Most Ovidrel Side Effects Are Mild — But Some Require Immediate Attention

If you've been prescribed Ovidrel (Choriogonadotropin Alfa) as part of your fertility treatment, it's completely normal to have questions about side effects. You're injecting a hormone into your body at a very specific time in your cycle, and you want to know what to expect.

The short answer: most people tolerate Ovidrel well. The most common side effects are injection site reactions and mild abdominal discomfort. But there are serious side effects — particularly Ovarian Hyperstimulation Syndrome (OHSS) — that every patient should know about before their trigger shot.

Here's what the clinical data and FDA labeling actually say, and how to tell the difference between normal and concerning symptoms.

What Is Ovidrel?

Ovidrel is a recombinant form of human chorionic gonadotropin (r-hCG) manufactured by EMD Serono. It comes as a 250 mcg prefilled syringe given as a single subcutaneous injection. It's used to trigger ovulation in women undergoing fertility treatments like IVF, IUI, or ovulation induction.

For a complete overview, see our guide: What Is Ovidrel? Uses, Dosage, and What You Need to Know.

Common Side Effects

These side effects were reported in clinical trials and are generally mild and temporary. Most resolve on their own within a few days:

Injection Site Reactions

• Injection site pain: 7.6-8.1% of patients — the most commonly reported side effect
• Injection site bruising: 3-4.7% of patients
• Injection site inflammation or reaction: 2-3% of patients

These are typical for any subcutaneous injection. Rotating injection sites (alternating between left and right sides of the abdomen or thigh) can help reduce discomfort. Applying a cold compress after injection may also help with bruising.

Gastrointestinal Symptoms

• Abdominal pain: 3-4.2% of patients
• Nausea: 3.4% of patients
• Vomiting: 2.5% of patients
• Flatulence: Reported in clinical trials (percentage not specified)

Some abdominal discomfort is expected, especially if your ovaries have been stimulated with follicle-stimulating hormones before the Ovidrel injection. Your ovaries are enlarged at this point in your cycle, which contributes to the bloated, uncomfortable feeling.

Other Common Side Effects

• Post-operative pain: 4.7% of patients (reported in IVF patients after egg retrieval)
• Ovarian cyst: 3% of patients

The post-operative pain is related to the egg retrieval procedure rather than Ovidrel itself, but it's reported in clinical trials because patients receive Ovidrel as part of the IVF protocol.

Serious Side Effects

While uncommon, these side effects require immediate medical attention. Know these warning signs before you take your trigger shot:

Ovarian Hyperstimulation Syndrome (OHSS)

This is the most important serious risk associated with Ovidrel and other hCG products. OHSS occurs when the ovaries over-respond to stimulation, causing fluid to shift from the bloodstream into the abdomen and, in severe cases, the chest cavity.

Mild OHSS symptoms (common, usually manageable at home):

• Abdominal bloating and discomfort
• Mild nausea
• Mild weight gain (1-2 pounds from fluid)
• Waist measurement increase

Moderate to severe OHSS symptoms (call your doctor immediately):

• Rapid weight gain — more than 2 pounds per day
• Severe abdominal pain or swelling
• Severe nausea and vomiting
• Difficulty breathing or shortness of breath
• Decreased urination
• Dizziness or fainting

Severe OHSS can be life-threatening. It may require hospitalization for IV fluids, drainage of abdominal fluid, and close monitoring. If you experience any moderate to severe symptoms, contact your fertility clinic or go to an emergency room right away.

Thromboembolic Events (Blood Clots)

Ovidrel can increase the risk of blood clots, particularly in patients with OHSS. Watch for:

• Leg pain, swelling, or warmth (especially if one-sided)
• Sudden chest pain or difficulty breathing
• Sudden severe headache

These symptoms require emergency medical care.

Ovarian Torsion

Because fertility medications cause the ovaries to enlarge, there's a risk of the ovary twisting on its blood supply (adnexal torsion). Symptoms include:

• Sudden, severe one-sided pelvic pain
• Nausea and vomiting accompanying the pain

This is a surgical emergency. If you experience sudden severe pelvic pain, seek emergency care immediately.

Other Serious Side Effects

• Ectopic pregnancy: Fertility treatment in general carries a higher risk of ectopic pregnancy. Report any unusual bleeding or one-sided pelvic pain after a positive pregnancy test.
• Multiple pregnancies: Ovidrel used with ovarian stimulation increases the chance of twins, triplets, or higher-order multiples. Your doctor monitors follicle count to manage this risk.
• Allergic reactions: Rare, but anaphylaxis has been reported. Seek emergency care for hives, swelling of the face or throat, or difficulty breathing after injection.
• Hemoperitoneum: Bleeding into the abdominal cavity — rare but serious.

Special Populations

Pregnancy

Ovidrel should not be used during pregnancy. However, since the entire purpose of Ovidrel is to help you become pregnant, your doctor will confirm you're not already pregnant before administering it. Once you've taken your trigger shot and either had your egg retrieval or timed intercourse/IUI, subsequent hCG levels in your blood come from early pregnancy — not from the Ovidrel injection.

PCOS Patients

Women with polycystic ovary syndrome (PCOS) are at higher risk for OHSS because they tend to produce more follicles in response to stimulation. Your doctor will monitor you more closely and may adjust your protocol if you have PCOS.

Patients With Prior OHSS

If you've had OHSS in a previous cycle, your doctor may consider an alternative trigger like Lupron (Leuprolide Acetate), which causes an endogenous LH surge and carries a lower OHSS risk than hCG-based triggers.

How to Manage Common Side Effects

Here are practical tips for dealing with the most common Ovidrel side effects:

For Injection Site Reactions

• Rotate injection sites between the left and right sides of your abdomen or thigh
• Apply a cold compress or ice pack (wrapped in cloth) for 10-15 minutes after injection
• Let the medication reach room temperature before injecting — cold solution can cause more discomfort
• Inject slowly and steadily

For Abdominal Discomfort and Bloating

• Stay hydrated — drink plenty of water and electrolyte-rich fluids
• Eat small, frequent meals rather than large ones
• Avoid high-sodium foods, which can worsen bloating
• Avoid strenuous exercise (your ovaries are enlarged, and vigorous activity increases torsion risk)
• Light walking is usually fine and can help with discomfort

For Nausea

• Eat bland foods like crackers, toast, or rice
• Ginger tea or ginger chews may help
• Ask your doctor if an anti-nausea medication is appropriate

Final Thoughts

Ovidrel is generally well-tolerated, and most patients experience nothing more than mild injection site discomfort and some bloating. But because of the risk of OHSS and other serious complications, it's important to know what to watch for — and to have your fertility clinic's contact information readily available.

Your clinic should provide an after-hours emergency number. Save it in your phone before your trigger shot, so you know exactly who to call if something doesn't feel right.

If you're looking for more information about Ovidrel, check out our guides on how Ovidrel works and how to save money on your prescription. And if you need help finding it at a pharmacy, Medfinder can show you where it's in stock.