Pregnyl is the brand name for a chorionic gonadotropin (hCG) injection — the hormone that tells the body to release mature eggs — best known in fertility care as the “trigger shot”: a single 5,000–10,000 IU intramuscular dose given about 34–36 hours before egg retrieval or insemination. It is also one of very few drugs FDA-approved for both female and male infertility indications.
This article is compiled by the ProIVF Medical Editorial Team from the official US prescribing information hosted on the National Library of Medicine’s DailyMed, peer-reviewed clinical trials indexed in PubMed, and public guidance from ASRM, ACOG, and the CDC ART program, and reviewed by the ProIVF Medical Advisory Board. It is educational content, not medical advice.
What Is Pregnyl Exactly?
Pregnyl is a purified preparation of human chorionic gonadotropin (hCG) extracted from the urine of pregnant women, manufactured by Organon USA under US License No. 2331. It ships as a white powder in a 10 mL multiple-dose vial (10,000 USP units per vial) plus a separate 10 mL vial of solvent, mixed before an intramuscular injection.
hCG is the hormone the placenta makes in early pregnancy, and its molecular shape is close enough to luteinizing hormone (LH) — the surge your pituitary releases mid-cycle — that the ovary cannot tell them apart. That mimicry is the entire mechanism:
- In an IVF or IUI cycle, one hCG injection substitutes for the natural LH surge and starts final egg maturation, which takes about 36 hours to complete.
- In a pregnant body, hCG keeps the corpus luteum (the leftover follicle) alive so it keeps making progesterone — which is why Pregnyl appears in some luteal-phase support protocols.
- In a male body, hCG acts on the testes the way LH does, stimulating testosterone production and sperm development.
Because the active ingredient is hCG, “Pregnyl,” “hCG injection,” and “chorionic gonadotropin” name the same molecule in this context — so “Is Pregnyl hCG?” has a simple answer: yes, Pregnyl is hCG, in a urinary-derived brand.
What Is Pregnyl FDA-Approved For — and What Do Clinics Prescribe Off-Label?
The official label lists three approved indications — and IVF triggering is notably not one of them:
| Use | Status | What the label or protocol says |
|---|---|---|
| Anovulatory infertility in women (secondary causes, after gonadotropin treatment) | FDA-approved | 5,000–10,000 USP units one day after the last gonadotropin dose |
| Hypogonadotropic hypogonadism in men (pituitary cause) | FDA-approved | 500–1,000 units 3×/week × 3 weeks, then 2×/week; or 4,000 units 3×/week for 6–9 months |
| Prepubertal cryptorchidism (undescended testicles, ages ~4–9) | FDA-approved | Various regimens, e.g., 500–1,500 units weekly × 6 weeks |
| Triggering final egg maturation in IVF/ICSI/IUI | Off-label (standard of care) | Single 5,000–10,000 IU IM dose ~36 h before retrieval/insemination |
| Luteal phase support after retrieval | Off-label (some clinics) | Repeat hCG doses; the label notes it “may be used for luteal phase support, but is discontinued upon confirmation of pregnancy” |
| Weight loss / obesity | Explicitly not effective | The label states in capital letters that hCG has not been shown to be effective adjunctive therapy for obesity |
Off-label prescribing is legal and, for hCG triggering, universal — every major reproductive-medicine guideline treats an hCG (or dual) trigger as the standard method for final oocyte maturation. A 2025 review in Fertility & Sterility framed the live question as not whether to use hCG, but hCG versus dual or double trigger strategies for specific patient groups.
One more useful fact from the label: the same vial approved for female ovulation induction is also approved for a male condition, which is why “Pregnyl for men” is a legitimate on-label fertility use — and why male protocols use hCG instead of testosterone.
How Is Pregnyl Dosed as a Trigger Shot?
For egg retrieval, the label and the trial literature agree on the numbers:
- Dose: 5,000 IU or 10,000 IU intramuscularly — the label’s own ovulation regimen is “5,000 to 10,000 USP units 1 day following the last dose of gonadotropins.”
- Trigger point: when leading follicles reach roughly 17–18 mm on ultrasound with matching estradiol levels; published trigger protocols commonly use at least two follicles at 17 mm as the threshold.
- Interval to retrieval: 34–36 hours after the injection — the 1992 University of Toronto randomized trial that helped establish agonist-vs-hCG triggering used hCG 5,000 IU IM with retrieval 34–36 hours later.
- For IUI: insemination is typically scheduled ~24–36 hours after the trigger instead of retrieval.
Does the Exact Trigger Dose Matter?
