatment protocol.

3. Can a Trigger Shot Cause Twins?

Yes, a trigger shot may increase your chances of giving birth to twins or multiples. The infertility treatment protocol causes the woman undergoing treatment to produce multiple follicles and multiple eggs. The trigger shot will cause all the mature eggs to release for fertilization, thus indirectly increasing your chance of having twins or multiple births.

Read Also: Basics Of IUI and IVF (Assisted Reproduction Techniques)

Editorial Team,

With a rich experience in pregnancy and parenting, our team of experts create insightful, well-curated, and easy-to-read content for our to-be-parents and parents at all stages of parenting.Read more.

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