Can the trigger shot cause a false positive on a pregnancy test?

Since hCG is the same hormone that the pregnancy tests detect, testing soon after the shot may show a false positive.

How long does the hCG stay in your system after the trigger shot?

Typically, hCG remains in your system for about 10 days. It is also advisable to avoid a pregnancy test during this time.

Can a trigger shot be used more than once in a cycle?

No, a trigger shot is administered only once per cycle, after your dominant follicle has developed. Your doctor may monitor you closely to ensure the shot is administered at the precise time.

Trigger Shots & hCG: Supporting Ovulation During Timed Intercourse

When you are on a fertility journey, timing is everything, especially for ovulation. That is where trigger shots come in. These prescription-based injections help you ovulate at the right time for conception.

Although a trigger shot may sound medicinal, it plays a very natural role. It helps release a mature egg to provide you with the best chance at conception. Of course, it needs to be paired with timed intercourse to achieve pregnancy.

Understanding how trigger shots work, their role in your body, and important considerations will help you prepare to receive them.

What Is a Trigger Shot?

A trigger shot is an injection that contains human chorionic gonadotropin (hCG). This hormone closely resembles the body’s natural luteinising hormone (LH), which causes ovulation.

In a typical menstrual cycle, LH rises mid-cycle, signalling your ovary to release an egg. If your body does not produce that surge or you are taking fertility treatments to conceive with timed intercourse, hCG helps in such cases.

It induces your ovulation, which is helpful when you are planning intercourse around your fertile window.

Why You Might Need a Trigger Shot

Your doctor may recommend a trigger shot for some common reasons as part of your fertility treatment plan.

Irregular ovulation: If your cycles are unpredictable, the shot helps to trigger ovulation at the right time.
Ovulation induction cycles: If you are taking medications like letrozole or clomiphene, a trigger shot stimulates follicle maturation and ovulation.
Timed intercourse plans: You can easily plan intercourse around 12 to 36 hours after getting a trigger shot.
Follicular monitoring: If your doctor is monitoring you via ultrasound, the shots can be planned after the follicles mature.

The aim is to improve the chances of fertilisation by timing your ovulation with sperm availability.

How Does the hCG Trigger Shot Work?

Your doctor may advise taking the trigger shot after your follicle reaches the right size, usually 18 to 20 mm. Here’s what happens next:

You can expect the following scenarios after the shot.

You receive the hCG shot, usually in your abdomen or thigh, depending on its formulation.
The hormone mimics your LH surge, signalling the ovary to release the egg.
Ovulation occurs, typically 36 to 40 hours later.

When you know the timing of your ovulation, you and your partner can schedule intercourse more effectively. This increases the chances of conception.

When Should You Have Intercourse After the Shot?

Timing your intercourse is critical after a trigger shot because the egg survives for only 12 to 24 hours. Since ovulation generally happens 36 hours after receiving the shot, most doctors suggest having intercourse at:

12 to 24 hours after the shot
Again, around 36 hours after the shot

You may also be suggested to start intercourse on the day you get the hCG injection. You can also continue for two more days to maximise your chances.

What to Expect During the Process

Most formulations are available in pre-filled syringes or require simple mixing. You can follow the steps mentioned below.

Rubbing the injection site with an alcohol swab
Inject the medicine using a small needle into the fat under your skin
Following up with your doctor for the next steps

Side effects are usually mild and may include bloating, tenderness at the injection site, or mild cramping.

Can You Feel Ovulation After a Trigger Shot?

You may experience any of the following symptoms.

Mild pelvic discomfort
Light spotting
Breast tenderness
Increased cervical mucus

All of these are positive reactions of your body responding to the hormone. However, do not rely solely on physical signs to determine when you are ovulating. Calculating the timing from your shot is more reliable.

How Is Success Measured?

Your doctor may confirm ovulation in a few ways:

Ultrasound follow-up: to check if the follicle has collapsed
Progesterone blood test: around 7 days after the shot
Basal body temperature: though this has less accuracy

Remember that the chances of getting a false positive on a pregnancy test are very high after administering the shot. Always wait until your doctor advises testing.

Are There Any Risks?

Generally, a trigger shot is safe, but like any fertility medication, it also has some risks.

Ovarian Hyperstimulation Syndrome (OHSS): More common with injectable gonadotropins, this condition causes swollen ovaries and fluid retention.
Multiple pregnancy: If more than one follicle releases an egg, the chances of twins or triplets are very likely.
Injection site reactions: You may have mild pain, which usually resolves on its own.

Your doctor will monitor your response and adjust the plan based on risks.

Is a Trigger Shot Necessary for Everyone?

A trigger shot is a valuable tool in fertility treatment, but it is not necessary for every person trying to conceive. Its requirement depends on your specific fertility condition, ovulation patterns, and treatment plan.

You don't need a trigger shot in the following situations.

You ovulate regularly on your own: You may not need a trigger shot if you have a regular menstrual cycle and ovulation.
You are using ovulation predictor kits (OPKs) effectively: You can detect the natural LH surge successfully using an OPK for a timed intercourse.
You are trying to conceive without fertility medications: In regular cycles, ovulation often happens without any need for hormonal support.

In the following scenarios, a trigger shot may be necessary for a successful ovulation to occur.

You have irregular or unpredictable ovulation: When you have inconsistent ovulation or none at all, the shot releases the egg at a predictable time.
You are undergoing fertility treatment: If you are taking medicines like letrozole or clomiphene to help a follicle develop, you can expect ovulation after the shot.
You are timing intercourse under medical guidance: Your doctor may suggest a timed intercourse after the shot for a positive outcome.
You want to optimise chances with precise timing: You can confidently plan conception because the shot triggers ovulation at a predictable time.

Ultimately, the need for a trigger shot depends on the individual’s fertility condition and advice from the doctor.

Trigger shots play an essential role in planning intercourse at the right time to support conception. By triggering ovulation at a predictable time, it gives you a clear indication of your fertile window.

Fertility treatments are overwhelming, but understanding how trigger shots work may feel reassuring. Knowing your steps in advance gives you a sense of control over your fertility health.