Yes, measurably. A Danish randomized trial published in Reproductive BioMedicine Online (2022) compared 5,000 vs 6,500 vs 10,000 IU hCG triggers and tracked endogenous progesterone through the luteal phase across 94 antagonist cycles.
Higher trigger doses produced significantly higher progesterone on days 8, 10, and 14 after retrieval (P < 0.001).
That measurable downstream effect on luteal function is why clinics individualize the dose rather than treat every patient identically.
Pregnyl vs. Ovidrel vs. Novarel: Same Hormone, Different Package
| Pregnyl | Ovidrel | Novarel | |
|---|---|---|---|
| Active ingredient | Urinary hCG | Recombinant hCG (choriocoriogonadotropin alfa) | Urinary hCG |
| Form | Powder + solvent, mix yourself | Ready-to-use pre-filled 0.5 mL syringe | Powder + solvent |
| Standard trigger amount | 5,000–10,000 IU | 250 µg (≈ 6,500 IU) | 5,000–10,000 IU |
| Route | Intramuscular (label) — some clinics give it subcutaneously | Subcutaneous | Subcutaneous or intramuscular |
| US availability | Intermittent shortages; clinics substitute | Consistently available | Intermittent availability |
The conversion most patients never see explained: Ovidrel’s 250 micrograms is roughly equivalent to 6,500 IU of urinary hCG — which is why the Danish trial above used 6,500 IU as one study arm. A chart note of “trigger 250 µg” is the recombinant world; “trigger 10,000 units” is the Pregnyl world; the physiological effect — an LH surrogate — is identical.
Availability is a real variable: urinary hCG brands including Pregnyl and Novarel have gone through repeated US supply interruptions. In the Danish trial, the researchers had to switch the 5,000 IU and 10,000 IU arms from urinary to recombinant hCG mid-study “as urinary HCG was removed from market.” If your clinic offers a recombinant substitute with no clinical downside, that is a supply decision, not a quality one.
What Are the Side Effects and Warning Signs?
Most people tolerate a single hCG injection well, and the expected effects mirror the natural LH surge:
- Injection-site pain, redness, or bruising (the powder vial contains benzyl alcohol as a preservative)
- Headache, fatigue, irritability, mild fluid retention
- Ovulation pain / mid-cycle cramping as the follicles release
The label’s serious warnings are the ones every stimulation patient should recognize:
- OHSS (ovarian hyperstimulation syndrome): the label states OHSS can progress rapidly, typically peaks about 7–10 days after treatment, and warns that severe pelvic pain, nausea, vomiting, and weight gain are the early signals. It explicitly instructs that if OHSS may be developing, withhold the hCG — and assess the patient for at least two weeks after administration. Severe OHSS can be life-threatening.
- Twins and higher-order multiples: reported across all gonadotropin therapy, which is why clinics cap the number of embryos transferred.
- Blood clots and ovarian torsion: rare, listed under warnings, mostly relevant alongside severe OHSS or a personal/family thrombosis history.
- Ectopic pregnancy: incidence is elevated in ART patients, and the label calls for early ultrasound to confirm the pregnancy is intrauterine.
- Pediatric note: children treated with hCG for undescended testicles can show transient signs of early puberty — worth understanding, not panicking about, and the reason that indication is supervised differently.
“Multi-fetal gestation and births have been reported with all gonadotropin therapy including hCG.” — Pregnyl (chorionic gonadotropin) US prescribing information, DailyMed, revised March 2025
How Long Until a Home Pregnancy Test Is Accurate After the Trigger?
Because Pregnyl is hCG, a home pregnancy test cannot distinguish trigger-shot residue from pregnancy hCG — after a 10,000 IU dose, detectable levels persist for roughly 10–14 days. The practical rules clinics use:
- A positive test under 10 days after the trigger is very likely leftover medication, not an implantation signal.
- The clinic’s own beta-hCG blood draw is timed (typically 9–14 days after retrieval, or ~14 days after IUI) with the trigger date already factored in — exactly why your nurse asks “what time did you take your trigger?”
- A faint early line on a home test is uninterpretable; wait for the scheduled blood draw. A line that fades day over day is what drug clearance looks like.
Our guide to hCG levels by week explains the doubling thresholds clinics apply to those blood results.
What Patients Say — Shared With Consent
Patient experiences are aggregated, anonymized accounts of common patterns reported by ProIVF users; names, exact figures, and circumstances are illustrative. Your protocol, medication brand, and costs will differ — verify everything with your clinic.
Mia, 34, egg freezing in California — powder vial, mixing at home. “My clinic sent Pregnyl because Ovidrel was on back-order. The nurse video-called me through reconstituting the powder — swirl, don’t shake. The shot itself stung more than the stimulation pens because it’s a muscle injection in the arm. Retrieval was scheduled 35 hours later and we hit the timing to the minute.”
