Ovidrel is a fertility injection that triggers ovulation. It contains a lab-made version of human chorionic gonadotropin (hCG), a hormone that mimics the natural surge your body produces to release a mature egg from the ovary. It’s used in both IUI (intrauterine insemination) and IVF (in vitro fertilization) cycles, and it’s typically the final step before either egg retrieval or timed intercourse/insemination.
How Ovidrel Triggers Ovulation
During a normal menstrual cycle, your brain releases a burst of luteinizing hormone (LH) that signals the ovary to release its mature egg. Ovidrel works by mimicking that LH surge. The active ingredient, choriogonadotropin alfa, is physically identical to natural hCG and binds to the same receptors as LH, telling your ovaries to complete the final stage of egg maturation and release the egg from its follicle.
This is why Ovidrel is often called a “trigger shot.” After days or weeks of follicle-stimulating medications that help eggs grow, Ovidrel provides the final signal that says “go.” Without it, or without a natural LH surge, the follicles may keep growing but never actually release an egg.
When It’s Given and Why Timing Matters
Your doctor will monitor your follicles with ultrasound throughout your stimulation cycle. Once one or more follicles reach roughly 18 mm in diameter, you’re ready for the trigger. Research shows that follicles between 12 and 19 mm on the day of the trigger are most likely to yield a mature egg.
Ovulation generally occurs 24 to 36 hours after the injection. That window is critical. For IUI cycles, insemination is scheduled within that timeframe so sperm are already present when the egg is released. For IVF, egg retrieval is typically performed just before ovulation would happen, usually around 36 hours post-injection, to collect the eggs while they’re still inside the follicles.
The standard dose is a single prefilled syringe containing 250 micrograms, which is clinically equivalent to 10,000 units of older, urine-derived hCG products. One injection is all it takes.
Who Uses Ovidrel
Ovidrel is prescribed across a range of fertility treatments. The most common scenarios include IUI cycles for unexplained infertility, mild male factor infertility, or ovulation problems like PCOS. It’s also used in IVF protocols as the trigger before egg retrieval. In some cases, doctors prescribe it alongside timed intercourse for people using oral fertility medications who need a reliable, predictable ovulation window rather than waiting for a natural LH surge.
How to Give Yourself the Injection
Ovidrel comes as a prefilled syringe, so there’s no mixing involved. Take it out of the refrigerator about 30 minutes before you plan to inject. Wash your hands, gather the syringe and an alcohol swab, and choose a spot on your lower abdomen at least one inch from your belly button.
With the needle pointing up, tap the syringe gently so any air bubbles rise to the top, then press the plunger slowly until a tiny drop appears at the needle tip. Clean the injection site with the alcohol swab, pinch the skin, and insert the full length of the needle at a 45 to 90 degree angle. Push the plunger slowly until all the medication is injected, then withdraw and dispose of the syringe in a sharps container.
Most people describe it as a quick pinch. The needle is small, and because it’s subcutaneous (just under the skin, not into muscle), it’s one of the more straightforward fertility injections to self-administer.
Storage Requirements
Keep Ovidrel refrigerated between 2°C and 8°C (about 36°F to 46°F) and don’t freeze it. If needed, it can stay at room temperature (below 25°C or 77°F) for up to 28 days, but it must be discarded after that. Keep it in its original packaging and out of direct light.
False Positive Pregnancy Tests
Because Ovidrel is literally hCG, the same hormone that pregnancy tests detect, it will cause a positive result on any pregnancy test taken too soon after the injection. The medication typically clears your system within about 10 days, but traces can linger longer in some people.
To avoid a misleading result, wait at least 14 days after the injection before taking a home pregnancy test. Your fertility clinic will likely schedule a blood test (beta hCG) around 14 to 16 days post-trigger, which can distinguish between leftover medication and a rising hCG level from an actual pregnancy. Testing earlier than this almost guarantees confusion, and a faint positive at 7 or 8 days post-trigger is far more likely to reflect the medication than implantation.
Ovarian Hyperstimulation Syndrome
The most significant risk associated with Ovidrel is ovarian hyperstimulation syndrome (OHSS). This condition is almost always linked to hCG administration; it’s extremely rare without it. OHSS happens when the ovaries overreact to hormonal stimulation, swelling significantly and leaking fluid into the abdomen.
Moderate OHSS occurs in roughly 3 to 6 percent of stimulated cycles. Symptoms include bloating, abdominal pain, nausea, and vomiting. In mild cases, this resolves on its own within a few days. Severe OHSS is much rarer, affecting 0.1 to 3 percent of cycles, but it can involve rapid weight gain from fluid retention, difficulty breathing, decreased urination, and in extreme cases, blood clots or kidney problems.
Your risk is higher if you have PCOS, are younger, have a low body weight, or developed a large number of follicles during stimulation. Your doctor monitors follicle count and estrogen levels throughout your cycle partly to gauge this risk. If OHSS seems likely, they may lower the trigger dose, switch to a different trigger medication, or in IVF cycles, freeze all embryos and delay transfer until the ovaries have calmed down.
Signs That Ovidrel Worked
Some people notice mild symptoms after the injection: light cramping or a pulling sensation on one side of the lower abdomen around the expected ovulation window, slight bloating, or breast tenderness. These are normal responses to the hormonal shift. Not everyone feels anything, though, and a lack of symptoms doesn’t mean the shot didn’t work.
In IVF, the clearest confirmation comes at egg retrieval, when the number of mature eggs collected shows whether the trigger did its job. In IUI or timed intercourse cycles, a follow-up ultrasound may show that the dominant follicle has collapsed, indicating the egg was released. Beyond that, the only real confirmation is a positive pregnancy test at the appropriate time.