Karen & Sam, 38 and 41, IUI in Texas — the false-positive scare. “I tested 8 days after the trigger and saw a faint line. We almost celebrated; the nurse just said ‘that’s still your shot.’ The real beta at 14 days was negative. On the second cycle I waited for the blood test and didn’t touch a home stick. Clinical pregnancy with our third IUI.”
Daniel, 36, secondary hypogonadism — the male use most people don’t know about. “My urologist chose hCG over testosterone replacement because I want kids. Injections several times a week for months; it keeps my own production going instead of shutting it down. Different dose and goal from the fertility trigger, but the same Pregnyl vial.”
How Much Does Pregnyl Cost in a Cycle?
Pregnyl itself is comparatively cheap — a single trigger vial typically lands in the low hundreds of US dollars at a dispensing pharmacy, well below recombinant products and a small fraction of a full cycle. What moves the total is monitoring (the ultrasounds and bloodwork around the trigger) and whichever procedure follows.
If you are budgeting a cycle at home or abroad, our IVF cost guide compares clinics and countries, and the ProIVF hospital directory lists verified clinics across six countries with pricing context.
For the bigger picture of which drug appears at which step, see our IVF medications guide and the injection-by-injection walkthrough.
FAQ
Q: Is Pregnyl the same as hCG?
Yes. Pregnyl is a brand name for urinary human chorionic gonadotropin.
The label describes it as a purified polypeptide hormone obtained from the urine of pregnant women, supplied as 10,000 USP units per vial plus a separate solvent vial.
Q: Why do IVF patients take Pregnyl?
As the trigger shot: 5,000–10,000 IU imitates the body’s own LH surge, and final egg maturation completes about 34–36 hours later, which sets the retrieval time. Some clinics also use repeat doses for luteal support, stopping once pregnancy is confirmed.
Q: How long does Pregnyl stay in your system?
Roughly 10–14 days after a 10,000 IU dose before it clears below home-test detection — the reason early positive tests after a trigger are usually residual medication. Clinic blood-test schedules are set with the trigger date factored in.
Q: Pregnyl vs. Ovidrel — which is better?
Same hormone, different manufacturing: urinary versus recombinant. Ovidrel (250 µg pre-filled, roughly 6,500 IU equivalent, subcutaneous) is more convenient; Pregnyl requires mixing and is usually intramuscular.
Trial evidence treats them as interchangeable for egg maturation, and availability and price drive most choices.
Q: Can men take Pregnyl?
Yes — it is FDA-approved for hypogonadotropic hypogonadism in men, where it stimulates the testes directly. Typical regimens run 500–1,500 units several times weekly over weeks to months, a very different schedule from a single female trigger dose.
Q: Does Pregnyl cause twins?
It can make a stimulated cycle release multiple eggs, and the label reports multi-fetal pregnancies with all gonadotropin therapy including hCG. The real driver is embryo numbers at transfer: with single embryo transfer the twin rate is about 0.9–1.2% (nearly all from one embryo splitting), while two embryos transferred push it above 30% — see our chances of twins with IVF guide.
Q: Is Pregnyl used for weight loss?
The label says no — in capital letters. It states hCG has not been demonstrated to be effective adjunctive therapy for obesity “alone or in conjunction with a low-calorie diet,” with no known effect on fat mobilization, appetite, or food intake.
The popular “hCG diet” protocols involve daily injections over 23–42 days — a completely different and ineffective use versus a single fertility trigger dose.
Q: My clinic gave me Novarel instead — is that a downgrade?
No. Novarel is the same urinary hCG in a different brand presentation, given subcutaneously.
Substitution during supply interruptions is routine and clinically equivalent.
Medical Disclaimer: This article is for general information only and does not replace professional medical advice, diagnosis, or treatment. Trigger timing, dose, brand selection, and monitoring are individual medical decisions; follow your clinic’s instructions precisely, especially regarding OHSS symptoms and testing windows. Always consult a licensed physician about any medication decision.
Editorial Process: Compiled by the ProIVF Medical Editorial Team from the official US prescribing information for Pregnyl on DailyMed, National Library of Medicine, revised 03/2025, randomized trials and reviews indexed in PubMed (PMID 1601147, PMID 35879196, PMID 41618353, PMID 42571040, PMID 40473012), and public guidance from ASRM, ACOG, WHO, and the CDC ART program. Reviewed by the ProIVF Medical Advisory Board. Patient accounts are anonymized, illustrative composites shared with consent.
Last updated: September 17, 2026
